Powder characteristics, sintering behavior and microstructure of sol–gel derived ZTA composites

A series of alumina/zirconia composites of varying compositions of zirconia were prepared through the sol–gel technique. Precursors were calcined at different temperatures ranging from 300 to 1400°C and sintered at 1530°C for 3 h. Compacts made from the powder calcined at 950°C yielded density up to >99% of theoretical density by pressureless sintering. Pore size distribution and the densification behavior were explained with respect to calcination temperature. Microstructural analysis of the sintered compacts revealed the uniform distribution of the zirconia grains in the alumina matrix. It is also observed that the faceted intergranular zirconia grains are at the grain junctions and the corners of the alumina matrix.