FABRICATION AND MECHANICAL-PROPERTIES OF NANOSIZED SIC PARTICULATE-REINFORCED YTTRIA-STABILIZED ZIRCONIA COMPOSITES

Nanocomposite technology was applied to 8 mol% yttria fully-stabilized zirconia (8YSZ) for improving its mechanical properties. 8YSZ and nan osized SiC powders with particle size of 40 to 100 nm were homogeneous ly mixed in ethanol using a ball milling technique. After milling, the mixed powders were sintered by hot-pressing routes Transmission elect ron microscopy (TEM) observations revealed that nanosized SIC particle s were homogeneously dispersed within the 8YSZ matrix grains and at gr ain boundaries. The fracture strength was improved two to three rimes compared with the monolithic 8YSZ. Maximum strength of 750 MPa was obt ained for the 8YSZ/20vol.% SiC nanocomposite. This strength improvemen t may be due refine and homogeneous microstructure and to the compress ive internal stresses caused by thermal mismatch between the 8YSZ and SiC particulates. (C) 1997 Acta Metallurgica Inc.