Effect of SiO2 and TiO2 additions on the phase formation, sinterability, and microstructure of alumina ceramics was studied by differential thermal analysis, X-ray powder diffractometry, SEM, TEM, and dilatometry. Alumina-based mixture powders were prepared from starting materials of α-Al2O3 powder, Si(OC2H5)4 and Ti(OC3H7)4. The silica gel obtained from the hydrolysis of Si(OC2H5)4 was coated on Al2O3 particles to form a thin surface layer. During the firing process, the silica gel didn't crystallize to cristobalite but reacted with Al2O3 to form mullite above 1500 °C. The silica gel, mullite and/or Al2O3-SiO2 liquid phase retarded the densification and the grain growth of alumina. As TiO2 was added to the alumina-silica gel mixture, the sinterability was enhanced and the formation temperature of mullite was lowered.
|Number of pages||5|
|Journal||Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan|
|Publication status||Published - 1993|
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Condensed Matter Physics
- Materials Chemistry