ALBERT

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): Rakesh Kumar, Krishna Kant Pandey, Aminul Islam, Anup Kumar Keshri〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Present article communicates the successful fabrication of plasma sprayed graphene nanoplatelets (GNPs) reinforced ceria (CeO〈sub〉2〈/sub〉) composite coating. Later, various characterizations confirm the presence of survived GNPs into CeO〈sub〉2〈/sub〉 matrix and its transformation to few layered graphene during plasma spraying. The reinforcement of GNPs led a significant enhancement in corrosion resistance and mechanical performance. Addition of 5 wt% GNPs in CeO〈sub〉2〈/sub〉 displayed an exceptional reduction in corrosion rate about ∼15 times in 3.5 wt% NaCl solution, while superior improvement of 50% in hardness, 98% in elastic modulus and 185% in fracture toughness during indentation has been observed. The GNPs acted as promising corrosion inhibitor and prevented infiltration of electrolytic salts (NaCl) through the coating. Apart from these, entanglement of few layer GNPs with CeO〈sub〉2〈/sub〉 matrix and GNP crack bridging between two crack banks enhanced the mechanical performance of the matrix. As a whole, GNPs reinforcement owed the combined improvement in corrosion resistance as well as mechanical performance, which would make it a better option for advanced technological applications.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Nqobile Xaba, Remegia M. Modibedi, Lindiwe E. Khotseng, Mkhulu K. Mathe, Nithyadharseni Palaniyandy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bimetallic SnBi film was deposited on a Cu foil substrate via the electrochemical atomic layer deposition (E-ALD) technique. The deposition attainment of Sn and Bi were investigated using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). The deposition potential of Bi was varied in the underpotential deposition (UPD) region and the concentration of Sn was varied in the SnBi bimetallic material. The materials were characterised using field emission scanning electron microscopy coupled with energy dispersive spectroscopy (FE-SEM/EDS) for morphology and elemental distribution, focused ion beam scanning electron microscopy (FIBSEM) for thickness, X-ray diffraction (XRD) for crystallinity and inductively coupled plasma mass spectroscopy (ICP-MS) for composition measurements. Bi deposited at different UPD regions was structurally different. The deposits were crystalline SnBi materials containing Sn, Bi and other phases of Cu and Sn. Bi was concentrated on the surface, while Sn was distributed evenly across the film. The SnBi electrodes were tested as anode materials in Na-ion batteries using galvanostatic cycling (GC), CV and electrochemical impedance spectroscopy (EIS). Initial discharge capacities of 1900 mAh g〈sup〉−1〈/sup〉 for SnBi (1:1) and 341 mAh g〈sup〉−1〈/sup〉 for SnBi (3:1) electrodes at 38.5 mA g〈sup〉−1〈/sup〉 were obtained, while the electrodes suffered capacity loss after 10 cycles.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Murillo H. de Matos Rodrigues, Priscila Afonso Rodrigues de Sousa, Kellen Cristina M. Borges, Luciana de Melo Coelho, Rosana de Fátima Gonçalves, Márcio Daldin Teodoro, Fabiana Vilella da Motta, Rubens Maribondo do Nascimento, Mario Godinho Júnior〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Forms of degradation of the environmental pollutant sulphamethoxazole have been studied over the years, and one form of degradation in heterogeneous photocatalysis. In this work a study was carried out to elaborate a photocatalyst capable of degrading the pollutant sulfamethoxazole, starting to elaborate heterojunctions between TiO〈sub〉2〈/sub〉 and CeO〈sub〉2〈/sub〉 doped with gadolinium, showing that the combination of both materials is able to contribute to the degradation of the pollutant, promoting 97% degradation. This favorable performance can be attributed by the formation of a characterized heterojunction with presence of mesopores that aid in the adsorption processes on the surface of the photocatalyst, and a high formation of active sites resulting from the formation of the electron pair, promoted by the excitation of the electrons of the band of valence for conduction band by means of photons.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329445-fx1.jpg" width="323" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Xin Yang, Xiangguo Zeng, Huayan Chen, Yuntian Wang, Liu He, Fang Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Molecular dynamics (MD) simulations are carried out to comprehensively investigate the Hugoniot curve, isotherms, isentropes, and internal energy, as well as the Mie-Grüneisen equation of state (EOS) for single-crystal Al and Pb via multi-scale shock technology (MSST) in the open source software Large-scale Atomic/Molecular Massively Parallel Simulator, or LAMMPS. The temperatures (〈em〉T〈/em〉〈sub〉〈em〉H〈/em〉〈/sub〉 and 〈em〉T〈/em〉〈sub〉〈em〉S〈/em〉〈/sub〉) along the Hugoniot curve and isentrope, the entropy increment (〈em〉ΔS〈/em〉〈sub〉〈em〉H〈/em〉〈/sub〉) along the Hugoniot curve, and the Grüneisen coefficient 〈em〉γ〈/em〉 are calculated and discussed based on the linear relation of shock wave velocity and particle velocity. Meanwhile, based on the assumptions that 〈em〉γ〈/em〉 is only a function of the specific volume 〈em〉V〈/em〉 and the specific heat 〈em〉c〈/em〉〈sub〉〈em〉V〈/em〉〈/sub〉 = constant, the typical incomplete Mie-Grüneisen EOS is thermodynamically extended to the complete equations of state (EOSs) utilizing the Hugoniot relation as the reference curve at pressures up to 300 GPa. The incomplete and complete Mie-Grüneisen EOSs show a concave surface in the pressure-specific volume-internal energy (〈em〉P〈/em〉–〈em〉V〈/em〉-〈em〉E〈/em〉), pressure-specific volume-shock Hugoniot temperature (〈em〉P〈/em〉–〈em〉V〈/em〉-〈em〉T〈/em〉〈sub〉〈em〉H〈/em〉〈/sub〉), and pressure-specific volume-entropy increment (〈em〉P〈/em〉–〈em〉V〈/em〉-〈em〉ΔS〈/em〉〈sub〉〈em〉H〈/em〉〈/sub〉) spaces.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Scripta Materialia, Volume 173〈/p〉 〈p〉Author(s): Qi Wang, Fangyang Liu, Li Wang, Liangxing Jiang, Qiyu Wang, Bo Hong, Yanqing Lai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Traditional preparation of Sb〈sub〉2〈/sub〉S〈sub〉3〈/sub〉 anode requires a long and complex process and high cost, which is difficult to realize commercialization. To overcome this challenge, we demonstrate a compact vapor transport deposition (VTD) process to prepare Sb〈sub〉2〈/sub〉S〈sub〉3〈/sub〉 thin-film anode from antimony sulfide ore. This VTD Sb〈sub〉2〈/sub〉S〈sub〉3〈/sub〉 anode show well crystallized nanosheets with porous microstructures and exhibit good cyclicality and high rate performance. The results indicate that this process is feasible and practical for simplifying Sb〈sub〉2〈/sub〉S〈sub〉3〈/sub〉 anode preparation.〈/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-S1359646219304403-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Yixiong Liu, Zhenxing Zheng, Mengdi Mao, Tiwen Lu, Genghua Cao, Dezhi Zhu, Weiping Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To investigate the effects of micron heterogeneous metal particles on the microstructure and mechanical properties of 7075Al hybrid composites, Ni based particles and Ti based particles in the same size were incorporated into SiC〈sub〉p〈/sub〉/7075Al composites using squeeze casting separately. The interfacial structure and mechanical property relationship of the hybrid composites was investigated using SEM, TEM, XRD and tensile tests. And the strengthening effects of heterogeneous metal particles were discussed. Results shown that different interfacial structures have been formed at the interface of the metal particles during the casting processes. Ni based particles formed low-temperature NiAl〈sub〉3〈/sub〉 intermetallic reaction layers. In contrast, only Ti–Al interdiffusion metallurgical bonding were detected at the interface of the Ti based particles. The composites incorporated with Ti based particles achieved higher tensile strength and plasticity of 573 MPa and 0.65%, respectively. The interdiffusion metallurgical bonding prove to be a more desired interfacial structure and would ensure the strengthening effects of metal particles.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 30 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 807〈/p〉 〈p〉Author(s): Jie Hu, Benqian Lu, Xueqian Wang, Huici Qiao, Hao Huang, Bin Wen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electrocatalysts for oxygen reduction reactions are the key to metal–air batteries. In this work, surface graphitized microdiamond (GMD) with a diamond core and graphitic carbon shell are prepared by spark plasma sintering technique. Perovskite-type LaMnO〈sub〉3〈/sub〉 (LMO) nanoparticle/surface GMD samples are prepared by a sol–gel method using GMD as support. The LMO/GMD hybrid catalyst exhibits higher electrocatalytic activity than pure LMO and LMO/graphene. The suitability of the hybrid catalyst is tested for primary zinc–air batteries. Results demonstrate that the hybrid catalyst shows a high voltage plateau and slow decay rate. The excellent electrochemical performance is ascribed to the corrosion resistance of diamond, the coral-like structure of composite, the formation of electron transfer connector, and the spill effect of oxygen-containing species. Comparing the performance of differently sized graphitized diamond components in the catalysts proves that approximately 1 μm diamonds are extremely important for improving electrocatalytic activity.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329172-fx1.jpg" width="285" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): O. Bazta, A. Urbieta, J. Piqueras, P. Fernández, M. Addou, J.J. Calvino, A.B. Hungría〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Pure ZnO and ZnO: 2%Y: x%Li (x = 0, 3, 5 and 7 at.%) thin films have been successfully prepared onto glass substrates under optimized conditions by spray pyrolysis technique at 450 °C and their suitability for the fabrication of efficient optoelectronic devices is demonstrated. The samples have been characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), UV–Visible absorption spectroscopy photoluminescence (PL) and Raman spectroscopy (RS), in order to investigate the effect of Y–Li co-doping on the structure, surface morphology, and optical features of the thin films. The films crystallized into a hexagonal structure, with a preferred orientation along the c-axis. No additional phases have been observed. SEM micrographs showed that Y and Li co-doping plays a key role in the grain size and morphology of the films. The optical study via transmittance and absorption measurements within the UV–vis region revealed that the films are highly transparent (82–90%). The optical bandgap (E〈sub〉g〈/sub〉) depends on the concentration of lithium added, which is explained by the Burstein-Moss (BM) effect. The PL measurements at room temperature under excitation with 325 nm wavelength, showed an appreciable improvement of ultraviolet emission by increasing the Li co-doping concentration. This enhancement reaches a maximum at 5 at.% Li content, and decreases after further increase in Li content. Raman scattering spectra were also carried out and revealed the presence of the wurtzite phase of ZnO exclusively.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): Honghong Zhang, Zeqing Li, Weifeng He, Chuansheng Ma, Bin Liao, Yinghong Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉For the purpose of optimizing the anti-impact performance of TiN film, a series of TiN films with different N/Ti ratios were investigated. The phase evolution and mechanical properties of TiN films were explored. In particular, the cyclic nano-impact tests with impact energy ranging from 0.1 μJ to 0.9 μJ were conducted to evaluate the anti-impact performance of TiN films. It was found that the non-stoichiometric phases of TiN〈sub〉0.30〈/sub〉, Ti〈sub〉2〈/sub〉N and TiN〈sub〉0.61〈/sub〉 reduced with increasing N/Ti ratio in TiN films. The hardness of film increased with increasing stoichiometric TiN phase in films, while as an indicator of toughness, the H〈sup〉3〈/sup〉/E〈sup〉2〈/sup〉 ratio decreased. The anti-impact performance of TiN films displayed a close relationship with both hardness and H〈sup〉3〈/sup〉/E〈sup〉2〈/sup〉 ratio, in which a high enough hardness was the prerequisite of outstanding impact resistance, and H〈sup〉3〈/sup〉/E〈sup〉2〈/sup〉 ratio was an important factor affecting the damage mechanism. As the H〈sup〉3〈/sup〉/E〈sup〉2〈/sup〉 ratio decreased, the damage mechanism of TiN film transformed gradually from plastic fatigue damage to brittle fracture failure. Especially, the TiN film featuring N/Ti ratio of 0.780 (TiN-16) was not only hard enough to resist penetration, but also tough enough to prevent the film from fracturing, thus it exhibited the best comprehensive anti-impact performance.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Yunfei Sun, Min Ma, Bo Tang, Sen Li, Li Jiang, Xiaohong Sun, Miaoling Que, Chongben Tao, Zhengtian Wu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The copper-benzene-1,3,5-tricarboxylate (Cu-BTC) attracts increasing attention because of its large BET surface area available for the adsorption of gases. However, low stability in water creates a barrier for its potential applications. In this study, graphene oxide (GO) and reduced graphene oxide (RGO) are adopted to modify the Cu-BTC. The influence of GO and RGO on the resulting BET surface area, pore diameter distribution, morphology and yield of the Cu-BTC are revealed. It is found that the adsorption abilities of the resulting composites for the polar and nonpolar gas molecules are closely related to the presence at surface of the functional groups of the used graphene samples, which provides a potential method to achieve selective adsorption. Furthermore, the preparation processes of the GO/Cu-BTC and RGO/Cu-BTC exert a significant effect on the performances of the resulting product, which is also studied in detail.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 810〈/p〉 〈p〉Author(s): Hualan Zhou, Yuan Wu, Yongxiang Su, Feng Wang, Shuai Yuan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The silicon-based materials show high capacities. However, the poor intrinsic conductivity and severe volume change during the process of lithiation and delithiation restrict the application. In this work, the nanoscale silicon (Si) with silver-polydopamine (Ag/PDA) hybrid coating was designed and successfully prepared by a simple one-pot liquid-phase redox reaction method. The electrochemical properties of the anode materials for lithium ion batteries were characterized, and the mechanism for the excellent cycling performance were investigated by cyclic voltammetry (CV), Electrochemical impedance spectra (EIS), scanning electron microscopy (SEM) and the operando visual observation during lithiation/delithiation process. According to the results, the presence of PDA and Ag is advantageous to enhance the electronic conductivity in the charge-discharge process. The Si/Ag/PDA ternary composite electrode exhibits high capacity and more stable cycling characteristics than Si and Si/PDA electrodes especially at large current densities, which remains 1168.8 mAh g〈sup〉−1〈/sup〉 and after 100 cycles at 2 A g〈sup〉−1〈/sup〉.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Se-Yun Kim, Sangwook Lee, Weon-Sik Chae, Joon-Hyung Lee, Young-Woo Heo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, we attempted to improve the optical stability via the complicated design of the X site composition of CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉Pb(Br〈sub〉1-x-y〈/sub〉Cl〈sub〉x〈/sub〉I〈sub〉y〈/sub〉)〈sub〉3〈/sub〉, such as CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉Pb(Br〈sub〉0.5〈/sub〉I〈sub〉0.5〈/sub〉)〈sub〉3〈/sub〉 and CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉Pb(Br〈sub〉0.5〈/sub〉Cl〈sub〉0.25〈/sub〉I〈sub〉0.25〈/sub〉)〈sub〉3〈/sub〉. It was observed that photo-stability improvement via the complicated design of the X site composition of CH〈sub〉3〈/sub〉NH〈sub〉3〈/sub〉Pb(Br〈sub〉1-x-y〈/sub〉Cl〈sub〉x〈/sub〉I〈sub〉y〈/sub〉)〈sub〉3〈/sub〉 would not occur. I-rich phase which was remained phase after small halide ion (Br or/and Cl) extraction was unavoidably formed through the preferential extraction of small halide ions, and this can be explained by the spinodal decomposition mechanism. Comparing the excitation dynamics of MAPb(Br〈sub〉0.5〈/sub〉I〈sub〉0.5〈/sub〉)〈sub〉3〈/sub〉 and MAPb(Br〈sub〉0.5〈/sub〉I〈sub〉0.25〈/sub〉Cl〈sub〉0.25〈/sub〉)〈sub〉3〈/sub〉, we could expect that the excitation dynamics would be relatively complicated in the presence of Cl. The reason for this is explained by the effect of mixed mobile ions, i.e., small ions are more easily diffused than large ions.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329494-fx1.jpg" width="317" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Shuai Zhang, Tao Sun, Fuquan Ji, Gang Dong, Yang Liu, Zhidong Li, Hui Zhang, Qingming Chen, Xiang Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, electrical and magnetic properties of La〈sub〉1-〈em〉x〈/em〉〈/sub〉Ag〈sub〉〈em〉x〈/em〉〈/sub〉MnO〈sub〉3〈/sub〉 (LAMO, 0 ≤ 〈em〉x〈/em〉 ≤ 0.5) polycrystalline ceramics with double−exchange (DE) effect and Jahn−Teller (JT) distortion were studied using a combination of first principles calculations and experimental methods. The GGA + U method was used to correct the self-interaction error (SIE) that was encountered in first principles calculations. With the increasing of Ag, energy band gaps (〈em〉E〈/em〉〈sub〉i〈/sub〉 or 〈em〉E〈/em〉〈sub〉d〈/sub〉) of LAMO ceramics and the JT effect decreased, while the DE effect was enhanced. LAMO polycrystalline ceramics (〈em〉x〈/em〉 = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) were prepared by conventional sol−gel method in order to verify the calculation results. The X−ray diffraction revealed that the structure of LAMO ceramics transformed from single phase to multiphase as 〈em〉x〈/em〉 was increased. The 〈em〉ρ〈/em〉−〈em〉T〈/em〉 curves suggested that the metal to insulator transition temperature (〈em〉T〈/em〉〈sub〉p〈/sub〉) and DE effect were improved as 〈em〉x〈/em〉 increased, which was in good agreement with the first principles calculations. In addition, the temperature coefficient of resistance (TCR) at the peak temperature (〈em〉T〈/em〉〈sub〉k〈/sub〉) and magnetoresistance (MR) at the peak temperature (〈em〉T〈/em〉〈sub〉m〈/sub〉) were obtained with different 〈em〉x〈/em〉. For 〈em〉x〈/em〉 = 0.5, the value of 〈em〉TCR〈/em〉 and 〈em〉MR〈/em〉 reached 8.58% K〈sup〉−1〈/sup〉 and 21.6%, and the 〈em〉T〈/em〉〈sub〉p〈/sub〉, 〈em〉T〈/em〉〈sub〉k〈/sub〉 and 〈em〉T〈/em〉〈sub〉m〈/sub〉 were 304, 291 and 298 K, respectively, implying that the electrical and magnetic devices of LAMO ceramics could operate at room temperature (300 K). XPS results indicated that the concentration of Mn〈sup〉4+〈/sup〉 ion increased with increasing 〈em〉x〈/em〉. The ratio of Mn〈sup〉4+〈/sup〉/Mn〈sup〉3+〈/sup〉 reached 1 ∶ 2, which had the strongest DE and magnetoelectric coupling effect for 〈em〉x〈/em〉 = 0.5.