ALBERT

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 357〈/p〉 〈p〉Author(s): Cristina Domínguez-Trujillo, Ana M. Beltrán, Maria D. Garvi, Alba Salazar-Moya, Julián Lebrato, Daniel J. Hickey, Jose A. Rodríguez-Ortiz, Paul H. Kamm, Clara Lebrato, Francisco García-Moreno, Thomas J. Webster, Yadir Torres〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, bacterial behavior on dense and porous titanium substrates is discussed. Porous titanium was fabricated by a space holder technique (using 50 vol%, NH〈sub〉4〈/sub〉HCO〈sub〉3〈/sub〉 with particle sizes between 250 and 355 μm). These substrates were coated by sulfonated PEEK (termed SPEEK). Characterization of the porous substrate was carried out using the Archimedes Method, Image Analysis, and three-dimensional X-ray Micro-Computed Tomography (including total and interconnected porosity, equivalent diameter, and pore shape factor), as well as mechanical characterization (specifically stiffness and yield strength). A detailed study was performed here to investigate the influence of substrate porosity on the adhesion and proliferation of 〈em〉E. coli〈/em〉, 〈em〉MRSA〈/em〉, and 〈em〉P. aeruginosa〈/em〉 (common causes of orthopedic device-associated infections). Bacterial colonization was examined in terms of the initial bacterial concentration, as well as bacterial adherence to and growth on the surface and inside the pores. Results suggest that fully dense titanium supported the least bacterial colonization, while the porous titanium promoted bacterial growth in the medium and inside the cavities. Furthermore, the SPEEK coating deposited onto the samples inhibited bacteria growth inside the porous materials. In this manner, this study showed for the first time that SPEEK could have potential antibacterial properties to offset the increase in bacteria growth commonly observed in porous materials.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0257897218312052-ga1.jpg" width="440" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 357〈/p〉 〈p〉Author(s): Xiaolong Cai, Lisheng Zhong, Yunhua Xu, Xin Li, Mingxin Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To improve the mechanical properties of the surface of iron-based alloys, a tungsten carbide-iron (WC-Fe) cemented carbide layer is produced on an alloy by adopting an isothermal annealing process, which was performed at 1050 °C for 4 h. By deeply etching the obtained sample, the morphologies of the WC ceramic grains in the WC-Fe hardmetal layer are characterized via scanning electron microscopy. The present results reveal three distinct morphologies consisting of rectangular, triangular prism and multi-layered shapes. Furthermore, the mechanical properties and fracture toughness of the WC-Fe layer are investigated through combined nanoindentation and Vickers indentation techniques. Nanoindentation testing is performed in a load range of 100 to 450 mN. Based on the data collected from the nanoindentation results, the average values of the hardness, Young' modulus and deformation ratio are evaluated, and the fracture toughness is determined to have a value of 3.08 MPa·m〈sup〉½〈/sup〉 at 450 mN. In the Vickers indentation technique, however, by identifying the crack type and choosing the appropriate model, the fracture toughness is calculated to be 1.85–3.44 MPa·m〈sup〉½〈/sup〉 at applied loads ranging from 0.98 to 4.9 N. The obtained fracture toughness results exhibit good consistence between the nanoindentation and Vickers indentation methods.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 357〈/p〉 〈p〉Author(s): Y. Le Guével, B. Grégoire, M.J. Cristóbal, X. Feaugas, A. Oudriss, F. Pedraza〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electrolytic dissolution of aluminide coatings on model (pure Ni, Ni20Cr) and René 125 Ni-based superalloy was conducted by alternated cathodic and anodic polarizations. The pure nickel aluminide dissolved homogeneously. In contrast, the inhomogeneity of dissolution increased with the incorporation of Cr in the coating. The coatings were however uniformly dissolved when the cathodic step was eliminated. XPS and TEM demonstrate that the occurrence of a passive layer containing Cr and Al oxy-hydroxides blocked dissolution.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉(a) TEM bright field images of the passive film of the aluminized Ni20Cr. (b) is a greater magnification showing the distance between the crystalline planes. (c), (d) and (e) are the selected area diffraction patterns of the three diffracted areas defined on (a). The distances marked in red correspond to “d”, i.e. the interplanar distance.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0257897218311976-ga1.jpg" width="343" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 357〈/p〉 〈p〉Author(s): Lijia Fang, Jing Huang, Yi Liu, Botao Zhang, Hua Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The booming ocean economy in recent decades crucially demands advanced anti-corrosion technologies for marine infrastructures. Among the marine protective coatings developed in past decades, thermal sprayed aluminium coating was evidenced to be one of the most economical and efficient corrosion protection layers. Yet, marine corrosion is always accompanied by biofouling which in most cases accelerates corrosion. Here we report arc spray fabrication of novel aluminium-copper coatings using home-made Al-Cu cored wires for both anti-corrosion and antifouling performances. Copper particles were dispersed in the as-sprayed coatings, and TEM characterization further revealed partial interaction of Cu particles with Al matrix during the coating deposition. The chemical reaction with the formation of Al〈sub〉2〈/sub〉Cu offered an anchoring effect for the coatings preventing Cu particles from quick releasing into aqueous environment. Electrochemical testing in artificial seawater showed that the presence of Cu in Al coatings did not trigger considerable deterioration in corrosion resistance. Further antifouling testing of the coatings by examining settlement and colonization behaviors of bacteria 〈em〉E. coli〈/em〉 and 〈em〉Bacillus〈/em〉 sp. and typical marine algae revealed their excellent antifouling performances. The antifouling properties were predominately attributed to the continuous release of copper ions from the coatings. The results give clear insight into constructing anti-corrosion/fouling inorganic coatings by the cored-wire arc spray technical route for marine applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 357〈/p〉 〈p〉Author(s): Jinjiao Xia, Wenping Liang, Qiang Miao, Diederik Depla〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Yttrium oxide thin films are grown by reactive magnetron sputtering. To achieve a high deposition rate, target poisoning is avoided by local oxygen addition at the substrate. In all deposited thin films only the monoclinic Y〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 phase is observed. A strong variation in the film texture across the sample for experiments with a stationary sample stage is noticed. This inhomogeneity can be partially traced back to an uneven oxygen gas distribution. Sample rotation resolves this problem, but still the gas distribution influences both the texture and the Bragg peak positions. Several configurations for the gas supply are tested with a different number of gas distribution pipes. An overview of all experiments shows an interesting correlation between the texture coefficient and the peak position of the monoclinic (111) Bragg reflection. When the peak shifts towards higher diffraction angles, the texture coefficient drops as a higher contribution of the 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si3.gif" overflow="scroll"〉〈mfenced close=")" open="("〉〈mrow〉〈mn mathvariant="normal"〉40〈/mn〉〈mover accent="false"〉〈mrow〉〈mn mathvariant="normal"〉2〈/mn〉〈/mrow〉〈mo mathvariant="normal"〉¯〈/mo〉〈/mover〉〈/mrow〉〈/mfenced〉〈/math〉 orientation is observed. This trend however is further complicated by the exact geometrical configuration on the deposition rate, and the energy/momentum of the species arriving at the substrate. As previously reported, an increasing energy/momentum per deposited atom results in monoclinic thin films with a preferential (111) out-of-plane orientation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): R. Jamshidi, O. Bayat, A. Heidarpour〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Pure Al coatings are extensively used in various industries but their poor wear resistance has introduced as the main drawback of them. In this study, the effect of the addition of Ti〈sub〉3〈/sub〉SiC〈sub〉2〈/sub〉 on the tribological and corrosion behavior of Al coating was investigated. The morphological and phase evolution of coating and powders was analyzed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) patterns. The corrosion behavior of samples was investigated by potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). The wear behavior of coating and substrate studied by the pin-on-disc test. The results indicated that the wear resistance of Al coating in terms of friction coefficient and wear rate was significantly improved by the presence of Ti〈sub〉3〈/sub〉SiC〈sub〉2〈/sub〉 inclusions. According to the result of potentiodynamic polarization tests in simulated 3.5% NaCl solution, the corrosion potential of the Al/Ti〈sub〉3〈/sub〉SiC〈sub〉2〈/sub〉 coating is nobler than that of the pure Al one. The electrochemical impedance spectroscopy (EIS) tests indicated that corrosion resistance of Al/Ti〈sub〉3〈/sub〉SiC〈sub〉2〈/sub〉 coating was increased as compared with pure Al coating.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 357〈/p〉 〈p〉Author(s): Małgorzata Norek, Łukasz Szamyjer〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A multi-variant process of cold rolling to different reductions of thickness (0–50%) and subsequent heating under different temperature was applied to Al substrates. Next, a comprehensive analysis of the influence of various microstructural, structural, and mechanical parameters of the Al substrates on the nanopore growth in anodic aluminum oxide (AAO), was performed. As an effect, new evidences concerning an important role of Al substrate state on the AAO growth were provided. The obtained results unambiguously show that the number of dislocations is the only parameter responsible for the regular pore formation is the AAO. Since the dislocation density is greatly reduced solely after recrystallization process, a significant reduction of the percentage of defects in AAO occurs only when Al substrate is annealed at the recrystallization temperature (483 °C), independent of percent cold work. All microstructural (elongation, circularity, and size of grains) or structural (texture, lattice strain) parameters are irrelevant for the pore formation, until the number of dislocations in the Al substrate remains high. Therefore, before anodization Al substrate should be annealed, at least for 1 h, under the temperature ≥ recrystallization temperature, not lower. Stress-relief anneal at temperature 〈 recrystallization temperature is not sufficient to induce a regular pore growth in AAO.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Yanming He, Chuanyang Lu, Wenjian Zheng, Jianguo Yang, Shuangjian Chen, Zhijun Li, Yuan Sun, Zengliang Gao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, a composite coating prepared by laser cladding on a Ni-17Mo-7Cr based superalloy was thermally exposed at 1073 K for 240 h. A detailed electron microscopy examination was performed to characterize the microstructure of the aged coating. Results indicate that: the original Mo〈sub〉6〈/sub〉Ni〈sub〉6〈/sub〉C dendrites in the aged coating were coarsened while the coarsening layers were essentially the Mo-deficient and Cr-rich Mo〈sub〉6〈/sub〉Ni〈sub〉6〈/sub〉C, due to low diffusivity of Mo. Long-term thermal exposure promoted a great amount of nano-sized Mo〈sub〉6〈/sub〉Ni〈sub〉6〈/sub〉C and micro-sized Cr〈sub〉3〈/sub〉C〈sub〉2〈/sub〉 particles being precipitated in the interdendritic zones. In the aged coating, three types of Cr〈sub〉3〈/sub〉C〈sub〉2〈/sub〉 were presented: discrete Cr〈sub〉3〈/sub〉C〈sub〉2〈/sub〉, Cr〈sub〉3〈/sub〉C〈sub〉2〈/sub〉 close to the graphite and Cr〈sub〉3〈/sub〉C〈sub〉2〈/sub〉 approaching to the Mo〈sub〉6〈/sub〉Ni〈sub〉6〈/sub〉C. The transformation of Mo〈sub〉6〈/sub〉Ni〈sub〉6〈/sub〉C to Cr〈sub〉3〈/sub〉C〈sub〉2〈/sub〉 merely occurred in the newly formed Mo〈sub〉6〈/sub〉Ni〈sub〉6〈/sub〉C rather than in the original Mo〈sub〉6〈/sub〉Ni〈sub〉6〈/sub〉C dendrites, because deficiency of Mo and enrichment of Cr in the new Mo〈sub〉6〈/sub〉Ni〈sub〉6〈/sub〉C depressed their stability. Lastly, the mechanical behavior of the aged coating was characterized by Vickers hardness, nano-indentation and nano-scratch tests with the aim to unveil the effect of microstructural evolution on mechanical properties. Our findings provide basic information to understand the aged-induced microstructural modification and its effect on mechanical properties for a laser-induced coating prepared on the Ni-17Mo-7Cr based superalloy. The results obtained cannot only apply to the investigated Ni-based superalloys, but also to other Hastelloy series superalloys.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 357〈/p〉 〈p〉Author(s): Anke Dalke, Igor Burlacov, Stephan Hamann, Alexander Puth, Jan Böcker, Heinz-Joachim Spies, Jürgen Röpcke, Horst Biermann〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Plasma nitrocarburizing based on active screen technology using a carbon-fiber reinforced carbon active screen was applied in an industrial-scale unit for thermochemical surface treatment of austenitic stainless steel. This concept is based on the use of a solid-carbon-source for the generation of highly reactive process gases directly in the active screen plasma. In this work, plasma nitrocarburizing of AISI 316L stainless steel was performed by means of the variation of the precursor gases H〈sub〉2〈/sub〉 and N〈sub〉2〈/sub〉 in the range of 0% N〈sub〉2〈/sub〉 up to 100% N〈sub〉2〈/sub〉 without the use of any additional carbon bearing gas. For a set of H〈sub〉2〈/sub〉-N〈sub〉2〈/sub〉 gas mixtures, the resulting reaction gas was monitored using infrared laser absorption spectroscopy (IRLAS). The four main stable species HCN, CH〈sub〉4〈/sub〉, NH〈sub〉3〈/sub〉 and C〈sub〉2〈/sub〉H〈sub〉2〈/sub〉 were detected. A detailed analysis of the surface microstructure resulting for each specific H〈sub〉2〈/sub〉-N〈sub〉2〈/sub〉 precursor gas mixture was performed. This included glow discharge optical emission spectroscopy (GDOES), optical microscopy, micro hardness measurements, as well as X-ray diffraction analysis.〈/p〉 〈p〉The concentrations of hydrocarbons CH〈sub〉4〈/sub〉 and C〈sub〉2〈/sub〉H〈sub〉2〈/sub〉 were most abundant in case of pure hydrogen plasma, and a carbon-expanded austenite layer with hardness values up to 600 HK0.01 and smooth hardness gradient resulted. The admixture of N〈sub〉2〈/sub〉 to the precursor gas significantly increased the concentrations of HCN and NH〈sub〉3〈/sub〉. Due to this, a duplex structure of nitrogen-expanded austenite γ〈sub〉N〈/sub〉 and carbon-expanded austenite γ〈sub〉C〈/sub〉 formed. With increasing content of N〈sub〉2〈/sub〉 up to 50% in the precursor gas, the resulting layer thickness increased and the hardness reached values up to 1300 HK0.01. At strong nitrogen excess in the precursor gas, the nitrogen concentration in the expanded austenite significantly increased, the Fe〈sub〉2–3〈/sub〉(N, C) phase was formed, and simultaneously the layer thickness decreased. Structure and properties of the expanded austenite layer significantly changed by only varying the H〈sub〉2〈/sub〉-N〈sub〉2〈/sub〉 ratio of the precursor gas mixture.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 357〈/p〉 〈p〉Author(s): Sima A. Alidokht, Stephen Yue, Richard R. Chromik〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cold spray is a relatively new method used to deposit WC reinforced composite coatings, where its low temperature is advantageous for avoiding oxidation and carbide decomposition. Previous studies demonstrated that using powders made from agglomerated WC resulted in higher WC retention in a sprayed coating when compared to that of cast WC. However, the influence of the morphology of the starting powders on the coating's microstructure, properties, and wear performance is not well understood. Here, we report cold spray deposition of Ni with two types of WC particles, i.e. cast and agglomerated. In both cases, ~30 vol% WC was retained in coatings, allowing for a side-by-side comparison. Coatings with cast WC featured a multi-modal distribution of WC particles ranging from 0.2 to 20 μm with a mean free path (MFP) between particles of 8.5 ± 0.7 μm. In comparison, coatings with agglomerated WC had WC size range of 0.3 to 1.3 μm and an MFP of 31 ± 4 μm. The sliding wear behavior of coatings was studied with a sliding speed of 3 mm/s under normal loads of 5 and 12 N. Coatings with cast WC were found to be more wear resistant than coatings with agglomerated WC. The multi-modal size distribution of cast WC with significantly lower MFP minimized adhesive wear and helped to develop a higher coverage of protective mechanically mixed layers (MMLs) that typically formed near WC particles. For coatings with cast WC, subsurface microstructure and chemical analysis suggested higher oxidation for MMLs with shallower depths of deformation in the metal matrix beneath the MMLs compared to coatings with agglomerated powder. The main factors for improved wear resistance of cast WC coatings compared to agglomerated WC coatings were the stability of the MMLs, and the wider size distribution with lower MFP, which offered better load supporting properties.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Fiorenza Fanelli, Anna Maria Mastrangelo, Gianvito Caputo, Francesco Fracassi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Dispersions of oleate-capped ZnO nanoparticles (NPs) in binary 〈em〉n〈/em〉-octane/1,7-octadiene solvent mixtures are injected, in aerosol form, in a dielectric barrier discharge to deposit hydrocarbon polymer/ZnO nanoparticles nanocomposite (NC) thin films at atmospheric pressure and room temperature. The chemical composition of the coatings, and in turn their morphology and wettability, can be tuned by simply changing the composition of the starting dispersion. Specifically, the increase of the NPs concentration in the dispersion (0.5–5 wt%) results in a continuous increase of both the ZnO content and deposition rate of the coatings. Moreover, when the concentration of 1,7-octadiene in the solvent mixture is very low (0.5–2 vol%), the incorporation of NPs is further promoted, while at concentrations 〉2 vol% the growth of the organic component starts to be favored. Overall, results reveal a considerable increase of the root-mean-square (RMS) roughness of the coatings with the ZnO loading. In addition, once the threshold ZnO loading and RMS roughness of 60 wt% and 350 nm are reached, respectively, the coatings are superhydrophobic and exhibit very low water contact angle hysteresis, due to the coexistence of the low surface energy conferred by the hydrocarbon polymer and the hierarchical multiscale surface texture induced by NPs incorporation.