Relationship of microstructure to mechanical and thermal properties of zirconia-alumina composites

Samples of the zirconia-ytria and alpha-alumina and also two zirconia-alumina composites where the alumina precursory phase was pseudoboehmite seeded with alpha-alumina, were formulated. The powders were suspended and dried off by spray-drying under optimized conditions. he powders were cold isostatically pressed at 200 MPa and isothermally sintered until reach high densification. The microestructure of samples was analyzed by SEM, and the Vicker's microhardness, Young Modulus and the fracture toughness, and also the thermal conductivity were determined. The microestructure was related with the mechanical and thermal properties. It was found that the macrocracking present in samples with alpha-alumina matrix, influences about the fracture toughness and the thermal conductivity.