Thermal decomposition of K1 − xCsxBSi2O6 borosilicates

• Published in: Glass physics and chemistry Vol. 39; no. 6; pp. 659 - 663
• Main Authors: Derkacheva, E. S., Krzhizhanovskaya, M. G., Bubnova, R. S., Filatov, S. K., Ugolkov, V. L.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.11.2013
• Subjects: Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Glass; Materials Science; Natural Materials; Physical Chemistry; Short Communications; borosilicates; Rietveld method; solid-phase decomposition; crystalline structure
• ISSN: 1087-6596; 1608-313X
• DOI: 10.1134/S1087659613060035

Thermal decomposition of mixed K 1 − x Cs x BSi 2 O 6 borosilicates by the methods of thermal analysis, annealing, and quenching, with the following refining of the structure by the Rietveld method on the example of solid solutions with x = 0.3 and 0.7 crystallizing in the space groups and , respectively, is studied. It is shown that the solid-phase decomposition of borosilicates proceeds with the release of the gas- eous phase and formation of cristobalite and/or tridymite of SiO 2 at the final stage. In this case the solid solutions enriched by potassium decompose in one stage with the formation of SiO 2 , while the solutions enriched by cesium decompose with the formation of the intermediate zeolite-like CsBSi 5 O 12 borosilicate, which also decomposes during further thermal treatment. According to the data of the structure, the refining of K 1 − x Cs x BSi 2 O 6 solid solutions obtained by thermal treatment at 1000°C for 20, 65, 80, and 100 h, it is detected that for the samples with x = 0.3 and 0.7 the parameter of the cubic cell of the leucite-like phase decreases and the vacancies in the position of alkaline cation appear. During the solid-phase decomposition of K 1 − x Cs x BSi 2 O 6 solid solutions the structure degrades.