Effect of zirconia powder prehistory on strength of zirconia-toughened nickel aluminide

The strength behaviour of NiAl/ZrO2 composites toughened by different zirconia dispersoids were examined. Two kinds of zirconia powders were used: (i) partially stabilised zirconia powder containing 2 mol% Y2O3 prepared by co-precipitation from aqueous solution of chlorides with ammonia and (ii) zirconia powder without stabilisers obtained by plasma-assisted vapour-phase chemical synthesis. Substantial improvement of the mechanical properties of the NiAl-matrix composites were achieved using both partially stabilised and non-stabilised zirconia dispersoids, but the resulting effect was strongly dependent on the prehistory of the zirconia powders. 9 refs.