Improvement on the thermal conductivity of Diamond/CVI-SiC composites using large diamond particles

The Diamond/SiC composites were fabricated via slip casting and chemical vapor infiltration (CVI) approaches. The effects of diamond particle size (50–500 μm) on microstructure, flexural strength, density, fracture toughness and thermal conductivity of Diamond/SiC composites were discussed. By using large-sized diamond particles, thermal conductivity of composites can be improved and the maximum value could reach up to 241 W/(m·k), which is 2.1 times higher than that of the Diamond/SiC composites prepared by tape-casting and CVI process. With increasing of diamond particle size, the density of Diamond/SiC composites increased, and the mechanical properties decreased. The maximal density, flexural strength and fracture toughness were 3.18 g/cm³, 287 MPa and 5.0 MPa·m^1/2 respectively. The fracture mechanism of the composites transferred from diamond particles transgranular fracture to interfacial debonding.