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0257897218312301-ga1.jpg" width="357" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): K. Bobzin, T. Brögelmann, N.C. Kruppe, M. Engels〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Due to their beneficial properties, chromium-based nitride hard coatings deposited by physical vapor deposition (PVD) are applied as protective coatings in many technical applications. In the deposition of these coatings, hybrid dcMS/HPPMS processes consisting of direct current and high power pulse magnetron sputtering can be used in order to benefit from both processes, dcMS and HPPMS. While dcMS provides a considerably higher deposition rate, coatings deposited by HPPMS usually exhibit a significantly higher hardness and show a denser morphology and a smoother surface. The overall aim of this work is to achieve an improved understanding of the hybrid process dcMS/HPPMS. Different nitride (Cr,Al)N coatings were investigated. These were deposited by industrial-like coating processes using an industrial coating unit equipped with six cathodes on the quenched and tempered tool steel AISI 420 (X42Cr13, 1.2083). The aim of the investigations was to analyze the influence of HPPMS on the hybrid dcMS/HPPMS process within the coating plasma at the substrate side and with regard to the deposited coatings. In a first step, the (Cr,Al)N coating plasma was analyzed with a fine spatial resolution along the rotation line of the substrates using dcMS, HPPMS and hybrid dcMS/HPPMS processes. Changes in the plasma composition were investigated from the substrate position using optical emission spectroscopy (OES). In a second step, (Cr,Al)N coatings were deposited using the same process parameters. The coatings were analyzed regarding morphology and deposition rate using scanning electron microscopy (SEM). Furthermore, the contents of Al and Cr in the coatings were analyzed by energy dispersive X-ray spectroscopy (EDS). By comparing the measurements, the influence of HPPMS on the plasma within the hybrid dcMS/HPPMS process was analyzed and compared to the resulting coating properties morphology, deposition rate and chemical composition. This new experimental methodology was introduced before using a large-volume coating unit, but modified with only two cathodes. Within the scope of this work, it was for the first time transferred to an industrial coating unit with six cathodes, different targets and applied under industrial-like process conditions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Jian Huang, Yuncheng Ma, Kefeng Yao, Chuangsheng Wu, Meng Cao, Jianming Lai, Jijun Zhang, Yan Sun, LinjunWang, Yue Shen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉SnS:In thin films have been deposited on Mo substrates by chemical bath deposition method in acidic solution. The influences of different In-doped concentrations on the morphological, structural, optical properties and phase purities of SnS thin films have been investigated. Many sheet-like particles exist in the deposited SnS:In thin films. The doping of indium will decrease the thicknesses of the deposited thin films. The studies of photo-electrochemical (PEC) properties of SnS:In (In,10 at.%) thin films indicate that their PEC properties are enhanced by the annealing process. The fabrication of Pt/CdS/annealed SnS:In/Mo photocathode can further enhance the photo-current density to 0.790 mA·cm〈sup〉−2〈/sup〉 at −0.4 V.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Marjan Shahpanah, Somayeh Mehrabian, Marzieh Abbasi-Firouzjah, Babak Shokri〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Plasma-polymerized silicon oxynitride (SiO〈sub〉x〈/sub〉N〈sub〉y〈/sub〉) oxygen barrier thin film was deposited on polyethylene terephthalate substrate by plasma enhanced chemical vapor deposition at low temperature. The deposition reactor utilizes capacitively coupled plasma operating at radio frequency (13.56 MHz). Nitrogen incorporation during the polymerization leads to a SiO〈sub〉x〈/sub〉N〈sub〉y〈/sub〉 dense film with low defects which assists to improve the oxygen barrier properties. The gas mixture of tetraethyl orthosilicate as organosilicon precursor with oxygen and nitrogen gases was used to deposit the transparent polymerized SiO〈sub〉x〈/sub〉N〈sub〉y〈/sub〉 thin films. The effects of nitrogen flow rate on deposition rate, refractive index, surface morphology, surface wettability, chemical structure and binding composition and oxygen permeability of the barrier films were investigated. Moreover, the plasma parameters were monitored by optical emission spectroscopy. SiO〈sub〉x〈/sub〉N〈sub〉y〈/sub〉 oxygen barrier films showed 〈em〉89–91%〈/em〉 transparency. Under the optimal deposition conditions the minimum oxygen permeability of 0.08cm〈sup〉3〈/sup〉/cm〈sup〉2〈/sup〉day bar was obtained.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Yanlong Wang, Shaoqian Zhang, Yimin Li, Qipeng Lv, Songwen Deng, Gang Li, Yuqi Jin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cerium oxide is of crucial importance for intrinsic redox reaction, which is attributed to the active sites neighboring oxygen vacancies. However, the role of oxygen vacancy (Ov) on the various properties of ceria films remains to be elucidated. Herein, ceria films were deposited by magnetron sputtering and the effect of electric current intensity on the creation of Ov was systematically investigated. X-ray photoelectron spectroscopy (XPS) results show that the Ce〈sup〉4+〈/sup〉 concentration decreases with the increase of current intensity, which demonstrates that Ov can be created and tuned during film deposition by controlling electric current intensity. The film fabricated by 6 A current intensity has 42% Ce〈sup〉4+〈/sup〉, approaching that of rhombohedral-Ce〈sub〉7〈/sub〉O〈sub〉12〈/sub〉, which is a stabilized bulk phase ceria. X-ray diffraction patterns reveal that 6 A film shows mixed crystalline phases with the majority of peaks very close to rhombohedral-Ce〈sub〉7〈/sub〉O〈sub〉12〈/sub〉, while 1 A, 2 A, and 4 A ceria films show simple crystalline phase. Raman analysis presents that dioxygen species are heavily absorbed on the surface of 6 A film with more active sites on different crystalline surfaces, which is confirmed by photocatalytic degradation of Methylene Blue. The calculated bandgap by DFT (density functional theory) + U is consistent with that obtained from Tauc plots curves. This work demonstrates that Ov plays an important role on the properties of the ceria film.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Ying Wu, Yan Liu, Hui Chen, Yong Chen, Hongyu Li, Wei Yi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to reveal the mechanism of microstructure evolution and crack propagation in laser-deposited Stellite 6 alloys, a quenching thermal fatigue test was conducted. Various detection methods were applied to observe differences between the coatings as deposited and after thermal fatigue. The results showed that the 〈em〉γ〈/em〉 → 〈em〉ε〈/em〉 martensitic transformation occurred in the as-deposited 〈em〉γ〈/em〉-Co matrix during the thermal fatigue process, driven by a fast cooling and thermal stress. The generated 〈em〉ε〈/em〉-Co phase presented variant selection, obeying Schmidt's law. In the 〈em〉ε〈/em〉-Co phase, the slip activity derived from different 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si25.gif" overflow="scroll"〉〈msub〉〈mfenced open="{" close="}"〉〈mrow〉〈mn〉1〈/mn〉〈mspace width="0.25em"〉〈/mspace〉〈mn〉1〈/mn〉〈mspace width="0.25em"〉〈/mspace〉〈mn〉1〈/mn〉〈/mrow〉〈/mfenced〉〈mi〉γ〈/mi〉〈/msub〉〈msub〉〈mfenced open="〈" close="〉"〉〈mrow〉〈mn〉1〈/mn〉〈mspace width="0.25em"〉〈/mspace〉〈mn〉1〈/mn〉〈mover accent="true"〉〈mrow〉〈mspace width="0.25em"〉〈/mspace〉〈mn〉2〈/mn〉〈/mrow〉〈mo stretchy="true"〉¯〈/mo〉〈/mover〉〈/mrow〉〈/mfenced〉〈mi〉γ〈/mi〉〈/msub〉〈/math〉 slipping systems that produced stacking faults and planar defects during the phase transformation. In addition, the stacking faults on {1 1 1}〈sub〉〈em〉γ〈/em〉〈/sub〉 planes promoted the precipitation of directional M〈sub〉7〈/sub〉C〈sub〉3〈/sub〉 fine particle carbides. The net-like eutectic structures and 〈em〉γ〈/em〉/〈em〉ε〈/em〉 interfaces acted as paths for thermal crack propagation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Yan Wang, Yongli Zhao, Geoffrey Darut, Thierry Poirier, Jorge Stella, Kuaishe Wang, Hanlin Liao, Marie-Pierre Planche〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Two kinds of cauliflower-like architecture yttria stabilized zirconia (YSZ) coatings with different amounts inter-columnar voids were prepared by suspension plasma spraying (SPS) under different spraying parameters. YSZ coatings with high and moderate porosity were infiltrated with polytetrafluoroethylene (PTFE) in order to form a novel structured ceramic-polymer composite coating. Subsequently, the composite coatings were tribologically evaluated. The tribology behavior of the denser as-sprayed YSZ coatings and pure PTFE coatings were also investigated as reference materials. The results indicated that the composite coatings exhibited a significantly improved wear resistance in terms of a remarkably reduced coefficient of friction and wear rate compared with the as-sprayed YSZ coatings because of the lubricating effect of PTFE. Additionally, it was noted that the existing YSZ framework in composite coatings reinforces PTFE contributing to an even higher wear resistance than that measured on pure PTFE.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Gerald Womack, Kenan Isbilir, Fabiana Lisco, Geraldine Durand, Alan Taylor, John M. Walls〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉A significant source of energy loss in photovoltaic (PV) modules is caused by reflection from the front cover glass surface. Reflection from the cover glass causes a loss of ~4% at the air-glass interface. Only a single air-glass interface can be coated on crystalline silicon solar modules as an ethylene-vinyl acetate (EVA) layer is inserted between the cover glass and the silicon absorber. A single-layer anti-reflection coating (ARC) on the outer surface of the cover glass is effective at reducing reflection losses over the wavelength range of most PV devices. The coating investigated in this work reduces the reflectance loss at the glass surface by 74%. However, the long-term durability of sol-gel coatings has not been established particularly for use in hot and humid climates. In this work, we investigate the damage resistance of a single-layer closed-surface hard coat ARC, deposited using sol-gel methods by applying a variety of accelerated weathering, scratch and abrasion test methods.〈/p〉 〈p〉The reflectance of the sol-gel ARC was measured and then the coating was put through a series of durability and environmental tests. The coating is resistant to damage from heating and can withstand temperatures higher than the phase change temperature of soda-lime glass. Scratch testing demonstrated that the sol-gel AR is relatively hard and difficult to remove from the substrate surface. Pull tests and cross-hatch testing also confirmed the strong adhesion of the coating. Weathering experiments show some degradation in weighted average reflectance, particularly an increase in reflectance of 0.6–0.9% after 1000 h of exposure to damp heat. Testing also showed a vulnerability to exposure to acid. These results indicate that the performance of this type of ARC could deteriorate and possibly delaminate in humid climate conditions The ARC had a low water contact angle, which means the coatings are hydrophilic and, therefore, hygroscopic increasing the risk of water damage over extended periods of time. This work shows that sol-gel anti-reflection coatings are currently unsuitable for use on PV and are unlikely to remain durable across the 25 year industry standard.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Desheng Wang, Ming Hu, Dong Jiang, Xiaoming Gao, Yanlong Fu, Jiayi Sun, Lijun Weng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel approach by texturing the WS〈sub〉2〈/sub〉 film with the nanocone-array Ni interlayer was adopted to improve the tribological property of WS〈sub〉2〈/sub〉 film particularly prolonging the wear life for application in space. The WS〈sub〉2〈/sub〉/Ni bilayer films were prepared by sputtering WS〈sub〉2〈/sub〉 layer onto electrodeposited Ni interlayers with different surface morphologies. The micro-structures and the tribological properties of the prepared WS〈sub〉2〈/sub〉/Ni bilayer films were investigated. The results showed that with the existence of the nanocone-array Ni interlayer, the textured WS〈sub〉2〈/sub〉 film showed a cabbage-like structure due to the growth of the WS〈sub〉2〈/sub〉 columnar plates surrounding the Ni nanocones. The cabbage-like WS〈sub〉2〈/sub〉/Ni bilayer thin film was benefited for improving the lubrication properties with a long wear life of 4.9 × 10〈sup〉5〈/sup〉 cycles while the wear life was only 0.7 × 10〈sup〉5〈/sup〉 cycles for the pure WS〈sub〉2〈/sub〉 and 3.2 × 10〈sup〉5〈/sup〉 cycles for rough Ni textured WS〈sub〉2〈/sub〉 film. The improved tribological property was mainly attributed to the reserve of the WS〈sub〉2〈/sub〉 lubricate by the Ni nanocones as well as the relative low friction coefficient of the nanocone-array Ni interlayer due to the obvious reduced real contact area.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Yankun Li, Minfang Chen, Wei Li, Qi Wang, Yansong Wang, Chen You〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Micro-arc oxidation (MAO) as an environmentally friendly technology is used to produce ceramic film on metal surfaces to improve its corrosion properties, and the films quality is mainly affected by the electrolyte composition and electrochemical parameters, Here, to improve the corrosion property and wear-resisting of low carbon steel, a compact, corrosion resistant α-Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 ceramic film was prepared on the surface of low carbon steel containing boron (10B21) by MAO. A Na〈sub〉2〈/sub〉SiO〈sub〉3〈/sub〉 and NaH〈sub〉2〈/sub〉PO〈sub〉4〈/sub〉 electrolyte system was designed with different content of Na〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉 and Na〈sub〉2〈/sub〉B〈sub〉4〈/sub〉O〈sub〉7〈/sub〉. The ceramic layer produced with Na〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉 and Na〈sub〉2〈/sub〉B〈sub〉4〈/sub〉O〈sub〉7〈/sub〉 showed improved corrosion resistance. The corrosion current density was 2.7 μA·cm〈sup〉−2〈/sup〉 and the impedance value reached 1900 Ω·cm〈sup〉2〈/sup〉. After 7 days of neutral salt spray corrosion, the corrosion rate of this sample coating reduced to 53 g·m〈sup〉−2〈/sup〉·h〈sup〉−1〈/sup〉. The influence mechanism is discussed. The cooperation of Na〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉 and Na〈sub〉2〈/sub〉B〈sub〉4〈/sub〉O〈sub〉7〈/sub〉 in the electrolyte is more effectively regulated the ionization and chemical reactions of the MAO process, catalyzing the formation of α-Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉. The coating had a uniform thickness of 100 ± 10 μm, no gap between the coating and the substrate was observed, which indicated that the bonding state was good. Thus, the MAO ceramic layer prepared on low carbon steel surface increases the service life of iron and steel components effectively, which can significantly expand its application in more fields.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): H. Luo, Y.G. Wang, C.Y. Cai, G.W. Zhou, Y.C. Zhou, L. Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Annealing-induced microstructural changes in yttria partially stabilized zirconia (YSZ) have been investigated by scanning transmission electron microscopy combined with computer simulation. It is shown that the high-temperature annealing results in the formation of voids in YSZ and structural ordering in the surrounding area of the voids. Atomic-scale 〈em〉Z〈/em〉-contrast imaging shows one-dimensional distortion of the cation sub-lattice by alternate arrangement of narrow and wide (100) planes of the cation sub-lattice along the [100] direction of the cubic ZrO2 structure. Such distortion of the cation sub-lattice is attributed to the 1/4[001] displacement of the oxygen atoms in the (100) plane, which is confirmed experimentally by annual bright field imaging along with the density-functional theory and computer simulations of the atomic-scale 〈em〉Z〈/em〉-contrast imaging and electron diffraction.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): S. Mirzaei, M. Alishahi, P. Souček, L. Zábranský, V. Buršíková, M. Stupavská, V. Peřina, K. Balázsi, Zs. Czigány, P. Vašina〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Low ductility and brittle deformation behaviors are major drawbacks of currently used commercial hard ceramic-based protective coatings. Recent ab-initio calculations revealed that the coexistence of metallic, boride and carbide bonds in a nanolaminate structure of crystalline W〈sub〉2〈/sub〉BC system provides a combination of high hardness together with moderate ductility. The present paper deals with coatings containing W, B and C with different compositions and investigates the effect of the boron to tungsten ratio (B/W) on the structural and mechanical properties of W-B-C coatings prepared by pulsed-DC magnetron sputtering at a moderate temperature. Coatings with low B/W were deposited in a nanocomposite structure, whereas coatings with high B/W ratios were near-amorphous. The structure of the coatings was not a decisive factor in determining their mechanical properties. These were, however, directly correlated with the chemical bonds present. All the coatings exhibited high fracture resistance. These properties together with good adhesion to cemented tungsten carbides make W-B-C coatings promising candidates for the future protective coatings of tools which undergo large deformation in their working cycle.