Study on the Cracking of Silica Films Prepared by Sol-Gel Process
FANG Ping?an, WU Zhao?ping (Shanghai Institute of Ceramics, Chinese Academy of Science, Shanghai 200050, China)
The silica films, which are used to strengthen glass-ceramics,were prefabrica- ted by sol-gel process on the silicate substrates. The reason for the cracking of films is discussed and analyzed in detail. The result shows that the cracking of the gel films is mainly related to the composition of sol and the unbalanced stress produced during drying and hea- ting process. The silica films without cracks, characterized by DTA, IR and high resolution optical microscope methods et al, were obtained by modifying the composition of sol and controlling the relative humidity and the heating rate of heat treatment.