ALBERT

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 521〈/p〉 〈p〉Author(s): Hao Xiong, Linjue Wang, Zheyao Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This paper reports the development of a hot embossing method for fabricating chalcogenide microlens arrays using soft polydimethylsiloxane (PDMS) stamps. The stamps are formed by molding PDMS on photoresist masters fabricated with sphere segments by thermal reflow. Upon proper temperatures, the chalcogenide glass softens and is embossed using PDMS stamps with low pressure. Void defects at the center and at the side of microlenses are found, and the mechanisms for the void formation are investigated and verified. The hot embossing parameters including pressure, temperature, embossing time, and the thicknesses of the PDMS stamps are optimized. A 400 × 400 microlens array with uniform profiles, smooth surface roughness, and good roundness have been successfully fabricated on both chalcogenide thin films and bulk wafers. The preliminary results demonstrate the feasibility of using hot embossing with soft PDMS stamps as a simple and low cost method to fabricate chalcogenide microlens arrays.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 521〈/p〉 〈p〉Author(s): Meng Xiao, Zhigang Zheng, Li Ji, Xin Liu, Zhaoguo Qiu, Dechang Zeng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, effects of Mo and V substitution for Fe on a direct aim of synchronously optimizing glass forming ability (GFA) and soft magnetic properties of Fe-based amorphous/nanocrystalline alloys fabricated by melt-spinning technology are investigated. The introduces of Mo and V had an effective impedance of atoms migration and contributed to the improvement of GFA of Fe〈sub〉73.5-x〈/sub〉Si〈sub〉15.5〈/sub〉B〈sub〉7〈/sub〉Cu〈sub〉1〈/sub〉Nb〈sub〉3〈/sub〉M〈sub〉x〈/sub〉 (M = Mo, V) soft magnetic alloys. The formation of 〈em〉α-〈/em〉Fe phase was kept in a stable temperature scale, while the residual amorphous precipitation showed a better thermal stability against precipitating Fe〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉B compounds. After a suitable annealing process at 〈em〉T〈/em〉〈sub〉a〈/sub〉 = 560 °C for 60 min, the 〈em〉α-〈/em〉Fe grains with introducing V had a smaller average size than that of introducing Mo. For the crystallized ribbons, the introduce of V revealed not only a slower decrease of 〈em〉B〈/em〉〈sub〉s〈/sub〉 but also a more sluggish increase of 〈em〉H〈/em〉〈sub〉c〈/sub〉. The 〈em〉B〈/em〉〈sub〉s〈/sub〉 and 〈em〉H〈/em〉〈sub〉c〈/sub〉 were in the range of 0.91 T - 1.07 T and 2.0–3.5 A/m, respectively. These alloys with V = 1 at.% and Mo = 0.5 at.% exhibited higher effective permeability (μ〈sub〉〈em〉e〈/em〉〈/sub〉) in the frequency range of 1–200 kHz and 60–200 kHz, respectively. Therefore, the balance between Fe, V and Mo is a key factor to keep 〈em〉B〈/em〉〈sub〉s〈/sub〉 in a moderate field and relatively lower 〈em〉H〈/em〉〈sub〉c〈/sub〉〈em〉,〈/em〉 meanwhile it can also improve 〈em〉μ〈/em〉〈sub〉e〈/sub〉 in testing frequency scale. V additions are more beneficial to restrain grain growth, reduce 〈em〉B〈/em〉〈sub〉s〈/sub〉 and increase 〈em〉H〈/em〉〈sub〉c〈/sub〉 rather than those of Mo. Therefore, V-doped Finemet-type soft magnetic alloy and its nanocrystalline derivations become a potential candidate as transformer core material in wide frequency scale of 1–200 kHz.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 521〈/p〉 〈p〉Author(s): N.A. Wójcik, S. Ali, D. Möncke, N.S. Tagiara, E.I. Kamitsos, H. Segawa, M. Eriksson, B. Jonson〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Be-Na-(Li)-Si oxide glasses containing up to 15 mol% of BeO were prepared. Their structure was characterized by X-ray powder diffraction and Raman as well as infrared spectroscopic techniques, while their chemical compositions were examined by Inductively Coupled Plasma Optical Emission Spectrometry. All materials were found to be amorphous and contain Al contaminations from minor dissolution of the alumina crucibles. The results of Raman and IR spectroscopies showed that BeO addition to Na-(Li)-Si glass systems resulted in the formation of [BeO〈sub〉4/2〈/sub〉]〈sup〉2−〈/sup〉 tetrahedra which are inserted into the silicate glass network, demonstrating the intermediate glass-forming role of BeO. In parallel, the effective destruction of Si-O-Si bridges was observed by vibrational spectroscopy. The glass transition temperature was studied by Differential Thermal Analysis and found to range from about 431 °C to 551 °C. A significant increase in 〈em〉T〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉 by 70 °C was found as SiO〈sub〉2〈/sub〉 was substituted by up to 15 mol% BeO.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 521〈/p〉 〈p〉Author(s): Akira Saitoh, Suguru Kitani, Satoru Matsuishi, Hitoshi Kawaji, Hiromichi Takebe, Hideo Hosono〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The photoelastic constant of nominal molar compositions RO(R'〈sub〉2〈/sub〉O〈sub〉3〈/sub〉)–SiO〈sub〉2〈/sub〉 (R = Pb, R' = Sb, Bi) decreases with increasing RO and R'〈sub〉2〈/sub〉O〈sub〉3〈/sub〉, which is in agreement with calculations based on the quantitative structural information of silicate tetrahedra determined by 〈sup〉29〈/sup〉Si MAS-NMR. Compositional dependence of the photoelastic property is attributed to the electronic polarizabilities of the constituent ions. To understand the relationship between the structure and photoelastic response, the reported electronic polarizability is modified to match the value that includes the observed density and refractive index based on Lorentz–Lorenz eq. A composition of photoelastic glass with zero photoelastic constant is identified by an empirical equation that provides the ratio of the metal‑oxygen bond length to the coordination number. Our finding is that the compositional response in the photoelastic constant is due to the variation in the electronic polarizability, despite the different ns〈sup〉2〈/sup〉-type metal cations incorporated in the silicate glass.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 521〈/p〉 〈p〉Author(s): Kuo-Hao Lee, Qiuju Zheng, Jinjun Ren, Collin J. Wilkinson, Yongjian Yang, Karan Doss, John C. Mauro〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this report, a topological constraint model is developed to predict the glass transition temperature (〈em〉T〈/em〉〈sub〉g〈/sub〉) and liquid fragility (〈em〉m〈/em〉) of 〈em〉x〈/em〉Bi〈sub〉2〈/sub〉O〈sub〉3〈/sub〉·(1-〈em〉x〈/em〉)NaPO〈sub〉3〈/sub〉 glass-forming systems by considering the hierarchy of temperature-dependent constraints, including contributions from the modifying cations (Bi〈sup〉3+〈/sup〉 and Na〈sup〉+〈/sup〉). The model is shown to give an accurate prediction of the 〈em〉T〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉 and 〈em〉m〈/em〉 as a function of composition (〈em〉x〈/em〉). The increase of 〈em〉T〈/em〉〈sub〉g〈/sub〉 with 〈em〉x〈/em〉 is mainly caused by the formation of the Bi〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O linear constraints and also contributions from O–Bi–O angular constraints, which increase the connectivity of the network. The model also accurately predicts the trend of 〈em〉m〈/em〉 with composition, which shows a minimum at around 〈em〉x〈/em〉 = 5 mol% due to the competition between the contributions from the Na〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O linear constraints and the O–Bi–O angular constraints.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 523〈/p〉 〈p〉Author(s): M. Farouk, K. Abdallauh, M. Attallah, Z.M. Abd El-Fattah〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Glassy system of composition 20R〈sub〉2〈/sub〉O-19ZnO-60B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-1V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉(R is Li, Na and K) was prepared by conventional melting technique. The measured density ρ and calculated molar volume V〈sub〉m〈/sub〉 were both found to increase linearly with the atomic number of the alkali element, reflecting the formation of non-bridging oxygen. Additional physical parameters such as vanadium ions concentration, inter-ionic distance of vanadium ions, polaron radius, field strength, refractive index and electrical susceptibility were calculated. Infrared spectra were recorded, vibrational modes were assigned, and the spectra were deconvoluted to calculate the N〈sub〉4〈/sub〉 value. The absorption edge and optical band gap were estimated from UV–Vis absorption spectra, and were found to exhibit a clear R〈sub〉2〈/sub〉O mol% dependence. The Spin Hamiltonian parameters were calculated from ESR spectra, and the V〈sup〉4+〈/sup〉 ions were found to exist as VO〈sup〉2+〈/sup〉 ions in octahedral coordination with tetragonal compression. Furthermore, the Δg〈sub〉||〈/sub〉/Δg〈sub〉┴〈/sub〉 values were decreased with R〈sub〉2〈/sub〉O mol% indicating a reduced tetragonal distortion.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 523〈/p〉 〈p〉Author(s): Xiuying Li, Zhuohao Xiao, Yongtao He, Yongqing Wang, Jinzhi Luo, Jijun Shi, Qin Huang, Lingbing Kong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Crystallization behavior, structure and properties of the glasses in SrO–Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉–P〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 ternary system, with the content of P〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 fixed to be 60, 50 and 40 mol%, were studied systematically. For vitreous samples, thermal expansion coefficients (TEC) and characteristic temperature were obtained by using a thermal dilatometer, while their thermal stability was examined by using a differential scanning calorimeter (DSC). Accordingly, their heat treatment schedules were determined. Furthermore, their chemical durability was characterized according to the dissolution rate (DR〈sub〉water〈/sub〉) in distilled water at 90 °C. Glass forming region of the SrO–Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉–P〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 ternary system at 1250 °C has been identified. It was found that crystallization behavior, crystalline phase compositions, structure and properties of the samples are closely related to the ratios of O/P and Fe/P. Specifically, the iron phosphate glasses were explored as the host matrices to immobilize high-level radioactive wastes (HLWs) with high contents of 〈sup〉90〈/sup〉Sr.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 523〈/p〉 〈p〉Author(s): Anjli Rana, Bhanu Pratap Singh, Raman Sharma〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Structural changes developed in Ge〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉S glassy alloy with incorporation of Ga have been investigated using vibrational spectroscopy. Thermal evaporation technique has been employed to deposit thin films of Ge〈sub〉20〈/sub〉S〈sub〉80−x〈/sub〉Ga〈sub〉x〈/sub〉 glassy alloy. Structural transformations in bulk and thin films have been examined from Raman and FTIR spectra recorded at room temperature. Observed left shift in the Raman spectra and right shift in the IR spectra are consequence of increase in reduced mass of the alloy. Ga occupy the Ge sites, due to atomic similarity, and results in the formation of Ge(Ga)S〈sub〉4〈/sub〉 tetrahedra units and S〈sub〉3〈/sub〉Ge(Ga)-(Ga)GeS〈sub〉3〈/sub〉 ethane like structures. Broadening of IR and Raman bands with Ga concentration reveals the conception of Ga〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉S bonds. Chemical changes developed in the Ge-S-Ga glass have been correlated with XPS (X-ray photoelectron spectroscopy) chemical shift. X-ray photoelectron spectroscopy analyses reveal the existence of metal-metal and S〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉S bonds in violation to the chemical ordered network model.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 523〈/p〉 〈p〉Author(s): V.P. Kaasik, A.A. Lipovskii, D.V. Raskhodchikov, I.V. Reshetov, D.K. Tagantsev〈/p〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): Leben Liang, Biao Ju, Xiongquan Long, Jiantao Liu, Siyuan Rong, Changming Xia, Yun Chen, Zhiyun Hou, Guiyao Zhou, Nan Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, a double-cladding Tm〈sup〉3+〈/sup〉/Al〈sup〉3+〈/sup〉 co-doped photonic crystal fiber (PCF) is fabricated with stacking and drawing technology based on laser sintering technology (LST) for the first time. The absorption, emission and loss properties of glass and fiber are studied experimentally, and the laser performances of fiber with different lengths are analyzed. The results demonstrate that Tm〈sup〉3+〈/sup〉/Al〈sup〉3+〈/sup〉 co-doped large-mode-area PCF fabricated based on laser sintering technology is potential materials for developing 2 μm high power fiber laser.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): Y.B. Xiao, Y. Ji, J.L. Liu, W.C. Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Fluoro-sulfo-phosphate poly-anionic glasses KPO〈sub〉3〈/sub〉–AlF〈sub〉3〈/sub〉–K〈sub〉2〈/sub〉SO〈sub〉4〈/sub〉 (KPFS) and Nd〈sup〉3+〈/sup〉-doped samples (Nd–KPFS) were prepared by conventional melt-quenching method and their physical properties were comprehensively analyzed. Their actual glass compositions were carefully checked by different methods. These glasses exhibit typically low linear refractive index 〈em〉n〈/em〉〈sub〉〈em〉d〈/em〉〈/sub〉 (~ 1.482) and nonlinear refractive index 〈em〉n〈/em〉〈sub〉〈em〉2〈/em〉〈/sub〉 (~ 0.86 × 10〈sup〉−13〈/sup〉 esu), high Abbe's number (~ 72.0) and moderate elasticity modulus 〈em〉E〈/em〉〈sup〉⁎〈/sup〉 (~ 50.2 GPa). The spectroscopic properties of Nd–KPFS specimens are further evaluated by the Judd-Ofelt theory, and the results suggest that the stimulated radiative parameters can be enhanced by tuning sulfate contents. Besides, Nd–KPFS glasses present relatively long lifetime 〈em〉τ〈/em〉〈sub〉〈em〉exp〈/em〉〈/sub〉 (~ 428 μs) and large figure of merit FOM (~ 9.29 × 10〈sup〉−24〈/sup〉 cm〈sup〉2〈/sup〉 s). All of the results imply that such fluoro-sulfo-phosphate glass would be a promising candidate for solid-state laser.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): Sultan Öztürk, Kürşat İcin, Merve Gençtürk, Metin Göbülük, Uğur Topal, Peter Svec〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, the effect of the heat treatment process on the surface morphology, crystallization process and magnetic properties of Fe〈sub〉38〈/sub〉Co〈sub〉38〈/sub〉Mo〈sub〉8〈/sub〉B〈sub〉15〈/sub〉Cu ribbons produced by melt spinning was investigated. Number of protrusions uniformly distributed on surfaces of as-quenched ribbons were identified by atomic force microscopy (AFM). AFM results also indicated that variation of surface morphology of density, size, and shape of protrusions along the ribbon surface. According to magnetic force microscopy (MFM) analysis, the magnetic domain walls were not observed for annealing temperatures of 300 °C–360 °C. After annealing at 420 °C, the domains grow wider and align parallel to each other. Minor amounts of bcc-FeCo nano-sized crystalline grains which homogeneously and randomly distributed to the residual amorphous matrix were observed by the transmission electron microscopy (TEM). The crystalline grains are enlarged and became more visible. The best coercivity and saturation magnetization values were obtained at 360–420 °C.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): Edan Lerner〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recent advances in computational glass physics enable the study of computer glasses featuring a very wide range of mechanical and kinetic stabilities. The current literature, however, lacks a comprehensive data set against which different computer glass models can be quantitatively compared on the same footing. Here we present a broad study of the mechanical properties of several popular computer glass forming models. We examine how various dimensionless numbers that characterize the glasses' elasticity and elasto-plasticity vary under different conditions — in each model and across models — with the aim of disentangling the model-parameter-, external-parameter- and preparation-protocol-dependencies of these observables. We expect our data set to be used as an interpretive tool in future computational studies of elasticity and elasto-plasticity of glassy solids.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 521〈/p〉 〈p〉Author(s): Yajun Huang, Song He, Mengmeng Feng, Huaming Dai, Yuelei Pan, Xudong Cheng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉An organic solvent-saving method of preparing silica aerogel is reported. The silica aerogel was made from water glass (WG) and used as the solvent. Na〈sup〉+〈/sup〉 was removed through ion exchange; prior to this ion exchange, concentrated hydrochloric acid (HCl) was added to the WG solution. The sol pH was adjusted to ~1 to suppress the condensation to the maximum extent. Ethanol was added to the sol after ion exchange. Surface modification was conducted with the assistance of hexamethyldisiloxane, which was catalyzed by HCl. The entire process can be finished in 6 h. The overall consumption of organic solvent is much lower than that in the previous preparation route. Characterization results indicate that the resulted silica aerogel has a uniform mesoporous structure and low thermal conductivity (0.0237–0.0245 W/m·K at 1 atm).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): Guglielmo Macrelli, Arun K. Varshneya, John C. Mauro〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Chemical strengthening of glass by ion exchange below its glass transition temperature has become a well-established technological process in the glass industry since its introduction in the 1960s. However, some questions related to the basic science of the ion exchange process still remain. In this paper we focus on the observation of a maximum in compression that is often observed below the surface, rather than at the surface as predicted by the Cooper theory. In some glasses, this anomaly appears in a dramatic form, where the surface compression reduces to zero and can even become tensile upon continued ion exchange. We provide an explanation of this anomaly based on a mechanism of volume shrinkage (densification) triggered by the large hydrostatic pressure inherent to ion exchange in some glasses. We propose a mechanical spring-and-dashpot model for the pseudo-viscoelastic behavior of glass to identify the mechanisms and associated time scales that can reproduce the experimental observations. Next, we modify Sane and Cooper's analysis by introducing a new “〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" altimg="si1.svg"〉〈mi mathvariant="bold-script"〉V〈/mi〉〈/math〉-factor” to account for the identified relaxation effects (fast β-relaxation, slow α-relaxation, and stress release due to volume and shear viscosities). The approach accurately reproduces the subsurface compression maximum anomaly. Our model therefore enables a clearer perspective on the evolution of the glass network during the chemical strengthening process.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 523〈/p〉 〈p〉Author(s): N.A. El-Alaily, O.I. Sallam, F.M. Ezz-Eldin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Changes of FTIR, UV–Visible spectra, photoluminescence with varying Sm content in phosphate glass containing sodium, lead and aluminum were studied. Refractive index values have been measured and their values were listed to be between ~ 1.5–1.7. Furthermore the effect of subjecting this glass to gamma rays was also investigated. The results showed that glass containing 1%Sm had the highest NBOs according to FTIR, UV-Visble results. The optical energy band gap and Urbach values supported this assumption. The presence of Sm〈sup〉3+〈/sup〉 which can be reduced to Sm〈sup〉2+〈/sup〉 in addition to the NBOs produced due to the addition of Sm ions in the glass matrix, causing a reduction of gamma rays effect. This may give a clue to the ability of using this glass as an immobilizer or shielded for gamma rays or as a burial for high energy radioactive materials.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): G. Sathiyapriya, K. Marimuthu, M.I. Sayyed, A. Askin, O. Agar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Structural, physical and gamma ray shielding properties of Dy〈sup〉3+〈/sup〉 doped telluroborate glasses have been discussed. The molar volume of the glasses is proportional to the TeO〈sub〉2〈/sub〉 content. The FTIR studies investigate the expansion of TeO〈sub〉2〈/sub〉 content and the dynamic change of tetrahedral [BO〈sub〉4〈/sub〉] units into trigonal [BO〈sub〉3〈/sub〉] units. Using the absorption spectra, optical band gap (E〈sub〉g〈/sub〉) and Urbach's energy (ΔE) values are calculated. The molar volume of oxygen (V〈sub〉O〈/sub〉) and boron‑boron separation (〈d〈sub〉B–B〈/sub〉〉) values are increasing while there is a fall in oxygen packing density (OPD) from 0% to 40% of TeO〈sub〉2〈/sub〉. The ionic nature of the present glasses is analyzed from the bonding parameter (δ), optical basicity (Λ〈sub〉th〈/sub〉), covalent and ionic characteristic factors. The gamma photon attenuation investigated employing GEANT4 code. The transmission factor (TF) shows that 0TBD sample (0 wt% of TeO〈sub〉2〈/sub〉) has the highest TF, while the 4TBD sample (40 wt% of TeO〈sub〉2〈/sub〉) has the lowest TF.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): D.C. Silva, D.V. Sampaio, J.H.L. Silva, A.M. Rodrigues, R.B. Pena, B.J.A. Moulton, P.S. Pizani, J.P. Rino, R.S. Silva〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Described herein is a new approach to produce glass materials using a CO〈sub〉2〈/sub〉 laser as unique heating source. In this study, the well-known PbO·SiO〈sub〉2〈/sub〉 (PS) system was chosen as a glass model because of its very good glass forming ability and stoichiometric crystallization. The laser-produced glasses presented the same temperature stability as the conventionally produced glass, as observed by DSC results, without the presence of crystalline phases according to XRD and Raman results. Additionally, no structural change was detected among the glasses, when probed by Raman and XANES. After thermal treatment at 730 °C for 1 h, the laser-produced glass crystalizes to the alamosite (PbSiO〈sub〉3〈/sub〉) phase which confirms the nominal stoichiometry without Pb volatilization. In optimal conditions, the total PS laser-produced glass was synthesized within 3 min., which is remarkably fast in comparison to conventional processes using an electric furnace that can last several hours.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): Chunyan Li, Xinling Li, Zhenxiang Zhao, Fuping Zhu, Shengzhong Kou, Yanchun Zhao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this study, different peak loads and varying cooling rates on creep behavior of (Zr〈sub〉0.6336〈/sub〉Cu〈sub〉0.1425〈/sub〉Ni〈sub〉0.1012〈/sub〉Al〈sub〉0.12〈/sub〉)〈sub〉97.4〈/sub〉Er〈sub〉2.6〈/sub〉 bulk metallic glass were studied by nanoindentation tester and atomic force microscopy (AFM). The results show that the change of different load and cooling rate has a great influence on the creep behavior of the alloy. Under high peak load conditions, the increasing of the creep displacement and the stress exponent (n) show strong indentation size effect. The hardness of the specimen without rare earth element is 5 times larger than the specimen with rare earth element. With the increase of the cooling rate, the creep displacement of the specimen is increasing and the time to enter the steady state creep is prolonging. The hardness and elastic modulus of the material are sensitive to the cooling rate relative to the load change.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): Nupur Gupta, Atul Khanna, Marina Gonzàlez Barriuso, Fernando Gonzàlez〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effects of addition of trivalent metal oxides: Gd〈sub〉2〈/sub〉O〈sub〉3〈/sub〉, Dy〈sub〉2〈/sub〉O〈sub〉3〈/sub〉, Eu〈sub〉2〈/sub〉O〈sub〉3〈/sub〉, Er〈sub〉2〈/sub〉O〈sub〉3〈/sub〉, Y〈sub〉2〈/sub〉O〈sub〉3,〈/sub〉 and B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 on the size and distribution of anti-glass phases of BiNbTe〈sub〉2〈/sub〉O〈sub〉8〈/sub〉 in the system: xR〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-(10-x)Bi〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-10Nb〈sub〉2〈/sub〉O〈sub〉5〈/sub〉-80TeO〈sub〉2〈/sub〉 (x = 1 and 2 mol%) are studied. The samples prepared by melt-quenching are predominantly glassy phase but contain co-existing inclusions (droplets) of anti-glass BiNbTe〈sub〉2〈/sub〉O〈sub〉8〈/sub〉. The incorporation of Gd〈sub〉2〈/sub〉O〈sub〉3〈/sub〉, Dy〈sub〉2〈/sub〉O〈sub〉3〈/sub〉, Eu〈sub〉2〈/sub〉O〈sub〉3〈/sub〉, Er〈sub〉2〈/sub〉O〈sub〉3,〈/sub〉 and Y〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 in the glass system enhances the glass transition temperature and promotes the growth of the anti-glass droplets. On the other hand the addition of B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 decreases the glass transition temperature and inhibits the growth of the inclusions and produces purely amorphous samples. The photoluminescence spectra show intense red emission in Eu〈sup〉3+〈/sup〉-doped samples while yellow light is emitted from Dy〈sup〉3+〈/sup〉 doped samples. The micro-Raman spectra of the glass and anti-glass inclusions are very similar which indicates same chemical composition and short-range structure of the glass and anti-glass phases.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): E.A. Anashkina, A.A. Sorokin, M.P. Marisova, A.V. Andrianov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We present the first theoretical analysis of optical frequency comb generation in tellurite microresonators with whispering gallery modes. The regime of dissipative soliton generation is simulated numerically in tellurite microbubbles pumped at 1.95 μm or at 2.3 μm by a Tm-doped tellurite fiber laser. Using microbubble geometry allows controlling the zero dispersion wavelength and obtaining anomalous dispersion needed for soliton generation at both pump wavelengths, whereas the zero dispersion wavelength of the analyzed TeO〈sub〉2〈/sub〉-WO〈sub〉3〈/sub〉-La〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 glass is 2.17 μm. The glass parameters measured in the previous experiments are used for modeling. It is shown that for the optimized characteristics of microbubbles, optical frequency combs with a spectral width of 200 nm (at the level of −30 dB) can be obtained with a low pump power threshold of about a few mW. Ultrashort pulses with a duration of about 130 fs and repetition rates of a few hundred GHz correspond to these combs in the time domain.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 523〈/p〉 〈p〉Author(s): Xue Yang, Zhongjun Qiu, Yuge Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The interaction between scratches has a significant influence on the material removal mechanism during scratching glass ceramic. To clarify the interaction mechanism, an analytical model of stress interference considering scratch distance is established based on the interaction features between scratches to analyse the relationship between stress distribution and crack propagation. A double scratch experiment with different scratch distances was conducted on lithium aluminosilicate (LAS) glass ceramics. Experimental and analytical results show that the crack is further extended by the enhanced maximum principal stress in the case of the scratch interference. In the interaction range, the maximum principal stress decreases with increasing scratch distance. Furthermore, larger scratch distance in the interaction range is prone to achieve ductile material removal while smaller scratch distance makes the brittle material removal occurring.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): N.A. Wójcik, B. Jonson, D. Möncke, E.I. Kamitsos, H. Segawa, J. Karczewski, S. Ali〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Two oxynitride glass series with the composition of 35Na〈sub〉2〈/sub〉O-5BeO-(60-x)SiO〈sub〉2〈/sub〉-xSi〈sub〉3〈/sub〉N〈sub〉4〈/sub〉 and 9Li〈sub〉2〈/sub〉O- 27Na〈sub〉2〈/sub〉O-5BeO-(59-x)SiO〈sub〉2〈/sub〉-xSi〈sub〉3〈/sub〉N〈sub〉4〈/sub〉, were prepared. The glasses' topography and structure were studied by Scanning Electron Microscopy and Raman spectroscopy. The composition was analyzed by Inductively Coupled Plasma Optical Emission Spectrometer, SEM-EDS and nitrogen and oxygen elemental analyzer. Na-(Li)-Be-silicate glasses were found to contain up to approximately 3.4 (or 5.2 for EDS measurements) at.% of N, respectively. The samples were homogenous in their topography and composition〈del〉s〈/del〉 of their cross-sections.〈/p〉 〈p〉The presence of three-fold coordinated nitrogen atoms in Na-Be-Si-O-N glasses results in higher degree of polymerization as was observed by Raman spectroscopy. The spectrum of analogous glasses with lithium did not show a significant decrease in Q〈sup〉2〈/sup〉 units but exhibit the presence of Q〈sup〉4〈/sup〉 units which also indicates a polymerization of the network. The incorporation of nitrogen in these glasses leads to the increase of the glass transition temperature and thermal stability.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): Qiuling Chen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Transition metal oxide WO〈sub〉3〈/sub〉 is attractive in photonics and magneto-optical applications due to its dual functions in glass network and electron transitions between different valences. In this paper, for the first time, we report the photoluminescence, magnetic and magneto-optical properties of WO〈sub〉3〈/sub〉 in Faraday rotation glasses taking advantage of its low band gap, high refractive index and empty d shell characters. Spectra analysis revealed that WO〈sub〉3〈/sub〉 co-existed as W〈sup〉6+〈/sup〉 and W〈sup〉5+〈/sup〉 in WO〈sub〉4〈/sub〉 and WO〈sub〉6〈/sub〉 groups, and their conversion is WO〈sub〉3〈/sub〉 concentration-dependent. Faraday rotating glasses showed stronger network connectivity after doping WO〈sub〉3〈/sub〉 due to its high field strength and network former role of WO〈sub〉4〈/sub〉 unit. Emission at 365 nm due to the band-to-band electron transition of W〈sup〉5+〈/sup〉was found in all WO〈sub〉3〈/sub〉 doped glasses, while emission at 468 nm due to oxygen defects presented only in ceramic. The small band gap, high polarizability and diamagnetic W〈sup〉6+〈/sup〉 ions contributed to the 4%WO〈sub〉3〈/sub〉 doped glass a giant diamagnetism of 9.86 × 10〈sup〉−4〈/sup〉 emu/g and big Verdet constant of 0.1788 min/G·cm.〈/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-S0022309319304557-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): M. Inui, Y. Kajihara, A. Chiba, K. Matsuda, S. Tsutsui, A.Q.R. Baron〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Inelastic x-ray scattering spectra of fluid S were measured from 403 K near the melting point to 1343 K in the supercritical region at 25 MPa. Although the dynamic structure factor in the supercritical region exhibits a single peak profile, the spectrum includes collective inelastic excitations besides the quasielastic component. The acoustic excitation energy in the supercritical region is close to the one predicted by the sound speed in the fluid consisting of S〈sub〉8〈/sub〉 molecules and the observed excitation energies of the stretching modes in S molecules suggest that few fraction of S〈sub〉2〈/sub〉 molecules in the supercritical region near the liquid-vapor critical point. This result indicates that the nearest neighbor coordination number in the supercritical fluid S obtained by x-ray diffraction [Inui et al., J. Phys. Conf. Ser. 98 (2008) 012008] was underestimated.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): Haijian Li, Jianhua Yi, Zhao Qin, Zhihua Sun, Yi Xu, Changjian Wang, Fengqi Zhao, Yucheng Hao, Xiaofeng Liang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effect of rare earth elements (Y, La, Nd, Sm, and Gd) on the structures, thermal expansion, chemical stability and crystallization behavior of phosphate-based glasses were characterized by using powder X-ray diffraction (PXRD), Scanning Electron Microscope (SEM), X-Ray Fluorescence (XRF), Diffuse reflectance UV–Visible spectra, thermal expansion coefficient, inductively coupled plasma mass spectrometry (ICP-MS) and Differential scanning calorimetry (DSC). UV–Vis spectra not only exhibit the absorption peaks of rare earth cations but also reveal the reduction of band gap (E〈sub〉g〈/sub〉) with increasing the cationic field strength (CFS) of rare earth elements, further establishing the change of non-bridging oxygen (NBOs) density in the glass structures. It is found that there is a decrease in thermal expansion coefficient (α) with increasing the CFS of rare earth, and the study shows a strong correlation between α values and NBOs in the rare earth phosphate glass systems. The chemical durability tests of glass blocks demonstrate that the normalized leach rates (NR〈sub〉RE〈/sub〉) increase with decreasing the radius of rare earth elements, and La-doped phosphate glass with high thermal expansion coefficient has good chemical durability. By a two-stage thermal treatment, a preliminary study of the crystallization mechanism for the rare earth phosphate glasses is carried out, and the major crystalline phases are identified.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): Mengting Guo, Chongyun Shao, Feng Shi, Fan Wang, Shikai Wang, Chunlei Yu, Lei Zhang, Jinjun Ren, Lili Hu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Homogeneous 89.9SiO〈sub〉2〈/sub〉-4Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-6P〈sub〉2〈/sub〉O〈sub〉5〈/sub〉–0.1Yb〈sub〉2〈/sub〉O〈sub〉3〈/sub〉/Eu〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 glasses were fabricated via a sol−gel method and sintered under vacuum at high temperature, and subsequently they were annealed at 850 °C for 15 and 75 h. Effect of thermal annealing time on structures and properties of glasses was systematically investigated. Solid state nuclear magnetic resonance (SSNMR) and Raman scattering spectra were employed to characterize the network structures. Pulse electron paramagnetic resonance (EPR) techniques and the emission and excitation spectra of Eu〈sup〉3+〈/sup〉 ions were used to study the local environment of Yb〈sup〉3+〈/sup〉 ions. SSNMR and Raman results indicate that AlPO〈sub〉4〈/sub〉 units increase at the expense of Al〈sup〉V〈/sup〉, Al〈sup〉VI〈/sup〉 and P〈sup〉(3)〈/sup〉 groups after annealing. The glass network structures have a significant influence on density and refractive index. EPR and Eu〈sup〉3+〈/sup〉 spectra indicate an increase in Al around Yb〈sup〉3+〈/sup〉 ions and a reduction in the asymmetry degree of Yb〈sup〉3+〈/sup〉 ligands. A correlation between structures and properties of glasses is developed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): Harish N., Kathyayini N., Bindhu B., Nagaraju N.〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Amorphous aluminophosphate (AmAlPO〈sub〉4〈/sub〉) materials were synthesized by conventional precipitation technique from different phosphate precursors (Na〈sub〉4〈/sub〉P〈sub〉2〈/sub〉O〈sub〉7〈/sub〉, NaH〈sub〉2〈/sub〉PO〈sub〉4〈/sub〉, Na〈sub〉2〈/sub〉HPO〈sub〉4〈/sub〉, (NH〈sub〉4〈/sub〉)H〈sub〉2〈/sub〉PO〈sub〉4〈/sub〉, (NH〈sub〉4〈/sub〉)〈sub〉2〈/sub〉HPO〈sub〉4〈/sub〉 and H〈sub〉3〈/sub〉PO〈sub〉4〈/sub〉) without using any structure directing agents. All the prepared materials were analyzed by 〈sup〉27〈/sup〉Al and 〈sup〉31〈/sup〉P MAS-NMR, PXRD, FT-IR, XPS, BET, NH〈sub〉3〈/sub〉- TPD and SEM-EDS. The catalytic activity of the materials was checked for synthesis of diphenyl urea (DPU). Phosphoric acid (H〈sub〉3〈/sub〉PO〈sub〉4〈/sub〉) as a precursor was found to be more active catalyst (which yielded 90% of DPU) than the salt forms. 〈sup〉27〈/sup〉Al and 〈sup〉31〈/sup〉P MAS-NMR studies showed the presence of variable percentages of tetra and penta coordinated Al species, which are attributed to the catalytic activity of AlPO〈sub〉4〈/sub〉. AmAlPO〈sub〉4〈/sub〉 materials prepared were amorphous having intrinsic mesoporosity, moderate surface area and moderately strong acidic sites. A synergetic combination of all these surface properties play a subtle role in determining the activity of the differently coordinated Al species in the catalysts.