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Huiwen Hu, Hongping Wan, Lingqing Dong, Jun Lin, Mohannad Saleh Hammadi Al-Furjan, Kui Cheng, Wenjian Weng, Huiming Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, hydrothermal treatment and ultraviolet illumination (254 nm) were utilized to regulate the surface hydroxyls of titanium dioxide (TiO〈sub〉2〈/sub〉) nanodots films. The effects on light-induced cell detachment behaviors were also investigated and discussed. Scanning electron microscopy, Raman, X-ray photoelectron spectroscopy and Circular dichroism were used to characterize the surface morphology, crystalline phase, surface composition and adsorption conformation of protein molecules. It was found that a combined process of ultraviolet illumination followed by hydrothermal treatment not only promoted cells adhesion but also showed the highest efficiency in light induced cell detachment. The reason is ascribed to that such process promotes the formation of terminal hydroxyl groups in TiO〈sub〉2〈/sub〉 surface, and subsequently affect the adsorption conformation of protein molecules. This study indicated that such treatment could effectively modulate the contents of surface hydroxyl groups in different states. That shows much potential in optimizing the biological performance of TiO〈sub〉2〈/sub〉 based biomaterials.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): X.J. Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A crack number density (CND) theory model is developed for air-plasma-sprayed thermal barrier coating (TBC), which describes the evolution of crack number and size distribution as function of exposure time. The model is compared in good agreement with experimental measurements from quasi-isothermal-cyclic oxidation tests. Both the CND model and experimental observations indicate that thermally-grown oxides (TGO) are responsible for crack nucleation and growth. The model can be used to define TBC failure (spallation) by coalescence of microcracks into a maximum allowable crack size with a given probability.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): M.A. Ghasemi, S.R. Falahatgar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper deals with crack growth simulation in brittle coating/substrate structures under three point bending. For this purpose, a discrete element method (DEM) code is prepared by the authors and is used as a numerical tool with great ability to capture the damages at micro scale. Coating and substrate were considered as isotropic materials. Bilinear cohesive contact model was implemented as bonds between coating and substrate constituent particles. The influence of fracture energy of coating and substrate and coating thickness on the failure of coating/substrate structure is investigated. The results showed that, when the fracture energy in coating and substrate are in the same range, cracks created in the coating were developed to the substrate. But, by increasing the fracture energy in the substrate, interfacial delamination was observed as the failure mode in the structure.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Kattareeya Taweesup, Patama Visuttipitukul, Niti Yongvanich, Gobboon Lothongkum〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this research, Ti-Cr-N coatings on tool steel were prepared using DC magnetron sputtering at 25 °C (RT), 130 °C and 190 °C. Coating corrosion behavior was observed in a 3.5% NaCl solution at 25 °C using Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy (EIS). EIS circuit models for corrosion kinetics were proposed and the surface area and porosity of the coatings were recorded. Corrosion resistance was found to be higher for the coatings grown at 190 °C. This could be attributed to high density as well as low porosity. The EIS circuit model suggests the penetration of corrosive electrolytes into pores reaching the steel substrate for the coatings grown at RT. Finite length diffusion inside pores was also observed. The slow infiltration of corrosive electrolytes into the steel substrate could be seen in coatings grown at 130 °C with diffusion inside the pore similar to that in the coatings grown at RT. However, the EIS circuit model did not exhibit a finite length diffusion of the coatings grown at 190 °C. Owing to high coating density and smaller pore size, corrosive electrolytes could hardly penetrate through and reach the steel substrate.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Hui Liu, Fu-Chi Yang, Yi-Jing Tsai, Xiaojian Wang, Wei Li, Chi-Lung Chang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The newly developed TiAlSiN/CrN multilayer films were deposited on silicon Si (100) substrates and tungsten carbide steel substrates by high power impulse magnetron sputtering technique (HiPIMS) at 80 °C working temperature. The effect of modulation structure on the microstructural and mechanical properties of thin films was analyzed systematically by TEM, SEM, XRD, nanoindenter, Scratch test, and Rockwell indenter. The grain size of columnar crystals decreases as increasing the Λ from 2 nm to 27 nm. Correspondingly, the crystallite size in the (111) and (200) directions exhibited an increasing tendency, which calculated by the Debye-Scherrer equation. The hardness and Young's modulus exhibited an initial increased with decreasing Λ from 27 nm to 7.5 nm, followed by a decrease. The TiAlSiN/CrN multilayer films with Λ of 7.5 nm reached the highest hardness of 26.6 GPa and the highest Young's modulus of 295.4 GPa. However, the thin film with Λ of 8.5 nm exhibited a hardness value of 25.3 GPa and the highest adhesion strength, which the highest critical load 〈em〉L〈/em〉c1 of 52 GPa and the morphology of Rockwell indentations can be classified as HF1. Therefore, based on both hardness and adhesion strength, an optimization TiAlSiN/CrN multilayer film is in the single layer thickness of 8.5 nm.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): S. Thirumalai, Z.H. Barber, J.A. Williams, A.L. Greer〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Iron-rich nanocomposite Fe-Ti-N coatings are deposited by reactive direct-current magnetron sputtering. Co-deposition from two targets (Fe and Ti) onto substrates placed at different locations gives a combinatorial approach to film composition effects, with the Fe/Ti atomic ratio varying from 0.5 to 38. The influence of substrate-temperature is also studied. The nanohardness of the coatings increases with Fe content, and is as high as ~15 GPa, far exceeding the value for pure-iron, and comparable alloy coatings. The nanowear resistance of the coatings scales as expected with their hardness, but their abrasive wear resistance is dependent on their adhesion to the substrate.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Samia K. Essa, Rong Liu, Matthew X. Yao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An interfacial fracture toughness model for thermal barrier coatings (TBCs) is proposed in which model parameters not only include the effect of high temperature and exposure period of TBCs but also demonstrate the mode mixity characteristics. The model is expressed in terms of the Arrhenius-type form showing a temperature-dependent feature and also exhibits a dependence of microcrack density distributed along the coating interface. Two scaling parameters are used in formulating the model, one is introduced to link dislocation Burgers vector to the crack tip opening displacement (CTOD), the other is utilized to describe the crack tip energy release rate associated with the P-N force responsible for dislocation movement. These scaling parameters can be obtained by fitting to the interfacial fracture toughness data at ambient temperature and the CTOD, respectively. Since the experimentally measured microcrack density exhibits thermal cycle dependent behavior, an attempt is made to explain the experimentally obtained toughness values using the proposed interfacial crack toughness model. The model predicts an increase in fracture toughness with exposure temperature and mode mixity. The limitation of the model and possible improvement scheme are discussed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Hua Zheng, Yina Zheng, Juanhong Wang, Jian Wang, Geng Zhang, Shaoqiao Zhang, Minxia Liu, Jun Hu, Yi Li, Yaohua Hu, Wei Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High-resolution passive-matrix polymer light-emitting displays with printed cathodes are achieved by combining delicate cathode deposition and multifunctional buffer layer fabrication. Unlike other printing methods and printed materials, ink-jetting conducting nano-particles as cathode can provide high-resolution cathode patterns and excellent continuity along the fine cathode lines without any mechanical pressure on the organic layers. The buffer layer between the printed cathode and the organic active layers, was fabricated by mixing the water/alcohol-soluble polymer poly[9,9-bis(3′-(〈em〉N〈/em〉,〈em〉N〈/em〉-dimethylamino)propyl)-2,7-fluorene-alt-2,7-(9,9-dioctylfluorene)] (PFNR〈sub〉2〈/sub〉) and a curable epoxy adhesive. It offers the functions of solvent-proof, electron-injection, and proper affinity with the cathode ink. While improving the performance of devices, especially blocking the leakage current greatly, the cross-linked buffer layer also induces a novel phenomenon of ‘linear 〈em〉η-J〈/em〉 plot’, which can be derived to interesting and realistic results. Red, green, and blue monochrome and full-color polymer light-emitting displays with a content format of 96 × 3 × 64 show neither dead pixels nor dead lines. Under optimized steps of curing, the nano silver ink forms continuous, defect-free, and low-resistance cathode rows without any distortion. The red, green, and blue displays exhibit the current efficiencies of 0.62, 4.38 and 0.93 cd/A, and CIE color coordinates of (0.63, 0.37), (0.39, 0.57) and (0.18, 0.16), respectively. The cathode printing technique removes the need of high vacuum for thermal evaporation of the cathode metal, which could lead to the industrial roll-to-roll process to manufacture the flat panel displays.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Shi-hang Kang, Wen-bin Tu, Jun-xiang Han, Zhi Li, Ying-liang Cheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Titanium alloys own a series of advantages such as low density, high specific strength, and biocompatibility. However, the poor wear resistance of titanium alloys impedes their wide applications in industry. In this study, we show that the wear resistance of the Ti6Al4V alloy can be greatly improved by a combined method of magnetron sputtering and plasma electrolytic oxidation (PEO). An ~13 μm pure aluminum layer was first applied on the Ti6Al4V alloy by magnetron sputtering and then PEO was employed for the second step treatment of the Al coated Ti6Al4V alloy. The PEO of the Al coated Ti6Al4V was carried out in aluminate (32 g l〈sup〉−1〈/sup〉) and silicate (16 g l〈sup〉−1〈/sup〉) electrolytes, respectively. Ball-on-disc tribological tests with an applied load of 10 N against a Cr steel ball were used to evaluate the wear performances of the samples. The coating formed in 32 g l〈sup〉−1〈/sup〉 aluminate electrolyte for 4 min shows superior wear performance, which sustained 1800 s sliding time against the steel ball and the wear rate is non-detectable. In contrast, the coating formed in the silicate electrolyte for 15 min has been destroyed during the tribological test, showing a wear rate of ~3.9 × 10〈sup〉−4〈/sup〉 mm〈sup〉3〈/sup〉/(N·m). The excellent wear performance of the coatings formed in the aluminate electrolyte can be attributed to its high growth rate and homogeneity in microstructure. The coating growth mechanisms have also been discussed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Yiqi Wei, Yinglin Yan, Yiming Zou, Mangmang Shi, Qijiu Deng, Nana Zhao, Shiyu Chen, Jiaming Lin, Rong Yang, Yunhua Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Lithium-sulfur (Li-S) battery processes high theoretical capacity (1675 mA h g〈sup〉−1〈/sup〉) and energy density (2600 Wh kg〈sup〉−1〈/sup〉), which was widely accepted as one of the most promising candidates for energy storage devices. In this presented study, bamboo-derived hierarchical porous carbon (BDPC) was adopted as a conducting substrate for containing S. Soft polystyrene (PS) and polyaniline (PANI), were prepared as coating layers. The main purpose is to figure out the specific roles that the polymer shells and the heteroatoms doped on polymer backbone play during cycles. The ternary products were characterized by structural analysis and electrochemical testing. The results indicate that, as compared to BDPC/S, the PS@BDPC/S electrode displays higher capacity retention during long-term cycles, especially at the high current rate. It is attributed to the integrated coating shell, which provides physical confinement and reserves spaces for restraining volume expansion. It is noted that the PANI@BDPC/S electrode presents a higher initial capacity, remarkable long-life performance, and excellent rate property. The outstanding performances are closely related to the nitrogen atom doped on PANI backbone, they provide not just abundant polar conducting sites for fast electron/Li-ion transport but strong chemical anchoring for restricting the migration of polysulfides. Therefore, our study poses a clearer understanding of the functionalized polymers used in Li-S battery.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Liang-Yu Chen, Tianxiang Xu, Haiyang Wang, Peng Sang, Sheng Lu, Ze-Xin Wang, Shujin Chen, Lai-Chang Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Although considerable endeavors have been dedicated to investigate the microstructures of the remelting-enhanced NiCrBSi coatings, the textures in the remelted coatings, which may result in property anisotropy, are rarely studied. In this work, the recrystallized fractions, grain orientations and interphase boundaries for Ni, Ni〈sub〉3〈/sub〉B and CrB in a plasma sprayed-remelted NiCrBSi coating were investigated by electron backscatter diffraction. The results demonstrate that the texture is induced by phase interaction during solidification. Cooling from the liquid, the firstly formed Ni grains possess a cube fiber texture of {001}〈001〉. The successively formed Ni〈sub〉3〈/sub〉B colonies are randomly oriented and keep specific orientation relationships with the surrounding Ni grains, resulting in formation of some weak texture components of Ni. The finally formed CrB grains have a considerably high frequency (40.8%) of lattice correlation boundary of (002)〈sub〉Ni〈/sub〉//(040)〈sub〉CrB〈/sub〉, but no specific orientation relationships with Ni〈sub〉3〈/sub〉B grains. Hence, the interaction of Ni and CrB grains leads to the formation of more texture components of Ni. As such, the phase interaction induced texture forms in the remelted NiCrBSi coating. This work would give an insight into the anisotropy in the remelted NiCrBSi coatings and provide a theoretical basis of further optimizing the remelting process technologies.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Yingying Zhang, Xiong Li, Denghui Xu, Fanwen Meng, Rong Hu, Jia Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Solvent additive can effectively regulate the phase-separated morphology of the active layer and improve the power conversion efficiency of polymer solar cells. In this study, the influence of solvent additives 1,8-dichlorooctane (DClO), 1,8-dibromooctane (DBrO) and 1,8-diiodooctane (DIO) on the morphology of PTB7:PC〈sub〉71〈/sub〉BM active layer films is investigated systematically, and the photovoltaic performance of the prepared bulk heterojunction polymer solar cells is analyzed detailedly. The DIO and DBrO additives facilitate PC〈sub〉71〈/sub〉BM diffusing into the PTB7 polymer network and forming interpenetrated bulk heterojunction junction morphology, while the DClO additive deteriorates the active layer morphology. The optimized morphology of DIO and DBrO additives promotes exciton dissociation efficiency, improves charge transport and collection efficiency. The optimum performances were obtained in the devices with DIO additive.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): H. Kovacı, İ. Hacısalihoğlu, A.F. Yetim, A. Çelik〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In recent years, hybrid surface treatments which include plasma nitriding combined with pre-shot peening operations have been proposed for the improvement of nitriding efficiency. The main objective of this study is to characterize the effects of dual process on the friction and wear behavior of metallic materials. For this purpose, AISI 4140 steel samples were shot peened at various densities of 16, 20 and 24 A. The pre-treated samples were plasma nitrided at a temperature of 500 °C for 1 and 4 h. The structural and mechanical properties of samples were analyzed by XRD, SEM and microhardness tester. Wear tests were performed under dry sliding conditions to determine the tribological properties of the samples. This study showed that the shot peening treatment formed finer grains, compressive residual stresses on the surface and increased the diffusion kinetics of the samples. The surface hardness and residual stresses increased with increasing shot peening density. It was evidence that the finer grains, increased dislocation density and surface defects increased the case depth obtained from plasma nitriding by enabling easier diffusion of nitrogen. The depth of the diffusion zones in shot peened plus plasma nitrided specimens was found almost two times thicker than that of the diffusion zones in specimens treated only by plasma nitriding. The highest surface hardness values were obtained from pre shot peened and plasma nitrided samples in consequence of the interactive effect from nitride phases/layers and increased surface compressive residual stress. As a result, pre-shot peened plus plasma nitrided samples exhibited higher wear resistance than specimens treated only by shoot peening and hybrid treating in glow a discharge atmosphere.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Maksim Krinitcyn, Gennady Pribytkov, Victoria Korzhova, Irina Firsina〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Coatings obtained by electron-beam overlaying of “titanium - titanium carbide” composite powders were investigated. The composite powders have been prepared by self-propagating high-temperature synthesis (SHS) in titanium and carbon reactive powder mixtures. Structural studies of the powders synthesized and of the clad coatings were carried out by X-ray diffractometry, optical metallography, and scanning electron microscopy. The coatings were tested on hardness and abrasive wear resistance. Testing results were discussed in the combination with structure investigation results.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): L. Cen, W.Y. Qin, Q.M. Yu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The interface delamination plays an important role in failures of thermal barrier coatings. An axisymmetric finite element model was built for air plasma sprayed thermal barrier coatings. The model incorporated a Fortran subroutine developed for the TGO growth. It is found that the stress conversion happens in the top-coat at high temperature under isothermal exposure. A simple numerical method was proposed to calculate the normal and tangential stresses at the top-coat/TGO interface and the bond-coat/TGO interface. The bond-coat/TGO interface is less likely to separate during thermal exposure because the interfacial stresses are limited mostly by the high-temperature yield strength of the bond-coat. The delamination of the bond-coat/TGO interface happens on cooling, which is supported by the experimental observation. As a result, the delamination of the bond-coat/TGO interface could be appreciated based on the corresponding normal and tangential stresses.