INTERACTIONS IN THE SOL-GEL PROCESSING OF ALUMINA-ZIRCONIA COMPOSITES

The combined effect of alumina and zirconia on the phase transformation and microstructure development of heat-treated alumina-zirconia composites has been studied The composites were prepared by the sol-gel process, using two different alumina matrices (polymer and particulate) and three different types of zirconia particles. The influence of the different zirconia particles on the phase transformation and microstructure development of the alumina matrix is clearly evident. In addition, stability of tetragonal zirconia in the alumina matrix is considerably changed, in respect to pure zirconia powder. These effects are explained by the existence of a mutual intel action between the zirconia and the transitional aluminas, which is stronger if the alumina and zirconia particles are smaller and more intimately mixed.