Zrc ceramics incorporated with different-sized SiC particles

Three different SiC powders with average particle sizes of 0.45, 3.5 and 10 mu m were used to prepare ZrC-20vol.-% SiC ceramics by hot pressing. The effects of SiC particle size on the densification, microstructure, mechanical properties and thermal properties of ZrC-SiC ceramics were studied. Ceramics prepared from SiC with finer particle sizes exert higher bending strength, hardness and lower thermal conductivity. The ZrC-SiC ceramics with a starting SiC particle size of 3.5 mu m has relative high fracture toughness than others. Analysis indicates that SiC grain size and the grain boundaries control the thermal conductivity ZrC-SiC ceramics. Ceramics prepared from SiC with the particle size of 10 mu m exhibits the highest thermal conductivity due to the larger grains and less grain boundaries.