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 521〈/p〉 〈p〉Author(s): Michael Kindle, Steven Kmiec, Igor d'Anciães Almeida Silva, Hellmut Eckert, Steve W. Martin, Min-Kyu Song, John S. McCloy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study elucidates the role of Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 in the lithium borovanadate (LBV) system, Li〈sub〉2〈/sub〉O-B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-V〈sub〉2〈/sub〉O〈sub〉5〈/sub〉, in improving the glass-forming region of LBV glass. This increased glass-forming tendency is likely due to formation of [AlO〈sub〉4〈/sub〉]〈sup〉−〈/sup〉 units. 〈sup〉11〈/sup〉B, 〈sup〉27〈/sup〉Al, and 〈sup〉51〈/sup〉V nuclear magnetic resonance measurements suggest an importance of V-O-Al linkages and distribution of Li for charge compensation of [AlO〈sub〉4〈/sub〉]〈sup〉−〈/sup〉 and [BO〈sub〉4〈/sub〉]〈sup〉−〈/sup〉 units. Intense 〈sup〉51〈/sup〉V NMR signals and resolved hyperfine coupling patterns in the electron paramagnetic resonance (EPR) spectra indicate that the majority of vanadium is pentavalent (V〈sup〉5+〈/sup〉) and minor amounts of paramagnetic vanadium (V〈sup〉4+〈/sup〉) are present. The EPR interaction parameters suggest that the vanadyl-like environments can be described as tetragonally compressed distorted octahedra. Based on V-2p〈sub〉3/2〈/sub〉 X-ray photoelectron spectroscopy, the V〈sup〉4+〈/sup〉 concentration is estimated at 〈3%. These vanadate glasses are attractive for energy storage applications, as they have higher specific capacities than commercial lithium-ion battery cathodes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): Yixuan He, Jinshan Li, Liyuan Li, Jun Wang, Eyub Yildiz, Eric Beaugnon〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The temperature-dependent liquid structures of Co-B melts were studied by in-situ measuring the magnetization. A magnetization anomaly in term of the non-Curie-Weiss temperature dependence of magnetization was observed in the overheated state, demonstrating a temperature-induced liquid-liquid structure transition. This anomalous behavior was found to be a universal formula for the Co-B binary alloy system. The transition point (〈em〉T〈/em〉〈sub〉0〈/sub〉) and two paramagnetic Curie temperatures (〈em〉θ〈/em〉〈sub〉〈em〉p〈/em〉〈/sub〉(L〈sub〉I〈/sub〉), 〈em〉θ〈/em〉〈sub〉〈em〉p〈/em〉〈/sub〉(L〈sub〉II〈/sub〉)) corresponding to two distinct kinds of liquids (i.e., high-magnetization liquid (HML) I and low-magnetization liquid (LML) II) were measured. With the increased concentration of Co, 〈em〉T〈/em〉〈sub〉0〈/sub〉, 〈em〉θ〈/em〉〈sub〉〈em〉p〈/em〉〈/sub〉(L〈sub〉I〈/sub〉) and 〈em〉θ〈/em〉〈sub〉〈em〉p〈/em〉〈/sub〉(L〈sub〉II〈/sub〉) shift to higher temperatures and the Curie constants for the HML and LML decrease. Based on the location of 〈em〉T〈/em〉〈sub〉0〈/sub〉, a guideline is drawn above the 〈em〉liquidus〈/em〉 in the Co-B phase diagram, which could provide a significant guidance to the practical melt treatment.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): I. Kashif, H. Farouk, A. Ratep, M. Al Mahalawy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The glass samples with the composition (50Bi〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 + 5TeO〈sub〉2〈/sub〉 + 1Dy〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 + xSiO〈sub〉2〈/sub〉+ (45-x) B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉) where x=10, 15, 20, 25, 30 and 35 mol % prepared. Density increased and the molar volume decreased with increasing the silicon content, which reveals that the glass samples became more compact as the SiO〈sub〉2〈/sub〉 increased. XRD showed that all glass samples were amorphous, The FTIR data indicated the existence of TeO3, BiO6, BO4, BO3, and SiO4 (with one non-bridging oxygen (Q3)) structural groups. UV–VIS–IR spectra revealed the presence of five bands from 〈sup〉6〈/sup〉H〈sub〉15/2〈/sub〉 to the 〈sup〉6〈/sup〉F〈sub〉5/2〈/sub〉, 〈sup〉6〈/sup〉H〈sub〉5/2〈/sub〉, 〈sup〉6〈/sup〉F〈sub〉9/2〈/sub〉, 〈sup〉6〈/sup〉H〈sub〉9/2〈/sub〉 and 〈sup〉6〈/sup〉H〈sub〉11/2〈/sub〉 according to the energy levels 12500, 11210, 9225, 7911, and 5952 cm〈sup〉-1〈/sup〉 respectively. The emission spectra showed two emission bands at around 480 nm and 575 nm corresponding to the 〈sup〉4〈/sup〉F〈sub〉9/2〈/sub〉 / 〈sup〉6〈/sup〉H〈sub〉15/2〈/sub〉 and 〈sup〉4〈/sup〉F〈sub〉9/2〈/sub〉 / 〈sup〉6〈/sup〉H〈sub〉13/2〈/sub〉 transitions, while the band at 664 nm corresponds to transition 〈sup〉4〈/sup〉F〈sub〉9/2〈/sub〉 / 〈sup〉6〈/sup〉H〈sub〉11/2〈/sub〉. These results, indicate that the co-doped (Dy〈sup〉3+〈/sup〉): SiBBiTe glassy samples having emission in the white region and thus can use for white LEDs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 522〈/p〉 〈p〉Author(s): N.A.M. Jan, M.R. Sahar, Sulhadi Sulhadi, R. El-Mallawany〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, we have five samples of NiO Nanoparticles (NPs) embedded in tellurite glass system of composition Neodymium doped tellurite nanostructured glass having a composition of (72.5-x)TeO〈sub〉2〈/sub〉-15MgO-10Na〈sub〉2〈/sub〉O-2.5Nd〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-(〈em〉x〈/em〉)NiO, x = 0.5, 1.0, 1.5, 2.0, 2.5 mol% has successfully been completed by melt-quenching procedure. Structure of crystallization is determined using XRD technique verifies amorphous natures of produced glass. Differential thermal stability analyser (DTA-Parkin-Elmer) is utilized to illustrate the thermal stability of a sample at a temperature ranged from 300 to 600 °C. A Transmission Electron Microscope (TEM) is used to detect the presence of NiO NPs and High-Resolution Transmission Microscope (HRTEM) is utilizing to measure the d-spacing of the NPs. The structure in glass network is identified by FT-IR and Raman spectrometer. The elemental trace in the glass sample is detected using the energy dispersive of X-ray (EDX) analysis. Meanwhile, magnetization measurements are carried out using Variable sample magnetometer (VSM). The transition temperature, 〈em〉T〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉 is found at 388 °C, the melting temperature 〈em〉T〈/em〉〈sub〉〈em〉m〈/em〉〈/sub〉 is ranged at 530-540 °C depending on composition while the thermal stability is around 117 °C. The structural and magnetic properties of the glass samples are observed to be delicate to NiO NPs concentration variations. The d-spacing at (111) plane having a size of 0.24 nm proves the presence of NiO NPs. The glass network contains of bending vibrations of Te-O-Te linkages centred at 448 cm〈sup〉−1〈/sup〉which is also the stretching band of NiO mode. It is also found that the glass structure is dominated with the existence of TeO〈sub〉3〈/sub〉, TeO〈sub〉3+1〈/sub〉 and TeO〈sub〉4〈/sub〉 tribypiramidal. The glass system reveals paramagnetic behaviour by magnetic hysteresis at room temperature with Hc values were observed to be decreased from 610 ± 30.5 to 139 ± 6.95 (Oe) and ratio of (Mr/Ms) from 0.153 ± 0.008 to 0.071 ± 0.004with the increase of NiO NPs concentration.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 521〈/p〉 〈p〉Author(s): Juan Xi, Baobiao Lu, Jingjing Chen, Guohua Chen, Fei Shang, Jiwen Xu, Changrong Zhou, Changlai Yuan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A novel CuO-ZnO-B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-Li〈sub〉2〈/sub〉O glass-ceramic was prepared by solid phase method, and. Its phase transition, sintering and dielectric performance was studied. No crystalline phase is observed for the specimen sintered at 560 °C. However, the samples sintered at 580 °C and 600 °C, consist of ZnB〈sub〉4〈/sub〉O〈sub〉7〈/sub〉 and Cu〈sub〉2〈/sub〉B〈sub〉4〈/sub〉O〈sub〉7〈/sub〉. And the Li〈sub〉2〈/sub〉CuB〈sub〉4〈/sub〉O〈sub〉8〈/sub〉 appears with further increasing temperature. The ε〈sub〉r〈/sub〉 and τ〈sub〉〈em〉f〈/em〉〈/sub〉 change slightly but the Q × 〈em〉f〈/em〉 value alter greatly with firing temperature. The glass-ceramic fired at 620 °C possesses optimum properties with ε〈sub〉r〈/sub〉 = 3.33, Q × 〈em〉f〈/em〉 = 17,724 GHz and τ〈sub〉〈em〉f〈/em〉〈/sub〉 ≈ 0 ppm/°C. Furthermore, the as-prepared glass-ceramic exhibits good co-firing compatibility with Ag and Al electrode. These properties qualify the dielectric material as promising alternatives for wireless communication applications.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 521〈/p〉 〈p〉Author(s): C. Dupuy, A. Gharzouni, I. Sobrados, N. Texier-Mandoki, X. Bourbon, S. Rossignol〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This study aims to develop a geopolymer binder, which requires a control of the reactive mixture setting time, viscosity and pH value. A previous study underlines the possibility of controlling the setting time, viscosity and pH value of geopolymer binders by the addition of phosphate- or boron–based compounds. To understand the structural evolutions responsible for these operating property changes, magic angle spinning (MAS) nuclear magnetic resonance (NMR) analysis were performed on the different binders. A batch of ten specific samples was studied by 〈sup〉11〈/sup〉B or 〈sup〉31〈/sup〉P (depending on the additive nature), 〈sup〉27〈/sup〉Al and 〈sup〉29〈/sup〉Si MAS NMR. The NMR spectral decomposition results were correlated with the operating properties of the different binders. The setting time increase was associated with the formation of a secondary phase based on boron or phosphorous. The pH variation is connected with both the modified Si/Al ratio and the asymmetric B〈sup〉III〈/sup〉 species associated with one non-bridging oxygen (NBO) atom. Thus, determination of the various NMR environments is a useful tool to predict the setting time and pH value evolutions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 October 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 521〈/p〉 〈p〉Author(s): Ding Zhou, Xianhang Zhao, Bingjin Li, Naidan Hou, Zihao Ma, Tianfu Sun, Bing Hou, Yulong Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The intrinsic fracture mechanism of bulk metallic glasses (BMGs) is often obscured with the involvement of normal stress. To decouple the normal-stress effect, a double-notched shearing technique is developed to investigate the mechanical properties of BMGs. Real-time shear banding and fracture behavior under quasi-static and dynamic shearing are captured by using high-speed photographing, which confirms multiple shear banding at low strain rates and single shear banding at high strain rates. More importantly, the transition from shear band to crack could be observed with little influence of normal stress. Such transition is found to be induced by cavitation mechanism and shows obvious rate dependence; that is originated from regularly distributed controllable cavities under quasi-static loading, while from a series of concentrated cavitation under dynamic loading. Referring to studies under compression and tension, we clarify that strain rate controls cavitation concentration level and normal stress controls cavitation instabilities, respectively.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): X.Y. Wang, S.L. Zhang, S.D. Feng, L. Qi, R.P. Liu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The structures of the Ti〈sub〉75〈/sub〉Al〈sub〉25〈/sub〉 alloy during rapid-quenching with and without external pressure are investigated by using molecular dynamic techniques. The amorphous phase can be obtained at the cooling rate 10.0 K/ps without pressure. The alloy is composed of crystal and amorphous phase at the cooling rate 0.1 and 1.0 K/ps without pressure, but the pure amorphous phase can be formed when the pressure exceeds the critical value. The critical pressure is about 20 and 30 GPa when the cooling rate is 0.1 and 1.0 K/ps, respectively. H-A indices analysis indicates that high pressure favors the formation of the ideal icosahedral structures in the amorphous Ti〈sub〉75〈/sub〉Al〈sub〉25〈/sub〉 alloy, and the content of 1551 bond-type can reach near to 50% when the pressure is 30 GPa. The amorphous state can be maintained if the external pressure is removed from the alloy step-by-step. The content of 1551 bond-type decreases with the deceasing of the pressure, but the 1541 and 1431 bond-types increase in this process.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Anne-Isabelle Bidegaray, Andrea Ceglia, Maria Rita Cicconi, Van-Thai Pham, Amandine Crabbé, El Amine Mernissi Cherigui, Karin Nys, Herman Terryn, Daniel R. Neuville, Stéphane Godet〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The analysis of iron, manganese and antimony in silicate glass is of great interest in chemistry, materials science, earth sciences and archaeological sciences. Yet, conclusions from different fields appear to be contradictory and many questions about redox reactions in glass remain. The purpose of this study is thus to discuss whether and how these multivalent elements interact in glass. Soda-lime silicate melts containing iron along with manganese and/or antimony have been analysed at different high temperatures under argon atmosphere. Using 〈em〉in-situ〈/em〉 XANES at the Fe K-edge, redox thermodynamics, kinetics and diffusivities have been assessed for the different compositions. The data obtained show that antimony is more efficient at oxidising iron compared to manganese at all temperatures. The oxidising power trend would thus be Sb 〉 Sb + Mn 〉 Mn. Furthermore, hypotheses on the formation of Fe-Mn complexes are also reported in glasses with stoichiometric proportions of iron and manganese. Based on the determination of redox diffusivities, it appears that presence of other multivalent elements does not significantly affect the iron redox mechanisms and that diffusivity is essentially controlled by the mobility of calcium.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Wentao Zhang, Feng He, Junlin Xie, Xiaoqing Liu, De Fang, Hu Yang, Zhihong Luo〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Glass ceramics from modified molten blast furnace (BF) slag were prepared. The crystallization behavior of the modified BF slag was characterized using differential thermal analysis (DTA), X-ray diffraction (XRD), and field emission scanning electron microscope (FESEM). The crystallization kinetics results indicated that the crystallization activation energy initially decreased and subsequently increased with increasing CaO/SiO〈sub〉2〈/sub〉. The crystallization temperature and the crystallization index (n) decreased from 916 to 867 °C, and 5.66–1.13, respectively. The crystallization mechanism transformed from bulk crystallization to surface crystallization. By XRD analyzing, Melilite was developed as the main crystal phase, and the transformation of crystal from akermanite to gehlenite was observed. The rapid surface crystallization was beneficial for maintaining the shape of glass ceramics. The complex replacement in melilite crystals resulted in the micro cracks in glass ceramics, therefore led to the decrease of flexural strength of glass ceramics〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): B.C. Jamalaiah〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Different amounts of GeO〈sub〉2〈/sub〉 activated tellurite tungstate glasses were prepared by melt quenching technique. Thermal stability and glass forming ability were studied using differential scanning calorimetry. The chemical composition, homogeneity and amorphous nature of studied glasses were investigated. The phonon energy was estimated to be 721.34 cm〈sup〉−1〈/sup〉. Experimentally determined refractive indices were compared with those determined from optical band gap (E〈sub〉g〈/sub〉) and optical electronegativity (Δ〈em〉χ〈/em〉〈sup〉∗〈/sup〉). The dielectric constant (K) and electronic polarizability (α) were determined using refractive index value. The presence of disorder was estimated in terms of Urbach energy (E〈sub〉U〈/sub〉). The average electronegativity (〈em〉χ〈/em〉〈sub〉〈em〉ave〈/em〉〈/sub〉), oxide ion polarizability (〈em〉α〈/em〉〈sub〉〈em〉O〈/em〉〈/sub〉〈sup〉2−〈/sup〉) and covalent character (C〈sub〉cov〈/sub〉) were determined. The content of GeO〈sub〉2〈/sub〉 was optimized to be 10.0 mol% to design a novel host material for solid state lasers and fiber devices.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Chunhe Jiang, Kejiang Li, Jianliang Zhang, Qinghua Qin, Zhengjian Liu, Minmin Sun, Ziming Wang, Wang Liang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉SiO〈sub〉2〈/sub〉-Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-CaO-MgO is the most significant slag system in the blast furnace ironmaking process and it is very important to investigate the microstructure and viscosity of the system. In this paper, molecular dynamics simulations were carried out to explore the effects of MgO/Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 ratio on structure and properties of the system. Based on the self-diffusion coefficients, the viscosities were calculated by Einstein-Stokes equation and compared with the experimental value and the Factsage value. The results showed that with the increase of MgO/Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 ratio, the stability of [SiO〈sub〉4〈/sub〉]〈sup〉4−〈/sup〉 and [AlO〈sub〉4〈/sub〉]〈sup〉5−〈/sup〉 tetrahedron became weaken and the relative proportions of bridge and non-bridge oxygen showed a decrease. And due to the increase of MgO, more Mg〈sup〉2+〈/sup〉 ions are used as network modifiers to reduce the degree of polymerization of the system, resulting in a decrease in the viscosity, which is consistent with experimental results. Finally, based on the present study, in the case of increasing Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 content of blast furnace slag, the fluidity of slag could be adjusted by controlling MgO/Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 ratio, thereby providing a basis for stable operation of blast furnace ironmaking.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): A.I. Popov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The definition of glassy state presented by the authors of the article “The glassy state of matter: Its definition and ultimate fate” E. Zanotto and J. Mauro is considered. The importance of the contribution to the glassy state problem made in the article is emphasized. At the same time consideration of the glassy state as unstable state of matter causes definite objections. It is more correctly to consider the glassy state as metastable state of matter.