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Onur Ertugrul, Tianbing He, Rub Nawaz Shahid, Sergio Scudino〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Al 2024 matrix composites reinforced with 20 and 40 vol% Ni〈sub〉60〈/sub〉Nb〈sub〉40〈/sub〉 metallic glass particles were synthesized through powder metallurgy using hot pressing and the effect of heat treatment (solution and artificial aging, T6) on microstructure and mechanical properties was examined. The microstructure of the unreinforced matrix shows the formation of CuAl〈sub〉2〈/sub〉 and Al〈sub〉2〈/sub〉CuMg precipitates after heat treatment, while the composites show the formation of additional CuNiAl and NbNiAl phases due to the reaction between the matrix and glassy particles. The yield strength is improved by the Ni〈sub〉60〈/sub〉Nb〈sub〉40〈/sub〉 addition in both as-sintered and heat-treated conditions, whereas the ductility is reduced for the composites with 40 vol% of reinforcement. The microstructural modifications due to the interfacial reactions in heat-treated composites result in a significant strengthening contribution.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329652-fx1.jpg" width="484" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): Bangzhi Ge, Zhongqi Shi, Chongjian Zhou, Jiabin Hu, Guiwu Liu, Hongyan Xia, Jingtao Xu, Guanjun Qiao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉CuFeS〈sub〉2〈/sub〉 is an eco-friendly n-type thermoelectric (TE) material but with poor performance. It is worth noting that the bandgap (〈em〉E〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉) reduction can enhance the carrier mobility (〈em〉μ〈/em〉〈sub〉〈em〉H〈/em〉〈/sub〉) which further leads to a higher electrical conductivity (〈em〉σ〈/em〉) and power factor (〈em〉PF〈/em〉). Density Functional Theory (DFT) calculation results indicated that Ag dopant in the CuFeS〈sub〉2〈/sub〉 compound can narrow down the 〈em〉E〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉. Hence, a series of Cu〈sub〉1-x〈/sub〉Ag〈sub〉x〈/sub〉FeS〈sub〉2〈/sub〉 (x = 0–0.14) alloys were prepared by vacuum melting combined with plasma activated sintering to enhance the TE performance via a bandgap tuning route. It can be found that the 〈em〉E〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉 is indeed shrinking from ∼0.45 to 0.39 eV with the increase of Ag dopant content, and the reduced 〈em〉E〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉 leads to an obviously enhanced 〈em〉μ〈/em〉〈sub〉〈em〉H〈/em〉〈/sub〉 without carrier concentration decreasing. Due to the elevated 〈em〉μ〈/em〉〈sub〉〈em〉H〈/em〉〈/sub〉, a higher 〈em〉PF〈/em〉 (0.76 × 10〈sup〉−3〈/sup〉 Wm〈sup〉−1〈/sup〉K〈sup〉−2〈/sup〉) can be obtained and a peak 〈em〉ZT〈/em〉 value of 0.45 is achieved at 723 K in Cu〈sub〉0.88〈/sub〉Ag〈sub〉0.12〈/sub〉FeS〈sub〉2〈/sub〉 sample. Therefore, the bandgap tuning can be regarded as an effective strategy for enhancing the TE performance of CuFeS〈sub〉2〈/sub〉.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Illustration of bandgap tuning for optimizing thermoelectric properties of CuFeS〈sub〉2〈/sub〉.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329500-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): Lanshu Xu, Haibin Wang, Jianmin Gao, Xiaojuan Jin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, flexible graphene supercapacitor electrodes were prepared from biomass-derived carbon dots/graphene composite film (CDGF) and hydrogel (CDGH) with/without an electrodeposited NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 layer. Results showed that the dispersive CDs with abundant heteroatoms effectively inhibited the aggregation of graphene sheets and increased the number of active sites. By combining CDs modification and NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 electrodeposition, the electrochemical performance of the prepared ternary composite electrodes is significantly enhanced. In particular, the CDGF-NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 electrode has a specific capacitance of up to 1348 F g〈sup〉−1〈/sup〉 at a current density of 0.5 A g〈sup〉−1〈/sup〉. The resultant CDGF-NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 flexible symmetric supercapacitor using 1.0 M H〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉 as aqueous electrolyte shows a large specific capacitance (313 F g〈sup〉−1〈/sup〉 at 0.5 A g〈sup〉−1〈/sup〉) and a high energy density of 85.1 Wh kg〈sup〉−1〈/sup〉 at a power density of 353 W kg〈sup〉−1〈/sup〉. By contrast, the CDGH-NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 flexible solid-state supercapacitor using polyvinyl alcohol (PVA)/H〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉 as gel electrolyte has improved cycling stability (83.1% capacitance retention after 10000 charging/discharging cycles) and a better mechanical flexibility (96.8% capacitance retention after 1000 bending cycles). This work demonstrates the importance of CDs and metal sulfides in modifying graphene-based composite electrodes for flexible supercapacitor.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉Schematic diagram for the preparation of flexible supercapacitors.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092583881933035X-fx1.jpg" width="292" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: Available online 10 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds〈/p〉 〈p〉Author(s): Pankaj Kumar, Sushobhan Avasthi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉High-entropy alloys nitrides (HEA-N) have been proposed as diffusion barriers to prevent metal diffusion. Due to their lack of grain-boundaries and large lattice distortion, HEA-N have lower diffusion than binary nitrides. Despite the interest, very few quantitative studies have been performed to precisely measure metal diffusion in HEA-N. Here we report, for the first time, Fe diffusion rates and activation energy in AlCrTaTiZrN HEA-N thin-films, and demonstrate that they are lower than reported value in TiN. AlCrTaTiZrN was deposited on steel from a metal alloy target using reactive radio frequency sputtering under various nitrogen flow rates. X-ray diffraction shows that as the nitrogen flow rate increases, microstructure of the films changes from amorphous to nanocrystalline. Thermal stability studies at 700–900 °C show that AlCrTaTiZrN remains chemically and structurally stable up to 800 °C. SIMS shows that the HEA-N films are effective barrier layers for Fe diffusion for temperatures up to 800 °C. At higher temperatures, the films are mechanically stable but not effective as barrier films, due to recrystallization in AlCrTaTiZrN. The measured diffusion coefficient is 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈mn〉7〈/mn〉〈mo linebreak="goodbreak" linebreakstyle="after"〉×〈/mo〉〈msup〉〈mrow〉〈mn〉10〈/mn〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉22〈/mn〉〈/mrow〉〈/msup〉〈msup〉〈mrow〉〈mtext〉m〈/mtext〉〈/mrow〉〈mrow〉〈mn〉2〈/mn〉〈/mrow〉〈/msup〉〈msup〉〈mrow〉〈mtext〉s〈/mtext〉〈/mrow〉〈mrow〉〈mo〉−〈/mo〉〈mn〉1〈/mn〉〈/mrow〉〈/msup〉〈/mrow〉〈/math〉 at 700 °C, 30 times lower than any polycrystalline nitride barrier reported in literature. The study not only conclusively demonstrate the effectiveness of HEA-N as diffusion barriers, it also provides quantitative data that can be used by engineers to precisely design barrier layers.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 30 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 807〈/p〉 〈p〉Author(s): J.B. Anooja, K.S. Dijith, K.P. Surendran, G. Subodh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, we investigate the electromagnetic interference (EMI) shielding properties of blends of easily available carbon black (CB) with high-surface-area reduced graphene oxide in a polydimethylsiloxane (PDMS) matrix. The chemical composition and morphology of the rGO@CB/PDMS composite are characterized using different techniques such as X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, atomic force microscopy, and field effect scanning electron microscopy. The hybrid filler could effectively improve the electrical conductivity and dielectric loss, and hence the shielding efficiency, and retain its performance even after repeated bending for 100 times. The microwave absorption mechanism of the samples is discussed in detail in terms of their complex permittivity and microstructure. A three-dimensional layered framework is formed within the composite, which in turn leads to multiple reflections of the microwaves at the layer boundaries, subsequently dissipating them as heat due to the presence of conductive CB particles. Because of this, the hybrid rGO@CB/PDMS composite displays superior absorption-dominated shielding property, with a shielding efficiency (SE) of ∼28 dB. The synergetic effect of the hybrid fillers resulting from multiple reflections suggests new pathways for designing flexible shielding materials for practical EMI applications.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329111-fx1.jpg" width="339" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 25 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 810〈/p〉 〈p〉Author(s): Yuefeng Liu, Jun Zhao, Yan Zhang, Huafang Zhang, Zhenlong Zhang, Huiping Gao, Yanli Mao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Upconversion nanoparticles (UCNPs) doped with lanthanide ions have potential applications in biomedical, solar cells and displays. However, the intensity of the upconversion luminescence (UCL) is limited by the surface effects of nanomaterials, lattice defects, etc. Here, a novel α-NaErF〈sub〉4〈/sub〉 hollow nanocube is fabricated by using divalent manganese ions (Mn〈sup〉2+〈/sup〉) to substitute trivalent erbium ions (Er〈sup〉3+〈/sup〉) in the NaErF〈sub〉4〈/sub〉 matrix. The hollow-shell structure can weaken the luminescence quenching and surface quenching effects, reduce the energy loss of higher energy levels in nanoparticles, and improve the light capture ability of nanoparticles. So the UCL of α-NaErF〈sub〉4〈/sub〉 hollow nanocubes is greatly improved, which is 14, 790 and 1071 times higher than that of the β-NaErF〈sub〉4〈/sub〉 under 808, 980 and 1530 nm laser excitation, respectively, and the emission in the red region is enhanced respectively by 69, 2049 and 2902 times. In particular, the hollow nanocubes emit intense single-band red emission under the three different wavelengths, respectively. Moreover, the magnetization of α-NaErF〈sub〉4〈/sub〉 hollow nanocubes is 2.16 emu g〈sup〉−1〈/sup〉 at room temperature, which is larger than that of gadolinium-based materials. Hollow-shell structure, excellent paramagnetism and single-band red upconversion emission excited by various wavelengths will create NaErF〈sub〉4〈/sub〉:40Mn UCNPs a good application prospect in the biomedical field.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉The α-NaErF〈sub〉4〈/sub〉:40Mn hollow nanocube emits a single red light under excitation of three wavelengths (808, 980 and 1530 nm), due to the energy transfer between Mn〈sup〉2+〈/sup〉 and Er〈sup〉3+〈/sup〉.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329949-fx1.jpg" width="279" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 30 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 807〈/p〉 〈p〉Author(s): Jian Wang, Jianwen Zhang, Yangyang Yin, Hongxia Jin, Shu Liu, Yan Li, Chengwei Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The ZnO-based devices are constantly taken into various extreme environments, the extreme natural conditions, such as extremely cold, wet, dirty, acidic and alkaline, etc, would have great damages on the devices, so their protection becomes necessary. Here the ZnO@stearic acid (ZnO@STA) superhydrophobic nanocone array surface is designed and grown by using a simple hydrothermal method on the Zn substrate and subsequent modification of each nanocone from head to toe with stearic acid, and the water contact angle attains 162°, and sliding angle is only 2°. Due to the strong binding force between the nanocone array and the Zn substrate, as well as the special modified array structure with self-reparability, its surface has superior mechanical stability and chemical stability, such as low surface energy, superlow adhesion, perfect abrasion resistance, good water shock resistance, ideal durability and well thermal stability in the working environment temperature range below 200 °C for the ZnO-based device, and so on. Meantime, it also exhibits remarkable omnipotent protection abilities: the high self-cleaning ability in the environments containing various solid and liquid pollutants, the well anti-corrosion performance in the acidic and basic environments, and the excellent freezing resistance in the harsh freezing conditions. The further tests illustrate the superlow adhesion and tiny contact area of liquid droplet caused by the superhydrophobicity and the unique nanocone array surface structure are the main reasons for these remarkable omnipotent protection abilities in the various extreme environments and superior mechanical stability.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 30 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 807〈/p〉 〈p〉Author(s): Feng Hu, Chenchen Yuan, Qiang Luo, Weiming Yang, Baolong Shen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The influences of Ho addition on the thermal stability of supercooled liquids, thermoplastic deformation as well as mechanical and soft-magnetic behaviors of Fe〈sub〉71-x〈/sub〉Ho〈sub〉x〈/sub〉Nb〈sub〉6〈/sub〉B〈sub〉23〈/sub〉 bulk metallic glasses (BMGs) were investigated. With increasing Ho content from 1 to 5 at. %, the supercooled liquid region (SCLR) increased from 48 to 90 K, and the thermal stability is largely enhanced through remained chemical short- or medium-ordering. Combined with the competitive formation process of the complex Fe〈sub〉23〈/sub〉B〈sub〉6〈/sub〉 and Ho〈sub〉2〈/sub〉Fe〈sub〉14〈/sub〉B phases, the glass-forming ability (GFA) of the alloy system was improved, allowing for the fabrication of glassy rods up to 3 mm in diameter. Due to the large SCLR and GFA, the Fe〈sub〉66〈/sub〉Ho〈sub〉5〈/sub〉Nb〈sub〉6〈/sub〉B〈sub〉23〈/sub〉 BMG with high fracture strength of 3.45 GPa shows outstanding thermoplastic forming ability accompanied with good soft magnetic performance.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Feifei Yuan, Yisheng Huang, Lehui Liu, Lizhen Zhang, Shijia Sun, Guofu Wang, Zhengting Du, Zhoubin Lin, Jinlong Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, the crystal growth, spectral properties, and laser performance of 5 at.% Yb doped Gd〈sub〉2〈/sub〉SrAl〈sub〉2〈/sub〉O〈sub〉7〈/sub〉 (Yb:GSAO) crystal were reported. The peak absorption cross-section is 5.22 × 10〈sup〉−20〈/sup〉 cm〈sup〉2〈/sup〉 at 979 nm and the peak stimulated emission cross section calculated by Füchtbauer-Ladenburg (FL) method is 1.22 × 10〈sup〉−20〈/sup〉 cm〈sup〉2〈/sup〉 at 1062 nm for the π polarization. Efficient continuous-wave (cw) laser action was demonstrated in the range of 1060.2–1069.5 nm with a c-cut crystal sample end pumped by a 980 nm laser diode, generating a maximum output power of 7.345 W with an optical-to-optical efficiency of 47.5% and a slope efficiency of 53.7%. The results indicate that Yb:GSAO is a good Yb laser material.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329482-fx1.jpg" width="499" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 30 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 807〈/p〉 〈p〉Author(s): X.T. Li, L.J. Huang, S. Jiang, Y.N. Gao, Q. An, S. Wang, R. Zhang, L. Geng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To improve oxidation resistance of the titanium matrix composites, the network structured Ti-Al-Si coating was successfully prepared on TiBw/Ti6Al4V composites with network microstructure utilizing hot dip siliconizing and subsequent heat treatment. The cycle oxidation tests showed that the weight gains of the Ti-Al-Si coating were only 8.98%, 5.99% and 3.65% of the TiBw/Ti6Al4V composites at 973K, 1073K and 1173K for 100 h. This result indicates super oxidation resistance of the network structured Ti-Al-Si of TiBw/Ti6Al4V composites, which can be ascribed to the three reasons: (1) the continuous Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 oxide scale was formed in the outermost layer, (2) there were no cracks existed in the oxidized coating due to the unique network structure of the coating, (3) the Ti〈sub〉5〈/sub〉Si〈sub〉4〈/sub〉 layer in the interface could effectively retard the interfacial reaction between the Ti(Al,Si)〈sub〉3〈/sub〉 coating and composite substrate.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329123-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Fanggong Cai, Xi Chen, Lanxin Qiu, Lili Jiang, Sude Ma, Qinyong Zhang, Yong Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bi〈sub〉2〈/sub〉S〈sub〉3〈/sub〉, an efficient sensitizer for TiO〈sub〉2〈/sub〉 nanotube arrays (TiO〈sub〉2〈/sub〉 NTAs), was synthesized by a hydrothermal method. The morphology and size of Bi〈sub〉2〈/sub〉S〈sub〉3〈/sub〉 nanostructures can be tuned by controlling the crystalline state of TiO〈sub〉2〈/sub〉 NTAs and the concentration of precursor solution. X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) were used to characterize the crystalline structure and morphologies, respectively, of all the samples. The growth mechanism of nanostructured Bi〈sub〉2〈/sub〉S〈sub〉3〈/sub〉 in TiO〈sub〉2〈/sub〉 NTAs was established in great detail in this work. In addition, the photoelectrochemical (PEC) properties of Bi〈sub〉2〈/sub〉S〈sub〉3〈/sub〉/TiO〈sub〉2〈/sub〉 NTAs composite electrodes were evaluated. The results demonstrated that the best PEC properties were obtained when amorphous TiO〈sub〉2〈/sub〉 NTAs were used as the starting material and the concentration of Bi〈sup〉3+〈/sup〉 ions (N) was 0.5 mM in precursor solution. With AM 1.5G illumination at 100 mW cm〈sup〉−2〈/sup〉, the short-circuit current density (〈em〉J〈/em〉〈sub〉sc〈/sub〉), open-circuit voltage (〈em〉V〈/em〉〈sub〉oc〈/sub〉) and photoconversion efficiency (〈em〉η〈/em〉) were 5.75 mA cm〈sup〉−2〈/sup〉, 0.89 V and 2.32%, respectively.