View in EDS

Phase composition, microstructure and conductivity of (85-α)VO2–15(Vanadium–Phosphate–Glass)–αCu glass–ceramics

Saved in:
Bibliographic Details
Title: Phase composition, microstructure and conductivity of (85-α)VO2–15(Vanadium–Phosphate–Glass)–αCu glass–ceramics
Authors: Ivon, A.I.1, Chernenko, M.1, Kolbunov, V.R. a_ivon@mail.ru
Source: Journal of Non-Crystalline Solids. Jun2007, Vol. 353 Issue 16/17, p1521-1528. 8p.
Subjects: Glass-ceramics, X-ray diffraction, Scanning electron microscopy, Porosity
Abstract: Abstract: Electric conductivity, microstructure and phase composition of (85-α)VO2–15VPG–αCu glass–ceramics (VPG=Vanadium–Phosphate–Glass) with copper content in the interval 0wt%⩽ α ⩽15wt% were investigated. VPG is the glass (molar %) 80V2O5–20P2O5. Only two phases: VO2 and VPG were identified when α ⩽5wt%. VO2 crystallites, VPG and pores are observed in these ceramic microstructures. Glass forms layers 1–2μm thick in the space between VO2 crystallites. The copper is dissolved in VPG during glass–ceramic synthesis. It increases the electric conductivity of the glass and provides improvement of electrical bonds between VO2 crystallites. Therefore glass–ceramics conductivity exhibits an abrupt change of approximately 100× in the vicinity of the phase transition temperature, T t, in VO2. A new crystalline phase appears in (85-α)VO2–15VPG–αCu ceramics when α ∼6wt%. This phase is observed as small crystallites with the sizes of 1–5μm. The increase in such phase content, with an increase in copper content is accompanied by a decrease in the content of VO2. Percolation along the new phase is a primary contributor to electric conductivity when α ⩾8wt%. In this case the conductivity exhibits no abrupt change in the vicinity of the temperature T t. The new phase is probably the bronze Cu x V2O4. It crystallizes from a liquid phase during glass–ceramics synthesis. [Copyright &y& Elsevier]
Copyright of Journal of Non-Crystalline Solids is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:Abstract: Electric conductivity, microstructure and phase composition of (85-α)VO2–15VPG–αCu glass–ceramics (VPG=Vanadium–Phosphate–Glass) with copper content in the interval 0wt%⩽ α ⩽15wt% were investigated. VPG is the glass (molar %) 80V2O5–20P2O5. Only two phases: VO2 and VPG were identified when α ⩽5wt%. VO2 crystallites, VPG and pores are observed in these ceramic microstructures. Glass forms layers 1–2μm thick in the space between VO2 crystallites. The copper is dissolved in VPG during glass–ceramic synthesis. It increases the electric conductivity of the glass and provides improvement of electrical bonds between VO2 crystallites. Therefore glass–ceramics conductivity exhibits an abrupt change of approximately 100× in the vicinity of the phase transition temperature, T t, in VO2. A new crystalline phase appears in (85-α)VO2–15VPG–αCu ceramics when α ∼6wt%. This phase is observed as small crystallites with the sizes of 1–5μm. The increase in such phase content, with an increase in copper content is accompanied by a decrease in the content of VO2. Percolation along the new phase is a primary contributor to electric conductivity when α ⩾8wt%. In this case the conductivity exhibits no abrupt change in the vicinity of the temperature T t. The new phase is probably the bronze Cu x V2O4. It crystallizes from a liquid phase during glass–ceramics synthesis. [Copyright &y& Elsevier]
ISSN:00223093
DOI:10.1016/j.jnoncrysol.2007.02.033