Tellurium Vanadate Glasses: V4+colorimetric Measure and Its Effect on Conductivity

This research comes as part of a broader resurgence of study on the electrical conductivity of glasses—and the mechanism for electronic motion in the amorphous network—spurred by interest in using glasses as matrices for solid-state batteries, taking advantage of the glasses' tailorable conductivity, chemical durability, and mechanical strength. The work presented in this study regards the preparation and characterization of some binary glasses belonging to the TeO2–V2O5 system. In particular, we focused on the glasses' electrical conductivity at room temperature and at higher temperatures as a function of the V4+ ion content in the glass structure. The amount of V4+ in the glass was determined by a colorimetric method. Moreover, density and thermal properties (Tg, Cp) were measured, and scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements were performed as well

Challenges in Ceramic Science: A Report from the Workshop on Emerging Research Areas in Ceramic Science

In March 2012, a group of researchers met to discuss emerging topics in ceramic science and to identify grand challenges in the field. By the end of the workshop, the group reached a consensus on eight challenges for the future:—understanding rare events in ceramic microstructures, understanding the phase-like behavior of interfaces, predicting and controlling heterogeneous microstructures with unprecedented functionalities, controlling the properties of oxide electronics, understanding defects in the vicinity of interfaces, controlling ceramics far from equilibrium, accelerating the development of new ceramic materials, and harnessing order within disorder in glasses. This paper reports the outcomes of the workshop and provides descriptions of these challenges

Structural and optical properties of cerium oxide doped barium bismuth borate glasses

This study focuses on the characterization of heavy metal oxide glasses containing CeO2 as dopant with the aim to enhance its density, as many optical applications of glasses (eg: heavy particles measurement in high energy physics) are heavily dependent on the density of the glass itself. Different concentrations of CeO2 were added to a barium bismuth borate base glass and the relative structural and optical properties were studied. The structure of the obtained material was analysed by means of density measurement, molar volume calculation, X-Ray diffraction, thermal analysis and Raman spectroscopy. The results show that CeO2 promotes the formation of a crystalline phase and improves the density of the base glass. Optical properties were studied, such as transmittance and luminescence, and the obtained results suggest that the crystalline formation scatters light transmittance through the sample, preventing luminescent emission. Further improvements in glass formulation have been suggested in order to enhance its optical properties together with its densit

A general study of packing in oxide glass systems containing alkali

The packing fraction, defined as the ionic volume divided by the molar volume, appears to hold promise as a general measure of the structure of alkali oxide modified glasses. For modifying ions having volumes larger than oxygen (K, Rb, and Cs), the packing is dominated by the modifier as alkali oxide concentration increases and is largely independent of glass former; we define this as ionic packing. For alkali smaller than oxygen (Li and Na) the packing is controlled by the oxygen covalent network and is heavily dependent on glass former; we call this covalent packing. In this paper we compare the packing fractions of alkali borate, silicate, germanate, phosphate, and vanadate glass systems. © 2004 Elsevier B.V. All rights reserved

Structural and optical properties of rare-earths doped barium bismuth borate glasses

Recently, great importance has been devoted to different glass systems doped with rare-earth ions because of their peculiar properties, in particular in the field of high-energy physics for particle energy measurement. The purpose of the present study was to investigate the optical and physical properties of Dy3 +, Er3 +, Nd3 + doped glasses belonging to the 20BaO-20Bi2O3-60B2O3 system in which several rare-earths oxide concentrations were added to encounter the requirements for particle energy measurement. High density, low refractive index, high emission intensity (or high scintillation yield) are required for this purpose. Moreover, molar volume, glass transition and melting temperatures, X-ray diffraction and Raman spectra were measured and discussed in order to characterize the glass state. All the properties measured have shown a non-linear trend moving from 1 mol% to 10 mol% of rare-earths content. At the same time comparison between the trend derived by samples with same stoichiometry but containing different rare earths highlight different behaviors. In particular the highest density has been reached with the glass where Dy2O3 is at 2,5 mol%

Challenges In Ceramic Science: A Report From The Workshop On Emerging Research Areas In Ceramic Science

In March 2012, a group of researchers met to discuss emerging topics in ceramic science and to identify grand challenges in the field. By the end of the workshop, the group reached a consensus on eight challenges for the future:-understanding rare events in ceramic microstructures, understanding the phase-like behavior of interfaces, predicting and controlling heterogeneous microstructures with unprecedented functionalities, controlling the properties of oxide electronics, understanding defects in the vicinity of interfaces, controlling ceramics far from equilibrium, accelerating the development of new ceramic materials, and harnessing order within disorder in glasses. This paper reports the outcomes of the workshop and provides descriptions of these challenges. © 2012 The American Ceramic Society

Quantitative measurement of Q(3) species in silicate and borosilicate glasses using Raman spectroscopy

Raman spectroscopy has been used to measure the fraction of tetrahedral silicate units connected at three corners into the network (Q(3)) in binary lithium silicate glasses and also in the more complex borosilicate glasses used for waste immobilization. Agreement within experimental error was obtained with Si-29 MAS NMR measurements of the same samples. Raman provides an alternative method of structural determination for silicon-containing glasses with a high content of paramagnetic species where NMR loses resolution. Analysis was performed on borosilicate glasses containing up to 11.98 mol% Fe2O3 and the Q(3) values obtained by Raman spectroscopy agree within error with the published Si-29 NMR results from borosilicate glasses containing the equivalent quantity of Al2O3. (C) 2007 Elsevier B.V. All rights reserved