MICROSTRUCTURE AND THERMAL-STABILITY OF FINE-GRAINED (Y, MG)-PSZ CERAMICS WITH ALUMINA ADDITIONS

Commercial powders within the system ZrO2-MgO-Y2O3-Al2O3 were used to produce zirconia ceramics with improved thermal stability. Different s intering routes were followed in order to determine the optimum condit ions. Fine-grained (Y, Mg)-PSZ ceramics with grain sizes below 10 mum were achieved. Microstructural evolution was studied after various iso thermal heat treatments. After ageing, the materials contain a large f raction of tetragonal phase which does not transform after a hydrother mal ageing treatment in an autoclave, but can still be transformed und er mechanical stress.