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): M.G. Syamala Rao, M.A. Pacheco-Zuñiga, L.A. Garcia-Cerda, G. Gutiérrez-Heredia, J.A. Torres Ochoa, M.A. Quevedo López, R. Ramírez-Bon〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, we developed a novel inorganic-organic hybrid gate dielectric by combining zirconium and hafnium components to form zirconium hafnium oxide strongly linked with polymethyl methacrylate (ZrHfO〈sub〉2〈/sub〉-PMMA) and deposited at low temperature (200 °C) by sol-gel method. The obtained 108 nm thick, high-quality hybrid gate dielectric showed an exceptionally low surface roughness (0.9-nm), a low leakage current density (7.7 × 10〈sup〉−6〈/sup〉 A/cm〈sup〉2〈/sup〉) and reasonable dielectric properties such as gate capacitance along with dielectric constant (77 nF/cm〈sup〉2〈/sup〉 & 9.4 @1 kHz) respectively. To examine the ZrHfO〈sub〉2〈/sub〉-PMMA hybrid dielectric electrical properties we constructed thin-film transistors (TFTs) with room temperature r.f sputtered n-type metal oxide semiconductors, a-IGZO and ZnO, as active channels. The bottom gate fabricated a-IGZO TFTs driving at as low as below 6 V, with extracted field effect mobility of 2.45 cm〈sup〉2〈/sup〉/V. s, a low threshold voltage of 1.2 V with large ON/OFF current ratio 10〈sup〉7〈/sup〉 respectively. On the other hand, for comparison we employed ZnO TFTs by applying same hybrid dielectric system, the obtained parameters of bottom gate ZnO TFTs were good field effect saturation mobility of 12.8 cm〈sup〉2〈/sup〉/V. s, threshold voltage of 1.8 V and ON/OFF current ratio of 10〈sup〉3〈/sup〉.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Weidi Zhu, Mark Lockhart, Bruce Aitken, Sabyasachi Sen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The viscoelastic properties of supercooled As〈sub〉x〈/sub〉Se〈sub〉100-x〈/sub〉 (0 ≤ x ≤ 30) and As〈sub〉x〈/sub〉Se〈sub〉100-x-y〈/sub〉I〈sub〉y〈/sub〉 (x = 20, 30 and y = 10, 20) liquids are studied using oscillatory parallel plate rheometry. In addition to the α-relaxation process, the shear relaxation of liquids with selenium chains longer than ~ 3 atoms is also characterized by a low-frequency polymeric mode. The temporal decoupling of this low-frequency soft/floppy relaxation mode from that of the α-relaxation mode is a unique function of the average selenium chain length. The floppy mode abruptly vanishes for liquids with average chain lengths shorter than ~ 3 Se atoms, thus implying a dynamical rigidity transition. When taken together, these results indicate that, contrary to the conventional wisdom, the pertinent structural variable associated with such transition in the viscoelastic behavior is not the average coordination number but instead the intermediate-range structural elements such as the average selenium chain length.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): M.S.A. Mohd Saidi, S.K. Ghoshal, K. Hamzah, R. Arifin, M.F. Omar, M.K. Roslan, E.S. Sazali〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report the influence of silver (Ag) and titania (TiO〈sub〉2〈/sub〉) nanoparticles (ATNPs) co-embedment on the photoluminescence (PL) properties of dysprosium ions (Dy〈sup〉3+〈/sup〉) doped zinc-magnesium tellurite glass system prepared using conventional melt quenching method. Both up- and down- converted PL spectra of glasses revealed three emission bands located at 482 (blue: 〈sup〉4〈/sup〉F〈sub〉9/2〈/sub〉 → 〈sup〉6〈/sup〉H〈sub〉15/2〈/sub〉), 574 (yellow: 〈sup〉4〈/sup〉F〈sub〉9/2〈/sub〉 → 〈sup〉6〈/sup〉H〈sub〉13/2〈/sub〉) and 664 nm (weak red: 〈sup〉4〈/sup〉F〈sub〉9/2〈/sub〉 → 〈sup〉6〈/sup〉H〈sub〉11/2〈/sub〉), where the band intensities were enhanced with the inclusion of ATNPs. Glasses with 0.2 mol% of ANPs and up to 0.3 mol% of TNPs disclosed highest PL intensity enhancement, which was majorly attributed to the ATNPs mediated localized surface plasmon resonance (LSPR) and large field enhancement (called hot spot) effects in the proximity of Dy〈sup〉3+〈/sup〉 ions. Absorption spectra of glasses displayed two plasmon bands characteristics of each type of nanoparticle. It was inferred that the superposition of localized SP modes from ATNPs could generate new hybridized modes (strong local field in the vicinity of Dy〈sup〉3+〈/sup〉 ions) shifted with respect to the single type of NPs resonance. HRTEM images showed the existence of both Ag and titania NPs inside the glass matrix. Glasses containing ATNPs exhibited anatase phase with (103) and (112) nanocrystalline lattice plane orientation. Proposed glass system may be useful for the development of solid state laser and photonic devices.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): G. Gorni, M.J. Pascual, A. Caballero, J.J. Velázquez, J. Mosa, Y. Castro, A. Durán〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The crystallization mechanism of LaF〈sub〉3〈/sub〉 in sol-gel oxyfluoride glass-ceramics in the system SiO〈sub〉2〈/sub〉-LaF〈sub〉3〈/sub〉 has been studied using DTA, XRD, FTIR, HRTEM and NMR. Based on classical calculations of non-isothermal DTA curves involving Ozawas's plots, a diffusion-controlled process should be responsible for the fluorides crystallization similarly to that obtained for melt-quenching oxyfluoride glass-ceramics. Therefore, an increase of the crystal size and fraction is expected when increasing the time and/or temperature of the treatment. Nevertheless, XRD, FIR, HRTEM and NMR demonstrated that neither bigger crystals nor higher crystal fraction are obtained for treatment times longer than 1 min at 550 °C. However, further heat treatment causes that the structural order of the crystals is lost. On the other hand, typical fluorides crystallization temperatures (~300 °C) in sol-gel materials are much lower than T〈sub〉g〈/sub〉 of the matrix (~1130 °C) thus being very different to what observed for oxyfluoride glasses prepared by melt-quenching. The proposed crystallization mechanism is a fast process that occurs when crystallization temperature is reached. This behavior is explained as a chemical reaction from the xerogels, followed by the fast precipitation of the nanocrystals without energy barrier. The nanocrystals are unstable in the surrounding SiO〈sub〉2〈/sub〉 matrix for aging at crystallization or higher temperatures. These treatments lead to a dissolution process, favored by the compositional gradient between matrix and crystals, which drive the material to reach the equilibrium.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): Jürn W.P. Schmelzer, Alexander S. Abyzov, Vladimir M. Fokin, Christoph Schick〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉General relations for the dependence of the thermodynamic driving force of crystallization and the specific interfacial energy melt-crystal of critical crystal clusters on temperature and pressure are derived. Its application to the analysis of experimental data on crystal nucleation seems to support at a first glance a proposal by Kauzmann on the existence of a pseudo-spinodal curve in melt-crystallization. Provided this assumption is true, Kauzmann temperature (and for pressure-induced nucleation, the Kauzmann pressure) cannot be reached by a metastable liquid due to intensive crystallization processes occurring in its vicinity. However, such suggestion cannot be retained taking into account the kinetic terms (diffusion coefficients, viscosity) in the expression for the nucleation rate. The absence of a pseudo-spinodal in melt-crystallization can be verified also in an alternative way by considering the characteristic time scales of crystallization and relaxation. Finally, it is shown that the phenomenon denoted commonly as Kauzmann paradox is merely an untypical as compared to normal conditions type of behavior. Neither in its original formulation nor in its consequences it results in any contradictions with basic laws of nature. They are prevented either by normal (not associated with a pseudo-spinodal) crystallization or a conventional glass transition.〈/p〉〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): J. Gilabert, M.P. Gómez-Tena, V. Sanz, S. Mestre〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉The effect of a post-synthesis thermal treatment on CoCr〈sub〉2−2Ψ〈/sub〉Al〈sub〉2Ψ〈/sub〉O〈sub〉4〈/sub〉 (0.0 ≤ Ψ ≤ 1.0) ceramic pigments synthesized by Solution Combustion Synthesis (SCS) has been studied. As-synthesized SCS pigments were treated at two different calcination temperatures (800 °C and 1000 °C) to study changes in mineralogy, microstructure and thermal behaviour, as well as their effect over the colouring power.〈/p〉 〈p〉Spinel-type 〈em〉Fd〈/em〉-3〈em〉m〈/em〉 crystalline structure was developed in all cases. Nevertheless, crystallinity parameters were highly affected by both analysed processing parameters: composition (Ψ) and post-synthesis calcination temperature (T〈sub〉c〈/sub〉). A Cr(III) enrichment along with T〈sub〉c〈/sub〉 increase favoured ion rearrangement to promote sample crystallization and crystallite growth. Fast kinetics of SCS makes Al-rich spinels with transition metals difficult to be synthesized. The application of a secondary thermal treatment resulted in a favourable evolution towards a well-crystallized structure. Lattice parameter did not seem to be affected by T〈sub〉c〈/sub〉, although it evolved indeed with composition. From a microstructural point of view, as-synthesized pigments were foamy, with a very low bulk density and nanometric grain size. After the thermal treatment, larger grain sizes were obtained, especially for the samples richer in Al and treated at higher T〈sub〉c〈/sub〉.〈/p〉 〈p〉All pigments developed intense colours in a transparent glaze without showing heterogeneities, indicating a stable behaviour against glazing process. Glaze colour evolved from green to perfectly blue shades, indicating an important dependence on composition. Nevertheless, colouring power seemed to be rather affected by calcination process.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): Joanna Pisarska, Marta Sołtys, Joanna Janek, Agata Górny, Ewa Pietrasik, Tomasz Goryczka, Wojciech A. Pisarski〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Oxyfluoride lead-based and lead-free germanate glasses were heat-treated in order to fabricate transparent glass-ceramics. Cubic β-PbF〈sub〉2〈/sub〉 nanocrystals are well formed during crystallization of lead germanate glass. The up-conversion luminescence spectra of Er〈sup〉3+〈/sup〉 ions in lead germanate glass-ceramic system are enhanced significantly due to partial incorporation of the optically active ions into fluoride crystalline phase. These effects are not significant in oxyfluoride lead-free germanate glass after heat treatment process. The crystallization of barium gallo-germanate glass with BaF〈sub〉2〈/sub〉 is more complex and the presence of four crystalline phases BaF〈sub〉2〈/sub〉, BaO, Ba〈sub〉3〈/sub〉Ga〈sub〉2〈/sub〉Ge〈sub〉4〈/sub〉O〈sub〉14〈/sub〉 and GeO〈sub〉2〈/sub〉 was verified by X-ray diffraction measurements.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Edgar D. Zanotto, John C. Mauro〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The comment by Popov raises two questions related to (a) whether the glassy state can more appropriately be described as 〈em〉metastable〈/em〉 or 〈em〉unstable〈/em〉 and (b) whether the supercooled liquid state exists below the glass transition temperature, 〈em〉T〈/em〉〈sub〉g〈/sub〉. We argue that the glassy state is thermodynamically unstable, as it continuously and spontaneously relaxes toward the metastable supercooled liquid state at any nonzero temperature. Moreover, the supercooled liquid state—the target for the glass relaxation process—exists at any temperature below the liquidus temperature of a system. There is no problem with having a missing target for the glass relaxation process, since this metastable supercooled liquid state can always be defined.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): B. Grosdidier〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, a rigorous mathematical method to calculate the order parameter in a binary amorphous or liquid alloy, is established even when the alloy is made up of very differently sized atoms. This method, based on the study of the eigenstates of the exchange operator of the alloy components, allows revealing different spherical layers whose inner and outer radii are solutions of a certain equation. These layers have no constant thickness but contain numbers of atoms of each species that are exactly in the ratio of the concentrations of these two species. Thus, each layer has exactly the average concentration of the alloy, allowing to properly formalize the order parameter. Thus the order parameter is formalized in each of these layers. This method makes possible to retrieve the subtle Bhatia-Thornton formalism [Phys. Rev., B2, 3004 (1970)] used for the description of binary alloys. We discuss the link between the zero 〈em〉q〈/em〉 value of concentration-concentration Bhatia-Thornton partial structure factor and the numbers of neighbours. We apply our method to study the order in the Bi〈sub〉0.3〈/sub〉Ga〈sub〉0.7〈/sub〉 liquid alloy. We are able to determine eight layers and their order parameter on the interatomic distance-range [0, 15 Å].〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Hongtu He, Tongjin Xiao, Qian Qiao, Jiaxin Yu, Yafeng Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉It is well-known that the sliding contact damage of glass materials is very sensitive to the presence of water, but the detailed mechanisms remain elusive. In this work, the effects of water and speed on wear behaviors of soda lime silica (SLS) glass are investigated upon a ball-on-flat reciprocating tribometer in dry and humid air. When water molecules are present at the sliding interfaces in humid air, the wear volume of SLS glass decreases with the increase in sliding speed from 0.25 mm/s to 8 mm/s, which is believed to be originated from the suppressed tribochemical reactions involving water molecules at high speed conditions, therein the wear volume of SLS glass decreases to ~6 times. However, when water molecules are absent at the sliding interfaces in dry air, the wear volume of SLS glass increases to ~12.5 times when the sliding speed increases from 0.25 mm/s to 8 mm/s. Analyses suggest that the wear of SLS glass in dry air is dominated by the adhesive wear and brittle exfoliation, which can be facilitated by the friction-induced temperature rise and surface cracking at high speed conditions. Our results indicate that the sliding speed can either promote or suppress the wear of SLS glass, depending on the presence of water molecules at the sliding interfaces. These results may provide a deep understanding on the effects of water and speed on the material damage of oxide glass materials during its manufacturing and operation processes.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): S.S. Chen, W.H. Li, X.R. Zeng〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this work, an enhanced room-temperature plasticity was achieved in a Zr〈sub〉62.8〈/sub〉Cu〈sub〉15〈/sub〉Co〈sub〉9.2〈/sub〉Ti〈sub〉6〈/sub〉Al〈sub〉7〈/sub〉 glassy alloy through the application of micro-arc oxidation (MAO) treatment. After treated for 15 and 30 min, the glassy alloy specimen exhibited an enhanced plastic strain of 5.5% and 7.9%, respectively. Both the introduction of nucleation sites for shear band at the coating/substrate interface owing to stress concentration and the physical constraint effect for the propagating shear bands from the in-situ formed coating are responsible for the enhanced plasticity. This finding may open a new avenue for developing ductile metallic glasses from a surface modification aspect.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Zhuang Guo, Song Ye, Ping Xiao, Deping Wang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this research, the Ag nanoclusters (Ag NCs) dispersed borosilicate glasses with the absence and presence of LiF were prepared by the melt-quenching method. The absorption, photoluminescence, FTIR results indicated that the doping of LiF plays dual effects on the size evaluation of Ag species: the introduction of F〈sup〉−〈/sup〉 and Li〈sup〉+〈/sup〉 can promote and restrain the formation of Ag NCs, respectively. It was also indicated that the promotion effect of F〈sup〉−〈/sup〉 is overwhelming at lower LiF doping concentration, while the restrain effect of Li〈sup〉+〈/sup〉 becomes dominated when increase LiF concentration to 8 mol%. Besides, our research further proved that the formation of Ag NCs is very sensitive to the presence of F content, even the introduction of rare earth ions in the form of fluoride or oxide can obviously modify the amount and size distribution of Ag NCs and thus affect the luminescence properties of the codoped glasses.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Zongwen Zhao, Yuxia Song, Xiaobo Min, Yanjie Liang, Liyuan Chai, Meiqing Shi〈/p〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Bo Huang, Changfu Xu, Zhen Zhang, Chun yang Zang, Lizhong Sun〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The near ~3 μm mid-infrared laser demonstrates real and potential applications in many military and civilian areas, but the lack of host materials with nice optical quality and the overlapped vibrations of OH〈sup〉–〈/sup〉 hamper the emission intensity. To eliminate the OH〈sup〉–〈/sup〉 absorption, ZnF〈sub〉2〈/sub〉 was adopted in Yb〈sup〉3+〈/sup〉/Ho〈sup〉3+〈/sup〉 codoped binary TeO〈sub〉2〈/sub〉-PbF〈sub〉2〈/sub〉 glass to partially till totally replace PbF〈sub〉2〈/sub〉. The high ZnF〈sub〉2〈/sub〉 concentration would raise the glass transition temperature and enhance the thermal stability of matrix, especially enhance the intensity of 2.85 μm mid-infrared luminescence obviously. TeO〈sub〉2〈/sub〉-ZnF〈sub〉2〈/sub〉 glass with 45.5% ZnF〈sub〉2〈/sub〉 original content has high ratio of the strength parameter 〈em〉Ω〈/em〉〈sub〉〈em〉4〈/em〉〈/sub〉〈em〉/Ω〈/em〉〈sub〉〈em〉6〈/em〉〈/sub〉 (=2.90) and possesses higher spontaneous transition probability (45.25 S〈sup〉−1〈/sup〉) along with the larger calculated emission cross section (0.96 × 10〈sup〉−20〈/sup〉 cm〈sup〉2〈/sup〉) corresponding Ho〈sup〉3+〈/sup〉: 〈sup〉5〈/sup〉I〈sub〉6〈/sub〉 → 〈sup〉5〈/sup〉I〈sub〉7〈/sub〉 transition. Fourier transmittance of infrared spectra revealed ZnF〈sub〉2〈/sub〉 could reduce the OH〈sup〉–〈/sup〉 concentration in glass substantially, which were favor of 2.85 μm mid-infrared emission. Our results indicated that the use of ZnF〈sub〉2〈/sub〉 to effectively remove the hydroxyl groups is an efficacious way to develop near ~3 μm mid-infrared optical glass with high efficient luminescence and thermochemical reliability.