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): Puyi Gao, Jiangkun Fan, Feng Sun, Jun Cheng, Lei Li, Bin Tang, Hongchao Kou, Jinshan Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The early stage (strain ranges from 3% to 7%) microstructure evolution of a newly developed metastable β titanium alloy Ti–7Mo–3Nb–3Cr–3Al under both tensile and compressive deformation at room temperature was investigated contrastively. Although the true strain-true stress curves and the corresponding strain hardening rate (SHR) curves of the samples under tensile/compressive deformation seems to distinct from each other, the dominate deformation product in all the processes proves to be Stress-Induced Martensite (SIM) with an orthorhombic structure. Strong variant selection of SIM happens under both tensile and compressive deformation. And lattice strain formed during β→α’’ phase transformation plays a key role to determine the variant selection process. In the 3% deformed samples (both tensile and compressive samples), the lath-shaped SIM with or without twinned structure is the main deformation product. With the increase of deformation strain, lath-shaped SIM remains to be the dominate deformation induced feature in the compressive samples, while the SIM configuration changes dramatically in the tensile samples. Morphology of SIM varies from grain to grain in the samples with 7% tensile strain, and the ratio of grains which have zigzag SIM with a 30° included angle increases obviously. Zigzag SIM with an approximately 150° included angle was found in the 7% compressive sample in the region near β grain boundaries. The features of these two kind of zigzag SIM were characterized in detail with the help of electron backscatter diffraction (EBSD) technology. Concrete analyses were conducted by employing the phenomenological theory of martensite crystallography (PTMC).〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329950-fx1.jpg" width="451" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): J.H. Jeon, D.H. Bae〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study evaluates the effect of cooling rate on the microstructures and conduction properties of an A356 sand cast alloy. To evaluate effect of cooling rate, computer recordable sand mold with four step-thickness (5 mm– 20 mm) was used and microstructures of T6 heat treated specimens with different cooling rates were observed. It was found that with increasing cooling rate, eutectic reaction temperature shifted to lower temperature and the supercooling also increased. Based on the coarsening model via solute diffusion, when the cooling rate increase, secondary dendrite arm spacing decreases, providing the enhanced thermal and electrical conductivities.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329895-fx1.jpg" width="389" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Tae-Hoon Kim, Gaoyuan Ouyang, Jonathan D. Poplawsky, Matthew J. Kramer, Valery I. Levitas, Jun Cui, Lin Zhou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Minimizing phase transformation (PT) hysteresis is of crucial importance for reliability of shape memory alloy (SMA)-based devices, where the lattice strain/stress caused by thermal hysteresis leads to functional degradation. As a result, understanding structural factors that control PT pathway is critical for development of materials with high reversibility. In this study, two distinct PT mechanisms (from 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈msubsup〉〈mrow〉〈mi〉γ〈/mi〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈mrow〉〈mo〉'〈/mo〉〈/mrow〉〈/msubsup〉〈/mrow〉〈/math〉 martensite to 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈msub〉〈mrow〉〈mi〉β〈/mi〉〈/mrow〉〈mrow〉〈mn〉1〈/mn〉〈/mrow〉〈/msub〉〈/mrow〉〈/math〉 austenite phase) in Cu–Al–Ni SMAs were revealed by 〈em〉in-situ〈/em〉 TEM observation. A growth-dominant conventional PT mechanism shows in the fast quench sample, whereas a nucleation-dominant PT mechanism that suppresses interface propagation and induces high thermal hysteresis displays in the slow quench sample. By characterizing the atomic scale composition and microstructure we discover that slow quenching induces nanoprecipitation that changes chemistry of the matrix alloy, which in turn causes the higher PT hysteresis and temperature, while fast quenching avoids the formation of these nanoprecipitates. Our finding provides valuable insights into the fabrication of SMAs with better reliability.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329767-fx1.jpg" width="300" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): Zhichao Yao, Xinyue Zhang, Jiawen Shen, Bo Chen, Ran Ang, Wen Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effective mass of band structure has been proven as a key parameter determining the electrical transport properties of thermoelectrics. Concretely, low effective mass along the transport direction always accompanies with a high carrier mobility, as well as an excellent electronic performance. This work focuses on n-type CdSnAs〈sub〉2〈/sub〉, possessing an intrinsically low effective mass, for its potential as a thermoelectric material. A single Kane band model with acoustic phonon scattering not only enables an assessment of the electrical transport properties, but also provides a well understanding of its underlying physics. Benefited by the low effective mass, an extremely high Hall mobility of ∼4500 cm〈sup〉2〈/sup〉/V-s is obtained in polycrystalline CdSnAs〈sub〉2〈/sub〉, experimentally leading to a high power factor of ∼12 μW/cm-K〈sup〉2〈/sup〉 at 600 K. Based on the model, an excellent peak 〈em〉zT〈/em〉 is expectable through minimizing lattice thermal conductivity and optimizing carrier concentration, which demonstrates it as a promising thermoelectric material.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: Available online 8 August 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds〈/p〉 〈p〉Author(s): Waqas Ali Haider, Muhammad Tahir, Liang He, Wei Yang, Aamir Minhas-khan, Kwadwo Asare Owusu, Yiming Chen, Xufeng Hong, Liqiang Mai〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉For portable electronics, the development of on-chip micro-supercapacitor (MSC) with high energy density is still a tremendous challenge. Carbon-based microelectrodes are very attractive for applications in MSCs, however, their potential window, porous structure and capacitance need to be enhanced and optimized. Herein, we report a pyrolyzed carbon/vanadium disulfide nanosheets (C/VS〈sub〉2〈/sub〉) microelectrode based MSC by modern micromachining photolithography and pyrolysis process. For this C/VS〈sub〉2〈/sub〉 composite microelectrode, carbon and VS〈sub〉2〈/sub〉 contribute synergistically with gel electrolyte and an improved volumetric capacitance with wide potential window is obtained. The fabricated MSC demonstrates a high specific volumetric capacitance of 86.4 F cm〈sup〉−3〈/sup〉, a high energy and a power densities of 15.6 mWh·cm〈sup〉−3〈/sup〉 and 2.88 W cm〈sup〉−3〈/sup〉, respectively with an extended potential window (0–1.2 V). In addition, it shows an excellent cycling behavior, retaining 97.7% capacitance after 10,000 CV cycles at a scan rate of 500 mV s〈sup〉−1〈/sup〉. This proposed approach provides a highly promising strategy of fabricating high-performance energy storage devices for miniaturized electronics.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Daniel Solís-Cortés, Ricardo Schrebler, Elena Navarrete-Astorga, M〈sup〉a〈/sup〉Cruz López-Escalante, Francisco Martín, José R. Ramos-Barrado, Enrique A. Dalchiele〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Thin films of IZO:Ga transparent conducting oxide (TCO) material have been deposited onto glass substrates, using RF magnetron sputtering under different conditions. Film thicknesses varying from 179 to 472 nm, an average Ga/(Ga + Zn + In) atomic ratio value of 1.3%, and In/Zn atomic ratios from 0.55 to 1.05, were obtained. It has been determined that as the In/Zn atomic ratio increases, the resistivity of the films decreases from 1.30 to 0.83 mΩ cm. A single hexagonal c-axis oriented IZO:Ga pure phase has been obtained. The average transmittance of the IZO:Ga film is ca. 80% for all position in the 400–700 nm wavelength region. FE-SEM images show that the IZO:Ga film exhibit a void-free surface with a rough morphology, containing round shape hexagons nanostructures with sizes between 100 and 200 nm. In this work, the electrochemical behavior (stability and electron transfer properties), and photoelectrochemical characteristics of IZO:Ga thin film samples have been examined. The electrochemical stability behavior has been examined by using electrochemical cyclic voltammetry (CV) technique in an acidic aqueous electrolyte, and compared to the behavior of two commercial TCOs on glass substrates (i.e.: ITO and FTO). The effect of IZO:Ga resistivity on the electrochemical performance was also examined by CV. It has been found that the standard electron transfer rate constant of hexacyanoferrate ion diminished at the less electrical conductive IZO:Ga sample (k〈sup〉o〈/sup〉 = 6.27 × 10〈sup〉−5〈/sup〉 cm s〈sup〉−1〈/sup〉) compared to the more conductive one (k〈sup〉o〈/sup〉 = 1.43 × 10〈sup〉−4〈/sup〉 cm s〈sup〉−1〈/sup〉). Photoresponse and photoelectrochemical properties IZO:Ga thin films have been evaluated in 0.1 M Na〈sub〉2〈/sub〉S + 0.1 M Na〈sub〉2〈/sub〉SO〈sub〉3〈/sub〉 aqueous electrolyte, and under AM1.5G (100 mW cm〈sup〉−2〈/sup〉) illumination. All of the IZO:Ga thin film samples demonstrate a typical anodic photocurrent response confirming their 〈em〉n〈/em〉-type conductivity behavior, with photocurrent values as high as 4 μA/cm〈sup〉2〈/sup〉 at anodic potential bias. These results provide useful insights into the behavior of this TCO material and serve as a starting point for the selection of appropriate substrate materials for evaluating novel electrocatalysts, photoelectrodes and optoelectronic devices. As a case study, ZnO nanorods arrays vertically oriented to the substrate plane, exhibiting 200 nm of average diameter, were electrochemically grown onto these synthesized substrates with encouraging novel results.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): G.L. Lu, F.H. Liu, X. Chen, J.F. Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Si@Cu quasi core-shell composite microsized particles with Cu〈sub〉3〈/sub〉Si interface, prepared by ball milling and subsequent heating treatment, were investigated as anode materials for lithium ion batteries. The influence of Cu/Si mass ratio and heating treatment on its electrochemical performance was investigated by means of CV, EIS and discharge/charge test. It is found that Si&2Cu600L composite powders, which were fabricated by heat treating the Cu–Si mixed powders with mass ratio 2 at 600 °C for 6 h, exhibit the best electrochemical performance with 865 mAhg〈sup〉−1〈/sup〉 discharge capacity and 649 mAhg〈sup〉−1〈/sup〉 charge capacity after the 1st cycle and maintaining the charge capacity as high as 523.9 mAh/g after 100 cycles, corresponding to an initial coulombic efficiency of 75% and an average capacity fading rate of 0.23% per cycle, respectively, owing to the synergetic effect of Cu shell with good mechanical flexibility and electrical conductivity as well as Cu〈sub〉3〈/sub〉Si phase both as a buffer layer accommodating the volume change of Si and as an adhesive layer increasing the electrical contact between Si and Cu upon cycling. Moreover, 10 wt% Cu nanowires, instead of carbon black, as conductive additives can further improve its rate capability significantly.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Chen Chen, Binxu Lan, Kang Liu, Hongbo Wang, Xu Guan, Shijie Dong, Ping Luo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Herein, a novel Al–Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉 composite was prepared by ball milling. The ball milling parameters were optimized. Hydrolysis experiments showed that the Al–15 wt% Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉 composite had an induction time of approximately 10 s, which could be eliminated by NaCl and AlCl〈sub〉3〈/sub〉 doping during ball milling. The activation energies of the Al–15 wt% Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉–5 wt% NaCl and Al–15 wt% Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉–5 wt% AlCl〈sub〉3〈/sub〉 composites were 9.43 kJ mol〈sup〉−1〈/sup〉 and 6.87 kJ mol〈sup〉−1〈/sup〉, as calculated by the Arrhenius formula. These low activation energies indicated that the composites reacted readily with water even at low temperatures. X-ray diffraction, scanning electron microscopy, energy-dispersive spectroscopy, and X-ray photoelectron spectroscopy were used to characterize the samples. The results showed that Bi and Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 were formed in situ during ball milling with the decomposition of Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉. However, Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉 had a flake morphology, and regenerated during the hydrolysis reaction. Therefore, Bi〈sub〉2〈/sub〉O〈sub〉2〈/sub〉CO〈sub〉3〈/sub〉 is expected to be useful as a recyclable catalyst to prepare composites that can react quickly with tap water at low temperatures.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Jianyu Li, Qing An, Shusen Wu, Fei Li, Shulin Lü, Wei Guo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The variations of microstructure and mechanical properties with Mg〈sub〉2〈/sub〉Si levels in 〈em〉x〈/em〉Mg〈sub〉2〈/sub〉Si/Al–5Cu (〈em〉x〈/em〉 = 1.5, 3, 5, 10 wt%) composites have been investigated, typically low Mg〈sub〉2〈/sub〉Si content for the first time. The XRD results confirm the presence of Mg〈sub〉2〈/sub〉Si phase without any impurity phases. The Mg〈sub〉2〈/sub〉Si phase is mainly in the form of short sticks from 0 wt% up to 3 wt%, and they distribute uniformly inside or around the Al〈sub〉2〈/sub〉Cu phase. Once the content of Mg〈sub〉2〈/sub〉Si increased to 5 wt%, Mg〈sub〉2〈/sub〉Si exists mainly in the forms of short sticks and with a small number of eutectic Mg〈sub〉2〈/sub〉Si like Chinese characters. Finally all eutectic Mg〈sub〉2〈/sub〉Si phases become coarse Chinese characters in the 10 wt% Mg〈sub〉2〈/sub〉Si/Al–5Cu composites. The 3 wt% Mg〈sub〉2〈/sub〉Si/Al–5Cu composites exhibit the optimal mechanical properties, and the ultimate tensile strength (UTS), yield strength and elongation in as-cast state are 330 MPa, 205 MPa and 7.0%, respectively. The UTS and yield strength are increased by 26.9% and 28.1% than the corresponding values of the Al–5Cu matrix alloy.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Vadahanambi Sridhar, Hyun Park〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Though the utility of manganese compounds such as oxides, sulphides has been well researched in energy storage applications such as super-capacitors and lithium-ion batteries, the utility of manganese nitrides hasn't been reported yet, especially as anode in sodium-ion batteries. In this manuscript we report synthesis of manganese nitride decorated reduced graphene oxide (MnN@rGO) prepared by simple microwave nitridation technique and its utility as anode material in sodium-ion batteries, electrodes in super-capacitors and in EMI shielding applications. In energy storage applications such as sodium ion batteries, MnN@rGO electrodes exhibited sodium storage capacity of 716 mAhg〈sup〉−1〈/sup〉 whereas when used as electrodes in super-capacitors, a high capacitance value of 639.2 Fg〈sup〉-1〈/sup〉 at scan rates of 10 mVs〈sup〉−1〈/sup〉 in 1 M Na〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉 aqueous electrolyte was achieved. The EMI shielding effectiveness measured in the X-band region of 2–18 GHz was about 30–32 dB which is 300% more than reduced graphene oxide.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Amaresh Dey, Debajyoti Das〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Advantages of spectral sensitivity in the infrared range and good stability against light exposure together have made nanocrystalline silicon–germanium alloy (nc-Si〈sub〉1-x〈/sub〉Ge〈sub〉x〈/sub〉) as an ideal absorber material at the bottom-cell in multi-junction Si thin film solar cells. Evolution of good quality SiGe thin films with sustained nanocrystallinity, particularly at low growth temperature (T〈sub〉S〈/sub〉), is a challenging task in view of very different chemical reaction behaviors controlled via different energy requirements of two frequently used source gases, e.g., SiH〈sub〉4〈/sub〉 and GeH〈sub〉4〈/sub〉. Growth of nc-SiGe:H thin films have been pursued at T〈sub〉S〈/sub〉 ∼220 °C, using H〈sub〉2〈/sub〉-diluted (by ∼96%) (SiH〈sub〉4〈/sub〉 + GeH〈sub〉4〈/sub〉) plasma in 13.56 MHz RF-PECVD, by varying the RF power applied to the parallel plate capacitively coupled electrodes of the reactor. At lower RF power Ge-dominated low band gap SiGe network has been produced with Si component in mostly amorphous configuration that leads to a low electrical conductivity. At high RF power Si–Si network becomes highly crystalline; however, Ge content reduces drastically. Breaking of weaker Ge–Ge bonds creates defects via dangling bonds and increased grain boundary defects around Si nanocrystals together produce relatively wider band gap SiGe network with degraded electrical conductivity. The novelty and significance of the present investigation remains in realizing the narrowing of the optical band gap (E〈sub〉g〈/sub〉 ∼1.499 eV) even at lower Ge content, through moderate crystallization in the SiGe network and a simultaneous high electrical conductivity of the nc-SiGe:H films (σ〈sub〉D〈/sub〉 ∼2.38 × 10〈sup〉−3〈/sup〉 S cm〈sup〉−1〈/sup〉) obtained at a high growth rate (∼9.5 nm/min), via optimization of the applied RF power at a moderate level (∼100 W). In such circumstances nanocrystallization of the network plays leading role in narrowing the optical band gap, overriding the effect arising out of the restricted presence of Ge.