Mechanical properties of ZrB₂-based ceramics reinforced by nano-SiC whiskers

In this paper, ZrB₂-based ceramics containing up to 15 vol% nano-SiC whiskers were prepared by hot pressing at 1950°C under 20MPa pressure in flow argon. SEM and XRD techniques were used to characterize the sintered compacts. A fine and homogeneous microstructure was observed. The relative density of ZrB2-based ceramic containing 10vol% SiC whiskers reached to 97.7%. The bending strength and fracture toughness of the composite were 550 MPa and 8.08 MPa·m^1/2 respectively, while those of the monolithic ZrB₂ ceramic (0 vol% SiC whiskers added) were 424 MPa and 4.52 MPa·m^1/2 respectively. The grain size of the ZrB ₂-based ceramics was reduced greatly by the addition of nano-SiC whiskers during the sintering process.