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Ana F. Kozmidis Petrović, Goran R. Štrbac, Dragana D. Štrbac〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉In this paper, the modified Kissinger equation and the Ozava type equation were obtained by using a process of homogenization from dimensional analysis, thus making them correct in relation to the application of a logarithmic function. An equation that holds at maximum reaction rate is applied for the chosen reference heating rate 〈em〉β〈/em〉〈sub〉〈em〉r〈/em〉〈/sub〉 and also for a heating rate 〈em〉β〈/em〉〈sub〉〈em〉i〈/em〉〈/sub〉 that was used. In that way the modified Kissinger equation 〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="block" altimg="si1.gif" overflow="scroll"〉〈mo〉ln〈/mo〉〈mfenced open="(" close=")"〉〈mrow〉〈mfrac〉〈msubsup〉〈mi〉T〈/mi〉〈mi mathvariant="italic"〉mr〈/mi〉〈mn〉2〈/mn〉〈/msubsup〉〈msubsup〉〈mi〉T〈/mi〉〈mi mathvariant="italic"〉mi〈/mi〉〈mn〉2〈/mn〉〈/msubsup〉〈/mfrac〉〈mfrac〉〈msub〉〈mi〉β〈/mi〉〈mi〉i〈/mi〉〈/msub〉〈msub〉〈mi〉β〈/mi〉〈mi〉r〈/mi〉〈/msub〉〈/mfrac〉〈/mrow〉〈/mfenced〉〈mo〉=〈/mo〉〈mo〉−〈/mo〉〈mfrac〉〈mi〉E〈/mi〉〈mi〉R〈/mi〉〈/mfrac〉〈mfrac〉〈mn〉1〈/mn〉〈msub〉〈mi〉T〈/mi〉〈mi mathvariant="italic"〉mi〈/mi〉〈/msub〉〈/mfrac〉〈mo〉+〈/mo〉〈mfrac〉〈mi〉E〈/mi〉〈mi〉R〈/mi〉〈/mfrac〉〈mfrac〉〈mn〉1〈/mn〉〈msub〉〈mi〉T〈/mi〉〈mi mathvariant="italic"〉mr〈/mi〉〈/msub〉〈/mfrac〉〈/math〉 was obtained. The modified Ozava type equation was obtained in the form.〈/p〉 〈p〉〈span〉〈math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"〉〈mo〉ln〈/mo〉〈mfenced〉〈mfrac〉〈msub〉〈mi〉β〈/mi〉〈mi〉i〈/mi〉〈/msub〉〈msub〉〈mi〉β〈/mi〉〈mi〉r〈/mi〉〈/msub〉〈/mfrac〉〈/mfenced〉〈mo〉=〈/mo〉〈mo〉−〈/mo〉〈mfrac〉〈mrow〉〈mi〉m〈/mi〉〈mi〉E〈/mi〉〈/mrow〉〈mrow〉〈mi〉n〈/mi〉〈mi〉R〈/mi〉〈/mrow〉〈/mfrac〉〈mfrac〉〈mn〉1〈/mn〉〈msub〉〈mi〉T〈/mi〉〈mi mathvariant="italic"〉mi〈/mi〉〈/msub〉〈/mfrac〉〈mo〉+〈/mo〉〈mfrac〉〈mrow〉〈mi〉m〈/mi〉〈mi〉E〈/mi〉〈/mrow〉〈mrow〉〈mi〉n〈/mi〉〈mi〉R〈/mi〉〈/mrow〉〈/mfrac〉〈mfrac〉〈mn〉1〈/mn〉〈msub〉〈mi〉T〈/mi〉〈mi mathvariant="italic"〉mr〈/mi〉〈/msub〉〈/mfrac〉〈/math〉〈/span〉where 〈em〉T〈/em〉〈sub〉〈em〉mr〈/em〉〈/sub〉 and 〈em〉T〈/em〉〈sub〉〈em〉mi〈/em〉〈/sub〉 are the temperatures of the maximum obtained with 〈em〉β〈/em〉〈sub〉〈em〉r〈/em〉〈/sub〉 and 〈em〉β〈/em〉〈sub〉〈em〉i〈/em〉〈/sub〉 respectively. In these equations, free terms are explicitly defined and from their values it is possible to calculate the value of activation energy 〈em〉E〈/em〉, as from the slope of straight lines. The main advantage of the modified equations compared to the original Kissinger equation and the Ozava type equation is not the more accurate value of the activation energy, but the more precise form of the equation.〈/p〉 〈p〉With the goal to overcome all imperfections of the Lasocka equation, we propose the modified relationship 〈em〉T〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉 〈em〉= A〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉 〈em〉+ B〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉 log〈em〉(β/β〈/em〉〈sub〉〈em〉r〈/em〉〈/sub〉 〈em〉+〈/em〉 〈em〉1)〈/em〉 between the glass transition temperature 〈em〉T〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉 and the heating rate 〈em〉β〈/em〉. In this equation, the logarithm is calculated from dimensionless values, where 〈em〉β〈/em〉〈sub〉〈em〉r〈/em〉〈/sub〉 is the chosen reference heating rate. In contrast to the original Lasocka equation, the modified Lasocka equation parameters 〈em〉A〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉 and 〈em〉B〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉 have the same units. The temperature 〈em〉T〈/em〉〈sub〉〈em〉g0〈/em〉〈/sub〉 = 〈em〉A〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉 can be obtained by extrapolation of experimental results to 〈em〉β〈/em〉 = 0. This is impossible to get from the original Lasocka equation, but it can be obtained from the modified one.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Collin J. Wilkinson, Evgeny Pakhomenko, Martha R. Jesuit, Anthony DeCeanne, Brittney Hauke, Michael Packard, Steve A. Feller, John C. Mauro〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A topological constraint model is developed to elucidate the coordination environment of alkali tellurite glasses. The model is derived from temperature-dependent constraint theory and provides a quantitative connection between the connectivity of the glass network and the compositional dependence of the glass transition temperature (〈em〉T〈/em〉〈sub〉〈em〉g〈/em〉〈/sub〉). Our model gives support to the model proposed by Barney et al. [〈em〉J. Phys. Chem. Lett.〈/em〉〈strong〉4,〈/strong〉 2312–2316 (2013)], confirming their model of the coordination environment in alkali tellurites. The model simultaneously serves as a framework that can be used in binary alkali glass-formers to predict an expected coordination the network forming cation in an oxide glass.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): Yasuhiro Nobuta, Yoshihiro Takahashi, Takamichi Miyazaki, Nobuaki Terakado, Noriko Onoue, Tsuyoshi Shinozaki, Takumi Fujiwara〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Recently, we have developed the borosilicate glass, in which ZrO〈sub〉2〈/sub〉 phase is singly crystallizable, and has found an emissive monoclinic ZrO〈sub〉2〈/sub〉 dendrites in the resulting GCs. In order to promote the formation of monoclinic phase, we have examined the effect of substitution of alumina Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 for ZrO〈sub〉2〈/sub〉 in the precursor glass composition, i.e., 15Na〈sub〉2〈/sub〉O–(15 − 〈em〉x〈/em〉)ZrO〈sub〉2〈/sub〉–〈em〉x〈/em〉Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉–30B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉–40SiO〈sub〉2〈/sub〉. It was found that the substitution of small amount of Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 (〈em〉x〈/em〉 = 1) gave a positive effect, i.e., increase in the amount of monoclinic phase and decrease in the crystal size. Furthermore, the substitution improved the internal quantum-yield. On the other hand, the further substitution (〈em〉x〈/em〉 ≥ 2) provided the decrease in amount of the monoclinic phase.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): Takumi Kato, Go Okada, Noriaki Kawaguchi, Hirokazu Masai, Takayuki Yanagida〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We have investigated photoluminescence (PL) and scintillation properties of 30BaO-15TiO〈sub〉2〈/sub〉-(55-〈em〉x〈/em〉)GeO〈sub〉2〈/sub〉-〈em〉x〈/em〉SiO〈sub〉2〈/sub〉 (BTGS〈em〉x〈/em〉: 〈em〉x〈/em〉 = 0, 13.75, 25, 30, 41.25 and 55) glasses and glass-ceramics prepared by the conventional melt-quenching method. In the PL spectra of all the samples, an emission band was observed around 490 nm. In addition, another emission band was detected around 530 nm in the BTGS30, BTGS25, BTGS13.75 and BTG55 glass-ceramics. From the PL decay time constants, the emission bands at 490 and 530 nm were confirmed to be due to the 〈sup〉3〈/sup〉T〈sub〉1〈/sub〉-〈sup〉1〈/sup〉A〈sub〉1〈/sub〉 transition of Ti〈sup〉4+〈/sup〉 ions and 〈sup〉2〈/sup〉E-〈sup〉2〈/sup〉T〈sub〉2g〈/sub〉 transition of Ti〈sup〉3+〈/sup〉 ions, respectively. The quantum yields of all the glass-ceramics were higher than those of the glasses of the same chemical compositions. In scintillation spectra, all the samples showed emission peaks similarly seen in PL. The scintillation intensities of the glass-ceramics were higher than those of the glasses of the same chemical compositions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): Dmytro Savytskii, Volkmar Dierolf, Nobumichi Tamura, Himanshu Jain〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We have investigated the occurrence of the sometimes observed grain boundaries, as initial seed is extended to form line in laser-fabricated single-crystal architecture in glass (SCAG). In particular, for Sb〈sub〉2〈/sub〉S〈sub〉3〈/sub〉 SCAG in Sb-S-I glass as a model system, grain boundaries are formed during the transition from laser-written initial seed dot to crystal line. Such grain boundaries during the growth of Sb〈sub〉2〈/sub〉S〈sub〉3〈/sub〉 crystals occur in 16SbI〈sub〉3〈/sub〉–84Sb〈sub〉2〈/sub〉S〈sub〉3〈/sub〉 glass, whereas they are absent in Sb〈sub〉2〈/sub〉S〈sub〉3〈/sub〉 glass. We correlate this difference in tendency to form multiple grains with the relative glass forming ability i.e. the dynamics of nucleation and crystal growth as determined by differential scanning calorimetry (DSC). On the basis of this understanding, methods to minimize the appearance of grain boundaries in the transition region are suggested.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): Go Okada, Kenji Shinozaki, Takayuki Komatsu, Naoki Kawano, Noriaki Kawaguchi, Takayuki Yanagida〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Tb〈sup〉3+〈/sup〉-doped BaF〈sub〉2〈/sub〉-Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 glass and glass-ceramic were synthesized, and the luminescence properties were investigated for potential applications in radiation measurements. The glass-ceramic can be obtained by heat-treating the glass, and it includes BaAlBO〈sub〉3〈/sub〉F〈sub〉2〈/sub〉 crystalline phase in glass matrix. The photoluminescence (PL) quantum yield is higher for glass than glass-ceramic. The reason can be due to the difference of the number of F〈sup〉−〈/sup〉 and O〈sup〉2–〈/sup〉 ions surrounding Tb〈sup〉3+〈/sup〉 activator ion. The lifetime of PL is slightly shorter than that of scintillation suggesting energy transfer process from the host to Tb〈sup〉3+〈/sup〉 is involved. The time-response of scintillation has significantly slow rise feature possibly due to excited state absorption. Both glass and glass-ceramic show efficient optically-stimulated luminescence (OSL) with equivalent sensitivities despite the large difference of PL efficiency. The latter observation suggests that the glass-ceramic includes large number of OSL active centres than glass. The OSL dynamic range was confirmed to be at least 10〈sup〉1〈/sup〉–10〈sup〉4〈/sup〉 mGy.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): Sergey I. Gutnikov, Yuriy V. Pavlov, Evgeniya S. Zhukovskaya〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The influence of low-frequency vibrational treatment on the crystallization of basalt wool fibers was studied. In this work, three series of samples were investigated. The first sample set was only one-sided heated at temperatures from 300 °C to 900 °C for 24 h. The second sample set was after only vibrational treatment with a frequency of 50 Hz and oscillations amplitude of 1 mm for 6–48 h. The third sample set was after simultaneous treatment of one-sided heating and vibration at temperatures from 300 °C to 600 °C with a frequency of 50 Hz and oscillations amplitude of 1 mm for 24 h. It is shown that at temperatures close to the glass transition temperature, vibration can influence on the relaxation processes in glasses and accelerate them. Mechanism of glass structure transformation in the basalt fiber does not change, but it starts at a slightly lower temperature. That is a consequence of an additional low-energy vibrational treatment. The vibrational treatment intensifies the crystallization process in basalt fibers and decreases the service temperature of the material by at least 40–50 °C.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): Jürn W.P. Schmelzer, Alexander S. Abyzov〈/p〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In classical nucleation theory, the thermodynamic driving force of crystallization is computed by comparing the bulk properties of the liquid and crystal phases for the respective macroscopic samples. Such approach represents a reasonable approximation as far as the bulk properties of the critical clusters do not deviate significantly from the properties of the newly evolving macroscopic phases. However, in general, this assumption is not true and may lead to incorrect results. As one consequence, the classical approach utilizing, in addition, the capillarity approximation overestimates as a rule the work of critical cluster formation and underestimates the steady-state nucleation rate. Based on a generalization of the classical Gibbs’ approach, the basic equations are formulated here allowing one a correct determination of the properties of the critical clusters and of the work of critical cluster formation. In this way, a new tool for the quantitative description of crystal nucleation has been advanced retaining the advantages of the classical treatment but avoiding its shortcomings. Several general consequences are discussed. In particular, it is demonstrated that this method opens a new perspective in the interpretation of possible effects of atomic-scale structure of the melts on the rate of crystal nucleation.〈/p〉〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volumes 503–504〈/p〉 〈p〉Author(s): Guang Wang, Yingchun Shan, Jianxin Xu, Yuzhen Chen, Jiujun Xu, Jiangtao Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉By formation β-SiAlON/Y-Si-Al-O-N glass-ceramic as interlayer, AlON ceramics (51.70 at.% O) were successfully joined at 1475 °C for 15 min. The effects of joining temperature on wettability of interlayer material on AlON ceramics, phase assemblages and microstructures of joints, and bending strength of the as-joined AlON ceramics were investigated. The wettability of the interlayer material on the AlON ceramics is positively correlated with joining temperature at 1300–1475 °C, and the minimum contact angle of 8° was measured at 1475 °C. Increasing joining temperature is helpful to improve the bonding strength, and the maximum bending strength of 125 MPa was achieved for the samples joined at 1475 °C, which is ~41.7% of AlON strength. The high bonding strength should be mainly attributed to the formation of high strength β-SiAlON crystalline in Y-Si-Al-O-N glasses and strong interface between AlON substrate and interlayer led by the excellent wettability of β-SiAlON/Y-Si-Al-O-N glass-ceramic on AlON ceramics.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volumes 503–504〈/p〉 〈p〉Author(s): Hristo Aleksandrov Solunov〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The molecules of the supercooled liquids in the cooperative molecular dynamics are partitioning to specific dynamic units, known as “beads”. The beads have been defined as the smallest units, forming the heat capacity of the supercooled liquids. The beads appear as a sub-molecular scale in the dynamics of the glass-forming liquids. In the Adam-Gibbs theory the number of molecules, rearranging simultaneously, has been defined as the size of the cooperative rearranging region and these regions form the second larger molecular scale in molecular dynamics. Due to a noticeable discrepancy in estimating the number of beads in the molecules by the empirical rules as well as by theoretical models the relations between these two scales are not well known. Recently, a new thermodynamic method for estimating the number of the beads in the molecules and a rule for the examination of their temperature dependence have been suggested. By these methods 48 low-molecular supercooled liquids are investigated and the relations between these two molecular scales and the structure of the molecules have been found. The estimated number of configuration beads is compared with the number of the structural units (the chemical groups, the ions and the atoms), with the assigned number by the empirical rules and with the ones calculated, based on a Lennar-Jones model of the random first order transition theory. A constant and two kinds of temperature dependence of the number of the beads in the molecules of different liquids have been revealed. A molecular basis, forming the fragility of the supercooled liquids, has been found. From the results obtained, the investigated liquids are classified in several groups following the logical line in the formation of the beads.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 502〈/p〉 〈p〉Author(s): Jung-Chang Kung, Yi-Jhen Chen, Yu-Ching Chiang, Chung-Lin Lee, Yuan-Ting Yang-Wang, Chun-Cheng Hung, Chi-Jen Shih〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉 〈p〉Many clinical cases show that the failure of root-canal treatment is primarily attributable to remnants of bacteria in root canal systems, especially 〈em〉Enterococcus faecalis〈/em〉 (〈em〉E. faecalis〈/em〉).〈/p〉 〈p〉In this study, silver nanoparticle (AgNP) confined mesoporous structured bioactive powder (M-BP-Ag) was prepared by the evaporation-induced self-assembly (EISA) method and evaluated for antibacterial activity against 〈em〉E. faecalis〈/em〉. The composition of the M-BP-Ag belongs to the SiO〈sub〉2〈/sub〉-CaO-P〈sub〉2〈/sub〉O〈sub〉5〈/sub〉 system. The M-BP-Ag was obtained with the composition ratios of Si, Ca, P, and Ag in mole% being (80-X), 15, 5, and X, where X = 0, 1, 5, or 10, respectively. X-ray diffraction (XRD), gas adsorption and desorption analyzer, and transmission electron microscopy (TEM) were used to characterize these M-BP-Ag.〈/p〉 〈p〉The antibacterial activity of the test samples against 〈em〉E. faecalis〈/em〉 was verified by the time-killing curve test and the colony-forming capacity assay. The samples' antibacterial activities depended on the confined AgNP position. From bacterial morphology observation, we also speculated the antibacterial mechanism of the M-BP-Ag test samples in this study.