Microstructure and mechanical properties of cubic zirconia (8YSZ)/SiC nanocomposites

The mechanical properties of cubic zirconia (8YSZ)/SiC “nanocomposites” were studied. These properties were found to be strongly dependent on the microstructure and processing conditions. For nanocomposites with SiC particles mostly inside the zirconia grains the bending strength, toughness and hardness were similar to that of monolithic 8YSZ. For nanocomposites with SiC particles located mainly on the grain boundaries, an improvement of the strength and an increase of the toughness were observed. The increase in strength is strongest at room temperature and decreases with rising temperature; the strengths of all materials are identical at ∼750°C. The higher strength cannot be completely accounted for by the observed increase in toughness, implying a reduced critical flaw size in the stronger material.