Structural evolution during calcination of sol-gel synthesized alumina and alumina-8 vol% zirconia composite

Alumina and alumina-8 vol% zirconia (3 mol% yttria) composite powders were synthesized via a sol-gel process using metal chlorides as precursors. Sol-gel synthesized alumina and alumina-zirconia composite powders were initially amorphous and contained structural water. Calcination was necessary to drive off the water and prompt crystallization of the powder. Calcination of synthesized powder was performed at various temperatures from 400–1300°C. Powder morphology and phase evolution during calcination were established using electron microscopy, X-ray diffraction, and thermogravimetric analysis. This revised version was published online in November 2006 with corrections to the Cover Date.