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092583881932835X-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Scripta Materialia, Volume 173〈/p〉 〈p〉Author(s): Francisco Gil Coury, Diego Santana, Yaofeng Guo, John Copley, Lucas Otani, Solange Fonseca, Guilherme Zepon, Claudio Kiminami, Michael Kaufman, Amy Clarke〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Co〈sub〉55〈/sub〉Cr〈sub〉40〈/sub〉Ni〈sub〉5〈/sub〉 multicomponent alloy was designed to be single-phase face centered cubic (FCC), display high strength, and have the ability to undergo transformation-induced plasticity (TRIP) during plastic deformation. The alloy was produced, and phase stability was monitored in-situ by synchrotron X-ray diffraction during thermomechanical deformation to observe the formation and evolution of the hexagonal close packed (HCP) martensite phase as a function of applied stress. The alloy displays a good combination of strength and ductility, owing largely to the TRIP effect, which increases the strain hardening rate during deformation.〈/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-S1359646219304634-ga1.jpg" width="469" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Anuradha Saini, Ranber Singh, A.A. AlShaikhi, Ranjan Kumar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We compute the temperature dependent relaxation time (〈em〉τ〈/em〉) of charge carriers in LiScX (X = C, Si, Ge) half-Heusler (hH) alloys using the deformation potential theory. This temperature dependent 〈em〉τ〈/em〉 of charge carriers is used to investigate its effect on the thermoelectric properties of these hH alloys. It is shown that there is a significant effect of temperature dependent 〈em〉τ〈/em〉 of charge carriers on the thermoelectric properties of these hH alloys.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Xue Ren, Yueyao Du, Mingyuan Song, Yajie Chen, Yuhao Zhou, Fangwei Ma, Jiafeng Wan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Mesoporous NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 materials with high specific surface area and suitable mesopores display excellent supercapacitor performance due to rich electroactive sites and short diffusion paths. Here, the mesoporous NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 microaggregates composed of nanoparticles are first successfully prepared by a simple anion exchange method to puff NiCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 cubes. The NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 microaggregates possess rich mesoporous structure with high surface area of 63.79 m〈sup〉2〈/sup〉 g〈sup〉−1〈/sup〉 and suitable pore size distribution centered at 6.1 nm. The NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉 microaggregates deliver high specific capacity of 249 mAh g〈sup〉−1〈/sup〉 (at 1 A g〈sup〉−1〈/sup〉) and good rate capability of 56.2% capacity retention from 1 to 20 A g〈sup〉−1〈/sup〉. The fabricated NiCo〈sub〉2〈/sub〉S〈sub〉4〈/sub〉//AC ACS exhibits a prominent energy density of 47.9 Wh kg〈sup〉−1〈/sup〉 at a power density of 783 W kg〈sup〉−1〈/sup〉 and immensely distinguished cycling stability (98.8% retention of the initial capacitance after 4000 cycles). These remarkable performances can corroborate superiority of the mesoporous structure for improving supercapacitor electrode properties.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819328609-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Scripta Materialia, Volume 173〈/p〉 〈p〉Author(s): A. Zafari, K. Xia〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A new strategy for future alloys by hybridising microstructures of existing alloys using selective laser melting was introduced. In particular, two existing Ti alloys were hybridised, leading to a new Ti, referred to as HYbrid Ti Alloy (HYTA). An excellent combination of high strength, work hardening and ductility was achieved, superior to conventional Ti. Further, individual properties of HYTA were manipulated via simple heat treatments, revealing great versatility. This novel approach can be applied to a vast variety of metals beyond Ti and contributes significantly to the coming era of microstructure-by-design.〈/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-S1359646219304397-ga1.jpg" width="457" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): S. Laha, J. Gopalakrishnan, S. Natarajan, J. Romero de Paz, E. Solana-Madruga, A.J. Dos Santos-García, S. García-Martín, O. Fabelo, E. Morán-Miguélez, R. Sáez-Puche〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Ln〈sub〉3〈/sub〉Ni〈sub〉2〈/sub〉RuO〈sub〉9〈/sub〉 (Ln = La, Nd) oxides (prepared by a solid state metathesis route) adopt a monoclinic (〈em〉P2〈/em〉〈sub〉〈em〉1〈/em〉〈/sub〉〈em〉/n〈/em〉) A〈sub〉2〈/sub〉BB'O〈sub〉6〈/sub〉 double perovskite structure wherein the two independent octahedral 2c and 2d sites are occupied by Ni〈sup〉2+〈/sup〉 and (Ni〈sup〉2+〈/sup〉〈sub〉1/3〈/sub〉Ru〈sup〉5+〈/sup〉〈sub〉2/3〈/sub〉) cations, respectively. In contrast to the expected ferromagnetic behavior, Ln〈sub〉3〈/sub〉Ni〈sub〉2〈/sub〉RuO〈sub〉9〈/sub〉 oxides show a spin-glass behavior without long range magnetic order down to 2 K. These results reveal the importance of competing nearest neighbor (NN), next nearest neighbor (NNN) and third nearest neighbor (third NN) interactions between the magnetic Ni〈sup〉2+〈/sup〉 and Ru〈sup〉5+〈/sup〉 ions in the partially ordered double perovskite structure that conspire to thwart the expected ferromagnetic order in these materials.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819328695-fx1.jpg" width="274" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Scripta Materialia, Volume 173〈/p〉 〈p〉Author(s): Dong Wang, Xu Lu, Di Wan, Zhiming Li, Afrooz Barnoush〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We show for the first time that a critical amount of dissolved hydrogen can induce a phase transformation from γ-austenite to ε-martensite in an interstitial metastable high-entropy alloy. This is demonstrated by in-situ hydrogen charging in combination with nanoindentation and scanning probe microscopy, plus further electron channeling contrast imaging, X-ray diffraction, and transmission Kikuchi diffraction techniques. The transformed martensites appear as bands on the surface along γ-{111} habit planes, leading to an irreversible increase of hardness. The hydrogen-induced internal stress together with the intrinsic hydrogen effects are proposed to be responsible for the martensitic transformation upon hydrogen charging.〈/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-S1359646219304506-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Ru Zhao, Houbing Huang, Wangqiang He, Haoyu Wang, Hasnain Mehdi Jafri, Junsheng Wang, Xingqiao Ma〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Magnetocaloric effects, because of their large entropy change, have been demonstrated to potentially revolutionize the solid-state cooling devices with high energy efficiency and environmental friendliness. However, the requirement of applying large magnetic fields obstructs the minimization of cooling devices. Here, we investigated electric-field-control magnetocaloric effects in magnetoelectric heterostructures by combining thermodynamic modelling and first-principle calculations. Based on strain-mediated mechanism, it is demonstrated that the interface strain of ferroelectric film under the electric field can tune the magnetic transition temperature from ferromagnetic to antiferromagnetic phases with 5 K shift under a small electric field of 0.1 MV/m and a giant entropy change of 14.9 J/(kg·K). In addition, we propose a potential multicaloric device including magnetocaloric and elastocaloric effects with high cooling efficiency based on magnetic-elastic-electric coupling phase transformations. The present study therefore contributes to the understanding of electric-field-control magnetocaloric cooling and provides guidance for experiments to design high efficiency and low-power consumption multicaloric cooling devices using magnetoelectric heterostructures.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Scripta Materialia, Volume 173〈/p〉 〈p〉Author(s): Wen Jiang, Xingwang Cheng, Zhiping Xiong, Hongnian Cai, Jian Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Cold deformation was realized in the transparent polycrystalline yttrium aluminum garnet (YAG) using Vickers indentation. Following this, annealing at 1500 °C for 2 h led to a grain refinement from 4.8 to 0.49 μm in the plastically deformed region, indicating the occurrence of recrystallization. It is supported by transmission electron microscope characterization that plastic deformation-induced dislocations are annihilated and rearranged, resulting in the formation of new grain boundaries during annealing.〈/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-S135964621930466X-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Scripta Materialia, Volume 173〈/p〉 〈p〉Author(s): Charles Manière, Guillaume Riquet, Sylvain Marinel〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Flash sintering is an approach allowing reducing the sintering time to mere seconds. To improve the microstructures and the properties of flash sintered specimens, this process has been successfully adapted to pressure assisted sintering such as the spark plasma sintering. This work is the exploration of the potential of this ultra-rapid sintering process for the improvement of the dielectric properties of well-known materials such as BaTiO〈sub〉3〈/sub〉 and CaCu〈sub〉3〈/sub〉Ti〈sub〉4〈/sub〉O〈sub〉12〈/sub〉. In particular, we focus on the potential improvement of the dielectric loss, colossal permittivity and microstructures of these materials after ~20 s sintering and annealing.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉FlashSPS of BaTiO〈sub〉3〈/sub〉 and CaCu〈sub〉3〈/sub〉Ti〈sub〉4〈/sub〉O〈sub〉12〈/sub〉, microstructure analysis and dielectric properties.〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S1359646219304671-ga1.jpg" width="352" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Jyoti, G.D. Varma〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Pure and Ag-CuO nanostructures with different Ag content (Cu〈sub〉1-x〈/sub〉Ag〈sub〉x〈/sub〉O, x = 0, 0.02, 0.05, 0.08 and 0.12) were synthesized via hydrothermal method and their composite films with reduced graphene oxide (rGO) were fabricated by drop casting method for the gas sensing measurements. Different techniques like XRD, FESEM, TEM, BET, Raman and XPS were used for the characterization of the samples. FESEM and TEM results depicted the formation of nanobrick like morphology for pure and Ag-CuO. Moreover, FESEM elemental mapping of Ag-CuO samples showed the homogeneous distribution of Cu, Ag and O in all the samples. The experimental results of the NO〈sub〉2〈/sub〉 gas sensing at different operating temperatures ranging from 22 to 100 °C revealed that Ag-CuO/rGO sensor with 5 at% Ag exhibited maximum response. At room temperature (RT) of ∼22 °C, Ag-CuO/rGO (5 at% Ag) showed 67.2% response to 20 ppm NO〈sub〉2〈/sub〉 which is 1.9 times of the CuO/rGO sensor. Thus the amount of Ag content in the CuO/rGO sensor influence the NO〈sub〉2〈/sub〉 gas sensing response. In addition, Ag-CuO/rGO (5 at% Ag) possessed excellent response time of 35 s for 20 ppm NO〈sub〉2〈/sub〉, good repeatability, stability and selectivity for NO〈sub〉2〈/sub〉 gas. Interestingly, Ag-CuO/rGO (5 at% Ag) sensor showed maximum response at an intermediate relative humidity (∼52%RH). Moreover, the sensing mechanism for improved sensing performances of the Ag-CuO/rGO sensor was discussed in this paper. The present work suggests that the Ag-CuO/rGO composite is a potential material for detection of NO〈sub〉2〈/sub〉 at RT.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Scripta Materialia, Volume 173〈/p〉 〈p〉Author(s): Quentin Flamant, David R. Clarke〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The possibility of identifying new classes of oxides having lower thermal conductivity at high temperatures is unlikely as the values are approaching the theoretical minimum. At the same time, the drive for higher engine efficiency requires higher gas temperatures, increasing the radiative heat flux. The significance of radiative heat transfer in the selection of coating materials is examined. It is concluded that optically opaque materials will perform better as coatings under high convective flow conditions, such as on blades, by minimizing radiative heating through the coating. This can be achieved by a combination of atomic level doping and scattering.〈/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-S135964621930449X-ga1.jpg" width="473" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Samira Yousefzadeh〈/p〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Hongsheng Chen, Huihui Nie, Wenxian Wang, Jun Zhou, Runfeng Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, novel-structured (Type A and Type B) laminar A6061/B〈sub〉4〈/sub〉C neutron absorber composites were designed and fabricated using spark plasma sintering followed by hot extrusion and rolling (SPS-HER). It was found that B〈sub〉4〈/sub〉C particles were evenly distributed in the fabricated composites. The interfaces between particle/matrix and different layers were bonded well. After hot rolling, regions containing large orientation gradient and high dislocation density were found near the B〈sub〉4〈/sub〉C particles, which helped dynamic recrystallization (DRX) and grain refinement in the composite. Compared with that of the as-extruded AA6061/B〈sub〉4〈/sub〉C laminar composite, yield and ultimate tensile strengths of the as-rolled AA6061/B〈sub〉4〈/sub〉C laminar composite are clearly improved. Two yield points were noticed in the material during the tensile test. The composite containing high B〈sub〉4〈/sub〉C particle content was found easy to fracture and the fracture mode was ductile.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Sungwon Yoon, Gwon Deok Han, Dong Young Jang, Jun Woo Kim, Dong Hwan Kim, Joon Hyung Shim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, we successfully fabricated an yttria-stabilized zirconia (YSZ) aerogel using the sol-gel method and CO〈sub〉2〈/sub〉 supercritical drying. We confirmed the successful thermal insulation function as a thermal barrier coating (TBC) on a high-temperature gas turbine surface. In order to evaluate the performance of the YSZ aerogel, the thermal conductivity and temperature profile were measured in addition to microstructure observation by scanning electron microscopy. The thermal conductivity of the YSZ aerogel was 0.212 W/m·K at 1000 °C, which is significantly lower than the reference values of YSZ materials. The low heat conduction is attributed to heat insulation by the fine pores and low heat conduction through the nanopore spaces in the aerogel structure. The heat insulation of the YSZ aerogel as the TBC was evaluated on a gas turbine blade material by monitoring surface temperature profiles on a heater at 300–700 °C. The heat-blocking performance of the YSZ aerogel coating was superior to that of a conventional YSZ TBC (by 30–50%). By comparison with a numerical calculation, the thermal conductivity of the YSZ aerogel coating was estimated to be 0.05 W/m·K, which is significantly lower (30–40 times) than that of the YSZ TBC used for commercial gas turbines. The porous structure of the aerogel was well preserved even after the high-temperature test confirming the good thermal stability. This study demonstrated that the YSZ aerogel is promising as a gas turbine TBC material.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Michalina Walas, Marta Lisowska, Tomasz Lewandowski, Ana I. Becerro, Marcin Łapiński, Anna Synak, Wojciech Sadowski, Barbara Kościelska〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Glasses and glass-ceramics with nominal composition 73 TeO〈sub〉2〈/sub〉– 4BaO– 3Bi〈sub〉2〈/sub〉O〈sub〉3〈/sub〉–18SrF〈sub〉2〈/sub〉-2RE〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 (where RE = Eu, Dy) have been synthesized by conventional melt-quenching technique and subsequent heat treatment at 370 °C for 24 h in air atmosphere. Various Eu〈sup〉3+〈/sup〉 to Dy〈sup〉3+〈/sup〉 molar ratio have been applied to investigate luminescence properties in both glass and glass-ceramic matrices. Especially, white light emission through simultaneous excitation of Eu〈sup〉3+〈/sup〉 and Dy〈sup〉3+〈/sup〉 has been studied in detail. Influence of crystalline SrF〈sub〉2〈/sub〉 phase on luminescence kinetics has been determined by luminescence decay time measurements. Presence of crystalline SrF〈sub〉2〈/sub〉 phase has been confirmed by X-ray diffraction technique XRD and transmission electron microscopy TEM. X-ray photoelectron spectroscopy XPS and Fourier-transform infrared spectroscopy FTIR have been applied to get further insight into structural properties of glass and glass-ceramic materials. Color tunable white light emission has been obtained using UV excitation. Influence of the SrF〈sub〉2〈/sub〉 crystallization on luminescence properties of prepared materials have been described in detail. Moreover, luminescence properties and especially emission color dependence on the Eu〈sup〉3+〈/sup〉 to Dy〈sup〉3+〈/sup〉 molar ratio have been exhaustively studied. Color-tunable white light emission has been observed as a result of simultaneous radiative transition of both, Eu〈sup〉3+〈/sup〉 and Dy〈sup〉3+〈/sup〉 ions when applying UV excitation. Judd – Ofelt and other optical parameters have been calculated based on luminescence emission spectra. Achieved results confirm that tellurite glass-ceramics containing SrF〈sub〉2〈/sub〉 nanocrystals are good hosts for RE〈sup〉3+〈/sup〉 ions and they can be considered as new phosphors for white light emitting diodes WLEDs.