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Qi Yang, Wenlong Zhou, Xiaobing Zheng, Zhiqiang Niu, Zhiqiang Li, Bowei Zou, Xuesong Fu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Dovetail joint specimens manufactured from the Ti-6Al-4V alloy were designed and used to investigate the fretting fatigue behavior of the blade/disk interface in gas turbine engines. Shot peening was combined with plasma-sprayed CuNiIn coating to improve the fretting fatigue resistance of the specimens. The finite element models were used to analyze the contact stress distribution in the fretting area. A plastic layer was added to simulate the CuNiIn coating that was sprayed on the surface of the dovetail blade. The fretting cracks tended to initiate at the contact edge, where the high stress concentration existed, and severe fretting wear damage occurred. The CuNiIn coating modified the local stress distribution under the fretting condition and mitigated the stress concentration degree of the contact edge. The surface strain hardening layer and the compressive residual stress were induced by the shot peening treatment, which promoted the wear and the fatigue resistance of the Ti-6Al-4V substrate under the fretting condition. The fretting fatigue property of specimens improved after the combined surface treatment.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Ma Guozheng, Chen Shuying, He Pengfei, Wang Haidou, Zhou Yangyang, Zhao Qing, Li Guolu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to optimize the supersonic plasma spraying process more scientifically, it is important to clearly understand the spreading behavior of molten droplet. In this study, the effects of spray parameters on the in-flight behavior and spreading behavior of Fe-based amorphous droplets were investigated. Additionally, since the morphology of the splats is a very important factor which determines the final properties of the coatings, the splats in this study were characterized in terms of their circularity, eccentricity, solidity, and spread factor. The porosity and micro-hardness of the Fe-based amorphous coatings were also evaluated. Results show that the spraying power is the most important parameters that influence the surface temperature of the Fe-based amorphous droplets, while the main factor affecting the in-flight velocity is the Ar flow rate. The melting index of in-flight particles reaches the maximum value at the spraying power of 60 kW and Ar flow rate of 110 L/min. The droplets present disk-shaped splats with the lowest solidity and eccentricity, and highest circularity and spread factor with the average velocity of 445 m/s and surface temperature of 2780 K. This is very crucial to reduce the defects of as-sprayed coatings and form fine-lamellar-structured supersonic plasma-sprayed coatings with outstanding mechanical properties.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Qingyu Hou, Xiaoyu Ma, Rongcheng Lu, Wei Wang, Ping Wang, Zhenyi Huang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tungsten-based coatings without TiC addition (TiC-free) and with 1.5 wt% TiC addition (TiC-doped) were fabricated by supersonic atmospheric plasma spraying (SAPS) technique, respectively. The as-sprayed coatings were then irradiated by laser. The results showed that the as-sprayed coatings were mainly composed of lamellar structure. TiC phase located mainly at lamellar gaps of the as-sprayed TiC-doped coating with a morphology of strip filled the gaps. The as-sprayed TiC-doped coating exhibited dense structure, lower porosity, reduced oxygen content and higher thermal conductivity as compared with the as-sprayed TiC-free coating. The as-irradiated coatings could be divided into remelted zone, un-remelted zone and/or mixing zone. Cracks were more easily formed in the as-irradiated TiC-free coating than in the as-irradiated TiC-doped coating. The stripped TiC phase in the as-sprayed TiC-doped coating changed into quasi-spherical/spherical ones in the remelted zone of the irradiated coating and distributed along the tungsten grain boundaries. The averaged tungsten grain size in the remelted zone of the as-irradiated TiC-doped coating was about 5.4 μm and that of the as-irradiated TiC-free coating was about 14.8 μm. There were about 96 wt% α(W) and about 4 wt% γ(W) existed in the remelted zone near the surface of the as-irradiated TiC-free coating. Only α(W) could be received in the remelted zone far from the surface of the as-irradiated TiC-free coating and the remelted zone of the as-irradiated TiC-doped coating. There were no obvious diffraction peaks for γ(W) could be indexed from the XRD patterns for the as-irradiated TiC-doped coating. The ability of the as-sprayed TiC-doped coating to resist laser irradiation was greater than the as-sprayed TiC-free coating, mainly attributing to the higher thermal conductivity of the as-sprayed TiC-doped coating and the refinement effect of TiC particles in the as-irradiated TiC-doped coating.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Xian-Feng Ma, Ya-Wen Wu, Jie Tan, Chui-Yi Meng, Liu Yang, Wei-An Dang, Xiu-Jie He〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To develop a nuclear fuel cladding that has high tolerance under normal operating conditions and accident conditions, TiAlCrN coatings were deposited onto Zr substrates by multi-arc ion plating technique. After a corrosion test in static pure water at 360 °C and 18.5 MPa, the TiAlCrN coating showed no obvious spallation and had a weight gain of one order of magnitude less than that of the uncoated Zr sample. The decomposition and oxidation of the TiAlCrN coating at high temperature is an endothermic and exothermic reaction, respectively. Owing to the oxidation in the coating, the formed oxide layers reduce the oxygen penetration through the coating and also reduce the thickness of the zirconia layer from 300 μm to 10 μm at 1060 °C in air. This work lays the foundation for the next oxidation of TiAlCrN coating in high temperature steam, and demonstrates that TiAlCrN is a promising candidate material for the development of nuclear fuel cladding.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Xiaolan Zhang, Xiaoxu Liu, Chen Yang, Na Li, Tianyi Ji, Kai Yan, Bo Zhu, Jinghua Yin, Jiupeng Zhao, Yao Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Hard carbon with high special capacity has been widely studied as anode for sodium ion batteries (SIBs). Its storage sodium performance still needs to be further improved. Herein, a composite electrode was synthesized through growing V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 nanosheet array on free-standing hard carbon fiber fabric by solvothermal reaction. The electrochemical properties of the composite electrode were significantly enhanced compared with pure hard carbon fiber electrode. The composite showed a specific capacity from 241 mA h g〈sup〉−1〈/sup〉 at 50 mA g〈sup〉−1〈/sup〉 to 77 mA h g〈sup〉−1〈/sup〉 at 1000 mA g〈sup〉−1〈/sup〉 and a good cycling ability of 184 mA h g〈sup〉−1〈/sup〉 after 100 cycles at 100 mA g〈sup〉−1〈/sup〉. Except good storage Na ability for V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 nannosheets, the improvement of electrochemical performances also benefited from and the synergistic effect from the ability of fast electron transfer of hard carbon and the toleration for Na〈sup〉+〈/sup〉 insertion of V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 nanosheet array, as well as the inhibitory effect on solid electrolyte interface (SEI) of nanostructure. Additionally, the free-standing electrodes could also increase the energy and power density. This will push the promising hard carbon material used as SIBs anode in practical applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): De Wang, Wenqin Wang, Mingsheng Wang, Yulong Li, Xingui Chen, Changtai Chi, Yujiang Xie〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉NiCoCrAlYTa-Y〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 metal matrix composite coatings were prepared on single crystal superalloy by electrospark deposition (ESD) to improve the wear- and oxidation resistance. The effect of operating voltage during ESD on the deposit morphology, coating growth kinetics, microstructure and properties was investigated. The results showed that, with increasing operating voltage, the dimension (both diameter and depth) of single-pulse deposit increased, leading to thinner deposit thickness, thus resulting in higher cooling rate, finer grains, stronger crystal orientation, and increasing microhardness. Whereas the motion of the molten deposit metal became more turbulent, giving rise to the defect of lack of fusion. However, the grain size increased obviously from bottom layer to top layer for 100 V condition, leading to decreasing microhardness. Meanwhile, the mass gain rate increased but the mass transfer coefficient decreased with the increase of operating voltage. The distribution pattern of Y〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 particles changed during electrospark deposition, from gathering in the boundary between the powders in the electrode to distributing homogeneously in the whole coating, which contributed to the increase of coating microhardness.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Xuan Zhang, Yanli Zhong, Yue Yan, Zhongqi Huo, Changshan Hao, Jingjing Peng, Guanli Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Three types of primer layers, including polyurethane (PU), acrylic, and silicone coatings, were developed and deposited on the poly(methylmethacrylate) (PMMA) substrates. Amorphous transparent indium zinc oxide (IZO) films deposited by direct current magnetron sputtering at room temperature on primer-treated and untreated PMMA substrates were investigated ex situ in terms of surface morphology, adhesion, nanoindentation and electrical properties. AFM images show that the microstructure of IZO films was determined by the morphology of the primer layers. IZO films deposited on silicone and acrylic-treated PMMA substrates presented the least surface roughness, which proved that the silicone and acrylic primer layers were more effective to get a dense surface. Nano-scratch tests indicated that the adhesion of IZO films deposited on substrate treated by silicone-based primer layers was superior to that on PU-treated and untreated substrate, which can be attributed to the better mechanical matches of the IZO/primer/PMMA system and the large values of hardness of the silicone primer, which can counterbalance the indentation load and prevent the failure of the films.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Guang-Xing Liang, Yan-Di Luo, Ju-Guang Hu, Xing-Ye Chen, Yang Zeng, Zheng-Hua Su, Jing-Ting Luo, Ping Fan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, the influence of annealed ITO thin film as a transparent electrode layer in pulse laser deposition (PLD) Cu〈sub〉2〈/sub〉ZnSnS〈sub〉4〈/sub〉 (CZTS) thin-film solar cell was investigated. The proposed annealed ITO thin film exhibits a high degree of crystallinity and large and evenly distributed grains. Thus, low resistivity and wide and high transmitted band in the UV/VIS light range with ideal optical band gap of 3.8 eV can be obtained. Devices built with these annealed ITO thin films on our PLD CZTS solar cell exhibit a significant improvement in power conversion efficiency from 0.2% to 1.92%.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Fan Wang, Guang-Nan Luo, Jianjun Huang, Ying Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tungsten coatings were deposited onto oxygen-free copper substrate by atmospheric plasma spraying technique. Annealing treatment was adopted to modify the inherent defects and improve the performance of the plasma sprayed tungsten coating. The effect of annealing under vacuum and hydrogen atmosphere on the properties of plasma sprayed tungsten coating was studied. The results show that the tungsten grains grow up after annealing treatment, the coatings are transformed from a disorganized structure into a columnar crystal structure with an orderly arrangement. Annealing treatment at a certain temperature can decompose and reduce the tungsten oxide in the coating into pure tungsten, thereby reducing the oxygen content and improving the purity of the coating. As a result, the thermal conductivity, microhardness and other performances of the APS-W coating are improved after annealing.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): L.L. Zhai, C.Y. Ban, J.W. Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉External signal steady magnetic field and electric-magnetic compound field were applied to investigate the influence of the electromagnetic field to the laser cladding NiCrBSi coatings. The macromorphology, phase composition and microstructure were identified by optical microscope (OM), confocal scanning laser microscope (CSLM), X-ray diffraction (XRD) and scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS). The experimental results demonstrated that the main phase composition of the coatings was γ-(Fe,Ni), Cr〈sub〉23〈/sub〉C〈sub〉6〈/sub〉, Cr〈sub〉7〈/sub〉C〈sub〉3〈/sub〉, CrB, Ni〈sub〉3〈/sub〉B with and without electromagnetic fields. Results showed that the dilution of the coating under electric-magnetic compound field was similar (14%) to the coating without auxiliary field. While the dilution of the coating had a decrease (10.8%) under signal steady magnetic field. Results of microstructure indicated the content of CrB phase in the coating increased obviously under electromagnetic field. The average microhardness of the coating under electromagnetic field was increased compared to that of the coating without auxiliary field. Corrosion resistance was also improved under electromagnetic field auxiliary laser cladding.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Jia-Hong Huang, You-Fu Chen, Ge-Ping Yu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The objectives of this study were to evaluate the fracture toughness of Ti〈sub〉1-x〈/sub〉Zr〈sub〉x〈/sub〉N hard coatings using the internal energy induced cracking (IEIC) method and to investigate the compositional effect on the fracture toughness, from which the optimum composition for fracture toughness could be attained. Ti〈sub〉1-x〈/sub〉Zr〈sub〉x〈/sub〉N was selected to be the model system, because Ti〈sub〉1-x〈/sub〉Zr〈sub〉x〈/sub〉N remained single phase structure in the entire compositional range at deposition temperature below 500 °C. Three compositions of Ti〈sub〉1-x〈/sub〉Zr〈sub〉x〈/sub〉N coatings, x = 0.25, 0.55 and 0.85, were deposited by unbalanced magnetron sputtering. The parameters of IEIC method included the residual stress determined by the laser curvature method, Young's modulus obtained from nanoindentation and the film thickness measured from SEM cross-sectional image. The residual stress and film thickness before specimen fracture were used to calculate the elastic stored energy (G〈sub〉s〈/sub〉), from which the fracture toughness (G〈sub〉c〈/sub〉) could be derived. The resultant G〈sub〉c〈/sub〉 of the Ti〈sub〉1-x〈/sub〉Zr〈sub〉x〈/sub〉N coatings varied with Zr fraction, ranging from 26.0 to 48.7 J/m〈sup〉2〈/sup〉, and reaching a maximum at a composition of Ti〈sub〉0.15〈/sub〉Zr〈sub〉0.85〈/sub〉N. The results showed that adding Zr atoms into TiN could effectively increase the fracture toughness. The maximum increase of fracture toughness lay in the intermediate range of composition (Zr = 0.55–0.85), suggesting that different properties of Ti and Zr atoms may play an important role on the fracture toughness of single phase Ti〈sub〉1-x〈/sub〉Zr〈sub〉x〈/sub〉N thin films. The increase of G〈sub〉c〈/sub〉 with Zr composition may be correlated with the change of configurational entropy of the Ti-Zr-N system. The atomic size difference of Zr and Ti may be crucial on increasing fracture toughness. The increase of fracture toughness for Zr-dominant Ti〈sub〉0.15〈/sub〉Zr〈sub〉0.85〈/sub〉N coating was higher than that for Ti-dominant Ti〈sub〉0.75〈/sub〉Zr〈sub〉0.25〈/sub〉N coating. This asymmetrical behavior could be attributed to the difference in lattice constants between Ti-rich and Zr-rich compounds, where the capability of increasing G〈sub〉s〈/sub〉 may be higher for a smaller Ti atom incorporated into a larger Zr site in ZrN lattice.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Yuanlin Xue, Wenge Chen, Qian Zhao, YongQing Fu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉For carbon fiber reinforced metal matrix composites, there are many potential problems such as severe agglomeration of carbon fibers (CFs), their poor interfacial wettability with the matrix, and poor mechanical strength. To solve these problems, we proposed to use electroless plating to coat a layer of Ni onto the CFs, and then studied their interfacial structures, fracture strain/strength and wettability. The coated Ni layer was uniformly distributed onto and well bonded with the CFs. The maximum strain of the CFs coated with the Ni layer was increased by 23.4%, though their average fracture strength was slightly decreased from 3.5 GPa to 2.25 GPa. The wettability of the Ni-coated fiber was significantly improved, verified from testing results using both a dip coating method and a fiber reinforced composite simulation test.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Rui-ting Tong, Bin Han, Ze-fen Quan, Geng Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, a molecular dynamics model is proposed to describe the collision friction of a hinge mechanism in the space environment. The EAM potential is used to describe the interaction between atoms. Based on the model, the collision friction process and thermal properties between the indenter and smooth gold film surface at different indenter amplitudes, frequencies and crystal orientations are studied. The temperature distribution and collision friction mechanism of the gold film are analyzed. The simulation results show that increasing the vibration frequency of the indenter in a certain frequency range can reduce the friction force. The amplitude of the indenter and crystal orientations at different frequencies shows different effects on the average friction force and the surface temperature of the substrate. In addition, textures are also made on the gold film and the effects of texture width and texture depth on the friction and thermal properties are investigated. The results show that the textured surface can significantly reduce the friction force. The average friction force and the surface temperature of the substrate decrease with the increase of texture depth, and increase with the increase of texture width. The average friction force and the surface temperature of the substrate are more sensitive to the texture depth.