Diopside–Ca-Tschermak clinopyroxene based glass–ceramics processed via sintering and crystallization of glass powder compacts

• Published in: Journal of the European Ceramic Society 2007, Vol.27 (5), p.2325-2331
• Main Authors: Goel, A., Tulyaganov, D.U., Agathopoulos, S., Ribeiro, M.J., Basu, R.N., Ferreira, J.M.F.
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Chemical industry and chemicals; Diopside–Ca-Tschermak; Exact sciences and technology; Functional applications; Glass-ceramics; Glasses; Mechanical properties; Sintering
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2006.07.016

The suitability of three new glass compositions for producing diopside–Ca-Tschermak clinopyroxene based glass–ceramics (GCs) was investigated. With respect to the formula of diopside, the first investigated composition resulted from the substitution 0.2(Si 4+ + Mg 2+) ↔ 0.4 Al 3+, which leads to a composition of 80 mol.% diopside and 20 mol.% Ca-Tschermak. The substitutions in the second compositions were 0.25(Ca 2+ + Si 4+) ↔ 0.25(Y 3+ + B 3+) and 0.2(Si 4+ + Mg 2+) ↔ 0.4Al 3+, and in the third composition 0.2Ba 2+ ↔ 0.2Ca 2+ and 0.2(Si 4+ + Mg 2+) ↔ 0.2(B 3+ + Al 3+). The influence of these substitutions on glass crystallization and the properties of the GCs produced between 850 and 1000 °C was experimentally investigated. The experimental results showed that the easily cast glasses, after melting at 1580 °C for 1 h, are prone to surface crystallization. Augite is predominantly crystallized, but Ca- and Ba-aluminosilicates can also form, according to the substitutions. The stability of the assemblage of the crystalline phases over a wide temperature range (850–1000 °C) and prolonged heat treatment (up to 50 h) and the properties of the produced GCs indicate a high potential of these compositions for several functional applications.