〈/p〉 〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 December 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 501〈/p〉 〈p〉Author(s): Mark J. Davis, Paula Vullo, Michaelene Kocher, Martun Hovhannisyan, Martin Letz〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We report on a non-ferroelectric, piezoelectric polar glass-ceramic specifically targeted for high-temperature sensor use (〈em〉T〈/em〉 〉 300 °C). Potential applications include accelerometers for turbine engines and in-cylinder pressure sensors for diesel engines. Choice of an alkali-free, Sr-fresnoite (Sr〈sub〉2〈/sub〉TiSi〈sub〉2〈/sub〉O〈sub〉8〈/sub〉) + added SiO〈sub〉2〈/sub〉 bulk composition led to desirably high electrical resistivity while maintaining good piezoelectric sensitivity. Piezoelectric properties are highly competitive with existing high-temperature single crystals and ceramics, consisting of 〈em〉d〈/em〉〈sub〉33〈/sub〉 = 10, 〈em〉d〈/em〉〈sub〉31〈/sub〉 = 1.5, and 〈em〉d〈/em〉〈sub〉15〈/sub〉 = 34 (pC/N). Support for the high value of the shear mode 〈em〉d〈/em〉〈sub〉15〈/sub〉 coefficient comes from both direct measurement as well as consideration of the expected variation in effective 〈em〉d〈/em〉〈sub〉33〈/sub〉 due to deviation in perfect (001) crystalline alignment, as demonstrated in this system by Wisniewski et al. (2012). Due to the low dielectric permittivity in this system (〈em〉ε〈/em〉〈sub〉33〈/sub〉〈sup〉〈em〉T〈/em〉〈/sup〉/〈em〉ε〈/em〉〈sub〉0〈/sub〉 = 11.5; 〈em〉ε〈/em〉〈sub〉11〈/sub〉〈sup〉〈em〉T〈/em〉〈/sup〉/〈em〉ε〈/em〉〈sub〉0〈/sub〉 = 16.5, both at 1 kHz), the voltage coefficients are quite high: 〈em〉g〈/em〉〈sub〉33〈/sub〉 = 103, 〈em〉g〈/em〉〈sub〉31〈/sub〉 = 15, and 〈em〉g〈/em〉〈sub〉15〈/sub〉 = 233 (×10〈sup〉−3〈/sup〉 V m/N). The room-temperature pyroelectric coefficient 〈em〉p〈/em〉〈sub〉3〈/sub〉 of +8 μC/m〈sup〉2〈/sup〉/°C is followed by a hysteretic peak, though repeatable, near 175 °C, attaining −70 μC/m〈sup〉2〈/sup〉/°C, but by 250 °C, 〈em〉p〈/em〉〈sub〉3〈/sub〉 has returned to low levels and passes through zero around 275 °C. Of crucial particular importance for high-temperature applications is high electrical resistivity, well exemplified by this material, with 〈em〉ρ〈/em〉 ~ 10〈sup〉12〈/sup〉 Ω-cm at 300 °C and 10〈sup〉6〈/sup〉 at 850 °C; higher levels of resistivity can be obtained through use of raw materials with lower levels of alkali contaminants. The combination of high electrical resistivity coupled with good piezoelectric sensitivity and the lack of a Curie temperature, with its associated aging effects, makes Sr-fresnoite glass-ceramics a realistic contender in the technically-challenging field of high-temperature piezoelectric materials.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 January 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volumes 503–504〈/p〉 〈p〉Author(s): W.C. Wang, Y.B. Xiao, B. Zhou, S.H. Xu, Q.Y. Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The structural, thermal, and luminescent properties of germanate glass containing heavily Dy〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 content are systematically investigated by means of differential scanning calorimetry, X-ray diffraction, Raman spectra, absorption and emission spectra, and dynamic lifetime decay curves. To seek a suitable composition, the optimal glass forming region is first predicted through the thermodynamic calculation method and their basic physical properties are further forecasted according to the phase diagram model. The experiment results show that the density, refractive index, characteristic temperature, and phonon energy of the glass host all exhibit a close connection with the rare earth concentration. Strikingly, when the amount of Dy〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 is up to 10.5 mol%, the transition temperature of the glass reaches 747 °C, which is higher than any other known germanate glass and is much advantageous to achieve a higher laser damage threshold. Moreover, the high doping caused the refractive index to increase significantly, which also prompted the glass to obtain a larger emission section and quality factor, increasing the possibility of laser output. Besides, three visible luminescence peaks of Dy〈sup〉3+〈/sup〉 at 480 nm (blue) and 575 nm (yellow), and 665 nm (red) are observed even at an extremely high Dy〈sup〉3+〈/sup〉 concentration. All the results demonstrate that this kind of germanate glass containing significant amounts of RE could be of interest for implementation of high-gain fiber lasers.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 500〈/p〉 〈p〉Author(s): Young Hoon Rim, Mac Kim, Jae-Hyeon Ko, Yong Suk Yang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We have studied the relationship between ionic conductivity and the ionic radius of A site in 2AO〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉2TiO〈sub〉2〈/sub〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉SiO〈sub〉2〈/sub〉 (ATSO; A〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/dbnd"〉Ca, Sr and Ba) glasses. Electrical measurements were carried out in the frequency range 100 Hz ~ 30 MHz and temperature range 300–540 °C. Raman spectroscopy and differential thermal analysis measurements were also performed. The exponents of the Cole-Cole plot, power-law conductivity and modulus formalisms reveal the nature of ionic transport and the conductivity relaxation. Raman spectroscopic data of ATSO glasses clarify the modification of vibrational networks of silicate and titanate complexes by alkaline-earth metals (Ca, Sr and Ba). The ratio of non-bridging oxygens per tetrahedrally coordinated cations (NBO/T) in the 2CaO〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉 and 2SrO〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉2TiO〈sub〉2〈/sub〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉SiO〈sub〉2〈/sub〉 glasses decreases rapidly, suggesting polymerization of the silicate and titanate networks. The disorder of the glass matrix in 2BaO〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉2TiO〈sub〉2〈/sub〉〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉SiO〈sub〉2〈/sub〉 glass is greatly reduced with increasing non-bridging oxygens per NBO/T and decreasing interionic Coulomb interactions. The conduction mechanisms of 〈em〉dc〈/em〉 and 〈em〉ac〈/em〉 for all ATSO glasses are the same but the ions hop through a different fractal structured conduction pathway. The dimension of ionic conduction pathway decreases with increasing ionic radius of alkaline-earth metals in ATSO glasses.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 499〈/p〉 〈p〉Author(s): K. Ullmann, P. Ádám, K. Sinkó〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the present work a new low-cost sol-gel method has been developed to prepare highly porous alumina systems. The prime consideration of this research work was to avoid the complicated and laborious preparation technique and the expensive drying processes. Aluminum oxide hydroxide gel systems were synthesized by a new sol-gel route. The sol-gel process starts from only two chemical compounds; from an aluminum salt and a solvent, and it does not adopt any basic agent or complex formation. All gel systems were dried at atmospheric pressure to obtain xerogels. Different chemical agents (such as gelation agent propylene oxide, surfactant characteristic citric acid and ethyl acetate or basic agent carbamide and urotropine) were applied. Their application was varied in the steps of the sol-gel procedure. Some wet gels were subjected to different treatments (microwave radiation and freezing in vacuum) before the drying process. The cryogels evolved by lyophilization was provided for the comparison. The route of propylene oxide’ addition to system reacted for 24 h produces a bead-like structure with the highest porosity and smallest pores in the present work.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 499〈/p〉 〈p〉Author(s): Ting Zhou, Lunlun Gong, Xudong Cheng, Yuelei Pan, Congcong Li, Heping Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The by-product silicon tetrachloride (SiCl〈sub〉4〈/sub〉) was usually obtained from polysilicon industry and was a cheaper alternative precursor. An economic method to produce silica aerogel using silicon tetrachloride under ambient pressure drying was presented in this work, which can also solve the pollution problem during the by-product silicon tetrachloride treatment process. The prepared aerogel samples were characterized by scanning electron microscopy, Brunauer-Emmett-Teller analysis, thermal conductivity analysis, contact angle test, Fourier transform infrared spectroscopy and thermogravimetric analysis. It was found that the molar ratio of H〈sub〉2〈/sub〉O/SiCl〈sub〉4〈/sub〉 could affect the properties of aerogels seriously. The density and thermal conductivity first decreased and then increased as the molar ratio increased from 13 to 32. The porosity showed an opposite trend with the density. Silica aerogel with high specific surface area (856.7 m〈sup〉2〈/sup〉/g), low density (0.077 m〈sup〉3〈/sup〉/g) and low thermal conductivity (0.0213 W/m·k) were obtained at the optimal conditions when the molar ratio was 25. The resulting aerogel is also mesoporous material with super hydrophobicity and have a huge application in thermal insulation field.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 500〈/p〉 〈p〉Author(s): Janis Snikeris, Vjaceslavs Gerbreders, Valdis Mizers〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Electron beam (EB)-induced deformations of the surface of thin Cr films on soda-lime glass and Si substrates were studied using atomic force microscopy. The thickness of the Cr films was within the range 20 to 500 nm. The thin films were irradiated with a 30 keV EB in the vacuum chamber of a scanning electron microscope. The EB current was within the range 10 pA to 15 nA, and the irradiation time was within the range 30 s to 10 min. The lateral size of the deformations was typically at the micrometre scale, while their vertical size was at the sub-micron and nanometre scales. Depressions of up to 80 nm deep and bulges of up to 700 nm high were observed. Irradiated areas were wet etched using K〈sub〉3〈/sub〉[Fe(CN)〈sub〉6〈/sub〉] in an alkaline solution. It was observed that EB irradiation can significantly decrease the etching rate and that wet etching can increase the height to width ratio of EB-induced deformations on Cr thin films. Possible physical mechanisms for formation of these deformations are discussed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 499〈/p〉 〈p〉Author(s): Sean W. King, Liza Ross, William A. Lanford〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Intermediate phases represent the so called “sweet spot” in amorphous material systems where the bond stretching and bond bending constraint forces are equally balanced by the total degrees of freedom in the system. They are sometimes also referred to as “Boolchand” phases in recognition of the seminal contributions of Dr. Punit Boolchand to the study of these materials. In a prior publication (King et al., 〈em〉J. Non-Cryst. Solids〈/em〉 379 (2013) 67), we presented possible evidence for the existance of an intermediate (i.e. “Boolchand”) phase in amorphous hydrogenated silicon carbide (a-SiC:H) with a wide range in mean atomic coordination (〈〈em〉r〈/em〉〉 = 2.4 − 2.7). Support for such a wide phase window was based primarily on a correlation between the post plasma deposition bi-axial film stress and 〈〈em〉r〈/em〉〉. However, we demonstrate in the present article that the apparent width of the Boolchand intermediate phase window in the prior study was inflated due to two competing film stress contributions, and that the true range in 〈〈em〉r〈/em〉〉 for the phase window is substantially narrower. Specifically, opposing tensile and compressive film stress components were identified to arise during the plasma enhanced chemical vapor deposition (PECVD) of a-SiC:H. The tensile film stress component was attributed to film/substrate thermal contraction mismatch on cooling from the deposition temperature, while the compressive stress component was attributed to ion bombardment of the a-SiC:H growth surface during PECVD. In the prior study, the energy of the ions during PECVD was primarily modulated by the addition of a low frequency bias to the plasma and was intentionally utilized to produce films with varying compressive stress and 〈〈em〉r〈/em〉〉. In the present study, the low frequency bias was removed from the PECVD of a-SiC:H and instead the deposition pressure was varied to produce films with varying 〈〈em〉r〈/em〉〉 and exclusively tensile stress. Through detailed analysis of the tensile bi-axial film stress and Young's modulus dependence on 〈〈em〉r〈/em〉〉, we found conclusive evidence that the film-substrate thermal contraction mismatch was the dominant film stress component in this case and that the magnitidue of the tensile stress was purely due to rigidity percolation in the a-SiC:H film. We therefore conclude that in our previous study the balance of the tensile and compressive stress components resulted in the deceptive appearance of a potentially wide Boolchand intermediate phase window for a-SiC:H. Based on the a-SiC:H films generated in the present study where only the tensile stress component was significant, we have found the window for a possible intermediate phase to be greatly narrowed at Δ〈〈em〉r〈/em〉〉 ≤ 0.05.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 500〈/p〉 〈p〉Author(s): C. Dong, A. Inoue, X.H. Wang, F.L. Kong, E.N. Zanaeva, F. Wang, A.I. Bazlov, S.L. Zhu, Q. Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉With the aim of developing a new inexpensive soft magnetic amorphous alloy exhibiting high saturation magnetic flux density (〈em〉B〈/em〉〈sub〉s〈/sub〉) above 1.7 T, we examined the formation, thermal stability and magnetic properties for melt-spun Fe-B-Si-C amorphous alloys with high (B + C)/Si content ratios. The high 〈em〉B〈/em〉〈sub〉s〈/sub〉 of 1.71–1.73 T exceeding the previously reported 〈em〉B〈/em〉〈sub〉s〈/sub〉 was obtained for annealed Fe〈sub〉82-82.5〈/sub〉B〈sub〉15〈/sub〉Si〈sub〉2〈/sub〉C〈sub〉0.5-1〈/sub〉 alloys. These high 〈em〉B〈/em〉〈sub〉s〈/sub〉 alloys exhibit low coercivity below 8 A/m and good bending ductility. The 82.5Fe alloy with the highest 〈em〉B〈/em〉〈sub〉s〈/sub〉 of 1.73 T also has the highest hardness. Besides, the 82.5Fe alloy has the largest nearest neighbor atomic distance among the present alloys. The correlation between the highest 〈em〉B〈/em〉〈sub〉s〈/sub〉 and the largest atomic distance is similar for (Fe,Co)〈sub〉83-86〈/sub〉B〈sub〉15-16〈/sub〉Si〈sub〉1〈/sub〉 amorphous alloys. The 82.5Fe and 82Fe alloys are located near the critical composition where the crystallization changes from two stages of α-Fe(Si) + amorphous ⇢ α-Fe(Si) + Fe〈sub〉3〈/sub〉(B,C) to a single stage of α-Fe(Si) + Fe〈sub〉3〈/sub〉(B,C). These results indicate the importance of the special alloy composition with the largest atomic distance and high stability to primary α-Fe precipitation, in addition to high (B + C)/Si content ratios, for the synthesis of a new ductile amorphous alloy with high 〈em〉B〈/em〉〈sub〉s〈/sub〉 and good magnetic softness.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 November 2018〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 499〈/p〉 〈p〉Author(s): Akira Takada〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Packing models have been used as one of powerful analytical tools to investigate atomic structures comprised of single element or metallic alloy. In this study, the structures of SiO〈sub〉2〈/sub〉 crystals and glasses were studied by a new packing model. To deal with two-element oxide systems like SiO〈sub〉2〈/sub〉, packing structures focused only on oxygen atoms were constructed using the Voronoi tessellation method. First, the method was applied to crystal polymorphs of SiO〈sub〉2〈/sub〉. Species of polyhedron, species of polygon and volume of each polyhedron were compared between the polymorphs. The calculated results captured not only structure features inherent in each crystal, but also the indication of structural changes such as α–β transition or corruption of crystal structure. Next, the method was applied to SiO〈sub〉2〈/sub〉 glass. The Voronoi analysis distinguished glass from crystals in terms of species of polyhedron. In addition, the same method could distinguish structural changes caused by thermal effects from those by pressure effects. The thermal effects change geometrical symmetry (i.e. shape of polyhedron and polygon) with little change in Voronoi volume, in contrast, the pressure effects change geometrical symmetry less with larger change in Voronoi volume. In addition, a new index, which represents a degree of geometrical similarity between crystals and glasses, was defined in terms of Voronoi polyhedron. In sum, the Voronoi analysis based on oxygen packing is expected to be a promising tool to investigate not only the structure of crystal polymorphs but also that of glass and liquid, taking the complimentary role to the conventional network model.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 514〈/p〉 〈p〉Author(s): Chunxiao Xie, Wen Li, Donghai Zheng, Kewei Wang, Yuanzheng Yang, Fanghua Shen, Li Xie, Zilong Liao, ShouYan Zhong〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A new magnetic Fe〈sub〉36〈/sub〉Co〈sub〉22〈/sub〉Cr〈sub〉17〈/sub〉Ni〈sub〉15〈/sub〉Zr〈sub〉10〈/sub〉 high entropy amorphous alloy has been prepared and its crystallization behavior and kinetics been studied. The results show that, under non-isothermal conditions, the crystallization activation energy 〈em〉E〈/em〉〈sub〉〈em〉x〈/em〉〈/sub〉 was calculated by the Kissinger equation, which yield 373 kJmol〈sup〉−1〈/sup〉. Relation plot of 〈em〉E〈/em〉〈sub〉〈em〉x〈/em〉〈/sub〉 vs crystallization volume fraction(〈em〉x〈/em〉) manifests the non-isothermal crystallization process is from difficult to easy. On the other hand, base on Arrhenius relation, the crystallization activation energy 〈em〉E〈/em〉〈sub〉〈em〉c〈/em〉〈/sub〉 under isothermal conditions was calculated to be 370 kJmol〈sup〉−1〈/sup〉. Relation plot of 〈em〉E〈/em〉〈sub〉〈em〉c〈/em〉〈/sub〉 vs 〈em〉x〈/em〉 manifests the isothermal crystallization process is from easy to difficult. The isothermal kinetics was modeled by Johnson-Mehl-Avrami(JMA) equation, as the isothermal annealing temperature increases, the nucleus growth mechanism from diffusion-controlled 3-D growth convert into interface-controlled 3-D growth. Though proper heat treatment, the saturation magnetization 〈em〉M〈/em〉〈sub〉〈em〉s〈/em〉〈/sub〉 of this alloy can reach up to 106.8A∙m〈sup〉2〈/sup〉∙kg〈sup〉−1〈/sup〉, it will become promising functional materials in the future.