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Moufida Saad, Habib Elhouichet〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Sodium zinc phosphate glasses containing silver nanoparticles (Ag NPs), Eu〈sup〉3+〈/sup〉 and Dy〈sup〉3+〈/sup〉 ions, have been prepared using the melt-quenching method. The structure, luminescence and spectroscopic properties were evaluated through experimental and theoretical studies. The results indicate that a dual mode energy transfer from Ag NPs and Dy〈sup〉3+〈/sup〉 ions to Eu〈sup〉3+〈/sup〉 ions leads to the enhancement of the emission bands related to Eu〈sup〉3+〈/sup〉 ions in addition to the local field effect of the silver NPs. Moreover, the excited Dy〈sup〉3+〈/sup〉 ions exchange energy with Eu〈sup〉3+〈/sup〉 in the presence of Ag NPs and Ag nanoclusters (Ag NCs) produces white color with varying tints. The present systematic study provides useful information for the development of light emitting diodes (LEDs) devices.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Dongming Zhang, Junjun Zhang, Haoyu Wang, Can Cui, Weizhou Jiao, Jing Gao, Youzhi Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, porous NiO with three-dimensional (3D) nanostructures are prepared by a chemical bath deposition (CBD) process in oxalic acid solution at a fixed temperature using Ni foam (NF) as the substrate and Ni source, and followed by an electrochemical activation treatment in an alkaline medium. The special 3D porous structure of the as-prepared NF based NiO (NiO/NF) electrode is benefit for the diffusion of fuels (CH〈sub〉3〈/sub〉OH/C〈sub〉2〈/sub〉H〈sub〉5〈/sub〉OH and urea) during the electrochemical reaction. Besides, the obtained NiO may combine with the remained nickel oxalate (NiC〈sub〉2〈/sub〉O〈sub〉4〈/sub〉) to further enhance the catalytic performance due to its synergistic effect. At 0.60 V, the electrooxidation current density reached 257 mA cm〈sup〉−2〈/sup〉 in 1.0 mol dm〈sup〉−3〈/sup〉 NaOH and 0.40 mol dm〈sup〉−3〈/sup〉 CH〈sub〉3〈/sub〉OH, and a high performance of 120 mA cm〈sup〉−2〈/sup〉 was achieved in 1.0 mol dm〈sup〉−3〈/sup〉 NaOH and 0.10 mol dm〈sup〉−3〈/sup〉 C〈sub〉2〈/sub〉H〈sub〉5〈/sub〉OH. The oxidation current density reached 222 mA cm〈sup〉−2〈/sup〉 in 0.1 mol dm〈sup〉−3〈/sup〉 urea with the NaOH concentration of 8.0 mol dm〈sup〉−3〈/sup〉 NaOH at around 0.48 V. The facile preparation method, high electrocatalytic activity, low cost and various applications make the NiO/NF be a promising electrode material.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Arvind Singh, Sumeet Kumar, Bilal Ahmed, Ranjan K. Singh, Animesh K. Ojha〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Rod shaped structures of molybdenum trioxide (MoO〈sub〉3〈/sub〉) were synthesized at low temperature using simple and low cost method. The synthesized materials were characterized by different characterization techniques. The effect of annealing temperature on crystal structure and optical properties of MoO〈sub〉3〈/sub〉 was investigated. The hexagonal phase (h-MoO〈sub〉3〈/sub〉) was observed up to 300 °C and beyond this temperature, the phase of the MoO〈sub〉3〈/sub〉 is changed to orthorhombic (α-MoO〈sub〉3〈/sub〉). The transition of crystal phase (h-MoO〈sub〉3〈/sub〉 to α-MoO〈sub〉3〈/sub〉) was investigated by analyzing the X-ray diffraction (XRD), Raman and DSC measurements. The shift in the wavenumber position of 971 cm〈sup〉−1〈/sup〉 (Mo–O stretching) peak with temperature also substantiates the phase transition in MoO〈sub〉3〈/sub〉 structure. The shape of nanostructured MoO〈sub〉3〈/sub〉 was modified with annealing temperature. The change in crystal phases and shapes with temperature may result defects in the structure, which essentially modify the structural and optical properties of the material. The photocatalytic properties of the synthesized materials were studied on methylene blue (MB) dye under UV-irradiation. The sample annealed at 400 °C (M4) show excellent photodegradation compared to other samples. It could be due to the combined effects of shape (helical) and defects (oxygen vacancies) present in M4, as supported by the electron paramagnetic resonance (EPR) measurements. Among the various radicals, OH〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/rad"〉 plays an important role in photodegardation of the MB dye.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Kosuke Takagi, Tsuyoshi Mayama, Yoji Mine, Yu Lung Chiu, Kazuki Takashima〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The deformation behaviour of single crystals of an Mg〈sub〉85〈/sub〉Zn〈sub〉6〈/sub〉Y〈sub〉9〈/sub〉 alloy with an 18R-LPSO structure was experimentally and numerically investigated using a micro-tensile testing method and a crystal plasticity finite element method, respectively. The deformation microstructure was characterised using optical and electron microscopy. The experimental results indicated that kink band was formed in the specimens depending on the initial crystal orientation relative to the loading direction. The kink banding was accompanied with remarkable ductility of over 50% nominal strain. The deformation behaviour observed was successfully reproduced in a crystal plasticity finite element analysis. The numerical results indicated that the kink band was formed by the accumulation of basal slip, which was enhanced by the geometrical softening owing to the lattice rotation. The growth of a kink band, which was reasonably explained by the changes in Schmid factor for a basal slip system due to lattice rotation, suppressed the localised failure at low strain. This resulted in the observed extended ductility, even in the LPSO structure with strong plastic anisotropy.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819328592-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Rekha Gupta, Jyoti Shah, C. Sharma, R.K. Kotnala〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Bilayer thin films of multiferroic oxide BiFeO〈sub〉3〈/sub〉 and metallic alloy Fe〈sub〉97〈/sub〉Si〈sub〉3〈/sub〉 deposited by RF-magnetron sputtering have been investigated to understand spin polarized electron transport across bilayer interface. Effect of BiFeO〈sub〉3〈/sub〉 thickness variation on magnetic and magnetotransport properties of bilayer thin films has been analyzed. An induced unidirectional magnetic anisotropy in bilayer thin films has been observed by interface coupling between antiferromagnetic BiFeO〈sub〉3〈/sub〉 and ferromagnetic Fe〈sub〉97〈/sub〉Si〈sub〉3〈/sub〉 spin magnetic moments. Increasing interface roughness with increase in BiFeO〈sub〉3〈/sub〉 film thickness has been found to be a regulatory factor for inducing in-plane unidirectional anisotropy and exchange interaction at bilayer interface. A high magnetic moment ∼315 emu/cc originated at room temperature by uncompensated interface spin density has been measured in 30 nm thick BiFeO〈sub〉3〈/sub〉 film. Magnetic inhomogeneities at interface give rise to a spin glass like phase responsible for spin flip scattering at bilayer interface. Enhanced low field magnetoresistance ∼30% in 60 nm thick BiFeO〈sub〉3〈/sub〉 film is ascribed to intensified scattering from disordered interface states with increasing BiFeO〈sub〉3〈/sub〉 thickness. Magnetodielectric measurements (applied magnetic field 1 kOe) have revealed five times increase in relaxation time of charge carriers inside grains confirming intergrain charge transport dominated by alignment of magnetic moments of nearby grains via exchange coupling. High value of magnetoresistance ∼46% in 60 nm thick film of increased grain size is due to enhanced critical length for charge transport. Observed room temperature magnetoresistive properties of BiFeO〈sub〉3〈/sub〉/Fe〈sub〉97〈/sub〉Si〈sub〉3〈/sub〉 thin films are critical for developing multiferroic antiferromagnetic based spintronic devices.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819328658-fx1.jpg" width="368" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): I. Stambolova, O. Dimitrov, S. Vassilev, St. Yordanov, V. Blaskov, N. Boshkov, M. Shipochka〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉One-component CeO〈sub〉〈strong〉2〈/strong〉〈/sub〉 coatings and bi-component CeO〈sub〉2〈/sub〉/ZrO〈sub〉2〈/sub〉 multilayer coatings were obtained by a sol gel process. The phase composition, surface morphology and roughness of the samples were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), Atomic force microscopy (AFM) and X-ray scanning electron microscopy (XPS). The corrosion resistance and protective ability were characterized by using salty solution of 3.5% NaCl at 25 °C. The multilayer configuration of CeO〈sub〉2〈/sub〉 and ZrO〈sub〉2〈/sub〉 ensure enhanced protection of the steel in comparison to the single CeO〈sub〉2〈/sub〉 coatings and uncoated steel. The surface morphology and anticorrosion properties depend significantly on the treatment temperature of both CeO〈sub〉2〈/sub〉 underlayer and ZrO〈sub〉2〈/sub〉 top layer. At lower treatment temperatures, they are relatively dense and smooth. The corrosion resistance of the multilayers slows down, when ZrO〈sub〉2〈/sub〉 coatings were heated above 500 °C. This probably is due to the more pronounced crystallization of cubic zirconium dioxide, resulting in deeper boundaries between the individual grains. The protective properties of a CeO〈sub〉2〈/sub〉/ZrO〈sub〉2〈/sub〉 multilayers could be attributed to the low crystallized structure with very fine crystallites. Potentiodynamic measurements showed that all multilayer systems have more negative corrosion potential values compared to the corrosion potential of the steel substrate and will protect it in the case of corrosion attack due to electrochemical reasons.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Lan Wu, Zhifeng Wang, Cuihua An, Guang He〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Lithium sulfur batteries have been recognized as a promising on-board energy-storage technology. One of the challenges in this system is the efficient inhibition of polysulfides shuttle with the low-cost sulfur hosts. In this work, we report the fabrication of nanoporous CeO〈sub〉2〈/sub〉 and TiO〈sub〉2〈/sub〉 by a novel chemical dealloying approach as a thin nonconductive interlayer to confine polysulfides in the cathodes. The abundant pores provide channels for the transportation of electrolyte, whereas the dissolved polysulfide species are chemically interacted with the metal oxides. Between the two interlayers, CeO〈sub〉2〈/sub〉 demonstrates superior performance over TiO〈sub〉2〈/sub〉, which is attributed to the appropriate redox window of the Ce〈sup〉3+〈/sup〉/Ce〈sup〉4+〈/sup〉 couple to in-situ catalyse the polysulfides. The cells with such a configuration exhibit significantly enhanced capacities and long-term stability. Even at a high sulfur loading of 6 mg cm〈sup〉−2〈/sup〉, it is demonstrated stable capacities of ∼600 mAh g〈sup〉−1〈/sup〉 over 120 cycles. These results suggest chemical dealloying is an efficient approach to prepare desired nanoporous interlayers to achieve practical cycling performance with a commercial sulfur host.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Ying-Kang Wei, Xiao-Tao Luo, Yi Ge, Xin Chu, Guo-Sheng Huang, Chang-Jiu Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, three types of fully dense aluminum-based (Al) coatings (pure Al, AA2219 and AA6061) were deposited on AZ31B magnesium (Mg) alloy by a recently developed in-situ micro-forging assisted cold spray process. The detailed microstructure, coating adhesion and corrosion protection performance were systematically investigated. Results show that the porosities of the pure Al, AA2219 and AA6061 coatings are as low as 0.34 ± 0.11%, 0.23 ± 0.09% and 0.24 ± 0.08%, respectively. Strong adhesion strength (83.6–91.5 MPa) was achieved for the Al-based coatings due to the in-situ micro-forging induced enhanced mechanical-interlocking between Al-based coating and the magnesium alloy substrate. The corrosion current density of the AZ31B Mg alloy decreases to 1.9–5.8 μA cm〈sup〉−2〈/sup〉 from 312.8 μA cm〈sup〉−2〈/sup〉 after coated with the Al-based coatings. The long-term corrosion tests further indicate that the Al-based coatings are not aqueous solution permeable during the entire 1000 h immersion, thus provided robust long-term corrosion protection of AZ31B Mg alloy substrate. Moreover, the difference in corrosion resistances among the three Al-based coatings was observed and was further explained based on their unique microstructures arising from the coating deposition process. The present in-situ micro-forging assisted cold spray process shows great potential for economical and effective corrosion protection of magnesium alloy and provides more freedom for industries to design and use magnesium alloy parts.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092583881932794X-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Andrey A. Chernousov, Ben Y.B. Chan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉〈em〉In situ〈/em〉 nitridation of pre-compacted aluminium flakes is shown to be a key to lightweight composites for many engineering applications such as more efficient and cost-effective construction vehicles. This new composite has the mechanical properties of high-strength streels while being ∼3.4 times lighter. This composite was produced by: (i) compaction of micrometric Al flakes into porous blanks, (ii) partial melting through rapid heating to 870 K in N〈sub〉2〈/sub〉 and (iii) annealing of the pre-melted blanks at 750 K in N〈sub〉2〈/sub〉, where different Al flake deoxidisers were used to control a sufficiently low level of H〈sub〉2〈/sub〉O/O〈sub〉2〈/sub〉 activating 〈em〉in situ〈/em〉 nitridation. The nitrided composites contained stellar dendrites composed of Al, AlN and γ-Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉, in which the ceramic fraction increases over the nitridation stage. The traces of H〈sub〉2〈/sub〉O in the N〈sub〉2〈/sub〉 atmosphere were found to be beneficial for strengthening, due to oxidation and suppression of the composite dendrites from overgrowing and segregation.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Woo-Jung Lee, Dae-Hyung Cho, Yi Do Kim, Myung-Woon Choi, Jin Chul Choi, Yong-Duck Chung〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In recent years, amorphous InZnO (a-IZO) film gets recognition for the possibility as a transparent conducting oxide (TCO) layer with outstanding its optical and electrical properties in photovoltaic devices. Generally, the sputtering technique is normally used to deposit a-IZO film, which suffers from plasma damage exerting a negative influence on device performance. Here, we suggest an alternative to deposit a-IZO film with a thermal evaporation technique using a simply customized system to compensate defects by plasma damage. Thermally grown IZO films by controlling two variables of Zn rate and substrate temperature show the distinguishable characters in terms of transparency, conductivity and crystalline structure with a substantial change of Zn content in In〈sub〉1-〈em〉x〈/em〉〈/sub〉Zn〈sub〉〈em〉x〈/em〉〈/sub〉O. Zn incorporation in IZO film is considered as a critical key to determining the crystal structure and IZO film quality. In the thermal evaporation system, phase transition occurs from crystalline to amorphous; the IZO film indicates the superior property in the amorphous phase than crystalline structure. We acquired the optimized IZO film with amorphous phase in the relative concentration of In〈sub〉0.73〈/sub〉Zn〈sub〉0.27〈/sub〉O grown at 200 °C. To demonstrate the feasibility of a-IZO film as a TCO layer, Cu(In,Ga)Se〈sub〉2〈/sub〉 solar cell was practically fabricated, which shows excellent performance. It is attributed to the absence of plasma damage during deposition of the a-IZO film, proved by the decrease of shunt resistance in the solar cell.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Chuan Jing, Yanmei Zhu, Xiaoying Liu, Xiaofei Ma, Fan Dong, Biqin Dong, Shaochun Li, Nan Li, Tian Lan, Yuxin Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Preparation of two-dimensional hybrid nanoarrays with porous structure and multiple active components is considered as an effective strategy to improve the electrochemical performance of supercapacitors. Herein, etched CoAl LDO/MnO〈sub〉2〈/sub〉 was in-situ prepared on Ni foam by a simple hydrothermal process and subsequent alkali etching treatment. The morphologies and structures of synthetic nanocomposites were examined by XRD, SEM, TEM, EDS, BET and XPS. The nanocomposites present unique hybrid nanoarrays in which etched CoAl LDO nanoarrays form a core and worm-like MnO〈sub〉2〈/sub〉 nanosheets create a shell. The electrochemical properties of etched CoAl LDO/MnO〈sub〉2〈/sub〉 electrodes were examined by CV, CC and cycling tests. The results exhibit an excellent areal specific capacitance of 991 mF cm〈sup〉−2〈/sup〉, desirable rate capability and outstanding cycling stability of 79.87% retention over 10000 cycles. The asymmetric supercapacitor using etched CoAl LDO/MnO〈sub〉2〈/sub〉//AG achieves the maximum energy density and power density of 16.6 Wh kg〈sup〉−1〈/sup〉 and 5000 W kg〈sup〉−1〈/sup〉, respectively. The excellent electrochemical performance of the as-prepared material suggests its potential application for clean energy storage.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Kun Bai, Ruosheng Zeng, Bao Ke, Sheng Cao, Xiaogang Xue, Rihui Tan, Bingsuo Zou〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Doping has been established as a powerful approach for endowing novel properties to perovskite nanocrystals (NCs).However, the fast formation of perovskites makes the fundamental understanding of doping processes in these NCs very rare. In the present work, a mild temperature (〈100 °C) approach to produce Mn〈sup〉2+〈/sup〉 doped CsPbCl〈sub〉3〈/sub〉 (Mn:CsPbCl〈sub〉3〈/sub〉) perovskite NCs in toluene is reported. The effects of the introduced Mn/Pb ratios in the raw materials as well as the temperature on the structure and photoluminescence (PL) properties of Mn:CsPbCl〈sub〉3〈/sub〉 NCs were investigated systematically. The as-synthesized Mn:CsPbCl〈sub〉3〈/sub〉 NCs shown a strong Mn〈sup〉2+〈/sup〉 emission at 594 nm with a PL quantum yield (QY) of 52%, and the doping concentrations can be easily tailored from 1.8 〈em〉atom〈/em〉% to 13.3 〈em〉atom〈/em〉% by changed the Mn/Pb feed ratios. The study revealed that the reaction temperature plays a key role in Mn:CsPbCl〈sub〉3〈/sub〉 NCs. Through elemental and microstructure characterization, it was surprisingly found that lattice ejection of Mn ions occurred at 100 °C. This result greatly enhances the understanding of the “basic process” of Mn〈sup〉2+〈/sup〉doping in CsPbCl〈sub〉3〈/sub〉 NCs, which provides some insights into the preparation of metal ion doped perovskite NCs.