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Yan Tang, Fang Wu, Liang Fang, Ting Guan, Jia Hu, ShuFang Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Layered double hydroxides (LDHs) have great potential as protective coatings on magnesium alloys due to their nanolamellar structure and exchangeability of interlayer anions. ZnAl layered double hydroxides films intercalated with nitrate anions (ZnAl-NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉-LDHs) was synthesized on the AZ31 magnesium alloy by hydrothermal method. In order to obtain better corrosion resistance, ZnAl-X-LDHs (X = Cl〈sup〉−〈/sup〉, VO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉, PO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉, or MoO〈sub〉4〈/sub〉〈sup〉2−〈/sup〉) were prepared by using ZnAl-NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉-LDHs as a precursor, and Cl〈sup〉−〈/sup〉, VO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉, PO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉, and MoO〈sub〉4〈/sub〉〈sup〉2−〈/sup〉 anions intercalated into the LDHs interlayers to replace NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉 through anion-exchange reaction. X-ray diffraction (XRD), scanning electronic microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy were used to investigate structure, morphology and composition of the ZnAl-LDHs. The corrosion resistance of ZnAl-LDHs intercalated with different anions was compared by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) measurements. The results show that the corrosion resistance of ZnAl-LDHs films is ranged in order as follows: ZnAl-VO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉-LDHs 〉 ZnAl-MoO〈sub〉4〈/sub〉〈sup〉2−〈/sup〉-LDHs 〉 ZnAl-PO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉LDHs 〉 ZnAl-Cl〈sup〉−〈/sup〉LDHs 〉 ZnAl-NO〈sub〉3〈/sub〉〈sup〉−〈/sup〉LDHs. ZnAl-VO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉-LDHs has the largest basal spacing distances d〈sub〉(003)〈/sub〉 value and strongest ability to release anions and absorb chloride ions, so ZnAl-VO〈sub〉4〈/sub〉〈sup〉3−〈/sup〉-LDHs films has the optimal corrosion resistance and can provide enhanced anticorrosion protection for magnesium alloys substrate.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0257897218312805-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Elia Vidal, Judit Buxadera-Palomero, Camille Pierre, José M. Manero, Maria-Pau Ginebra, Sophie Cazalbou, Christèle Combes, Elisa Rupérez, Daniel Rodríguez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Metallic implants have some limitations related to bioactivity and bacteria colonization leading to infections. In this regard, calcium phosphate coatings can be used as carrier for drug delivery in order to improve the mentioned drawbacks. The present work proposes the introduction of an antibacterial agent in the course of a pulsed and reverse pulsed electrodeposition. Calcium phosphate coatings were prepared in 30 min using different pulse waveforms (unipolar-bipolar), current densities (2–5 mA/cm〈sup〉2〈/sup〉) and temperatures (40–60 °C). Mechanical stability of the as-coated surfaces was studied in order to select the optimal electrodeposition conditions. Subsequently, selected coatings were loaded with an antiseptic agent, chlorhexidine digluconate (CHX), 〈em〉via〈/em〉 a single-step co-deposition procedure. CHX concentration added to the electrolyte was adjusted to 3 mM based on the antibacterial efficacy of the loaded coatings evaluated 〈em〉in vitro〈/em〉 with 〈em〉Staphylococcus aureus〈/em〉 and 〈em〉Escherichia coli〈/em〉 bacteria strains. Whereas the same chlorhexidine concentration was added to the electrolyte, results showed that the amount of CHX loaded was different for each condition while release kinetics was maintained. The results of this work demonstrate that a pulsed co-deposition strategy has great potential to modulate local delivery of antibacterial agents such as chlorhexidine digluconate, which may prevent early phase infections of metallic implants after insertion.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0257897218312477-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Shuwei Ge, Bizhuang Zhang, Chengtao Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Er-doped AlN thin film was deposited on sapphire substrates (0001) by RF magnetron sputtering at different sputtering times. The crystalline structure, surface morphology and electrical properties of the thin films have been investigated. The XRD patterns and the SEM sectional diagram indicate that Er-doped AlN thin films present the preferred orientation of C axis. The crystalline quality of the films rises first and then decreases with the increase of sputtering time and reaches best at 90 min. Piezoelectric coefficient d〈sub〉33〈/sub〉 indicates maximum value of 9.53 pm/V. Correspondingly, the best surface morphology of thin film was obtained at 90 min and the surface roughness reached a minimum of 2.012 nm. In addition, the change of resistance is same with change of the crystalline quality and the resistivity reached a maximum of 4.36 ∗ 10〈sup〉12〈/sup〉 Ω·cm at 90 min.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): V.A. Burdovitsin, D.A. Golosov, E.M. Oks, A.V. Tyunkov, Yu.G. Yushkov, D.B. Zolotukhin, S.M. Zavadsky〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We describe a novel method for electron-beam nitriding of metal (titanium) under medium (fore-vacuum) pressures (2–8 Pa) of nitrogen. Titanium sample was heated by a dc electron beam generated by a fore-vacuum plasma-cathode electron source with current up to 100 mA and energy up to 8 kV; this beam also generated beam-produced plasma with active nitrogen atoms, ions and other reactive species near the sample. SEM chemical composition analysis of the nitride layer have shown the presence of approximately 25 wt% of N, wt. 68% of Ti and only wt. 6% of O atoms within the processed layer. The X-ray diffraction spectrum of the nitride sample showed that the modified layer has a crystalline structure predominantly orientated along the crystallographic directions (111), (200), (220), characteristic of δ-TiN with a face-centered lattice. Besides the δ-TiN phase, there are present in the nitrided layer a γ phase of Ti〈sub〉2〈/sub〉N (tetragonal nitride) with predominant orientation (200). These results show the advantage of using forevacuum sources for electron beam and plasma nitriding of metals.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Stefan Saager, Bert Scheffel, Olaf Zywitzki, Thomas Modes, Markus Piwko, Susanne Doerfler, Holger Althues, Christoph Metzner〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Porous silicon thin films were fabricated by an innovative method using vacuum processing for the application as high capacity anode in lithium ion batteries. The deposition procedure comprises a co-evaporation of silicon and zinc, resulting in a deposition of a compound layer with deposition rates up to 100 nm/s and a subsequent thermal annealing. Due to its high vapor pressure, the zinc fraction is expelled and hence, a porous silicon matrix is formed. Herein, we introduce a novel and potentially scalable synthesis method for porous silicon films and show first analytical investigations concerning the layer morphology and the electrochemical properties. With the novel silicon anode excellent electrochemical performance, particularly high capacities of ≥3000 mAh/g, reasonable coulombic efficiencies of ≥90% in the initial cycle and comparably high cycle life 〉150 cycles can be demonstrated, which reveals their great potential for battery anode applications.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S025789721831274X-ga1.jpg" width="249" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): K.A. Habib, D.L. Cano, José Antonio Heredia, J.S. Mira〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The purpose of this paper is to understand and to quantify the effect of the re-melting technique on the microstructure and tribological behaviour of oxy-fuel (OF) thermally sprayed NiCrBSi coatings in the mixed lubrication regime. Two different re-melting techniques have been used: Surface Flame Melting (SFM) and laser re-melting processes. The microstructure of the obtained coatings was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Deposited coatings demonstrated similar phases but manifested notable differences in their morphology, size, distribution and relative proportions of the observable phases. These differences in microstructure may explain the differences in coating properties. Tribological experiments were carried out using a pin-on-disc approach at different sliding speeds and contact pressures. Wear and indentation tests have also been conducted. Laser re-melted coatings achieve higher hardness, less friction and lower accumulated wear volume in lubricated conditions. Test data were fitted with regression models. The fitted equations allow a robust assessment of the effect of the re-melting technique and working conditions on the friction coefficient in components that operate in the mixed lubrication regime. Therefore, these equations may help to select the adequate coating and tribological parameters for specific applications.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S025789721831315X-ga1.jpg" width="306" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Jian Chen, Hong Hu, Yindong Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recently, microchannel jetting dispenser technology has been widely used in many industrial applications such as an assembly of micro-electronics. The microfluidic channel of the dispensing needle affects significantly the jetting dispensing process. In order to increase the insufficiency and instability of contact inkers, the novel microchannel structure with the diamond film coating was proposed in this paper. The surface morphology, structure and hardness of the TiAIN films have been observed. The TiAIN film coating can enhance the tightness and stability and shows the improvement in the non-contact dispensing process. The experimental investigation about the effect of the nozzle with TiAIN film coating was provided in this study.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Longcheng Yin, Xinxin Ma, Guangze Tang, Zhongyuan Fu, Shuxin Yang, Tingjian Wang, Liqin Wang, Liuhe Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The case-hardened 14Cr14Co13Mo4 martensitic stainless steel is carburized by low-pressure carburizing method. Plenty of second phase particles appear in the case layer. C concentration is measured by Carbon and Sulphur analyzer. Precipitation of second phase induces the improvement of C concentration in case layer. XRD results indicate that the second phase is composed of M〈sub〉23〈/sub〉C〈sub〉6〈/sub〉, M〈sub〉6〈/sub〉C, M〈sub〉7〈/sub〉C〈sub〉3〈/sub〉 and intermetallic χ phase. EBSD results show layering distribution of carbides varied with C concentration. Phase diagram of 14Cr14Co13Mo4 steel is calculated by Thermo-Calc software to explain the phase transformation during the carburizing. Low-pressure carburizing process is simulated by DICTRA software to explain C diffusion in 14Cr14Co13Mo4 steel. The simulated C concentration profile agrees well with the experimental measured carbon values, which means that low-pressure carburizing parameters can be optimized by this modeling method.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Biswajyoti Mukherjee, Aminul Islam, Krishna Kant Pandey, O.S. Asiq Rahman, Rishow Kumar, Anup Kumar Keshri〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Yttria stabilized Zirconia thermal barrier coatings with around 200 μm overlay of Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 and CeO〈sub〉2〈/sub〉 were deposited on Inconel substrate using atmospheric plasma spray technique. Hot corrosion tests were carried out on the thermal barrier coating in molten salt mixtures (45 wt% Na〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉 + 55 wt% V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉) at 1150 °C for 30 h. Although the YSZ and Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/YSZ coatings were gradually degraded by the infiltration of the molten salt, the CeO〈sub〉2〈/sub〉/YSZ coatings remarkably restrained the infiltration of the molten salt into the YSZ coating. For the YSZ coating without any overlay, the YSZ reacted with V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 to form YVO〈sub〉4〈/sub〉 during exposure to the molten salt, leading to the formation of a large amount of monoclinic phase of ZrO〈sub〉2〈/sub〉 due to the leaching of Y〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 from YSZ. For the Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/YSZ coating, the Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 overlay reduced the rigorous infiltration of the molten salt, which caused in lesser amount of leaching of Y〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 from YSZ. However, for the CeO〈sub〉2〈/sub〉/YSZ coatings, CeO〈sub〉2〈/sub〉 not only physically prevented the molten salt infiltration, but also completely reacted with V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 to form CeVO〈sub〉4〈/sub〉 and completely restrained the infiltration of the molten salt into the YSZ coating. Additionally, the Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/YSZ and CeO〈sub〉2〈/sub〉/YSZ showed 17% and 52% increase in thermal shock resistance respectively compared to YSZ coating.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0257897218312581-ga1.jpg" width="380" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Haijuan Mei, Quanshun Luo, Xueli Huang, Ji Cheng Ding, Teng Fei Zhang, Qimin Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The variations of microstructure, mechanical properties, and oxidation behavior of Mo-V-Cu-N coatings are directly correlated to the chemical compositions, which significantly affects their tribological behavior. The aim of this work was to characterize Mo-V-Cu-N coatings with different chemical compositions deposited by high power impulse magnetron sputtering (HIPIMS) using single Mo-V-Cu segmental target, and to investigate the correlations between the lubricative oxides formed on coating surfaces with the variation of tribological behavior at different temperatures. The oxidation of Mo-V-Cu-N coatings started at 400 °C with the lubrication oxides of Mo-O and Cu-Mo-O were formed, which led to the decrease in coefficients of friction and wear rates of the coatings. It was found that the rapid outward diffusion of Mo and Cu atoms took place preferentially at around the growth defects (e.g. microparticles and pores). The incorporation of V atoms into Mo-Cu-N coatings enhanced the oxidation resistance at temperatures below 400 °C. At 500 °C, all the fcc B1-MoN and VN phases disappeared due to the severe oxidation, and the V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 phase was first appeared. Even though a relatively low coefficient of friction was obtained at 500 °C, the wear resistance of Mo-V-Cu-N coatings was decreased due to the severe oxidation and loss of mechanical strength.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Sheida Shiri, Akindele Odeshi, Ning Chen, Renfei Feng, Ronny Sutarto, Qiaoqin Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tantalum (Ta) exists in body-centered cubic (α phase), tetragonal (β phase), and face-centered cubic (fcc) crystal structures. The β phase is a metastable structure formed in thin films and is often mixed with the α phase. The fcc phase has only previously been reported as dispersed fine grains embedded in α or β phase. In this study, Ta thin films were deposited on silicon substrates by magnetron sputtering. A mixture of α and β phases was observed in the films when the deposition temperature was lower than 400 °C. The β phase content decreased gradually with the increase in deposition temperature, and completely disappeared at 400 °C. It is interesting that when the deposition temperature reached 500 °C, both α and β phases disappeared, and Ta films became a fcc structure. The structure and the stabilization of the fcc Ta thin films were further investigated using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy, and the results are presented in the present paper. This new finding would open new research and application directions for Ta materials.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): V. Dalbauer, S. Kolozsvári, J. Ramm, C.M. Koller, P.H. Mayrhofer〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The structural evolution of cathodic arc evaporated Al-Cr-O coatings with hugely different Al, Cr, and O contents was investigated by 〈em〉in-situ〈/em〉 XRD measurements upon annealing in oxygen up to 1200 °C. Different chemical compositions are achieved by arc evaporation of Al〈sub〉0.90〈/sub〉Cr〈sub〉0.10〈/sub〉, Al〈sub〉0.75〈/sub〉Cr〈sub〉0.25〈/sub〉, Al〈sub〉0.70〈/sub〉Cr〈sub〉0.30〈/sub〉, Al〈sub〉0.50〈/sub〉Cr〈sub〉0.50〈/sub〉, or Al〈sub〉0.25〈/sub〉Cr〈sub〉0.75〈/sub〉 cathodes and using either 20 standard cubic centimetres per minute (sccm) Ar, 50 sccm O〈sub〉2〈/sub〉, or 100 sccm O〈sub〉2〈/sub〉 per active source (p.a.s.). Generally, the crystallinity of the as-deposited coatings decreases with increasing O〈sub〉2〈/sub〉 flow rate during arc evaporation, while their Al/Cr ratio increases significantly (with respect to the cathode composition). The coatings prepared from Al-rich cathodes show first indications for the formation of corundum structured α-(Al,Cr)〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 phases at ~900 °C during annealing in O〈sub〉2〈/sub〉 atmosphere. Those, prepared from the Cr-rich cathode (Al〈sub〉0.25〈/sub〉Cr〈sub〉0.75〈/sub〉) with 20 sccm Ar or 50 sccm O〈sub〉2〈/sub〉 p.a.s., exhibit the formation of α-(Al,Cr)〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 phases already at 700–800 °C. Their corresponding coatings prepared with the highest oxygen flow rate of 100 sccm p.a.s., exhibit a considerable phase fraction of α-(Al,Cr)〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 already in the as-deposited state.