Effects of B₂O₃ and P₂O₅ doping on the microstructure evolution and mechanical strength in a lithium aluminosilicate glass-ceramic material with TiO₂ and ZrO₂

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• 作者：Yu-Han Wu^a ; ^{yuhanwu@mx.nthu.edu.tw} ; Kuo-Chuan Hsu^b ; Chih-Hao Lee^a ; ^c
• 关键词：Lithium aluminosilicate glass&ndash ; ceramic ; XANES ; 尾-Spodumene solid solutions ; Flexural strength ; Low thermal expansion
• 刊名：Ceramics International
• 出版年：2012
• 期刊代码：13_02728842
• 类别：ms
• 出版时间：July, 2012
• 卷：38
• 期：5
• 页码：4111-4121
• 文件大小：1348 K

摘要

During the devitrification process, the coordination number of Ti changes from 4 and 5 to 6; and the coordination number of Zr changes from 6 to 8 in a lithium aluminosilicate glass-ceramic material. The flexural strength of the glass-ceramics strongly depends on the composition of additives. The strength of a well-crystallized sample increases 45%by doping with B₂O₃ and decreases 56%by doping with P₂O₅. Thermal expansion mismatch and microstructure non-uniformity are the proposed mechanisms responsible for the changes in strength. The effects of doping concentration of B₂O₃ and P₂O₅ and thermal treatment conditions on the microstructure and mechanical strength of a lithium aluminosilicate glass-ceramic material with TiO₂ and ZrO₂ were studied. The local environment around Ti and Zr correlated to the secondary phase development, such as TiZrO₄ and ZrSiO₄, during the crystallization process was observed by X-ray absorption near edge structure. The electronic structure of each peak in the X-ray absorption near edge spectra was also assigned in terms of phase evolutions. The phase transformation temperature of 尾-quartz solid solutions to 尾-spodumene solid solutions is decreased for about 100 掳C by adding B₂O₃ and P₂O₅.