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Jiyu Fan, Yunfei Xie, Fengjiao Qian, Yanda Ji, Dazhi Hu, Rujun Tang, Wei Liu, Lei Zhang, Wei Tong, Chunlan Ma, Hao Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉For achieving more functionalities of perovskite manganese oxides film, an epitaxial La〈sub〉0.8〈/sub〉Sr〈sub〉0.2〈/sub〉MnO〈sub〉3〈/sub〉 (LSMO) film was deposited on a flexible substrate (mica) by pulsed laser deposition. The film shows a paramagnetic-ferromagnetic (PM-FM) phase transition at 134 K together with metal-insulator transition (MIT) at 149 K. The measurement of hysteresis loop indicates that the easy-magnetization axis lied in film plane. The transport behavior can be fitted well with the small polaron model, giving out the activation energy E〈sub〉〈em〉hop〈/em〉〈/sub〉 = 176.9 meV. Different from the common anisotropic magnetoresistance (AMR) in manganite film, an isotropic magnetoresistance (IMR) effect was observed in LSMO film and the relatively small thickness of LSMO film (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈mo〉∼〈/mo〉〈/mrow〉〈/math〉50 nm) is a major reason for it. After the cyclic flexural bending for 1.0〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈mo〉×〈/mo〉〈/mrow〉〈/math〉10〈sup〉4〈/sup〉 times, we found the magnetic properties of LSMO film were improved. Micromagnetic detection shows that the activation energy for polaron hopping (E〈sub〉〈em〉a〈/em〉〈/sub〉 = 144.7 meV) remarkably decreases by the cyclic flexural bending process. We suggested that the inhomogeneous/incompact part located at the zone of neighbouring domains become uniform and tight after circulating bending, which facilitates the rotation of domains and the polarons hopping so that the magnetic and electronic performance are enhanced.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Xian-Sheng C.A.O.〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The magnetic entropy change (MEC) properties of 〈em〉BiFeO〈/em〉〈sub〉3〈/sub〉 (BFO) were investigated theoretically by means of quantum microscopic calculations based on the Green's function, the classical thermodynamical theory and Maxwell's relation. The MEC increase as the temperature rises, while decline steeply from max to zero at the magnetic phase transition temperature 〈em〉T〈/em〉〈sub〉N〈/sub〉. This anomaly of the MEC can be explained as the antiferromagnetic phase transition. The temperature dependence of MECs shows two kinks. One kink appears at the temperature 〈em〉T〈/em〉〈sub〉1〈/sub〉 = 425K, which is interpreted as the result of the dependence of the spin cycloid anharmonicity on temperature. Another abnormal kink of MEC appears at nearly T〈sub〉2〈/sub〉 = 550 K, which is associated with the onset of structural changes. Besides, it is found that 〈em〉T〈/em〉〈sub〉N〈/sub〉 shifts to higher temperature as the exchange coupling constants (〈em〉J〈/em〉〈sub〉1〈/sub〉) between one magnetic spin and its nearest neighbor, the exchange coupling constants (〈em〉J〈/em〉〈sub〉2〈/sub〉) between the two next- nearest neighbor magnetic spins, the exchange coupling constant (〈em〉I〈/em〉) between the nearest neighbor pseudo-spin and magnetoelectric coupling constant (〈em〉g〈/em〉) increase. What's more, it is also found that the magnetic entropy is decrease as the 〈em〉J〈/em〉〈sub〉1〈/sub〉 and 〈em〉J〈/em〉〈sub〉2〈/sub〉 increase. At last but not least, the 〈em〉I〈/em〉 and 〈em〉g〈/em〉 affect magnetic entropy only in the vicinity of 〈em〉T〈/em〉〈sub〉N〈/sub〉. Those achieved conclusions are in good accordance with the experimental results and other theory findings.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Xiaowei Wang, Feng Liang, De-gang Zhao, Desheng Jiang, Zongshun Liu, Jianjun Zhu, Jing Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Three InGaN/GaN MQWs samples with different QB layers growth temperatures were grown on sapphire substrate by metalorganic chemical vapor deposition (MOCVD). It is found that the electroluminescence intensity increases first and then decreases with increasing growth temperature of GaN barrier layers when the growth temperature increases from 800 °C to 880 °C. The XRD and AFM measurements show that a better interface quality exists in InGaN/GaN MQW whose GaN barrier layers grown at a higher temperature. However, when the growth temperature of GaN barriers is too high, a quality degradation of QWs will occur for underlying InGaN well layers, resulting in a decrease of the luminous intensity of the active region. Finally, we proposed that using three temperature growth scheme could improve the electroluminescence efficiency of the active region compared to conventional dual-temperature growth method.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Stefan Schwarzmüller, Fangshun Yang, Oliver Oeckler〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In contrast to the solid solution series (LiSbTe〈sub〉2〈/sub〉)〈sub〉1-〈em〉x〈/em〉〈/sub〉(GeTe)〈sub〉〈em〉x〈/em〉〈/sub〉, compounds with compositions (NaSbTe〈sub〉2〈/sub〉)〈sub〉1-〈em〉x〈/em〉〈/sub〉(GeTe)〈sub〉〈em〉x〈/em〉〈/sub〉 are not thermodynamically stable at room temperature, but can be obtained as metastable phases by quenching melts with x ≤ 0.5. For x 〉 0.5 and in slowly cooled melts, samples are inhomogeneous. Despite the metastability, the lattice parameters of (NaSbTe〈sub〉2〈/sub〉)〈sub〉1-〈em〉x〈/em〉〈/sub〉(GeTe)〈sub〉〈em〉x〈/em〉〈/sub〉 show a Vegard-like behavior. The limited tendency toward forming solid solutions is due to the fact that the ionic radius of Na〈sup〉+〈/sup〉 is much larger than that of Ge〈sup〉2+〈/sup〉 or Li〈sup〉+〈/sup〉 and thus the lattice parameter of NaSbTe〈sub〉2〈/sub〉 (〈em〉a〈/em〉 = 6.32 Å) being significantly larger than that of LiSbTe〈sub〉2〈/sub〉 (〈em〉a〈/em〉 = 6.11 Å). Measurements of transport properties revealed an increasing Seebeck coefficient with increasing GeTe content. Electrical and thermal conductivities of all members of the series (NaSbTe〈sub〉2〈/sub〉)〈sub〉1-〈em〉x〈/em〉〈/sub〉(GeTe)〈sub〉〈em〉x〈/em〉〈/sub〉 with x ≤ 0.5 are low with ∼15 mS cm〈sup〉−1〈/sup〉 and 0.5 W m〈sup〉−1〈/sup〉 K〈sup〉−1〈/sup〉, respectively, which is consistent with the inherently low electrical conductivity of NaSbTe〈sub〉2〈/sub〉. Nevertheless, this model system explains both the low thermoelectric performance of other chalcogenides with high Na contents and the widely recognized potential of Na as doping agent in thermoelectric materials.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819327628-fx1.jpg" width="215" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Shintetsu Kanazawa, Yoshinori Yanagisawa〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recently, we proposed a method of joint by incongruent melting (JIM) for making a superconducting connection between two multi-filamentary Bi2223 tapes. At high temperatures, the Bi2223 phase separates into solid Bi2212 and a liquid phase by incongruent melting. In the JIM method, the Bi2223 filaments in a tape are first melted to Bi2212 and liquid. Then, Bi2212 is connected by the liquid to form a superconducting current pathway. In the present experiment, a joint between multi-filamentary Bi2223 tapes was prepared, resulting in a superconducting joint with a critical current of 8 A at 77 K. We then investigated the microstructure of the superconducting joint interface using X-ray diffraction and SEM/EDS, to clarify the superconducting joint formation. In examining samples prepared using the JIM method, Bi2212 and Sr-Ca-Cu-O system compounds were found at the joint interface, which had a high crystalline orientation.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): S.K. Das, Gopal K. Pradhan, Prabal Dev Bhuyan, Sanjeev K. Gupta, Satyaprakash Sahoo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Doping of nonmagnetic impurities in technologically important ZnO has opened a new window for achieving room temperature ferromagnetism, 〈em〉p〈/em〉-type carrier conduction, and enhancement of ferroelectric properties. Here, we report on the confined optical phonon and bandgap engineering in highly oriented Li implanted ZnO thin films. Using resonance Raman scattering condition, the confined longitudinal optical phonon lineshapes in uniaxial hexagonal wurtzite crystal are analyzed in detail using the phonon confinement model. We have demonstrated that phonon confinement model can yield a meaningful result for the interpretation of resonance Raman lineshapes if one considers the contribution of both the E〈sub〉1〈/sub〉 (LO) and A〈sub〉1〈/sub〉 (LO) modes, particularly while dealing with oriented ZnO thin films. Furthermore, with the increase in Li dose, the bandgap of ZnO is found to show a blue shift, and such blue shift in bandgap is explained using first principles calculation.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Debajyoti Nath, S.K. Mandal, A. Nath〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Magnetoelectric coupling, magnetoimpedance and dielectric properties are investigated for spin–charge dependent magnetoelectric LaFeO〈sub〉3〈/sub〉-poly(vinylidene fluoride) hybrid nanocomposites. The X-ray diffraction pattern indicates that both LaFeO〈sub〉3〈/sub〉 and poly(vinylidene fluoride) phases coexist in the nanocomposites. The magnetoelectric coupling measurement confirms the multiferroic in nature of the nanocomposites. Magnetoelectric and magnetocapacitance (∼42%) effects are ascribing the improvement of space charge polarization of nanocomposites. The light of classical electrodynamics causes the room temperature magnetoimpedance effect (∼94%). Temperature dependent ac conductivity suggests the observation of negative temperature coefficient resistance behavior that also obeys the single Jonscher's power law. The conduction mechanism of the system is controlled through small and large polaronic hopping. Activation energy of those polymer based hybrid nanocomposites is estimated using Arrhenius relation. The magnetoelectric coupling of the nanocomposites is enhanced with an increase in poly(vinylidene fluoride) content. The inorganic-organic based nanocomposites could be a favorable candidate for improvement of magnetoelectric devices, smart energy storage and energy harvesting device applications.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Qing Yan, Yinlin Shen, Yingchun Miao, Min Wang, Meng Yang, Xiangyu Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Vanadium oxychloride (VOCl) with layered structure may be a potential cathode material for rechargeable aluminum batteries (RABs) due to its large interlayer spacing and high theoretical capacity. Herein, the VOCl material is employed as the cathode material of RABs for the first time. The corresponding electrochemical performance and mechanisms of the VOCl cathode are investigated. The VOCl cathode after the first charge delivers a high reversible discharge capacity of 124.7 mAh g〈sup〉−1〈/sup〉, which is ascribed to the AlCl〈sub〉4〈/sub〉〈sup〉−〈/sup〉 deintercalation and the subsequent Al〈sup〉3+〈/sup〉 intercalation. However, the discharge capacity fades to 41.5 mAh g〈sup〉−1〈/sup〉 after 100 cycles, which is mainly caused by the irreversible AlCl〈sub〉4〈/sub〉〈sup〉−〈/sup〉 intercalation/deintercalation during cycling. The electrochemical capacity of the VOCl cathode in the RAB is dominated by the Al〈sup〉3+〈/sup〉 intercalation/deintercalation after the first cycle, as confirmed by the electrochemical tests, energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). In addition, it is found that there is no evident lattice expansion when the AlCl〈sub〉4〈/sub〉〈sup〉−〈/sup〉 or Al〈sup〉3+〈/sup〉 is intercalated into the interlayers of VOCl.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Jie Tang, Hui Zhang, Jie Teng, Dingfa Fu, Fulin Jiang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Zn content has significant influence on the hot workability and final properties of Al–Zn–Mg–Cu alloys. In the present work, single and double stage hot compression tests have been performed on Al–Zn–Mg–Cu alloys with various Zn contents at temperatures of 300 °C and 400 °C, and strain rates of 0.01 s〈sup〉−1〈/sup〉 and 0.1 s〈sup〉−1〈/sup〉, respectively. The results showed that the static softening curve plateau was observed, both the duration of static softening plateau and softening fraction decreased with increasing Zn content at deformation temperature of 300 °C. When deformation temperature increased to 400 °C, the static softening curves appeared approximate typical sigmoidal shape with slight influence from Zn content. By combining additional 〈em〉in-situ〈/em〉 electrical resistivity measurement, hardness testing and microstructural observations, the static softening mechanisms were found to be the functions of static recovery and precipitates coarsening at lower temperature, and static recovery and static recrystallization at higher temperature. The increased Zn addition mainly affected static softening mechanisms at 300 °C by forming precipitates. The simplified static softening kinetics were also investigated based on Johnson-Mehl-Avrami-Kolmogorov model which coupling static recovery and static recrystallization.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Thi Kim Oanh Vu, Dong Uk Lee, Eun Kyu Kim〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The influence of oxygen partial pressure and annealing on the properties of thin films of β-Ga〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 grown by pulsed laser deposition were studied. The Ga〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 samples were deposited at a substrate temperature of 250 °C at an oxygen pressure of 0–50 mTorr and then annealed at a temperature of 600 °C. We observed the crystallinity of Ga〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 enhanced with annealing and with increasing oxygen pressure. The full width at half maximum of annealed 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.svg"〉〈mrow〉〈mtext〉β〈/mtext〉〈/mrow〉〈/math〉 -Ga〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 (〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si2.svg"〉〈mrow〉〈mrow〉〈mover accent="true"〉〈mn〉4〈/mn〉〈mo〉¯〈/mo〉〈/mover〉〈/mrow〉〈mn〉01〈/mn〉〈/mrow〉〈/math〉) peaks decreased, corresponding to the grain size increasing from 6.76 nm to 11.25 nm. The conductivity of the obtained, as-grown Ga〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 films increased with oxygen pressure from 2.1 to 7.9 mScm〈sup〉−1〈/sup〉. As a result, the conductance and the energy band gap of β-Ga〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 without annealing were controlled by the oxygen partial pressure. This was attributed to the oxygen vacancies, based on the composition ratio between O and Ga ions. These results clearly showed that the energy band gap and conductance of β-Ga〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 thin films could be controlled in such a way that could be utilized for high-performance photo-electronic devices.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Mikhail P. Kuz'min, Paul K. Chu, Abdul M. Qasim, Leonid M. Larionov, Marina Yu Kuz'mina, Petr B. Kuz'min〈/p〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): Yunlong Liao, Qian Ma, Youxian Shan, Junwu Liang, Xiaoyu Dai, Yuanjiang Xiang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉2D Tantalum disulphide (TaS〈sub〉2〈/sub〉) has been widely studied as a typical transition metal dichalcogenides (TMDCs) with excellent optical, chemical and electrochemical properties. However, there is little research on the comprehensively characterizing the interaction between light and the 2D TaS〈sub〉2〈/sub〉 material. In this work, we studied the nonlinear optical response of the high quality few-layer TaS〈sub〉2〈/sub〉 nanosheets and its all-optical applications. Our research shows that 2D TaS〈sub〉2〈/sub〉 nanosheet has a broadband characteristic and exhibits a strong Kerr nonlinear optical response based on the spatial self-phase modulation (SSPM). More importantly, by taking advantage of the highly nonlinear optical response of the2D TaS〈sub〉2〈/sub〉, typical all-optical phenomena, such as all-optical switching and nonreciprocal light propagation, have been demonstrated experimentally. This work can be viewed as an important demonstration of a TMDCs-based application prototype in nonlinear photonics, which could potentially indicate an essential step toward miscellaneous TMDCs-based passive photonic devices (all-optical diodes, all-optical switches, etc.)〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): M. Puchalska, E. Zych, P. Bolek〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the present work, bismuth-doped CaAl〈sub〉4〈/sub〉O〈sub〉7〈/sub〉 phosphor powders were obtained via modified Pechini citrate process and their photoluminescence, radioluminescence and thermally stimulated luminescence properties were studied down to 20 K. At room temperature excitation in UV led to broad-band 〈sup〉3〈/sup〉P〈sub〉0,1〈/sub〉 → 〈sup〉1〈/sup〉S〈sub〉0〈/sub〉 Bi〈sup〉3+〈/sup〉 luminescence with three maxima located in blue-green part of spectrum as well as Bi〈sup〉2+〈/sup〉 emission around 760 nm assigned to the 〈sup〉2〈/sup〉P〈sub〉3/2〈/sub〉 → 〈sup〉2〈/sup〉P〈sub〉1/2〈/sub〉 transition. At 150 K an additional Bi〈sup〉3+〈/sup〉 emission band peaking at 370 nm appeared and its intensity increased significantly upon further cooling. The presence of a few luminescent centers of Bi〈sup〉3+〈/sup〉 in CaAl〈sub〉4〈/sub〉O〈sub〉7〈/sub〉 was assigned to the presence of defects disturbing the local symmetry of activator ions. The radioluminescence spectra showed only two bands, an intense one at 760 nm clearly related to Bi〈sup〉2+〈/sup〉 and a very weak component at 555 nm associated with one of the Bi〈sup〉3+〈/sup〉 sites. These two emissions were also observed in the thermoluminescence of the material following its exposure to X-rays. The Bi〈sup〉3+〈/sup〉 luminescence is suitably positioned to contribute the cyan color to white-LEDs. Its quantum yield is satisfactory, close to 40%. The Bi〈sup〉2+〈/sup〉 720–850 nm emission is attractive for bioimaging as it appears in the I〈sup〉st〈/sup〉 biological window.