〈/p〉 〈p〉Upon oxidation at 1200 °C, most coatings are basically composed of α-oxides, with a wide range of their Al/Cr-ratio. The coatings prepared with 100 sccm O〈sub〉2〈/sub〉 p.a.s., however, show the formation of α-(Al,Cr)〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 with a rather narrow Al/Cr-ratio, which is due to the sufficient mixing of Al, Cr, and O species already in the as-deposited state. Furthermore, selective oxidation (preference for Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉) leads in most cases to the formation of Cr, which is detectable up to 1200 °C.〈/p〉 〈p〉Between 950 and 1050 °C, the formation of θ-(Al,Cr)〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 could be detected for cathodes with Al ≥ 50 at.% prepared with 20 sccm Ar or 50 sccm O〈sub〉2〈/sub〉 p.a.s. Coatings prepared with Al〈sub〉0.75〈/sub〉Cr〈sub〉0.25〈/sub〉, Al〈sub〉0.70〈/sub〉Cr〈sub〉0.30〈/sub〉, and Al〈sub〉0.50〈/sub〉Cr〈sub〉0.50〈/sub〉 cathodes and 100 sccm O〈sub〉2〈/sub〉 p.a.s. show the formation of θ-(Al,Cr)〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 already in the as-deposited state. α-(Al,Cr)〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 could only be detected for as-deposited coatings when preparing them with Al〈sub〉0.25〈/sub〉Cr〈sub〉0.75〈/sub〉 and 100 sccm O〈sub〉2〈/sub〉 p.a.s.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Hui Sun, Sheng-Chi Chen, Chung-Hsien Wang, Yu-Wei Lin, Chao-Kuang Wen, Tung-Han Chuang, Xin Wang, Song-Sheng Lin, Ming-Jiang Dai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, (Al, Co)-ZnO films were co-sputtered on glass substrate through radio frequency sputtering at 100 °C. The film's structure, electrical and magnetic properties as a function of Al doping content is investigated. The results indicate that (Al, Co)-ZnO films crystallinity can be suppressed by Co doping or (Co, Al) co-doping. With the substitution of Zn〈sup〉2+〈/sup〉 by Al〈sup〉3+〈/sup〉, the film's conductivity improves. All the films present ferromagnetic behavior at room temperature. Upon increasing the Al doping amount, the film's saturation magnetization expresses a carrier-concentration dependent behavior. Three different regions can be defined, where BMP model and carrier-mediated exchange mechanisms play a role in the various regions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Naixiu Hu, Yijia Wang, Jiaxin Li, Qiuping Wei, Yunlu Jiang, Li Ma, Zhiming Yu, Kechao Zhou, Hangyu Long〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To enhance the field emission performance and understand the emission essence of carbon materials, carbon films with different morphology and phase composition were fabricated by regulating the reactive gas flow ratio in a hot filament chemical vapor deposition system with the assistance of electric field and magnetic field. The characterization of carbon film quality and measurement of their field emission performance indicated that carbon nanostructures, including nanoclusters, nanopillars and nanotips, which were determined by the methane concentration in the process, were formed under the assistance of electric field. Further magnetic field assistance could lead to the formation of finer nanostructures with higher crystallinity. Field emission performance was highly dependent on the morphology and phase composition of the carbon films. Among all the samples, carbon nanotips, deposited in high methane concentration with the co-assistance of magnetic and electric field, possessed the best field emission performance, with the lowest turn-on field of 6.5 V·μm〈sup〉−1〈/sup〉 (J = 10 μA·cm〈sup〉−2〈/sup〉). Besides, a comparative study on the fitting degree of several conduction mechanisms revealed that the essence of field emission was the combination of several emission mechanisms, which was also dependent on the morphology and phase composition of these carbon films.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0257897218313604-ga1.jpg" width="487" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Julien Keraudy, Rommel Paulo B. Viloan, Michael A. Raadu, Nils Brenning, Daniel Lundin, Ulf Helmersson〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effects of a positive pulse following a high-power impulse magnetron sputtering (HiPIMS) pulse are studied using energy-resolved mass spectrometry. This includes exploring the influence of a 200 μs long positive voltage pulse (〈em〉U〈/em〉〈sub〉rev〈/sub〉 = 10–150 V) following a typical HiPIMS pulse on the ion-energy distribution function (IEDF) of the various ions. We find that a portion of the Ti〈sup〉+〈/sup〉 flux is affected and gains an energy which corresponds to the acceleration over the full potential 〈em〉U〈/em〉〈sub〉rev〈/sub〉. The Ar〈sup〉+〈/sup〉 IEDF on the other hand illustrates that a large fraction of the accelerated Ar〈sup〉+〈/sup〉, gain energies corresponding to only a portion of 〈em〉U〈/em〉〈sub〉rev〈/sub〉. The Ti〈sup〉+〈/sup〉 IEDFs are consistent with the assumption that practically all the Ti〈sup〉+〈/sup〉, that are accelerated during the reverse pulse, originates from a region adjacent to the target, in which the potential is uniformly increased with the applied potential 〈em〉U〈/em〉〈sub〉rev〈/sub〉, while much of the Ar〈sup〉+〈/sup〉 originates from a region further away from the target over which the potential drops from 〈em〉U〈/em〉〈sub〉rev〈/sub〉 to a lower potential consistent with the plasma potential achieved without the application of 〈em〉U〈/em〉〈sub〉rev〈/sub〉. The deposition rate is only slightly affected and decreases with 〈em〉U〈/em〉〈sub〉rev〈/sub〉, reaching ~90% at 〈em〉U〈/em〉〈sub〉rev〈/sub〉 = 150 V. Both the Ti〈sup〉+〈/sup〉 IEDF and the small deposition rate change indicate that the potential increase in the region close to the target is uniform and essentially free of electric fields, with the consequence that the motion of ions inside the region is not much influenced by the application of 〈em〉U〈/em〉〈sub〉rev〈/sub〉. In this situation, Ti〈sup〉+〈/sup〉 will flow towards the outer boundary of the target-adjacent region, with the momentum gained during the HiPIMS discharge pulse, independently of whether the positive pulse is applied or not. The metal ions that cross the boundary in the direction towards the substrate, and do this during the positive pulse, all gain an energy corresponding to the full positive applied potential 〈em〉U〈/em〉〈sub〉rev〈/sub〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Wen Xi, Wenqiang Ding, Shengwang Yu, Naiming Lin, Tianxu Meng, Qi Guo, Xiaozhen Liu, Xiaoping Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to obtain the combination of improved abrasion and corrosion resistances, TaC/Ta composite coatings were made on C17200 beryllium copper alloy by two steps, surface Ta-alloying at 800 °C for 2 h followed by carburizing at 670 °C for 0.5 h. The corrosion property of TaC/Ta coatings in H〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉 solution (10%) was investigated by polarization curves and electrochemical impedance spectroscopy. The microstructure of the composite coatings and corroded surface were analyzed by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope equipped with energy dispersive spectrometer, respectively. The results showed that the composite coating, 8.79 μm in thickness, was composed of the TaC top layer and Ta-Cu intermediate layer. The untreated bare C17200 alloy substrate revealed a poor corrosion resistance. After Ta-alloying and carburizing, the corrosion resistance of C17200 alloy increased due to a higher self-corrosion potential and lower self-corrosion current of TaC/Ta coatings. In addition, TaC/Ta coatings had wider frequency scope, larger radius of capacitive semi-circles, phase angle and |Z| value compared with bare alloy. The protection efficiency of TaC/Ta coatings calculated from electrochemical impedence and potentiodynamic polarization was over 90%. The dense corroded surface and Ta oxide formed in the corroded surface caused an improved anti-corrosion property of TaC/Ta coatings.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0257897218313963-ga1.jpg" width="389" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Gui-hong Song, Qian-Nan Liu, Hao Du, Fang Hu, Chao Wang, Chun-lin He〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Mg〈sub〉2〈/sub〉(Si,Sn) solid solutions films have been deposited on single crystalline Si(111) substrates under temperatures from 130 to 400 °C by magnetron sputtering using a Mg-Si-Sn alloy target. The phase components, microstructures and the thermoelectric properties of these films were investigated. It is indicated that the films deposited under lower temperature (≤300 °C) possess a cubic anti-fluorite structure phase and their structures transform into orthorhombic and hexagonal with the increasing temperature to 400 °C. Meanwhile, the tetragonal structure metal Sn phase occurs on samples deposited under temperatures of 350 °C and 400 °C. Furthermore, the film deposited under 350 °C is composed of cubic anti-fluorite structure and orthorhombic structure phase, and possesses the highest absolute value of Seebeck coefficient and the highest electrical resistivity. On the other hand, the film deposited under 130 °C which is composed of only cubic anti-fluorite structure possesses the highest power factor at all measured temperature due to higher absolute value of Seebeck coefficient and lower electrical resistivity. It is suggested that the Mg〈sub〉2〈/sub〉(Si,Sn) solid solutions film with cubic phase structure has higher power factor than that with orthorhombic and hexagonal phase structure.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 23 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology〈/p〉 〈p〉Author(s): Kui Wen, Xuezhang Liu, Kesong Zhou, Min Liu, Huichao Zhu, Jian Huang, Zhongcheng Zhang, Renzhong Huang, Jie Mao, Xingchen Yan, Hanlin Liao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The coating quality and reproducibility of plasma spraying are significantly affected by the characteristic of plasma jet that is closely related to the arc root attachment. In this study, a 3D time-dependent numerical model based on the Local Thermodynamic Equilibrium (LTE) assumption was developed to investigate the arc dynamics and its effect on the distributions of temperature and flow field both inside and outside of the torch. The results show that there is the coexistence of multiple arc roots, and the particular attachment location of plasma arc leads to a significant asymmetry in distributions of temperature, velocity as well as electric potential and field strength. The continuous movement of the plasma arc not only caused the fluctuations of the arc voltage drop, but also resulted in the temporal variations of the plasma temperature and velocity. Moreover, the predicted temperature and velocity distributions of plasma jet were in good agreement with experimental measurements.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Fa Chang, Bingjie Cai, Chong Zhang, Biao Huang, Shuai Li, Pinqiang Dai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The FeCr〈sub〉x〈/sub〉CoNiB (x values in molar ration, x = 0.5–3) high-entropy alloys coatings were prepared by laser cladding on an AISI 1045 steel substrate. Annealing and high temperature oxidation experiments were performed on the FeCr〈sub〉x〈/sub〉CoNiB (x = 0.5–3) coatings at 900 °C. The phase structure, morphology, and composition of the coatings and oxidation layers were analyzed by XRD, TEM, SEM, and EDS. Results demonstrated that the FeCr〈sub〉x〈/sub〉CoNiB coatings are composed of simple face-centred cubic (FCC) phase and boride. The hardness value of the coatings is significantly improved due to the boride, which is achieved 860 HV at x = 0.5. Cr is conducive to inhibiting the coarsening of boride and enhancing the resistance of coatings to high-temperature softening. The oxidation kinetics curve of FeCr〈sub〉x〈/sub〉CoNiB coatings basically follows oxidation dynamic the parabolic law. The selective oxidation in the FeCr〈sub〉x〈/sub〉CoNiB coatings changed from the oxidation of Fe to the oxidation of Cr as an increase in Cr content, and finally formed continuous Cr〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 film. The high temperature oxidation resistance of the FeCr〈sub〉x〈/sub〉CoNiB coatings dropped with adding boron into the coatings, which improved contributing to Cr increasing. FeCr〈sub〉x〈/sub〉CoNiB coatings gain a better high temperature oxidation resistance as x ≥ 2 (33.3 at.%).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Guo Peitao, Tang Mingyang, Zhang Chaoyang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ceramic coatings have been successfully fabricated on the surface of Magnesium alloys (AZ31D) by plasma electrolytic oxidation (PEO) in an alkaline silicate electrolyte with and without the addition of graphite. The influence of graphite on the surface morphology, microstructure, phase composition, chemical composition, corrosion resistance, and tribological behavior of ceramic coatings was scrutinized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), potentiodynamic polarization, MFT-4000 multifunctional material surface performance instrument. The ceramic coating with the addition of graphene exhibits better corrosion resistance and tribological performance.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Ioana-Laura Velicu, Gabriela-Theodora Ianoş, Corneliu Porosnicu, Ilarion Mihăilă, Ion Burducea, Alin Velea, Daniel Cristea, Daniel Munteanu, Vasile Tiron〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bipolar Pulse High Power Impulse Magnetron Sputtering (BP-HiPIMS) was investigated and used in this work to control the ion bombardment process of growing thin films and to improve their structure and properties. Energy-resolving mass spectroscopy was used to investigate the effect of reverse target voltage on the ion energies and fluxes during BP-HiPIMS of a high-purity copper target, in argon gas. It was found that the reverse target voltage provides a wide range of ion energies and fluxes incident to the growing film, which, in turn, produce a wide variety of effects during the deposition process, improving the adhesion strength and influencing both surface and bulk properties. Fast ICCD imaging was used to investigate both HiPIMS and BP-HiPIMS plasma dynamics. The temporal and spatial distributions of plasma potential measurements were performed in order to explain the mechanisms for accelerating the ions. The topological, structural and mechanical properties of the deposited coatings were investigated using atomic force microscopy (AFM), X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), thermal desorption spectroscopy (TDS), scanning electron microscopy (SEM), nanoindentation and scratch tests. The obtained results indicate an energy-enhanced deposition process during BP-HiPIMS, the deposited films being characterized by smooth surfaces, dense microstructure, small inert gas inclusions, high elastic strain to failure, scratch resistance and good adhesion to the substrate. These improvements in the films' structure and properties may be attributed to the intense and energetic ion bombardment taking place during the deposition process. During BP-HiPIMS operation, there is no net increase in the deposition rate as compared to the monopolar regime due to the re-sputtering process.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Jun Hu, Shijun He, Zhen Wang, Jianbo Zhu, Liping Wei, Zhong Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 composite films with micro-nanostructure are prepared on the N80 steel surface by a two-step hydrothermal method, followed by heat treatment. The prepared dual-scale film, after the modification with stearic acid, shows superhydrophobic property with a water contact angle of 159.6° and sliding angle of 2.2°. The greatly decreased corrosion current density and the largely increased impedance indicate the superhydrophobic surface can protect steel sample well from corrosion. Furthermore, the superhydrophobic Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 composite film also showed excellent self-cleaning ability and was able to maintain its anti-wettability when immersed in water. Our work finds that the concentration of NaOH in the second hydrothermal method is a critical factor for the morphology of the Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 film and the annealing treatment plays a significant role in realizing the superhydrophobic stearic acid coated micro-nanostructure Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 composite.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): E.J.D.M. Pillaca, M.A. Ramírez, J.M. Gutierrez Bernal, D.C. Lugo, V.J. Trava-Airoldi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, the pulsed-DC PECVD deposition system was used to produce Diamond-like carbon (DLC) film on the internal surface of a long metal tube (200 cm in length and 10 cm in diameter) employed as the deposition chamber itself. Firstly, the features of plasma discharges and the temperature distribution along the tube external surface were studied using argon, silane, and acetylene. The experimental results demonstrate that a stable discharge can be established inside the tube. It was found that when the precursor gas is employed, a temperature gradient on the tube surface is formed. Secondly, PECVD experiments regarding DLC film deposition inside the inner surface of the tube are described. For this purpose, polished stainless steel and silicon wafer samples were mounted on the inside tube surface for subsequent analysis of the coatings. It was found that the growth rate and the structure properties of the DLC film varied along the axial direction of the tube. However, surfaces of DLC film with high sp〈sup〉3〈/sup〉 content provided better tribological characteristics. These results were mainly attributed to complex processes of local dissociation and activation happened by collision between the electrons and neutrals.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Jiwang Zhang, Xing Li, Bing Yang, Huaqiang Wang, Jinxin Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, the precipitate strengthened Cu-Ni-Si alloy was micro-shot peened by ceramic balls with a diameter of 40 μm. The fatigue tests using the peened specimens were conducted in air and in salt atmosphere respectively. The results show that a fine and hardening layer is formed on the surface of peened specimen and the compressive residual stress is introduced. There is no fatigue limit for specimens in both test conditions. The S-N curve of specimens in salt atmosphere shows a continuous decrease with the increasing number of loading cycles, while that in air shows a step-wise shape. Compared with the un-peened specimens, the fatigue strengths of specimens at 10〈sup〉7〈/sup〉 cycles are increased by 47% and 67% in air and in salt atmosphere respectively. The peened specimens in air condition failed from subsurface zone in high cycle fatigue region, while all the other specimens failed from surface. The micro-shot peening can improve the surface property and delay the crack initiation and propagation, so as to enhance the fatigue strength greatly.