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Dmitry Usanov, Aleksey Nezhdanov, Mikhail Kudryashov, Ivan Krivenkov, Aleksey Markelov, Vladimir Trushin, Leonid Mochalov, Daniela Gogova, Aleksandr Mashin〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Chalcogenide arsenic sulphide thin films were obtained by reacting arsenic and sulfur vapors in a low-temperature plasma discharge. Photoluminescence (PL) of As-S films with compositions As〈sub〉34〈/sub〉S〈sub〉66〈/sub〉 and As〈sub〉53〈/sub〉S〈sub〉47〈/sub〉 is studied in detail. An increase in the arsenic concentration leads to the emergence of a crystalline phase in the As〈sub〉53〈/sub〉S〈sub〉47〈/sub〉 films. In addition, these films exhibit an intense broad PL band with a maximum at 2.2 eV upon a continuous 473 nm laser excitation. The interplay between composition, structure and optical properties is revealed. By coupling of PL, Raman spectroscopy and absorption data, possible mechanisms of radiative recombination in the context of the glass structure formation in the plasma discharge are discussed.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Guohua Cao, Kun Liu, Gaopeng Liu, Haitao Zong, Hari Bala, Baoqing Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉(Zr〈sub〉47〈/sub〉Cu〈sub〉44〈/sub〉Al〈sub〉9〈/sub〉)〈sub〉100−x〈/sub〉Nb〈sub〉x〈/sub〉 (x = 0, 1, 2, 3, and 5 at.%) bulk metallic glasses (BMGs) were prepared by copper mould casting. The influence of Nb addition on glass-forming ability (GFA), thermal stability and mechanical properties of ZrCuAl alloys was studied. The GFA of Zr〈sub〉47〈/sub〉Cu〈sub〉44〈/sub〉Al〈sub〉9〈/sub〉 BMGs is enhanced obviously after the addition of Nb. The critical size of completely amorphous sample increases from 4 mm for Zr〈sub〉47〈/sub〉Cu〈sub〉44〈/sub〉Al〈sub〉9〈/sub〉 to 10 mm for (Zr〈sub〉47〈/sub〉Cu〈sub〉44〈/sub〉Al〈sub〉9〈/sub〉)〈sub〉98〈/sub〉Nb〈sub〉2〈/sub〉 alloy. The average activation energy of crystallization is 505 kJ/mol for (Zr〈sub〉47〈/sub〉Cu〈sub〉44〈/sub〉Al〈sub〉9〈/sub〉)〈sub〉98〈/sub〉Nb〈sub〉2〈/sub〉 BMG, which is larger than that of Zr〈sub〉47〈/sub〉Cu〈sub〉44〈/sub〉Al〈sub〉9〈/sub〉 BMG with 443 kJ/mol. The fracture strength and plasticity are sensitive to the Nb content. (Zr〈sub〉47〈/sub〉Cu〈sub〉44〈/sub〉Al〈sub〉9〈/sub〉)〈sub〉98〈/sub〉Nb〈sub〉2〈/sub〉 BMG exhibits high fracture strength of 2397 MPa and prominent plastic strain of 13.2%, and multiple shear bands with high density were observed. Furthermore, the possible mechanisms involved in obtaining high GFA and large plasticity were explored.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Farah Laariedh, M.I. Sayyed, Ashok Kumar, H.O. Tekin, Ramandeep Kaur, T-B. Badeche〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Heavy metal oxide glasses of composition (50 – x) PbO – 10 WO〈sub〉3〈/sub〉–10 Na〈sub〉2〈/sub〉O – 10 MgO – (20 + x) B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 (where x = 0, 5, 10, 15 and 20 mol%) have been fabricated using melt quenching technique. The X-ray diffraction (XRD) spectra confirm the amorphous nature of the glasses. The Fourier Transform Infrared Spectroscopy (FTIR) throws the light on the various structural properties of the glasses. UV – Visible spectra has been recorded in the range 190–1100 nm. The direct and indirect band gap energies increase from 2.695–2.805 eV and 3.126–3.237 eV as percentage of lead decreases. This value of indirect band gap is further used to calculate the other optical parameters such as refractive index, dielectric constant, optical dielectric constant, reflection loss, molar refractivity, metallization and molar polarizability. Besides, the mass attenuation coefficients have been obtained in the energy range of 0.01–10 MeV using MCNPX code and XCOM program. The obtained results are found to be in agreement. These values are further used to calculate the effective atomic numbers and half value layers of the present glasses. All the shielding parameters are found to depend on the chemical composition and energy of the gamma radiations. But the PB50B20 glass sample is found to possess the highest effective atomic number and the lowest value half value layer. The PB50B20 glass sample (contains 50 mol% PbO) owns the best gamma shielding characteristics.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Süleyman Bolat, Murat Durandurdu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Using a reliable 〈em〉ab initio〈/em〉 molecular dynamics method, we investigate the rapid solidification of the zircon melt. Accompanied by amorphization, a drastic volume expansion of 27% is perceived. This value is fairly larger than 18% observed in the metamict zircon. Such a large volume swelling leads to a significant decrease in the mean coordination number of Zr atoms, which is about 5.66 and the lowest one reported so far. On the other hand, the volume expansion is found to have almost no impact on the average coordination number of Si atoms 〈em〉i.e.〈/em〉, they maintain their tetragonal coordination. As suggested by earlier investigations, the polymerization of SiO〈sub〉4〈/sub〉 units is witnessed but our model shows the highest polymerization with respect to the previous simulations. Based on our findings, we propose that our model does not represent the metamict zircon but a very low density amorphous phase of zircon.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Maxwell A.T. Marple, Martha Jesuit, Ivan Hung, Zhehong Gan, Steve Feller, Sabyasachi Sen〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Despite its chemical simplicity, a definitive description of the structure of TeO〈sub〉2〈/sub〉 glass has remained elusive due to the complexity of the Te-O coordination environment. In this work we probe the Te-O coordination environment in glassy TeO〈sub〉2〈/sub〉 using 2D 〈sup〉125〈/sup〉Te isotropic-anisotropic chemical shift correlation nuclear magnetic resonance (NMR) spectroscopy. The NMR results are consistent with the presence of two Te-O environments in this glass, characterized by their distinct set of 〈sup〉125〈/sup〉Te chemical shift parameters. The dominant environment (~89%) is a distorted trigonal bipyramidal TeO〈sub〉4〈/sub〉 unit, reminiscent of that observed in crystalline γ-TeO〈sub〉2〈/sub〉. A second, minor (~11%) component can be assigned, on the basis of its chemical shift parameters, to a TeO〈sub〉3〈/sub〉 unit. The resulting average coordination number, n〈sub〉TeO〈/sub〉, measured by 〈sup〉125〈/sup〉Te NMR (n〈sub〉TeO〈/sub〉 ≈ 3.9) is higher than its previously reported value obtained using neutron diffraction (n〈sub〉TeO〈/sub〉 ≈ 3.7).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 514〈/p〉 〈p〉Author(s): F.H. Duan, J. Pan, Y. Lin, Y. Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉We revealed the significant structural relaxation with unprecedent hardness increment of 120% in an electrodeposited amorphous Mo〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉O alloy upon annealing, which is much higher than that in the conventional metallic glasses (〈15%). The relaxation kinetics was well described by a stretched exponential function with a Kohlrausch index of 0.51 and relaxation time of 115 s at 623 K. In addition, the significant structural relaxation was also reflected by a much higher creep resistance and smaller strain rate sensitivity after annealing. The significant hardness increment suggested that the as-deposited amorphous alloy has a highly disordered glassy state equivalently obtained by quenching at ~10〈sup〉12〈/sup〉 K s〈sup〉−1〈/sup〉. This was consistent with the structural observation that the as-deposited amorphous alloy has a low volume fraction (7%) of icosahedral-like medium range ordered (IMRO) clusters. Upon annealing, significant structural relaxation stemmed from the structural ordering, where the volume fraction of IMRO clusters increased to 19%.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): A.A. Menazea, A.M. Abdelghany, W.H. Osman, N.A. Hakeem, F.H. Abd El-Kader〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉This work presents a new route to synthesis nanomaterials for nonlinear optical devices, Nd:YAG laser irradiation is considered as recent technique for precipitation of nanoparticles in glassy matrix. Precipitation of silver nanoparticles (AgNPs) in silicate glasses is achieved by Nd:YAG nanosecond laser irradiation to soda lime silicate glasses doped with silver nitrate (AgNO〈sub〉3〈/sub〉) using melt annealing technique. The influences of different concentrations of AgNO〈sub〉3〈/sub〉 on the optical and the structural characterization of the precipitated glasses were investigated using; XRD, FT-IR, UV–Vis, and HRTEM. An obvious change in color was observed inside the silicate glasses regions after laser irradiation, which was attributed to the growth of silver nanoparticles in the glass.XRD patterns indicate the presence of sharp diffraction peaks of AgNPs after laser irradiation due to precipitated AgNPs in silicate glasses. FT-IR spectra of the precipitated samples show a little change in intensity for the sample before and after the laser irradiation combined with the identification of a new band that approves the precipitated AgNPs. The optical absorption spectra confirm the formation of the precipitated AgNPs inside the silicate glasses by appearance of Surface Plasmon Resonance (SPR) and the intensity of the absorption peak increases with an increase of the silver nitrate concentration. TEM micrographs confirm the precipitation of silver within the samples after laser irradiation.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Yansen Li, Yanpeng Wei, Kun Zhang, Yating Zhang, Yang Wang, Weiqi Tang, Bingchen Wei〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The structural and mechanical responses of Ti-based and Zr-based metallic glasses (MGs) treated by the nanosecond laser shock wave were investigated. A rejuvenation transition was observed, due to the structural rearrangement of neighboring atoms in the instantaneous shock process. Plenty of embryonic shear bands occurred along the shock-affected zone. A damped model of the shock pressure was established to describe the characteristic of the embryonic shear bands. The results showed that the shear band initiation in the nanosecond scale along the length direction was divided into two stages: the initial low propagation stage and the following fast propagation stage, because of the reduction of the shock pressure. The hardness of the shock-affected zone displayed a maximal decrease of 25% in the critical zone between the two propagation stages, due to the combined effect of the structural rejuvenation and the compressive residual stress. A schematic of the energy landscape was proposed to explain the relationship between the rejuvenation and the formation of the embryonic shear bands. The maximum tensile plasticity increased by 0.46%. The results demonstrated that the MGs possessed different shear band propagation modes in the initiation stages, which deepened the understanding of the deformation mechanism in the MGs.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 May 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 512〈/p〉 〈p〉Author(s): 〈/p〉

Description: 〈p〉Publication date: 15 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 514〈/p〉 〈p〉Author(s): P. Naresh, B. Kavitha, Hajeebaba K. Inamdar, D. Sreenivasu, N. Narsimlu, Ch. Srinivas, Vasant Sathe, K. Siva Kumar〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉To study the modifier role of ZnO on the structural and transport properties, the quaternary glass system xZnO-(30-x) Li〈sub〉2〈/sub〉O-10TeO〈sub〉2〈/sub〉–60B〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 (x = 0, 5, 10, 15 and 20 mol%) was prepared by the conventional melt quenching technique. Amorphous nature of the prepared glasses was confirmed by X-ray diffraction studies. Density (ρ) of the glass samples was measured by Archimedes' principle and it was found to vary non-linearly between 3.06 and 3.44 g/cm〈sup〉3〈/sup〉 with the addition of heavy metal oxide (ZnO) mole concentration. Oxygen packing density (OPD) values also varied non-linearly between 66.78 and 74.69 g atm/1. Glass transition temperature (T〈sub〉g〈/sub〉) of the glass system was measured using temperature modulated differential scanning calorimeter and Tg was found to increase from 429 °C-449 °C with the increase of ZnO content. Based on the density and molecular weight of the glass composition, mechanical properties like Young's modulus (E), Shear modulus (S), Bulk modulus (K) etc., have been calculated with the help of Makishima-Mackenzie model in terms of the packing ratio (Vρ) and dissociation energy (G〈sub〉t〈/sub〉). FTIR and Raman spectroscopy studies reveal that the glass network consists of various types of BO〈sub〉3〈/sub〉, BO〈sub〉4〈/sub〉 units along with TeO〈sub〉3〈/sub〉, TeO〈sub〉4〈/sub〉 and ZnO〈sub〉4〈/sub〉 structural units. To study transport properties, AC conductivity measurements were carried out on the glass system in the frequency range 5 Hz-35 MHz and it was observed that the ionic conductivity plays significant role. At low temperatures (30 °C and 50 °C) the results of conductivity did not give good results. AC conductivity of the studied glass system is increased with increase in frequency and temperature. The highest value of AC conductivity of the glass network is of the order 10〈sup〉−2〈/sup〉 Ω〈sup〉−1〈/sup〉 cm〈sup〉−1〈/sup〉. Impedance plots (Cole-Cole) exhibited semicircle behaviour.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Satwinder Singh Danewalia, Supreet Kaur, Neetu Bansal, Savidh Khan, K. Singh〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The present report is an investigation of morphological, structural and magnetic properties of multicomponent glass-ceramics with respect to content of nucleating agent (TiO〈sub〉2〈/sub〉) as well as thermal processing parameters. Structural features of these glass-ceramics were explored by their crystalline phase analysis and morphological studies after sintering at various temperatures (850–1000 °C) for 2 h (h). The samples exhibited near superparamagnetic nature which would be helpful for heat generation purposes (such as in hyperthermia treatment of cancer). Magnetic properties of the glass-ceramics are dependent on the crystallized phases grown upon sintering. Concentration dependent role of TiO〈sub〉2〈/sub〉 is discussed based upon the obtained results.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 514〈/p〉 〈p〉Author(s): Kai Yang, Benjamin Yang, Xinyi Xu, Christian Hoover, Morten M. Smedskjaer, Mathieu Bauchy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Understanding and predicting the compositional dependence of the stiffness of silicate glasses is key for various technological applications. Here, we propose a new topological model for predicting the Young's modulus of silicate glasses. We show that the Young's modulus is governed by the volumetric density of bond-stretching and bond-bending topological constraints acting in the atomic network. The predicted Young's modulus values offer an excellent agreement with molecular dynamics and experimental data over a wide domain of compositions (the entire calcium aluminosilicate ternary system) and a large range of Young's modulus values (from around 80 to 160 GPa).〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 514〈/p〉 〈p〉Author(s): Pradeep Gupta, Natraj Yedla〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Molecular dynamics (MD) simulations are carried out to study the tensile-compression cyclic loading behavior and structural changes in Al (metal)-Cu〈sub〉50〈/sub〉Zr〈sub〉50〈/sub〉 (metallic glass) thin film interface model (TFIM). The model comprises of 2.88 million atoms, interactions between Al, Cu and Zr atoms are modeled using EAM (Embedded Atom Method) potential. The tensile-compression test cycles are performed at a temperature of 100 K and strain rate of 10〈sup〉9〈/sup〉 s〈sup〉−1〈/sup〉 at two pre-strains (e = 0.033 and e = 0.2). The stress-strain curves reveal that during cycle-I tensile loading, TFIM exhibits yield strength of 266 MPa and peak strength of 760 MPa. Increase in the tensile pre-strain from e = 0.033 to e = 0.2 has no significant effect on the compressive yield stress. The deformation mechanism in Al is by slip by partial dislocation nucleation. Shockley partial dislocation density (2 × 10〈sup〉17〈/sup〉–4.5 × 10〈sup〉17〈/sup〉 m〈sup〉−2〈/sup〉) is observed to be the highest of all the other types of dislocations. Complete SFT (stacking fault tetrahedra) is formed in Al region when strained beyond e = 0.033 and during compression cycles only. The number of SFT increases from 8 during tensile to 28 during the compression cycle indicating that compressive test assists the formation of SFT. Beyond the elastic strain, the collapse of (00120) and (0 2 8 2) polyhedral network is observed in Cu〈sub〉50〈/sub〉Zr〈sub〉50〈/sub〉 metallic glass region at distance of 25 Å from the interface resulting in the creation of low dense regions.