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 806〈/p〉 〈p〉Author(s): S.J. Sun, Y.Z. Tian, H.R. Lin, X.G. Dong, Y.H. Wang, Z.J. Wang, Z.F. Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Single-phase equiatomic CoCrFeMnNi high-entropy alloy (HEA) specimens with three different grain sizes (0.65 μm, 2.1 μm and 105 μm) were processed by cold rolling and annealing treatment. Tensile properties were investigated over a broad temperature range from 77 K to 873 K. Superior strength-ductility balance can be achieved by refining grain size and decreasing temperature. The Hall-Petch relationship was well fitted, and the fitting parameters have a negative relation with temperature. The thermal and athermal contributions to the yield strength were revealed. This work has unveiled the superior mechanical property of HEAs at cryogenic temperatures.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Scripta Materialia, Volume 173〈/p〉 〈p〉Author(s): Z.H. Cao, Y.J. Ma, Y.P. Cai, G.J. Wang, X.K. Meng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, we have synthesized dual-phase high entropy alloys (DP-HEAs) multilayers with a tunable layer thickness through a bottom-up approach. The DP-HEAs' multilayers reach the maximum hardness of 13.3 GPa at a critical thickness of 10 nm. The main strengthening mechanism is that dislocation movement is locked by both interior columnar grain boundaries and heterogeneous interfaces. A crystalline-to-amorphous transition occurs when layer thickness is below the critical thickness. The formation of amorphous DP-HEAs deformed by shear transformation zones with collective atomic rearrangement is responsible for the softening behavior.〈/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-S1359646219304889-ga1.jpg" width="486" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Scripta Materialia, Volume 173〈/p〉 〈p〉Author(s): Zhao Shen, David Tweddle, Mark Thomas Lapington, Benjamin Jenkins, Donghai Du, Lefu Zhang, Michael P. Moody, Sergio Lozano-Perez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉It is often assumed that internal oxidation cannot occur at temperatures below 400 °C. However, in the present work, internal oxidation was observed in a 20% cold-worked Fe-17Cr-12Ni stainless steel (SS) after exposure to simulated primary water of a pressurized water reactor at 340 °C and not in a similarly tested sample without prior cold-work. The formation of discrete Cr-oxide precipitates and the role of cold-work are discussed. The internal oxidation model is also proposed as a plausible stress corrosion cracking mechanism of Fe-17Cr-12Ni SS at that temperature.〈/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-S1359646219304890-ga1.jpg" width="496" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): Shikun Cheng, Qiang Ru, Peng Liu, Honglin Yan, Zhenglu Shi, Xianhua Hou, Shichen Su, Lingzhi Zhao, Francis Chi-Chung Ling〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉1D porous ZnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 cuboids tailored by green natural soybean oil (SZCO) were harvested by a facile micro-emulsion strategy and were used as anodes for lithium ion batteries (LIBs). The as-prepared ZnCo〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 particles in a length range of 20–50 μm are characterized by 1D porous cuboid architecture and large specific surface area, exhibiting a high initial coulombic efficiency of 80.6%, good cycling durability and considerable specific capacity of 1029.3 mA h g〈sup〉−1〈/sup〉 at 1000 mA g〈sup〉−1〈/sup〉 even after 400 cycles. Furthermore, the electrode owns superior rate capability such as 1309.8, 1190.5, 954.9 and 724.4 mA h g〈sup〉−1〈/sup〉 at current densities of 500, 1000, 2000, and 4000 mA g〈sup〉−1〈/sup〉, respectively. The achieved electrochemical properties are ascribed to the favourable morphology, which increases the number of electrochemical active sites, contains effective diffusion channels, and inhibits drastic volume variations during repetitive Li-incorporation and removal.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329366-fx1.jpg" width="456" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): Jie Lian, Lingshan Xiong, Ru Cheng, Dongqiang Pang, Xiuquan Tian, Jia Lei, Rong He, Xiaofang Yu, Tao Duan, Wenkun Zhu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Doping of heteroatoms is an effective way to improve the specific capacitance of carbon-based supercapacitors. In this paper, we prepared an active biomass carbon electrode with a considerable nitrogen content of 10.82%. In the N-doped biomass carbon materials, pyridine nitrogen and pyrrole nitrogen were the main forms of nitrogen, and the presence of sp〈sup〉3〈/sup〉 hybrid nitrogen greatly enhanced the specific capacitance. Among the precursors of biomass in this study, fungal hypha (FH) enabled the best electrochemical performance of carbon electrode with specific capacitances of up to 279 F/g and 190 F/g at a high current density of 1 A/g and 20 A/g, respectively. In addition, the sample possessed an excellent anti-radiation capability, with the specific capacity of 227 F/g at 1 A/g after irradiated by γ-ray (50 kGy). This universal and cost-friendly method will expand the specific surface area of biomass materials and augment the amount of nitrogen in biomass carbon materials.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092583881932897X-fx1.jpg" width="497" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 25 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 810〈/p〉 〈p〉Author(s): Hong Sun, Lijiang Guo, Nan Deng, Xiaoyu Li, Jiangtao Li, Gang He, Jianqiang Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Actuated by the needs of high power electronic devices heat dissipation, diamond/Cu composites with excellent thermal dissipation properties have been considered as the next generation of thermal management material. Herein, an easy-to-operate intermittently electroplated method is developed for coating micro-sized particles and successfully applied to prepare Cu-coated diamond powders for the first time. The Cu coating is covered evenly and densely on the diamond particles surface, and its volume fraction in diamond/Cu composite powders could be precisely controlled by adjusting the plating time. The dense diamond/Cu composites bulks with varied Cu volume fractions were obtained by hot-press sintering process. The as-sintered microstructures of diamond/Cu bulks present that diamond particles are bonded strongly by Cu shell layer, which is conducive to promoting densification capacity. The maximal diamond/Cu composite bulk possesses high thermal conductivity of 638 W/(m·K) and low coefficient of thermal expansion (CTE) of 4.11 × 10〈sup〉−6〈/sup〉/K at 55 vol% diamond. The bending strength of 45 vol% diamond/Cu composite reaches 276 MPa. The combination of these excellent thermal and mechanical properties, coupled with the simple, efficient powder-preparation process, demonstrate the large potential of intermittently electroplated method applying in the development of thermal management material.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 810〈/p〉 〈p〉Author(s): Ranxi Liang, Anjun Hu, Minglu Li, Zhiqun Ran, Chaozhu Shu, Jianping Long〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In energy storage and conversion field, it is an eternal theme to develop effective and stable catalysts. Carbon composites with embedded metal/metal oxides as electrochemical catalysts has attracted extensive research attention. However, severe carbon evaporation causes the aggregation of metal particles during the pyrolysis synthesis, which directly leads to poor dispersion of the active sites and a decrease in catalytic stability. To solve this issue, cobalt encapsulated within porous nitrogen-doped carbon nano-frame (Co, N–CNF) is prepared by template-induced calcinations strategy using mental organic framework (MOF) as precursor and mesoporous SiO2 as template. This strategy leverages the template to capture volatile carbon and nitrogen species and retains the structure of the MOF precursor after pyrolysis. The prepared Co, N–CNF catalyst has a multi-layered spherical graphite shell with sp2 hybrid orbital and metallic cobalt core with fully exposed catalytic active site. Li–O2 batteries based on this core-shell structured cobalt-encapsulated catalyst show excellent electrochemical performance, including high specific capacity (5288 mA h g-1) and remarkable cycle stability without significant voltage attenuation after 500 cycles. These excellent properties are attributed to the unique core-shell structure, as well as the fully exposed metallic cobalt active sites.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 810〈/p〉 〈p〉Author(s): Luhui Zhou, Peng Du, Quan Zhang, Jiujun Zhu, Yafei Hou, Laihui Luo, Weiping Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The Pr〈sup〉3+〈/sup〉-doped Ba〈sub〉0·77〈/sub〉Ca〈sub〉0·23〈/sub〉TiO〈sub〉3〈/sub〉 ferroelectric ceramics, which were sintered by means of a high-temperature solid-state reaction technology, were prepared. The Rietveld X-ray diffraction refinement and Raman spectrum proved that the resultant compounds had tetragonal phase. With the addition of Pr〈sup〉3+〈/sup〉 ions, the highest remanent polarization of the resultant ceramics was nearly two times higher than that of the pure Ba〈sub〉0·77〈/sub〉Ca〈sub〉0·23〈/sub〉TiO〈sub〉3〈/sub〉 ceramics. With the aid of a theoretical calculation based on the temperature-dependent dielectric constant, it is found that the synthesized compounds pertained to the relaxor-like ferroelectrics. Furthermore, through the piezoresponse force microscopy technique, the effect of Pr〈sup〉3+〈/sup〉 ions doping on the domain structure of the Ba〈sub〉0·77〈/sub〉Ca〈sub〉0·23〈/sub〉TiO〈sub〉3〈/sub〉 ferroelectric ceramics was studied. Additionally, the prepared ferroelectric ceramics can exhibited the characteristic emissions of Pr〈sup〉3+〈/sup〉 ions when excited by 450 nm light. The strongest emission intensity was achieved when the dopant content was 0.5 mol% and the dipole-quadrupole interaction contributed to the relevant concentration quenching mechanism.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: December 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Scripta Materialia, Volume 173〈/p〉 〈p〉Author(s): Ankur Chauhan, Xiangyu Sun, Kaliat T. Ramesh, Kevin J. Hemker〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Boron carbide is an excellent protection material but it is also very brittle, and granular flow, triggered by progressive fracture during impact, greatly influences its ballistic performance. Transmission electron microscopy observations of samples recovered from controlled pressure-shear plate impact experiments have elucidated the extent to which local failure mechanisms accompany dynamic granular flow. These observations point to the interplay of quasiplasticity, the formation of nanoscale amorphous bands, cleavage and intragranular cracking. Association of these mechanisms with granular flow and identification of a critical velocity for the onset of amorphization provides a foundation for modeling and predicting armor performance.〈/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-S1359646219304737-ga1.jpg" width="500" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 810〈/p〉 〈p〉Author(s): Xinxin Zhang, Lei Yang, Xueqin Lu, You Lv, Dan Jiang, Yang Yu, Zhuo Peng, Zehua Dong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the present work, with the addition of ZnO nanoparticles (NPs) as Zn source, the Zn-incorporated TiO〈sub〉2〈/sub〉 coatings were successfully produced by the facile one-step micro-arc oxidation (MAO) method. The influence of current density on the microstructural features and biological properties of Zn-incorporated TiO〈sub〉2〈/sub〉 MAO coatings were systematically examined. It is revealed that, at a relatively low current density of 0.1 A/cm〈sup〉2〈/sup〉, Zn species either locate on the coating surface as ZnO nano-sheet clusters or entrap within the coating. By contrast, Zn species tend to fuse into the coating at a relatively high current density of 0.5 A/cm〈sup〉2〈/sup〉, which exhibits a three-layered structure with significant difference of crystallinity, composition and morphology between different layers. The biological experiments indicate that different current densities result in different osteogenic activities and antibacterial properties of Zn-incorporated TiO〈sub〉2〈/sub〉 coatings. The presence of a Zn-depleted amorphous outer-layer on the MAO coating produced at the current density of 0.5 A/cm〈sup〉2〈/sup〉 favours the deposition of apatite-like phases, but retards the release of Zn ions, which thus results in its higher osteogenic activity with lower antibacterial capability compared to that produced at the current density of 0.1 A/cm〈sup〉2〈/sup〉. In summary, dual-functional Zn-incorporated TiO〈sub〉2〈/sub〉 coatings could be successfully produced through the facile one-step MAO method, with both antibacterial property and bone formability significantly affected by the current density of MAO process.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 810〈/p〉 〈p〉Author(s): M. Ptak, B. Pilarek, A. Watras, P. Godlewska, I. Szczygieł, J. Hanuza〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report the structural, phonon and luminescence properties of Eu〈sup〉3+〈/sup〉-doped Gd〈sub〉3-x〈/sub〉Eu〈sub〉x〈/sub〉NbO〈sub〉7〈/sub〉 niobates prepared by conventional solid state reaction. Although a few different crystal structures of pure Gd〈sub〉3〈/sub〉NbO〈sub〉7〈/sub〉 have been reported so far, their properties still remain controversial and the mechanism of their structural phase transition is not well understood. The temperature-dependent IR and Raman spectra show a structural phase transition occurring at 340 K. The detailed analysis of vibrational spectra and correlation diagrams as well as theoretical factor group considerations allowed us to propose the detailed assignment of the observed bands, define the symmetry of low and high-temperature phases and explain the mechanism of their structural transformation from the 〈em〉Pmcn〈/em〉 to the 〈em〉Cmcm〈/em〉 centrosymmetric orthorhombic space group. Powder X-Ray diffraction patterns confirm our analysis. The temperature-dependent emission, room-temperature excitation spectra and luminescence decay times are reported to achieve more information on structural and optical properties of the studied niobates.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): Changlin Yu, Fanyun Chen, Zhen Liu, Kai Yang, Hongbing Ji, Dehao Li, Wenyu Xie, Shaoyu Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A series of robust AgCl/WO〈sub〉3〈/sub〉 composite microrods (0.1–0.2 〈em〉μ〈/em〉m) with different Ag/W molar ratios (0.25, 0.50, 0.75, 1.00, 1.25) were synthesized 〈em〉via〈/em〉 hydrothermal-calcination process. The obtained samples were characterized by XRD, SEM, TEM, FT-IR, UV-vis DRS, PL, BET, Raman, transient TPRT and EIS. The photocatalytic test for organic dyes degradation showed that AgCl/WO〈sub〉3〈/sub〉 microrods possess much higher photocatalytic activities and stability than bare AgCl and WO〈sub〉3〈/sub〉. With optimal AgCl/WO〈sub〉3〈/sub〉 molar ratio (0.75〈strong〉∼〈/strong〉1), 2〈strong〉∼〈/strong〉5 times increase in dye decomposition efficiency was obtained over AgCl/WO〈sub〉3〈/sub〉 microrods. The formation of intimate WO〈sub〉3〈/sub〉/AgCl heterojuction (interface) largely enhanced the separation efficiency of photogenerated carriers. This investigation suggested that AgCl/WO〈sub〉3〈/sub〉 microrods could a promising photocatalyst for environmental remediation.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S092583881933083X-fx1.jpg" width="267" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 25 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 810〈/p〉 〈p〉Author(s): C. Shang, Z.C. Xia, B. Zhao, X.Z. Zhai, D.W. Liu, Y.Q. Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The tuning effects of Al〈sup〉3+〈/sup〉 doping on the magnetic and magnetotransport properties of La〈sub〉0·6〈/sub〉Ca〈sub〉0·4〈/sub〉MnO〈sub〉3-〈em〉δ〈/em〉〈/sub〉 have been studied by preparing series La〈sub〉0·6〈/sub〉Ca〈sub〉0·4〈/sub〉Mn〈sub〉1-〈em〉x〈/em〉〈/sub〉Al〈sub〉〈em〉x〈/em〉〈/sub〉O〈sub〉3-〈em〉δ〈/em〉〈/sub〉 (〈em〉x〈/em〉 = 0, 0.1, 0.125 and 0.15). Al〈sup〉3+〈/sup〉 doping suppresses the ferromagnetic metal phase of La〈sub〉0·6〈/sub〉Ca〈sub〉0·4〈/sub〉MnO〈sub〉3-〈em〉δ〈/em〉〈/sub〉 by weakening the double-exchange interaction of Mn〈sup〉3+〈/sup〉-O〈sup〉2-〈/sup〉-Mn〈sup〉4+〈/sup〉, leading to a phase separation state. Al〈sup〉3+〈/sup〉 doping dependent irreversible metamagnetic transitions are observed at lower temperatures, especially a martensitic-like transition appears in 〈em〉x〈/em〉 = 0.125 and 0.15 system below 4.2 K. Phase diagrams of La〈sub〉0·6〈/sub〉Ca〈sub〉0·4〈/sub〉Mn〈sub〉1-〈em〉x〈/em〉〈/sub〉Al〈sub〉〈em〉x〈/em〉〈/sub〉O〈sub〉3-〈em〉δ〈/em〉〈/sub〉 (0.1 ≤ 〈em〉x〈/em〉 ≤ 0.15) in the 〈em〉B〈/em〉-〈em〉T〈/em〉 plane are presented, in which the antiferromagnetic insulator and ferromagnetic metal phases boundary is figured out. The antiferromagnetic matrix and magnetic disorders caused by the random distribution of Al〈sup〉3+〈/sup〉 ions and the spontaneous oxygen vacancies grow into a pinning center to pin the Mn moments. As magnetic field is increased to the critical field, the localized magnetic moments rotate to parallel to the magnetic field direction, leading to a martensitic-like transition.