Broad band transmitting glasses from visible to mid-infrared with good mechanical strength, chemical durability, glass-forming ability, and thermal stability are preferred for optics and laser technology applications. Generally, low phonon energy glasses possess an extended transmission cutoff toward mid-infrared, but at the same time, retention of other desired properties is challenging for the researchers. In this work, we have shown that mixed alkaline earth (Ba/Sr) would have the potential to improve overall glass properties while retaining its low phonon energy when CaO is partially substituted by BaO/SrO in calcium magnesium zinc silica-aluminate (CMZSA) glass.
View Article and Find Full Text PDFSilicate glasses containing silicon, sodium, phosphorous, and calcium have the ability to promote bone regeneration and biodegrade as new tissue is generated. Recently, it has been suggested that adding SrO can benefit tissue growth and silicate glass dissolution. Motivated by these recent developments, the effect of SrO/CaO-CaO/SrO substitution on the local structure and dynamics of Si-Na-P-Ca-O oxide glasses has been studied in this work.
View Article and Find Full Text PDFThe short-range and medium-range structures of TeO glass and melt are elucidated by Reverse Monte Carlo (RMC) simulations of High-Energy X-ray Diffraction data sets published in an earlier study by Alderman et al. ((1) (2020)427-431). The RMC analysis reveals that there exists a wide range of Te-O bond lengths in both TeO glass and melt short-range structures.
View Article and Find Full Text PDFIn this study, we investigated the influence of BiO and WO on both structure and optical properties of 50ZnO:(49 - x)BO:1BiO:xWO; x = 1, 5, 10 glasses doped with 0.5 mol% EuO. IR spectroscopy revealed the presence of trigonal BØ units connecting superstructural groups, [BØO] metaborate groups, tetrahedral BØ units in superstructural groupings (Ø = bridging oxygen atom), borate triangles with nonbridging oxygen atoms, [WO] tetrahedral, and octahedral WO species.
View Article and Find Full Text PDFDeep geological repository is widely considered as the preferred solution for the final disposal of high-level radioactive waste. Investigation representative of the Hungarian disposal concept was conducted using mock-up diffusion cells to study the chemical changes of S235JR carbon steel canister and CEM II/B concrete of the Public Limited Company for Radioactive Waste Management under anerobic and water saturated conditions at 80 °C. Micro-Raman, Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy, fluid and potentiometric analysis were performed over a period of 12 months.
View Article and Find Full Text PDFThere is still a safety challenge for the long-term stabilization of nuclear waste. Due to its affordable price and easy manufacturing, cement is one of the most promising materials to immobilize a large volume of low- and intermediate-level radioactive liquid waste. To investigate the effect of borate on the cementation of radioactive evaporator concentrates and to provide more data for solidification formula optimization, simulated liquid waste in various concentrations was prepared.
View Article and Find Full Text PDFThe presence of lanthanide-tellurite "anti-glass" nanocrystalline phases not only affects the transparency in glass-ceramics (GCs) but also influences the emission of a dopant ion. Therefore, a methodical understanding of the crystal growth mechanism and local site symmetry of doped luminescent ions when embedded into the precipitated "anti-glass" phase is crucial, which unfolds the practical applications of GCs. Here, we examined the LnTeO "anti-glass" nanocrystalline phase growth mechanism and local site symmetry of Eu ions in transparent GCs produced from 80TeO-10TiO-(5 - )LaO-5GdO-EuO glasses, where = 0, 1, 2.
View Article and Find Full Text PDFActa Crystallogr B Struct Sci Cryst Eng Mater
April 2021
xLiO-(100 - x)TeO (x = 20 and 25 mol%) and xVO-(25 - x)LiO-75TeO (x = 1, 2, 3, 4 and 5 mol%) glasses were prepared by melt-quenching and their thermal and structural properties were characterized by differential scanning calorimetry, Raman spectroscopy, high-energy X-ray diffraction and neutron diffraction and reverse Monte Carlo (RMC) simulations. The glass transition temperature increases steadily with an increase in VO mol% in lithium tellurite glasses due to an increase in the average single bond energy of the glass network. The X-ray and neutron diffraction structure factors were modelled by RMC technique and the Te-O distributions show the first peak in the range 1.
View Article and Find Full Text PDFExploring the reasons for the initiation of Al-O-Al bond formation in alkali-earth alumino silicate glasses is a key topic in the glass-science community. Evidence for the formation of Al-O-Al and Al-NBO bonds in the glass composition 38.7CaO-9.
View Article and Find Full Text PDFAluminosilicate glasses are considered to follow the Al-avoidance principle, which states that Al-O-Al linkages are energetically less favorable, such that, if there is a possibility for Si-O-Al linkages to occur in a glass composition, Al-O-Al linkages are not formed. The current paper shows that breaching of the Al-avoidance principle is essential for understanding the distribution of network-forming AlO and SiO structural units in alkaline-earth aluminosilicate glasses. The present study proposes a new modified random network (NMRN) model, which accepts Al-O-Al linkages for aluminosilicate glasses.
View Article and Find Full Text PDFAn assessment is undertaken for the formation of anorthite crystalline phase in a melilite-based glass composition (CMAS: 38.7CaO-9.7MgO-12.
View Article and Find Full Text PDF