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 514〈/p〉 〈p〉Author(s): Zhuanhui Yue, Qiang Li, Wenbiao Zhang, Mingcan Li, Haiming Duan, Chuntao Chang, Hongxiang Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In order to study the effect of the mutual substitution of Fe and Ni on the plasticity of Fe/Ni-based metallic glasses (MGs) from the atomic arrangement structure perspective, we investigate the short-range order (SRO) and medium-range order (MRO) structures of Fe〈sub〉80〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉, Fe〈sub〉40〈/sub〉Ni〈sub〉40〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 and Ni〈sub〉80〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 MGs using ab initio molecular dynamics (AIMD) simulations method. The results reveal that Fe〈sub〉40〈/sub〉Ni〈sub〉40〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 MG has more vertex-sharing clusters and less edge-sharing clusters compared to Fe〈sub〉80〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 and Ni〈sub〉80〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 MGs, indicating that Fe〈sub〉40〈/sub〉Ni〈sub〉40〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 MG possesses more cavities or boundaries on MRO, which are beneficial for plastic deformation. In addition, large clusters have a relatively strong connection with comparatively smaller clusters in Fe〈sub〉80〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 and Ni〈sub〉80〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 MGs while the clusters with the similar size tend to form the nearest neighbor in Fe〈sub〉40〈/sub〉Ni〈sub〉40〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 MG. Compared with the former, the connection mode of the latter may form relatively loose packing, which can facilitate plastic deformation. Fe〈sub〉40〈/sub〉Ni〈sub〉40〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 MG has larger population of 142×, 1441 and 1661 bond pairs, which are crystal-like clusters, and relatively smaller 1551and 1541. Besides, Fe〈sub〉40〈/sub〉Ni〈sub〉40〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 MG has less 〈0 0 12 0〉, 〈0 1 10 2〉 and 〈0 2 10 1〉 clusters and more 〈0 4 4 3〉 and 〈0 4 4 6〉 compared to Fe〈sub〉80〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 and Ni〈sub〉80〈/sub〉P〈sub〉14〈/sub〉B〈sub〉6〈/sub〉 MGs, indicating the replacement of Fe by Ni or Ni by Fe in Fe/Ni-based MGs reduces five-fold rotational symmetry, which is beneficial to plasticity.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Mingzhi Zhao, Jianwei Cao, Zhi Wang, Guohua Li〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In this paper, an iron-rich CaO-MgO-Al〈sub〉2〈/sub〉O〈sub〉3〈/sub〉-SiO〈sub〉2〈/sub〉 glass-ceramic was prepared basing high iron chromium slag. We employ DSC, XRD and SEM validated the thermal behavior and the microstructure of the glass/glass-ceramics, and reveal a mechanism of the dual effect of high Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 addition on the crystallization. Here we show that Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 facilitates the formation of spinel, but inhibits the precipitation of pyroxene. Infrared spectroscopy analysis shows that its promotion to the precipitation of spinel is attributed to the depolymerization of the glass network. Scanning electron microscope observation shows that the inhibition to the crystallization of pyroxene due to the region where nucleation dose not occurs. The increase of Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 addition enlarges the volume ratio of the non-nucleated region in the microstructure, and increases the crystallization activation energy of the pyroxene. In addition, we find that the crystallinity of the glass-ceramics decreased with the increase of Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 addition, but the average size of the pyroxene grains reduced from 116 ± 4 nm to 84 ± 3 nm. We also show that the distribution of chromium in glass-ceramics was largely influenced by Fe〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 addition. This study is particularly instructive for controlling the crystallization of the iron-rich CMAS glass-ceramics, and provides some insight for solidifying chromium in high iron waste slag.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): O. Kıbrıslı, A.E. Ersundu, M. Çelikbilek Ersundu〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the present work, a series of Dy〈sup〉3+〈/sup〉 ion doped tellurite glasses in the (50-〈em〉x〈/em〉)TeO〈sub〉2〈/sub〉-25WO〈sub〉3〈/sub〉-25Li〈sub〉2〈/sub〉O-〈em〉x〈/em〉Dy〈sub〉2〈/sub〉O〈sub〉3〈/sub〉 system were synthesized using conventional melt quenching technique to investigate colorimetric and radiative properties of Dy〈sup〉3+〈/sup〉 ions in a new and stable host for their evaluation as solid-state lighting materials. Physical and structural properties were studied through density calculations, refractive index measurements, and Fourier-transform IR spectroscopy analysis. Thermal properties of glasses – glass transition (〈em〉T〈/em〉〈sub〉g〈/sub〉) and crystallization (〈em〉T〈/em〉〈sub〉c〈/sub〉/〈em〉T〈/em〉〈sub〉p〈/sub〉) temperatures and temperature difference (Δ〈em〉T〈/em〉) – were determined using differential scanning calorimetry. Optical absorption spectra of glasses were recorded with Vis-NIR spectrophotometer. CIE color coordinates, correlated color temperature, color rendering index and yellow to blue emission intensity ratio values were obtained through photoluminescence analysis. Radiative properties such as, radiative transition probability, stimulated emission cross-section, branching ratio and optical bandwidth gain were calculated according to Judd-Ofelt theory. The obtained optical spectroscopy results were found to be comparable or better than other reported glass systems. From the derived results, glasses with Dy〈sup〉3+〈/sup〉 ion concentration lower than 0.5 mol% were found to show the closest CIE color coordinate values to pure white light and highest CCT and CRI values revealing good potentiality to be used for applications in white LEDs and solid-state lasers.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Nisha Deopa, Babloo Kumar, Mukesh K. Sahu, P. Rekha Rani, A.S. Rao〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Zinc Bismuth Strontium Borosilicate (ZnBiSrBSi) glasses doped with varying concentrations of samarium (Sm〈sup〉3+〈/sup〉) ions have been synthesized via melt quenching technique and characterized by using XRD, SEM, optical absorption, excitation, Photoluminescence (PL) and decay spectral measurements. The amorphous nature of the as prepared glass has been confirmed by XRD and SEM measurements. The PL spectra recorded for the as-prepared glasses under 403 nm excitation show four emission bands from 〈sup〉4〈/sup〉G〈sub〉5/2〈/sub〉 level to 〈sup〉6〈/sup〉H〈sub〉J〈/sub〉 (J = 5/2, 7/2, 9/2 and 11/2). Among the four emission transitions, 〈sup〉4〈/sup〉G〈sub〉5/2〈/sub〉 → 〈sup〉6〈/sup〉H〈sub〉7/2〈/sub〉 transition at 600 nm is having highest intensity. The intensity of PL spectra in the titled glasses increases with increase in Sm〈sup〉3+〈/sup〉 ions concentration up to 0.5 mol% and beyond decreases due to concentration quenching. Dexter theory applied to the emission spectral features reveals the energy transfer mechanism between Sm〈sup〉3+〈/sup〉- Sm〈sup〉3+〈/sup〉 ions as dipole-dipole in nature. The experimental lifetimes measured from the PL decay profiles for the intense 〈sup〉4〈/sup〉G〈sub〉5/2〈/sub〉 → 〈sup〉6〈/sup〉H〈sub〉7/2〈/sub〉 transition decreases with increase in Sm〈sup〉3+〈/sup〉 ions concentration due to energy transfer between Sm〈sup〉3+〈/sup〉-Sm〈sup〉3+〈/sup〉 ions. All the aforementioned studies finally reveal that 0.5 mol% of Sm〈sup〉3+〈/sup〉 ions in ZnBiSrBSi glasses is optimum in fabricating the reddish orange luminescent devices.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): D.V. Krishna Reddy, T. Sambasiva Rao, Sk. Taherunnisa, A. Suchocki, Ya. Zhydachevskyy, M. Piasecki, M. Rami Reddy〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Yttrium alumino bismuth borosilicate (YABiBS) glasses doped with RE〈sup〉3+〈/sup〉 ions (Eu〈sup〉3+〈/sup〉, Dy〈sup〉3+〈/sup〉, Dy〈sup〉3+〈/sup〉- Eu〈sup〉3+〈/sup〉) have been synthesized via standard melt quenching technique and their emission properties were investigated. Optical analysis of these glasses is characterized by absorption and luminescence. XRD spectra reveal that these glasses have amorphous nature. The absorption spectra of these co-doped glasses consist five bands of Dy〈sup〉3+〈/sup〉 which are assigned to 〈sup〉6〈/sup〉H〈sub〉15/2〈/sub〉 → 〈sup〉6〈/sup〉F〈sub〉3/2〈/sub〉 (750 nm), 〈sup〉6〈/sup〉F〈sub〉5/2〈/sub〉 (796 nm), 〈sup〉6〈/sup〉F〈sub〉9/2〈/sub〉 (1085 nm), 〈sup〉6〈/sup〉F〈sub〉11/2〈/sub〉 (1264 nm)〈sub〉,〈/sub〉 〈sup〉6〈/sup〉H〈sub〉11/2〈/sub〉 (1677 nm) and another four bands of Eu〈sup〉3+〈/sup〉 assigned to 〈sup〉7〈/sup〉F〈sub〉0〈/sub〉 → 〈sup〉5〈/sup〉L〈sub〉6〈/sub〉 (393 nm) Meza-Rocha et al. (2017) [5],〈sup〉5〈/sup〉D〈sub〉2〈/sub〉 (464 nm), 〈sup〉7〈/sup〉F〈sub〉6〈/sub〉 (2097 nm)〈sub〉,〈/sub〉 and 〈sup〉7〈/sup〉F〈sub〉1〈/sub〉 → 〈sup〉7〈/sup〉F〈sub〉6〈/sub〉 (2202 nm). It is also witnessed a broad band having electronic transition 〈sup〉1〈/sup〉S〈sub〉0〈/sub〉 → 〈sup〉1〈/sup〉P〈sub〉1〈/sub〉 is due to Bi〈sup〉3+〈/sup〉 ions. Optical band gaps, nephelauxetic ratio, and bonding parameters are discussed by using optical absorption data. Eu〈sup〉3+〈/sup〉 single doped glasses show five emission bands, with the n-UV excitation wavelength 393 nm, in which characteristic feature red emission (612 nm) is recognized with transition (Meza-Rocha et al., 2017 [5])D〈sub〉0〈/sub〉 → 〈sup〉7〈/sup〉F〈sub〉2〈/sub〉. At the same time, Dy〈sup〉3+〈/sup〉 single doped glasses illuminated with the excitation wavelength of 385 nm shows their known natural emissions blue (481 nm) and yellow (574 nm), having transitions 〈sup〉4〈/sup〉F〈sub〉9/2〈/sub〉 → 〈sup〉6〈/sup〉H〈sub〉15/2〈/sub〉 and 〈sup〉4〈/sup〉F〈sub〉9/2〈/sub〉 → 〈sup〉6〈/sup〉H〈sub〉13/2〈/sub〉 respectively. Emission for co-doped glasses Dy〈sup〉3+〈/sup〉-Eu〈sup〉3+〈/sup〉 are excited with the different selected ultraviolet wavelengths such as 464 nm, 392 nm, 385 nm, 363 nm, and 348 nm. It can be observed that tunable emission from both the ions (Dy〈sup〉3+〈/sup〉, Eu〈sup〉3+〈/sup〉) from orange reddish emission to white emission. The energy transfer from Dy〈sup〉3+〈/sup〉 to Eu〈sup〉3+〈/sup〉 is manifested by the quadrupole-quadrupole mechanism, which is confirmed by Inokuti-Hirayama (I〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉H) modal based on lifetime decay curves. Also, the efficiencies and probabilities of energy transfer are determined based on the results of decay curves. The CIE color coordinates of DE1.0 glass with the excitation 348 nm gives x, y coordinates as (0.332, 0.342) which confers the good white emission. CCT value for this glass is around 5520 K shows that useful for cool WLED applications.〈/p〉〈/div〉 〈/div〉 〈div xml:lang="en"〉 〈h5〉Graphical abstract〈/h5〉 〈div〉〈p〉〈figure〉〈img src="https://ars.els-cdn.com/content/image/1-s2.0-S0022309319301656-ga1.jpg" width="301" alt="Unlabelled Image" title="Unlabelled Image"〉〈/figure〉〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Murat Celtek〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉The effects of the concentration on the glass formation, the crystallization process, and atomic structure of Zr〈sub〉100-x〈/sub〉Co〈sub〉x〈/sub〉 (x = 10, 30, 50, 70, and 90) alloys were investigated by classical molecular dynamics simulation based on the embedded atom method during rapid quenching. The structural evolution of these systems was evaluated by analyzing some structural functions and structural characterization methods. The calculated coordination number and structure factor were compared with the experimental data and it was observed that there was a good agreement between the molecular dynamics simulation and experimental results. Simulations performed for this study revealed that the local environment depends on the atomic composition in the Zr〈img src="https://sdfestaticassets-eu-west-1.sciencedirectassets.com/shared-assets/16/entities/sbnd"〉Co alloy. The liquid - glass transition was observed for the concentrations of Co in the range of 30–90%, which is consistent with the experimental glass forming range for Zr〈sub〉100-x〈/sub〉Co〈sub〉x〈/sub〉 alloys. The Voronoi and Honeycutt–Andersen pair analysis showed that the number of pairs and bonds reflecting the development of the icosahedral short range order increased with increased Co concentration and the Zr〈sub〉30〈/sub〉Co〈sub〉70〈/sub〉 alloy, having a large number of ideal and distorted icosahedrons with respect to other compositions considered in present study, has the highest fraction of Co-centered full icosahedral ⟨0,0,12,0⟩ clusters. Analysis results showed that in Zr〈sub〉90〈/sub〉Co〈sub〉10〈/sub〉 alloy, the number of ⟨0,6,0,8⟩ clusters denoting the transition to 〈em〉bcc〈/em〉 structure remarkably increased, and ⟨0,3,6,4⟩, ⟨0,5,2,6⟩ and ⟨0,4,4,6⟩ clusters play a key role during the crystallization process.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 15 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 514〈/p〉 〈p〉Author(s): Dale Igram, Horacio E. Castillo, D.A. Drabold〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉A ternary glassy chalcogenide material, Ag〈sub〉20〈/sub〉Ge〈sub〉28〈/sub〉Se〈sub〉52〈/sub〉, is analyzed for structural, electronic, vibrational, and ion dynamical properties. The structural analysis has revealed some interesting substructures, which are typically found only in Se-rich or Ge-rich materials. The radial distribution function of the Ag〈sub〉20〈/sub〉Ge〈sub〉28〈/sub〉Se〈sub〉52〈/sub〉 model illustrates reasonably good agreement with experiment. The vibrational density of states (VDOS) is characterized, and the nature of the modes is revealed as a function of energy. Finally, the dynamics of Ag are explored by investigating diffusion and hopping characteristics of Ag, and the character of trapping centers.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Taylan Günes〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉In the present study the magnetic, magneto-optical, morphological and microstructural properties of the amorphous Fe〈sub〉83〈/sub〉Cu〈sub〉1〈/sub〉Nb〈sub〉3〈/sub〉Si〈sub〉5〈/sub〉B〈sub〉8〈/sub〉 alloy were thoroughly investigated in accordance with various annealing circumstances. The kinetic nanocrystallization temperatures of certain ribbon were determined at the range of 500–515 °C. Furthermore, optimum heat treatment conditions were sought in the air atmosphere (AA), in vacuum (VA) and in vacuum with the presence of longitudinal magnetic field (LFA) at 70 A/m. This study aimed to put forward a quantitative explanation of the advantages of LFA in terms of several factors such as magnetic properties, microstructural evaluation and magneto-optical effects. The present nanocrystalline Fe〈sub〉83〈/sub〉Cu〈sub〉1〈/sub〉Nb〈sub〉3〈/sub〉Si〈sub〉5〈/sub〉B〈sub〉8〈/sub〉 alloy has allowed the yielding of ultrafine grain structure correlated with the literature results. Accordingly, average grain size of 5.9 nm, saturation induction of 1.84 T and coercivity of 6.4 A·m〈sup〉−1〈/sup〉 and saturation magnetostriction as low as 6 ppm were obtained as a result of LFA implementation. However, the sample subjected to VA under the same circumstances showed relatively lower magnetic and microstructural capability, with an average grain size of 9.8 nm, saturation induction of 1.73 T, coercivity of 14.7 A·m〈sup〉−1〈/sup〉 and saturation magnetostriction of 14 ppm, in comparison with LFA. To ensure precise average grain size, both XRD data and TEM micrographs were separately considered. Even though saturation magnetostriction could not be completely eliminated, it was significantly minimized from 52 ppm to 35 ppm, 14 ppm and 6 ppm in the samples subjected to AA, VA and LFA, respectively.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Yunfei Mo, Zean Tian, Lin Lang, Rangsu Liu, LiLi Zhou, Zhaoyang Hou, Ping Peng, Tianyi Zhang〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Molecular dynamic simulations have been carried out to investigate the crystallization mechanism during rapid cooling and isothermal relaxation for Zirconium (Zr) under a pressure of 100 GPa. The properties of the simulated system are analysed in terms of the system energy, the pair distribution function (PDF), and the largest standard cluster analysis. It is found that the so called topologically close-packed (TCP) local structures dominate in number in liquid, supercooled liquid and the final solid. Both solidification and relaxation crystallize into an A15 phase rather than the simple bcc or hcp crystals, the metastable and stable crystal of Zr under the ambient condition. Interestingly on PDF curves for liquids and super-liquids, left to the first major peak (at around 〈em〉r〈/em〉 = 3.0 Å) there is a mini-peak (at around 〈em〉r〈/em〉 = 1.87 Å) that decreases with the decrease of temperature and vanishes when crystallization ends. Further analysis reveals that the mini-peak originates from dynamical compact atomic pairs that are however almost nothing to do with TCP local structures. In addition, the multi characteristic lengths of the A15 unit (composed of Z12 and Z14 local structures with ratio of 1:3) result in the distinct split of the first and second peaks on the PDF curves.〈/p〉〈/div〉 〈/div〉

Description: 〈p〉Publication date: 1 June 2019〈/p〉 〈p〉〈b〉Source:〈/b〉 Journal of Non-Crystalline Solids, Volume 513〈/p〉 〈p〉Author(s): Xinxin Li, Jin Wang, Jingyu Qin, Bangshao Dong, Shaopeng Pan〈/p〉 〈div xml:lang="en"〉 〈h5〉Abstract〈/h5〉 〈div〉〈p〉Other than Fe–based amorphous alloys, the atomic configurations of amorphous pure Fe exhibit abundant topological local structures and exclude chemical effects on the local magnetic moment of a Fe atom. We thus employed amorphous pure Fe to investigate the structural–magnetic properties relationship by ab initio molecular dynamics simulations. Our results showed that the decreased volume leads to a reduction of absolute values of both positive and negative magnetic moments, which agrees with earlier investigations. Further, we employed the minimum coordination polyhedrons with the coordination number of 5–10 to depict the local structures, and found that there is a strong correlation between the minimum coordination polyhedrons and local magnetic moments. The local magnetic moments increase with the coordination number of the minimum coordination polyhedron; the larger distortion of the minimum coordination polyhedron corresponds to larger average magnetic moments.〈/p〉〈/div〉 〈/div〉