Time-temperature-transformation diagrams for borosilicate glasses and preparation of chemically durable porous glasses
- Kyushu Univ., Fukuoka (Japan)
To clarify the effects of glass composition and heat-treatment conditions on phase separation and crystallization, time-temperature-transformation (TTT) diagrams for the system (65 {minus} x)SiO{sub 2}{center_dot}25B{sub 2}O{sub 3}{center_dot}(10 {minus} y)Na{sub 2}O{center_dot}yCaO{center_dot}xZrO{sub 2}, which is used for fabricating alkali-durable porous glasses, were determined. The microstructures and properties, such as resistance to alkaline attack as a function of ZrO{sub 2} content, of the porous glasses fabricated on the basis of the developed TTT diagrams were examined. CaO and ZrO{sub 2} additions were shown to affect the locations of the noses in the TTT curves for phase separation and crystallization. The substituting of CaO for Na{sub 2}O was effective for retaining ZrO{sub 2} in the skeleton of the porous glasses. The alkali resistance of ZrO{sub 2}containing porous glasses was 8--10 times superior to that of the porous glass without ZrO{sub 2}. The results demonstrate that TTT diagrams can be used as guides for heat-treatment scheduling in processing or predicting of glass-forming ability and the onset of phase separation and crystallization in glass-forming systems.
- Sponsoring Organization:
- Ministry of Education, Science and Culture (Japan)
- OSTI ID:
- 512048
- Journal Information:
- Journal of the American Ceramic Society, Vol. 80, Issue 5; Other Information: PBD: May 1997
- Country of Publication:
- United States
- Language:
- English
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