When a phase‐separated glass is leached, stresses develop because of release of thermal stresses, creation of surface area, ion exchange, and hydration. Analyses are presented for the thermal stresses, including the portion that develops on cooling from the heat‐treatment temperature to the setting temperature of the less viscous phase. During leaching, the interfacial energy of the residual phase increases, so that phase tends to contract. A more important effect is the contraction caused by removal of alkali and B2O3 from the residual phase during leaching. The extent of removal of B2O2 decreases with heat‐treatment time, tH, because the scale of the microstructure increases as t1/3H. The change in residual B2O2 content with tH is shown to be consistent with diffusion‐controlled ion exchange. The dependence of stress on tH in partially leached glasses, measured by Drexhage and Gupta, results principally from the change in extent of ion exchange; the reduction in surface area with increasing tH also has a significant effect on the stresses.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of the American Ceramic Society|
|State||Published - Aug 1985|
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry