Zrc ceramics incorporated with different-sized SiC particles

Three different SiC powders with average particle sizes of 0.45, 3.5 and 10 µm 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 µm 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 µm exhibits the highest thermal conductivity due to the larger grains and less grain boundaries.