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Tianyi Sun, Zaifeng Shi, Xiaopeng Zhang, Xianghui Wang, Linhua Zhu, Qiang Lin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉For the first time, a bifunctional CeO〈sub〉2〈/sub〉–Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 material was synthesized and employed for the photocatalytic degradation of p-arsanilic acid (p-ASA) under UV light irradiation and simultaneous thorough removal of the released inorganic arsenic by adsorption from solution. The effects of major factors, including the initial pH, concentration of chloride ion, ammonia nitrogen and humic acid, on the p-ASA degradation were investigated. Under various water quality conditions, an excellent removal of p-ASA could always achieved in the CeO〈sub〉2〈/sub〉–Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 photocatalytic process, and p-ASA could be completely converted to As(V) within 28 min. Simultaneously, the released As(V) could be adsorbed onto the CeO〈sub〉2〈/sub〉–Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanoparticles surface with high efficiency above 98% at the initial pH range of 4–7. The p-ASA degradation efficiency significantly decreased in the presence of Cl〈sup〉−〈/sup〉 and humic acid by scavenging ·HO, while NH〈sub〉4〈/sub〉〈sup〉+〈/sup〉 had insignificant effect on the degradation of p-ASA. Based on the UV–vis, FTIR, XPS analysis and the major degradation products detected, the mechanism of the p-ASA photocatalytic degradation and the released As(V) adsorption by CeO〈sub〉2〈/sub〉–Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanoparticles were proposed. Combined with the photocatalytic property and high adsorption capacity of As(V), the synthesized magnetic CeO〈sub〉2〈/sub〉–Fe〈sub〉3〈/sub〉O〈sub〉4〈/sub〉 nanoparticles have significant potential applications for controlling the risk of p-ASA in aquatic environment.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329226-fx1.jpg" width="326" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): A.V. Serdtsev, N.I. Medvedeva〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Alluaudite-type compounds have been recently proposed as new promising cathode materials for sodium batteries due to their high operating voltage, high capacity and good cyclability. In this work, we present the GGA and GGA + U studies of sodium diffusion and (de)intercalation mechanism in alluaudite Na〈sub〉〈em〉x〈/em〉〈/sub〉Mn〈sub〉2〈/sub〉(MoO〈sub〉4〈/sub〉)〈sub〉3〈/sub〉, as well as its electronic structure and magnetic properties. We predict that, unlike the known alluaudite sulphates, the Na-ion migration in this molybdate should occur not only through one-dimensional channels along the 〈em〉c〈/em〉 axis, but also due to their cross-linking, which is responsible for two-dimensional diffusion. These cross-channel sodium hops with the low-energy barriers may reduce the negative influence of defects and improve rate. They can also provide additional mobile ions to the main channels and play an important role in (de)intercalation. The charging process involves the Na〈sup〉+〈/sup〉 extraction in a specific sequence from different Na sites, which is accompanied by a Mn〈sup〉3+/〈/sup〉Mn〈sup〉2+〈/sup〉 redox reaction and has an average redox potential of 3.89 V. A large volume shrinkage during the last desodiation stages narrows the Na migration channels that impedes the diffusion and removal of all Na from Na〈sub〉〈em〉x〈/em〉〈/sub〉Mn〈sub〉2〈/sub〉(MoO〈sub〉4〈/sub〉)〈sub〉3〈/sub〉.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): An-Nan Chen, Lu Lu, Li-Jin Cheng, Jia-Min Wu, Rong-Zhen Liu, Shuang Chen, Ying Chen, Shi-Feng Wen, Chen-Hui Li, Yu-Sheng Shi〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel preparation method for significantly improving mechanical properties of SLS-formed porous mullites was proposed. MnO〈sub〉2〈/sub〉 sintering aid was coated on mullite powder surface via a liquid phase co-precipitation reaction between MnC〈sub〉4〈/sub〉H〈sub〉6〈/sub〉O〈sub〉4〈/sub〉·4H〈sub〉2〈/sub〉O (Mn(Ac)〈sub〉2〈/sub〉·4H〈sub〉2〈/sub〉O) and KMnO〈sub〉4〈/sub〉. With increasing Mn(Ac)〈sub〉2〈/sub〉·4H〈sub〉2〈/sub〉O content from 6 to 48 mL, the generated MnO〈sub〉2〈/sub〉 content increased from 3.64 to 5.17 wt% which promoted the high-temperature sintering performance and accelerated the re-arrangement of mullite particles to enhance the densification of porous mullite. Then the microstructure evolution and grain growth of mullite grains and the effect of MnO〈sub〉2〈/sub〉 sintering aid on mechanical strengthening mechanism of SLS-formed porous mullites were evaluated in depth from the perspective of TEM analysis. It was found that the aspect ratio of mullite grains decreases gradually with increasing Mn(Ac)〈sub〉2〈/sub〉·4H〈sub〉2〈/sub〉O content, and the accelerated radial growth of mullite grains contributed an increase of fracture toughness from 0.11 ± 0.04 to 0.53 ± 0.01 MPa m〈sup〉1/2〈/sup〉. With increasing Mn(Ac)〈sub〉2〈/sub〉·4H〈sub〉2〈/sub〉O content, the MnO〈sub〉2〈/sub〉 crystal changed from ramsdellite structure γ to a stable tetragonal structure β type. Moreover, the fine MnO〈sub〉2〈/sub〉 particles preferentially precipitated between interwoven mullite grains at the initial stage and then grew into the large ones pinned between mullite grains, resulting in an improvement of compressive strength from 3.8 ± 0.1 to 22.1 ± 1.0 MPa. These values of mechanical properties were significantly improved by 1–2 orders of magnitude compared with that of mullites adding no MnO〈sub〉2〈/sub〉.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819330427-fx1.jpg" width="337" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): Wei Chen, Shu-Chang Wu, Zhi-Jun Xia, Guo-Bo Huang, Jun Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this research, we rationally designed and synthesized quantum dots self-decorated SnIn〈sub〉4〈/sub〉S〈sub〉8〈/sub〉/g-C〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 (QDs-SISCN) nanocomposites by in situ anchoring quantum dot (QDs) self-decorated SnIn〈sub〉4〈/sub〉S〈sub〉8〈/sub〉 (SIS) nanosheets onto the surface of mesoporous graphite carbon nitride (CN) nanosheets in a mixed solvothermal environment. The photoreduction of 4-nitroaniline (4-NA) was used to assess their photocatalytic activity. In this framework, the construction of CN nanosheets-supported QDs-decorated SIS homojunctions can integrate the advantages of both homojunctions and heterojunctions. Benefiting from those favourable properties, the QDs-SISCN nanocomposites exhibit superior photocatalytic activity towards 4-NA reduction under visible-light irradiation (λ 〉 400) as a result of the optimizied amount of CN nanosheets added. The recycling experiments also reveal high stability of the QDs-SISCN nanocomposites during photocatalytic reactions for 4-NA reduction. Moreover, the investigation of the photocatalytic mechanism from systematic characterizations, including measurements of the photocurrent response, electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) indicate that the improved separation efficiency of charge carriers is a critical parameter for the enhanced photocatalytic activity for 4-NA reduction. We expect this research to provide a promising path to the design and synthesis of highly efficient hybrid photocatalysts for functional-group transformations.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819330981-fx1.jpg" width="500" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 30 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 807〈/p〉 〈p〉Author(s): H. Wang, X. Zhang, G.B. Wang, J. Shen, G.Q. Zhang, Y.P. Li, M. Yan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉IN738LC is an important high performance Ni-based superalloy. Its additive manufacturing via selective laser melting (SLM), however, is rather challenging due to the cracking-prone nature of the alloy whose chemical composition contains high amount of alloying elements namely Ti and Al. We address this significant problem by this study through systematic investigations on the pre-processing, SLM optimization, and post-processing of the material, as well as using advanced analytical tools such as micro-CT. A comprehensive process map for achieving crack-free, high-density samples (∼99.76%) is provided. Mechanisms influencing densification, cracking and mechanical properties are discussed. Excellent mechanical properties have been achieved at both room temperature (895/1010 MPa as the yield and tensile strengths) and elevated temperature of 850 °C (720 MPa tensile strength and 14.4% elongation). A demonstrative as-printed turbine blade is also presented, highlighting the capability of SLM to simultaneously achieve excellent mechanical property and good geometric integrity.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): Yan Jiang, Feng Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present work is conducted to study microstructure and mechanical properties of as-cast 6016 Al alloy modified with Sc or/and Ge. Thermodynamic calculation, composition analysis, microstructure examination and mechanical tests have been carried out to show significant effects from Ge and Sc additions. The addition of Ge, as mainly composed of α-Al, Mg〈sub〉2〈/sub〉Si and Si particles, brings forth new formation of Mg〈sub〉2〈/sub〉Ge, and induces eutectic structure forming at grain boundaries (GBs) and nanoscale Si particles in grain interiors (GIs), as a substitution for flaky Mg〈sub〉2〈/sub〉Si phase. The addition of Sc introduces primary Al〈sub〉3〈/sub〉Sc, which obviously refines coarse dendrites of 6016 Al alloy into euiaxed grains, and then stimulates formation of primary AlSc〈sub〉2〈/sub〉Si〈sub〉2〈/sub〉, thus refining Si and Mg〈sub〉2〈/sub〉Si phases. Accordingly, yield stress (YS) of as-cast 6016 Al alloy is moderately increased by Ge addition while obviously enhanced comprehensive properties by Sc addition. An optimal combination of 218 MPa in tensile strength and 22% in elongation to failure (EL) is obtained for 6016 with addition of 0.5% Sc and 0.2% Ge. Different roles of Ge and Sc in adjusting the microstructure and mechanical properties have been discussed.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): Rui Mao, Zhaofeng Wu, Zeying Wang, Zihan Pan, Meihua Xu, Zhihe Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉FeSe〈sub〉1-x〈/sub〉Te〈sub〉x〈/sub〉 (x = 0.5, 0.6 and 0.7) single crystals were prepared by the chemical reaction sealed in a small quartz tube with high vacuum. The angular dependence of resistance was measured in different magnetic field at a constant temperature, and scaled by the anisotropic Gingzburg-Landau theory, respectively, for these single crystals. The field dependences of critical temperature and flux pinning energy were obtained from resistance versus temperature curves measured in various magnetic fields perpendicular and parallel to the c-axis. The critical current density and the flux pinning force were calculated by the Bean model from the magnetization loops. The Te-doping had an obvious effect on the critical temperature T〈sub〉c〈/sub〉, the critical current density J〈sub〉c〈/sub〉 and the flux pinning energy U; but there was a weak effect on the anisotropy of FeSe〈sub〉1-x〈/sub〉Te〈sub〉x〈/sub〉 single crystals. The flux pinning characteristics were also discussed.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): Jinjia Liu, Tao Yang, Aiju Xu, Richard L. Martin, Yong Yang, Haijun Jiao, Yongwang Li, Xiao-Dong Wen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A systematic study on structural, electronic and magnetic properties of transition metal monoxides (TMOs with TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) is performed using the screened hybrid functional, also so-called Heyd-Scuseria-Ernzerhof hybrid functional (HSE). Our results demonstrate that the screened hybrid HSE functional could give reasonable predictions for structural, magnetic and electronic properties of transition metal monoxides when compared with available experimental data. ScO and TiO are predicted to be metals, VO, CrO, MnO, and FeO to be Mott insulators, CoO, NiO and CuO to be charge transfer insulators and ZnO for band insulator. The magnetic moment of the first-row transition metals presents a volcano shape, the moment of Sc and Zn is zero, while MnO locates at the summit. The interactions of 〈em〉d〈/em〉 electrons in ScO and TiO are not as strong as in later monoxides. For later transition metal monoxides (MnO, FeO, CoO and NiO), they are typically strongly-correlated compounds, and HSE functional presents a much better performance in predictions of electronic properties. This work not only provides a good reference for exchange-correlation functional development, but the systematic study on magnetic and electronic properties paves the way for designing functional electromagnetic and photocatalysis materials of transition metal oxides.〈/p〉〈/div〉 〈/div〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0925838819329408-fx1.jpg" width="254" alt="Image 1" title="Image 1"〉〈/figure〉〈/p〉〈/div〉

Beschreibung: 〈p〉Publication date: 25 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 810〈/p〉 〈p〉Author(s): Raj Kumar Samudrala, P. Abdul Azeem〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The importance of the current investigation was to understand the 〈em〉in vitro〈/em〉 studies of tantalum (Ta) containing amorphous glass system, i.e., B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉–SiO〈sub〉2〈/sub〉–CaO–Na〈sub〉2〈/sub〉O–Ta〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 (TaBG). The bioactivity and cytocompatibility studies of the glass system was performed with physiological fluid i.e., simulated body fluid and MTT assay respectively. The glass system B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉–SiO〈sub〉2〈/sub〉–CaO–Na〈sub〉2〈/sub〉O–Ta〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 was prepared by conventional melting and annealing technique and characterized for 〈em〉in-vitro〈/em〉 biological and mechanical properties. Bioactivity study was performed with simulated body fluid, by immersing amorphous powder samples up to twenty-one days. Different techniques like structural (XRD), functional (FTIR), morphological (SEM) and elemental (EDS) analytical methods were performed to assess the apatite-forming ability i.e., bioactivity. Cytocompatibility has been performed by the ISO 10993–5. Microhardness has been measured with indentation method. Bioactivity of the tantalum doped glasses was affected by the incorporation of tantalum content. Microhardness significantly improved and cell viability was not affected for the glass system by the addition tantalum. Hence, the findings in the present study were encouraging to be used as bone implant for appropriate medical applications.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 5 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 808〈/p〉 〈p〉Author(s): T.N. Prasanthi, C. Sudha, S. Raju, S. Saroja〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper presents the results of an experimental and computational study on interdiffusion and related structure-property changes in 304 L stainless steel/Ti–5Ta–2Nb system. Diffusion annealing treatments were carried out in the temperature range of 873–1173 K, above and below the β transus temperature of Ti. The formation of σ, FeTi and Fe〈sub〉2〈/sub〉Ti phases at the interface as well as stabilization of α-Fe and β-Ti in 304 L SS and TiTaNb respectively has been unambiguously established in this study. Growth kinetics of the reaction zones has been determined and effective interdiffusion coefficients in various phases were calculated using Wagner's approach. Temperature dependant variations in the mechanical property of the base materials and diffusion couples have also been predicted using JMatPro® and compared with literature. Finally, the evolution of microstructure at the interface and diffusion path in the diffusion couples were compared with SS/Ti based diffusion bonded joints and explosive clads to understand the interdiffusion behavior under equilibrium and non-equilibrium conditions.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 15 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 809〈/p〉 〈p〉Author(s): R. Machado, A. Di Loreto, A. Frattini, M. Sepliarsky, M.G. Stachiotti〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A first-principles based atomistic model is developed to investigate intrinsic effects of Mg incorporation into A- and B-sites of BaTiO〈sub〉3.〈/sub〉 We find that the replacement of Ba by Mg at A-site positions generates local electric dipoles due to Mg off-centering along [001] directions, which increase the Curie temperature and decrease the cell volume. The inverse dependence is observed for B-site doped compositions, where the defect dipoles decrease the Curie temperature and expand the volume. Temperature-composition phase diagrams are constructed for both site locations and the effect of the two types of defects on the switching process is investigated. The theoretical predictions are used to shed light on experimental results of Mg-doped ceramics manufactured to induce a given occupation site. The comparison indicates that the incorporation of Mg into the B-site is thermodynamically favorable whereas the properties observed for the A-site ceramics cannot be explained from the intrinsic effects described by the model.〈/p〉〈/div〉 〈/div〉

Beschreibung: 〈p〉Publication date: 25 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Alloys and Compounds, Volume 810〈/p〉 〈p〉Author(s): Jingyao Ma, Chunhui Lu, Changji Liu, Mei Qi, Xiang Xu, Dan Yang, Xinlong Xu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Photoactive heterostructures with low recombination rate of photocarriers, high photostability, and easy fabrication methods are desirable for the future photoelectrochemical applications. Herein, photostable ZnSnO〈sub〉3〈/sub〉 and MoS〈sub〉2〈/sub〉 based heterojunction photoanodes were synthesized readily via an electrophoretic deposition method. The photoelectrochemical measurements revealed that the maximum photocurrent density of these ZnSnO〈sub〉3〈/sub〉/MoS〈sub〉2〈/sub〉 heterojunction photoanodes is ∼2.3 times and ∼27.3 times larger than that of pristine ZnSnO〈sub〉3〈/sub〉 and pristine MoS〈sub〉2〈/sub〉 photoanodes at the same experimental condition, respectively. According to the high-resolution X-ray photoelectron spectroscopy analysis, we can confirm that the ZnSnO〈sub〉3〈/sub〉/MoS〈sub〉2〈/sub〉 interface forms a type II band alignment. Photoelectrochemical property of the ZnSnO〈sub〉3〈/sub〉/MoS〈sub〉2〈/sub〉 photoelectrodes is enhanced mainly attribute to the separation improvement of photogenerated carriers at the ZnSnO〈sub〉3〈/sub〉/MoS〈sub〉2〈/sub〉 interface, which is proved by the impedance spectroscopy analysis. This work confirms that two-dimensional materials such as MoS〈sub〉2〈/sub〉 as a most stable narrow band-gap materials can alleviate the photocarrier recombination rate to improve the traditional photoactive materials, which have great potential applications in photoelectrochemical cells.〈/p〉〈/div〉 〈/div〉