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Neha Verma, Giridharan Krishnamurthy, Frans D. Tichelaar, Amarante J. Böttger〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, the effect of the deposition parameters of a magnetron sputtered Ti adhesive intermediate layer on the morphology and hydrogen absorption properties of thin Pd films of about 100 nm was investigated. The insertion of an adhesive layer between a Pd film and a rigid substrate usually suppresses or reduces hydrogen absorption. In this study, it is shown that by tuning the surface topography of the intermediate layer the morphology, crystallographic texture and hydrogen absorption properties of the Pd film can be controlled. The surface topography of the Ti layer was characterized using atomic force microscopy. The surface topography strongly depends on the Ti deposition conditions and can vary from widely spread large islands to densely packed small-grained islands depending on thickness (between 1 and 6 nm) and sputter pressure (0.4 and 3 Pa). TEM and XRD analysis led to the conclusion that rough Ti intermediate layers result in Pd films with an open columnar structure with small voids, and a weak and broad (111) texture. Smooth Ti intermediate layers promote the formation of Pd films with a dense columnar structure with fewer voids, and a strong and sharp (111) texture. Changes in the Pd adatom surface diffusion and shadowing effects are the main cause of the observed differences. Pd films with an open columnar morphology and weaker texture show better hydrogen absorption properties with respect to absorption capacity and kinetics of the films with dense columnar morphology. By tuning the surface topography of the Ti adhesive layer, Pd films with controlled morphology and texture can be prepared such that no delamination from the substrate occurs without compromising on absorption properties.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): N. Abu-warda, A.J. López, M.D. López, M.V. Utrilla〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High velocity oxy-fuel (HVOF) technique was used to deposit an Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-30(Ni20Al) coating on AISI 304 stainless steel substrate to improve its corrosion and wear performance at high temperature. First, thermal cycling tests at 750 and 850 °C were conducted in air atmosphere on both coated and uncoated stainless steel substrates to study the effectiveness of coating protection system at different exposure times (2, 6, 10 and 15 days). Then, high temperature corrosion and wear mechanisms were studied by SEM and XRD techniques. These analyses revealed that uncoated specimens were severely corroded but no oxidation on the coated substrates was detected. Oxide growth on the uncoated substrate was mainly formed by spinel (MnCr〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 and FeCr〈sub〉2〈/sub〉O〈sub〉4〈/sub〉) and corundum (Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 and Cr〈sub〉2〈/sub〉O〈sub〉3〈/sub〉) type oxides. Meanwhile, these oxides were not found on the coated substrate. Wear rate of the coated specimen was found to be reduced from 6.9·10〈sup〉−4〈/sup〉 to 8.3·10〈sup〉−5〈/sup〉 mm〈sup〉3〈/sup〉/N·m compared to that of the uncoated specimen. The exposure to high temperatures improved coating wear resistance: wear rate was four times lower in the coated sample exposed to high temperatures compared to that of the non-exposed coated sample due to the formation of a harder phase of NiO.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0257897218313598-ga1.jpg" width="324" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 25 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 358〈/p〉 〈p〉Author(s): Muhammad Atiq Ur Rehman, Muhammad Azeem Munawar, Dirk W. Schubert, Aldo R. Boccaccini〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electrophoretic deposition (EPD) of composite coatings based on chitosan, gelatin and copper doped bioactive glass (Cu-BG) particles on 316L stainless substrates (SS) was investigated. Despite the fact that EPD offers easy control over the thickness and morphology of the produced coatings, the optimization of the EPD process is a tedious task due to the fact that a high number of variables (applied voltage, deposition time, distance between the electrodes, concentration of the suspension and pH of the suspension) is involved. Therefore, we used the Taguchi Design of Experiments (DoE) approach for accurate and economical process (reduced number of experiments) optimization. The suspension composition (chitosan, gelatin and Cu-BG ratio) and electric field related parameters (voltage and time) were optimized by L〈sub〉25〈/sub〉 type Taguchi array. The best coatings were obtained at the applied voltage of 30 V, deposition time of 5 min and the concentration ratio between chitosan/gelatin was 50:50 (vol%). Scanning electron microscopy (SEM) images revealed that Cu-BG particles were fairly homogenously dispersed in the chitosan/gelatin matrix. Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy confirmed the presence of chitosan, gelatin and Cu-BG particles (qualitatively). The tape test (ASTM D3359-97 and B571-97) elucidated the appropriate adhesion strength of coatings (obtained by EPD using optimized parameters) for orthopedic applications. Moreover, chitosan/gelatin/Cu-BG coatings exhibited suitable hydrophilicity.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0257897218313252-ga1.jpg" width="403" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Huanli Liu, Xinggang Hou, Tingting Sun, Jianghong Yao, Ping Wu, Dejun Li, Jing Li, Jing Han〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The N〈sup〉+〈/sup〉 ions doped TiO〈sub〉2〈/sub〉 nanotubes (TNTs) were prepared by the methods of ion implantation and anodization. Phase and chemical composition, surface morphology and water contact angle of the samples were examined. The corrosion behavior of the samples in simulated body fluids was estimated by electrochemical impedance spectroscopy and polarization resistance measurements. L-929 fibroblast cells were used to identify the cytotoxic response of N〈sup〉+〈/sup〉 ions implanted TNTs. The density of the viable cells was determined by MTT assay. The antibacterial activities of N〈sup〉+〈/sup〉 ions implanted TNTs were studied by sterilization of 〈em〉E〈/em〉. 〈em〉coli〈/em〉 in the dark. Compared to TNTs, N〈sup〉+〈/sup〉 ions implanted TNTs exhibited more regular surface, and the corrosion resistance of N〈sup〉+〈/sup〉 ions implanted TNTs was improved. The N〈sup〉+〈/sup〉 ions implanted TNTs possessed better hydrophilicity. The water contact angle of implanted samples was decreased with the increase of implanted dose. In vitro cell culture experiments, it identified that the N〈sup〉+〈/sup〉 ions implanted TNTs were more favorable for cell attachment and proliferation. All the implanted samples showed antibacterial activity in the dark. The amounts of 〈em〉E〈/em〉. 〈em〉coli〈/em〉 on the implanted sample with 5 × 10〈sup〉17〈/sup〉 ions/cm〈sup〉2〈/sup〉 reduced by about 63.1% after 24 h compared to control sample.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Y.S. Wu, P.T. Lee, W.Z. Hsieh, T.T. Kuo, C.E. Ho〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recently, a Au/Pd(P)/Ni(P) surface finish with an ultrathin Ni(P) thickness (〈1 μm) has received a great deal of attention from microelectronic industry because of the requirements of the fine-pitch packaging and the signal performance for high-frequency applications. The effect of Ni(P) and Pd(P) thickness on the solderability had been previously investigated in the literature; however, information regarding the P content effect of the Pd(P) film on this reliability issue is still seriously lacking to date. The focus of this study was to examine the interfacial reaction and mechanical reliability between a Sn-3Ag-0.5Cu alloy and an ultrathin-Ni(P)-type Au/Pd(〈em〉x〈/em〉P)/Ni(P)/Cu metallization pad, where the thicknesses of Au/Pd(〈em〉x〈/em〉P)/Ni(P) were 0.08 μm/0.13 μm/0.13 μm and 〈em〉x〈/em〉 were 0 wt%, 1–2 wt%, and 4–6 wt%. We found that the growth morphologies of intermetallic compounds (IMCs) at the Sn-3Ag-0.5Cu/Au/Pd(〈em〉x〈/em〉P)/Ni(P)/Cu joints strongly depended on 〈em〉x〈/em〉 and reflow number. The shear resistance of the solder joints could be greatly enhanced by reducing 〈em〉x〈/em〉, especially for one reflow; however, this difference was nearly alleviated after multiple reflows. This investigation provided valuable information about the role of P in the Sn-3Ag-0.5Cu/Au/Pd(P)/Ni(P)/Cu reaction system and the strategy to enhance the solderability of the Au/Pd(P)/Ni(P) surface finish.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Benjamin Grégoire, Gilles Bonnet, Fernando Pedraza〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The mechanisms of formation of nickel aluminide coatings from alternate deposition of Al and Cr microparticles and subsequent heat treatment in Ar were studied on pure nickel. For this purpose, tailored amounts of Al and Cr water-based slurries were successively deposited on pure nickel following two different architectures (Al/Cr and Cr/Al double-layer systems). Regardless of the coating architecture, the addition of Cr microparticles was found to decrease the thermodynamic activity of Al upon aluminizing through the formation of Al〈sub〉x〈/sub〉Cr〈sub〉y〈/sub〉 phases. This considerably limited the inward diffusion of Al towards the substrate at low temperature (e.g. 650 °C). Whereas the formation of δ-Ni〈sub〉2〈/sub〉Al〈sub〉3〈/sub〉 was still observed with the Al/Cr double-layer system, its formation was completely suppressed with the Cr/Al one. By adjusting the composition of the deposited layers, i.e. the thickness of both Cr and Al layers, it was possible to directly form the β-NiAl phase with a further annealing at high temperature (e.g. 1000 °C for 3 h). This fostered the outward diffusion of nickel and the dissolution of synthesized Al〈sub〉x〈/sub〉Cr〈sub〉y〈/sub〉 phases. Undissolved Cr-rich phases were also observed in the diffusion layers, which confirmed the outward growth of the coating typical of low-activity aluminizing.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): A.V. Bondarev, S. Vorotilo, I.V. Shchetinin, E.A. Levashov, D.V. Shtansky〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Powders based on tantalum disilicide and silicon carbide were fabricated by mechanical activation-assisted SHS of reaction mixtures, with SiC concentration varied from 10 to 70%. The single- and double-layer composite targets were produced by hot pressing and further utilized for deposition of Si-Ta-C-(N) coatings by magnetron sputtering. The optimal hot pressing regimes, which allowed the production of dense ceramics with a hierarchical structure at 10 and 30% SiC, were determined. These ceramics were characterized by a relative density of 96–97%, hardness of ~19 GPa, and fracture toughness of 6.5–6.7 MPa × m〈sup〉1/2〈/sup〉. The nanocomposite Si-Ta-C-N coatings consisted of 〈em〉fcc〈/em〉 Ta(Si,C,N) solid solution (TaSi〈sub〉2〈/sub〉–30%SiC target) and Ta〈sub〉5〈/sub〉Si〈sub〉3〈/sub〉 compound (TaSi〈sub〉2〈/sub〉–10%SiC target) embedded in an amorphous matrix. Depending on the elemental composition, hardness and Young's modulus of the coatings were 16–26 GPa and 155–268 GPa, respectively. The coatings are characterized by high thermal stability and oxidation resistance at temperatures up to 800 °C. Tribological tests demonstrated the decrease of the coefficient of friction (CoF) of the coatings with increasing temperature: from 0.38 (25 °C) to 0.28 (600 °C) and 0.23 (800 °C). The low wear rate and CoF of the Si-Ta-C-N coatings at elevated temperatures are explained by the formation of a thin (~100 nm) oxide layer and TaSi〈sub〉x〈/sub〉O〈sub〉y〈/sub〉 microfibers on the coating surfaces.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Fan Ye, Jun-Jie Zeng, Yi-Bin Qiu, Xing-Min Cai, Bo Wang, Huan Wang, Dong-Ping Zhang, Ping Fan, Yi-Zhu Xie, Xiu-Fang Ma, Fan Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Nitrogen atoms exist as nitrogen molecules in cuprous oxide doped with nitrogen and the thermal stability of nitrogen doping has not been studied. Here phase-pure cuprous oxide doped with nitrogen was prepared with a direct current magnetron sputtering system. The samples were then annealed at 400 °C in Ar or Ar plus N〈sub〉2〈/sub〉 for 30, 60 and 90 min and the influence of annealing is studied. The results show that annealing results in the presence of metallic copper and the release of the tensile strain in the nitrogen-doped films. In nitrogen-doped cuprous oxide without annealing, nitrogen is found to exist as atomic nitrogen (β-N) and strongly chemisorbed π-bonded nitrogen molecules (α-N〈sub〉2〈/sub〉). After annealing, atomic nitrogen (β-N) is absent and the strongly chemisorbed π-bonded nitrogen molecules (α-N〈sub〉2〈/sub〉) partially turn into weakly chemisorbed nitrogen molecules (γ-N〈sub〉2〈/sub〉). Annealing can improve the transmittance of about 550–750 nm and widen the forbidden gap. Annealing can change the hole density by changing the density of donor defects, and the density and types of nitrogen molecules doped into cuprous oxide.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Chao Zhang, Biqi Yang, Jian Wang, Huifen Wang, Gang Liu, Baosen Zhang, Longjie Liu, Kai Feng, Zhuguo Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ti-MoS〈sub〉2〈/sub〉 film and LaF〈sub〉3〈/sub〉 doped Ti-MoS〈sub〉2〈/sub〉 composite films are deposited using UDP 650 closed-field unbalanced magnetron sputtering. The microstructural and friction behavior of these films are investigated at various LaF〈sub〉3〈/sub〉 contents. SEM results revealed that the compact microstructure is presented in LaF〈sub〉3〈/sub〉 doped Ti-MoS〈sub〉2〈/sub〉 films 〈em〉via〈/em〉 increment of LaF〈sub〉3〈/sub〉 contents. The LaF〈sub〉3〈/sub〉 doped composite films exhibit excellent adhesion to the substrate and hardness of the films are enhanced at higher LaF〈sub〉3〈/sub〉 content. The wear test results show that suitable LaF〈sub〉3〈/sub〉 doped Ti-MoS〈sub〉2〈/sub〉 composite film can improve the wear endurance life as twice as that of Ti-MoS〈sub〉2〈/sub〉 film. A deterioration of tribological properties is observed with incorporation of higher LaF〈sub〉3〈/sub〉 contents. The denser columnar microstructure is attributed to excellent wear resistant of LaF〈sub〉3〈/sub〉 doped composite films. The wear mechanism is further elucidated as two kinds of typical model for different content of LaF〈sub〉3〈/sub〉 dopant.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Caiping Wang, Xiang Yu, Yuejuan Zhang, Shengting Cai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study investigated the mechanism of the tip effect in an external field: that is the influence of an electric field on the tip shape, and a temperature field on the film uniformity, of a micro-needle during diamond coating. A bias field during magnetron sputtering was used to investigate the electric effect on the tip and hot-filament chemical vapor deposition (HFCVD) was used to investigate the thermal effect on the tip. The results showed that, (1) in the bias field during magnetron sputtering, the tip shape was affected by the accumulation of electric charge exerting an electric force on the tip; (2) in the temperature field of HFCVD, the film uniformity on the tip degenerated as a result of the high diffusion and evaporation of activated free radicals arising from the thermal effect; this hindered the nucleation and growth of the diamond film; (3) under the action of the external field, the internal free electrons of the micro-needle moved to preferentially occupy the tip, which has a large curvature, leading to a tip effect.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Yujing Ran, Huiping Lu, Shujun Zhao, Liuwei Jia, Yinglan Li, Zhaotan Jiang, Zhi Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Transition metal nitrides have become a kind of promising alternative plasmonic materials. Ti〈sub〉〈em〉x〈/em〉〈/sub〉Zr〈sub〉1−〈em〉x〈/em〉〈/sub〉N〈sub〉〈em〉y〈/em〉〈/sub〉 ternary nitride films were prepared by magnetron co-sputtering method, and the effects of bias voltage and temperature on the structure and dielectric properties of the films were investigated. The experimental results show that all the films are fcc-structured, and high substrate bias and temperature can significantly improve the N and Ti content. Increasing substrate bias voltage or temperature can reduce the crossover frequency 〈em〉ω〈/em〉〈sub〉〈em〉c〈/em〉〈/sub〉 at which the films transit from dielectric to metallic phase. Also, a high bias can greatly influence the energy loss of the films. Furthermore, the plasmonic quality factor can be effectively tailored by bias and temperature. Increasing bias can decrease the quality factor while high temperature (600 °C) can enhance the quality factor significantly. The study demonstrates that the Ti〈sub〉〈em〉x〈/em〉〈/sub〉Zr〈sub〉1−〈em〉x〈/em〉〈/sub〉N〈sub〉〈em〉y〈/em〉〈/sub〉 films, as one kind of alternative plamonic materials, have considerable performances, and their dielectric and plasmonic properties can be modulated by varying the bias voltage and temperature in a wide range.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Kai Tao, Haiping Yi, Lihua Tang, Jin Wu, Peihong Wang, Nan Wang, Liangxing Hu, Yongqing Fu, Jianmin Miao, Honglong Chang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Zinc oxide (ZnO) is an environmental-friendly semiconducting, piezoelectric and non-ferroelectric material, and plays an essential role for applications in microelectromechanical systems (MEMS). In this work, a fully integrated two-degree-of-freedom (2DOF) MEMS piezoelectric vibration energy harvester (p-VEH) was designed and fabricated using ZnO thin films for converting kinetic energy into electrical energy. The 2DOF energy harvesting system comprises two subsystems: the primary one for energy conversion and the auxiliary one for frequency adjustment. Piezoelectric ZnO thin film was deposited using a radio-frequency magnetron sputtering method onto the primary subsystem for energy conversion from mechanical vibration to electricity. Dynamic performance of the 2DOF resonant system was analyzed and optimized using a lumped parameter model. Two closely located but separated peaks were achieved by precisely adjusting mass ratio and frequency ratio of the resonant systems. The 2DOF MEMS p-VEH chip was fabricated through a combination of laminated surface micromachining process, double-side alignment and bulk micromachining process. When the fabricated prototype was subjected to an excitation acceleration of 0.5 g, two close resonant peaks at 403.8 and 489.9 Hz with comparable voltages of 10 and 15 mV were obtained, respectively.