Fabrication and mechanical properties of nanosized SiC particulate reinforced yttria stabilized zirconia composites

Abstract

Nanocomposite technology was applied to 8 mol% yttriafully-stabilized zirconia (8YSZ) for improving its mechanical properties. 8YSZ and nanosized SiC powders with particle size of 40 to 100 nm were homogeneously mixed in ethanol using a ball milling technique. After milling, the mixed powders were sintered by hot-pressing routes. Transmission electron microscopy (TEM) observations revealed that nanosized SiC particles were homogeneously dispersed within the 8YSZ matrix grains and at grain boundaries. The fracture strength was improved two to three times compared with the monolithic 8YSZ. Maximum strength of 750 MPa was obtained for the 8YSZ/20vol.% SiC nanocomposite. This strength improvement may be due to fine and homogeneous microstructure and to the compressive internal stresses caused by thermal mismatch between the 8YSZ and SiC particulates.