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Ke Wang, Shuo Dong, Zhan Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rare-earth transition metal ultra-thin TbFeCo amorphous films in the thickness range from 3.5 to 35 nm are radio frequency (RF)-sputtered based on a composition target method. Perpendicular magnetic anisotropy (PMA) is found to be strongly related to the thickness of sputtered TbFeCo film in this thickness range. No PMA can be observed in the 3.5 nm film, which may be too short to form local intrinsic single ion anisotropy. Strong PMA develops with the increasing film thickness. A critical compensation thickness of ~14 nm is found, where both the largest coercivity and lowest saturation magnetization are demonstrated. Across this critical thickness the change in polarity of the EHE loops is observed, corresponding to a transition from a FeCo-dominant to a Tb-dominant configuration. Additionally, the magnetic properties of the alloy films are shown to be significantly affected by the substrates used for deposition, which can be mainly attributed to preferential oxidization of the rare-earth Tb element in the films at the interfaces between the film and the substrates. Our results provide a simple method to manipulate magnetic properties of ultra-thin TbFeCo alloy films for the applications in spintronic devices.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Chunyan Zhang, Bin Liu, Baoxing Yu, Xiaopeng Lu, Yong Wei, Tao Zhang, J.M.C. Mol, Fuhui Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Surface pretreatment is generally applied before application of protective coatings on Mg alloys, which influences surface microstructure and electrochemical activity of the substrate and has an effect on the coating properties. The effect of various pretreatment processes (sand-blasting, grinding and polishing) on the microstructure and corrosion protection performance of phosphate conversion coating (PCC) on AZ91D Mg alloy was investigated in the present study. Sand-blasting cleaning significantly increases the surface roughness and electrochemical activity of the substrate, leading to formation of a porous PCC with inferior corrosion protection performance. In the case of ground/polished Mg alloy, the uniformity and corrosion resistance of the resultant conversion coating are mainly related to the surface roughness. Relatively low surface roughness of the substrate facilitates formation of a corrosion protective PCC.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Lianchang Qiu, Yong Du, Shaoqing Wang, Liye Du, Zhuo Chen, Jiong Wang, Zhiqiang Zhong, Haidong Shi, Layyous Albir〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, the impact of temperature, pressure and gas flow on the chemical compositions, phases and deposition rates of MTCVD (Moderate Temperature Chemical Vapor Deposition) Ti(C,N) coatings is investigated by integrating thermodynamic calculations and computational fluid dynamics (CFD) simulations with key experiments. The thermodynamic calculations predict that both the C and the N contents of the films increase with increasing temperature under constant mixed gases and pressure, with the former increasing faster than the latter. CFD simulations indicate that the coating deposition rate decreases with increasing distance to the source gas for the hard metal samples loaded on the same tray. Subsequently, MTCVD-Ti(C,N) coatings were deposited at three different temperatures to verify the predicted chemical compositions and deposition rates. The experimental investigations are in reasonable agreement with the theoretical predictions. The present work applies a well-established strategy to meet the requirements of a controlled and robust process for MTCVD-Ti(C,N) coating with industrial applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Shuting Sun, Hanguang Fu, Xuelong Ping, Xingye Guo, Jian Lin, Yongping Lei, Wenbo Wu, Jianxin Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉As a surface repair and strengthening technology, (Ti, Nb)C/Ni coatings with different amount of CeO〈sub〉2〈/sub〉 were fabricated to repair the automobile dies. The phase constitution, microstructure, texture characteristics of oriented growth, micro-hardness, tensile properties and the action mechanism of CeO〈sub〉2〈/sub〉 were investigated. The results showed that the diffraction peaks of γ-Ni(Fe), (Ti, Nb)C, Cr〈sub〉7〈/sub〉C〈sub〉3〈/sub〉 and Cr〈sub〉23〈/sub〉C〈sub〉6〈/sub〉 drifted slightly as a result of solute atoms incorporation. The compact and homogenized microstructure of coatings was dominated by small striped precipitated phases and particles according to SEM and TEM results. The size of (Ti, Nb)C particles were suppressed by rare earth element Ce, which was prone to accumulate at the interface of grain boundary or crystalline phases. The unmelted CeO〈sub〉2〈/sub〉 can also become the heterogeneous nucleation basement of (Ti, Nb)C, Cr〈sub〉23〈/sub〉C〈sub〉6〈/sub〉 and Cr〈sub〉7〈/sub〉C〈sub〉3〈/sub〉 particles. EBSD results showed that the grain growth orientation of coatings was changed by the effect of CeO〈sub〉2〈/sub〉 on the fluidity of molten pool, as well as the growth of particles. In addition, the tensile properties of coatings were improved, and the fracture behavior was transformed from the quasi-cleavage fracture to brittle fracture with the increase of CeO〈sub〉2〈/sub〉 addition.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Jie Li, Minshuai Yin, Chunli Guo, Huaiping Zhang, Taotao Li, Huaiyan Wang, Yinghui Wei, Lifeng Hou, Chuankun Jia〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A belt-like MnO〈sub〉2〈/sub〉 nanomaterials is designed as cathode material to enable neutral aqueous, high energy density and ultra-long life asymmetric supercapacitor. The energy density and power density can reach as high as 33.8 Wh kg〈sup〉−1〈/sup〉 and 5000 W kg〈sup〉−1〈/sup〉 respectively even in the high-voltage region of 0–2 V. The asymmetric supercapacitor exhibits 91% capacity retention after 10,000 cycles indicating outstanding cycling property. The ultra-stability of the belt-like MnO〈sub〉2〈/sub〉//activated carbon asymmetric supercapacitor makes it a promising device for large-scale applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: Available online 22 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology〈/p〉 〈p〉Author(s): Il-Cho Park, Seong-Jong Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, the effect of lead nitrate stabilizer concentration on the electroless nickel (EN) plating properties of gray cast iron was investigated in a sulfuric acid plating bath. The specific critical stabilizer concentration was found to vary the EN coating properties. At the critical stabilizer concentration or more, plating rate and the chemical composition of the EN coating were changed because the deposition of Ni and P was inhibited by excessive stabilizer concentration. The surface morphology of the EN coating was strongly influenced by the plating rate change with the stabilizer concentration and the galvanic coupling effect due to the microstructure of the substrate. The crystallinity of the EN coating tended to increase with increasing stabilizer concentration. As a result, the EN plating properties of gray cast iron were greatly affected by the stabilizer concentration in the plating bath and the microstructure of the substrate.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Bingwen Lu, Xiufang Cui, Lipeng Jiang, Erbao Liu, Dan Zhang, Xiangru Feng, Meiling Dong, Guo Jin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to obtain metallurgical shape memory alloy with a better quality, electro-magnetic stirring (EMS) technology is selected as an aiding method during plasma arc deposition (PAD) process. In this work, Ti〈sub〉51〈/sub〉Ni〈sub〉49〈/sub〉 alloys were successfully produced by EMS-assisted PAD technology. Influence of EMS on the microstructure, phase transformation behavior, micro-hardness and wear resistance of PAD TiNi alloy have been systematically investigated. The PAD TiNi alloy is composed of TiNi coarse columnar dendrites with a certain number of Ti〈sub〉2〈/sub〉Ni phases distributed in the inter-dendritic regions. Under the action of EMS, TiNi coarse columnar dendrites transform into fine non-dendrites or spheroid grains and the homogeneity of microstructures improves significantly. The implementation of EMS during PAD do not change the path of phase transformation, but improve the degree of phase transformations and reduce the transformation temperatures of PAD TiNi alloy. The EMS-PAD TiNi alloy possesses better dry wear resistance than the PAD TiNi alloy, which can be attributed to the higher degree of pseudo-elasticity of TiNi phases and strengthening of Ti〈sub〉2〈/sub〉Ni phases.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Ya-ru Dong, Wan-chang Sun, Xiao-jia Liu, Zong-wei Jia, Fang Guo, Min Ma, Yu-yao Ruan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A kind of novel anti-wear and self-lubricating Ni-GO-CNTs composite coatings were deposited on the surface of AZ91D magnesium alloys substrates by an integrative method involved electrophoresis and electrodeposition with various CNTs (carbon nanotubes) concentration. The surface and cross-sectional morphologies of Ni-GO-CNTs composite coatings were studied by scanning electron microscope equipped with an energy dispersive spectroscope. The micro-indentation hardness as well as friction and tribological properties of Ni-GO-CNTs composite coatings were tested by micro-hardness tester, friction and wear tester separately. Results showed that the Ni-GO-CNTs composite coatings prepared successfully were strongly combined with the copper coating and the magnesium alloys substrates. The maximal micro-indentation hardness value of Ni-GO-CNTs composite coating was obtained with 0.04 g/L CNTs added. The wear resistance of Ni-GO-CNTs composite coating increased initially and then decreased with increasing the CNTs concentration. When the concentration of CNTs was 0.04 g/L, the friction coefficient and wear capacity of the composite coating exhibited the minimum value, which is mainly due to the cross-linking effect of CNTs and GO (graphene oxide) that enhanced the physicochemical properties of the CNTs and GO, indicating better mechanical properties of Ni-GO-CNTs coating.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Hao Zhou, Xiaodi Wei, Wei Wei, Cong Ye, Rulin Zhang, Li Zhang, Qing Xia, Hong Huang, Bin Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, the resistive switching (RS) characteristics of Ti-doped HfO〈sub〉2〈/sub〉 under different doping concentration and annealing condition were theoretically investigated by using the first-principles calculation method. For a 2 × 2 × 2 HfO〈sub〉2〈/sub〉 supercell, the formation energy of an oxygen vacancy (Vo) reaches the minimum when three Hf atoms were substituted by three Ti atoms. Based on the 3‑Ti-doped HfO〈sub〉2〈/sub〉 supercell model, numerical results show that low oxygen partial pressure, high annealing temperature and N〈sub〉2〈/sub〉 annealing atmosphere would lead to a low Vo formation energy. By calculating the migration energy of a Vo, we found that the Vo tends to migrate near and towards the Ti dopants. The concentration of Vo and N〈sub〉2〈/sub〉 annealing atmosphere are also beneficial for the connection of conducting filaments. Our numerical results show reasonable agreement with previous experiment about the RS performance of ITO/Ti:HfO〈sub〉2〈/sub〉/Pt device.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Lixin Fu, Yun Guo, Shengsen Pan, Jian Huang, Linjun Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Here we report that a novel type of Tourmaline@ZnO core-shell composite equipped with carbon dots (CDs) as multi-band light active sensitizer has been successfully designed and efficiently ultilized as the superior photocatalyst towards the degradation of methyl orange (MO) under Xenon lamp at room temperature. The bare ZnO, CDs/ZnO, Tourmaline@ZnO and CDs/Tourmaline@ZnO were systemically synthesized following the facile homogeneous precipitation process and characterized in detail by XRD, FTIR, FESEM, HRTEM, UV-Vis, PL, PC and EIS investigations in succession. Bare ZnO displays as 3-dimensional hierarchical nano-flowers with large specific surface area reaching up to 62.049 m〈sup〉2〈/sup〉/g by BET measurement, while the other composite products confirm the core-shell structures with CDs inlaying on ZnO layer surfaces. The photocatalytic activities of the polynary hybridations obtain effective enhancements compared to pure ZnO, the ternary system (CDs/Tourmaline@ZnO) deserves more attention for achieving the maximum (91.25%). It should been the synergistic effect on the highly efficient catalysis performances exerting by the presence of CDs modifier and the Tourmaline core, which make ZnO matrix receive more photo-generated electrons and broaden the visible light response originated from CDs, and synchronously hinder the recombination of electrons-hole pairs by the spontaneous polarization and surface electric field of Tourmaline.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Nina Schalk, Michael Tkadletz, Velislava L. Terziyska, Marco Deluca, Ilse Letofsky-Papst, Jozef Keckes, Christian Mitterer〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the last years, quaternary oxynitrides have emerged as a new class of materials due to their tunable properties. Within the present work, a graded TiAl(O)N film was grown by magnetron sputter deposition, using TiAl targets with a Ti/Al atomic ratio of 40/60, constant nitrogen and stepwise increasing oxygen partial pressure over the film thickness. The microstructural evolution of the film was investigated by transmission electron microscopy and synchrotron X-ray nanodiffraction. Complementary, cross-sectional μ-Raman spectroscopy was performed to further validate the phase evolution. The first layer, grown without the addition of oxygen, showed a prevalent wurtzite (w) structure and a subordinate face centered cubic (fcc) phase fraction. The addition of small amounts of oxygen resulted in the stabilization of the fcc-phase and the w-phase vanished. With increasing film thickness and thus, increasing oxygen content, increasing amounts of an additional amorphous phase fraction were observed. In the first layers, tensile in-plain strain was determined, which turns to compressive towards the film surface. Cross-sectional nanonindentation revealed increasing hardness and elastic modulus with increasing oxygen content in the first layers as a result of the w to fcc transition; however, towards the film surface the hardness decreases, which can be related to the increasing amorphous phase fraction.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S025789721831380X-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): N.V. Gavrilov, A.S. Kamenetskikh, P.V. Trernikov, D.R. Emlin, A.V. Chukin, Yu.S. Surkov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The results of studying the parameters of the plasma generated in an arc with a self-heating hollow cathode and a vaporizable anode placed in a magnetic field of two oppositely connected solenoids are presented. Compression of the discharge column in an inhomogeneous magnetic field provides an increase in power density on the surface of the crucible anode to ~1 kW/cm〈sup〉2〈/sup〉 and an increase in the degree of ionization of the metal vapor to 50–80%. Using the method of reactive evaporation of aluminum in the Ar/О〈sub〉2〈/sub〉 gas mixture we obtained Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 coatings at the rate of 4–8 μm/h under an ion current density of 6–11 mA/cm〈sup〉2〈/sup〉, a bias voltage of 50–200 V, and a temperature of 620 °С. It is shown that, with an increase in the ion current density and ion energy, the fraction of the α-phase in the Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 coating increases to 100%. The single-phase α-Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 coatings are characterized by the predominant orientation of crystallites (300).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Jintao Xiao, A.V. Rogachev, V.A. Yarmolenko, A.A. Rogachev, Yiming Liu, Xiaohong Jiang, Dongping Sun, M.A. Yarmolenko〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The work aimed at examining the structure of a new bioactive phosphate‑calcium coating, its transformation while annealing and interaction with a biologically active medium that simulates blood chemistry, the effect of coating on the corrosion properties of Ti6Al4V alloy. Bioactive phosphate‑calcium layer, initiating the growth of hydroxyapatite in a biological environment, was formed in the process of electron-beam deposition of layers based on magnesium, calcium, phosphorus oxide and silicone resin without depressurization of the vacuum chamber. Calcium layer is suggested to be formed by means of exposure of low-energy electron beam to calcium hydride. Heat treatment (500 °C) leads to the formation of crystalline regions in the coating volume and cross-linked organosilicon particles, which act as nucleation centers of hydroxyapatite (HA). It is noted that the presence of the organosilicon component and the conduct of heat treatment are not a prerequisite for the HA occurrence on the surface and in the volume of the deposited layer. It has been established that the application of the annealed four-layer system to the surface of the Ti〈sub〉6〈/sub〉Al〈sub〉4〈/sub〉V alloy improves its corrosion properties.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 February 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Surface and Coatings Technology, Volume 359〈/p〉 〈p〉Author(s): Yinhua Zhang, Shengming Xiong, Wei Huang, Kepeng Zhang, Xiaoxi Tian〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In recent years, multi-spectral optical system is steadily growing popularity due to miniaturization and multi-function of optical system. Antireflection coatings is critical important in multi-spectral device working in the wavelength region of 0.5–10 μm since optics of high refractive index materials are used. A six-spectral antireflection coating on multispectral zinc sulfide substrate, which is suitable for the wavelength range of 0.5–10 μm, has been designed, fabricated and characterized. The six-spectral antireflection coating is composed of 29-layer alternative stacking high-index layer of zinc sulfide and low-index coating material of ytterbium fluoride, which deposits by thermal evaporation. In order to overcome the stress problem in the coating, the maximum layer thickness is restricted about 0.6 μm. This coating conforms to environmental stability standards and shows 94% transmission at 0.532 μm, 97% transmission at 1.064 μm and over 98% transmission at 2.1 μm, 3.9 μm, 4.8 μm and 9.5 μm.〈/p〉〈/div〉 〈/div〉