Thermal properties of SiC-bonded diamond materials produced by liquid silicon infiltration

Abstract

Silicon carbide bonded diamond composites are a class of materials with great potential for a wide range of demanding applications in industry. They can be produced by pressureless infiltration of diamond preforms with liquid silicon. In addition to their high hardness and very high wear resistance, the materials have a high thermal conductivity of up to 636 W/m⋅K, which is about 50 % higher than the value of silver. The analysis of materials with different diamond contents and grain sizes shows that the thermal conductivity increases with increasing grain size of the diamonds as well as with the volume content. Based on the experimental data, an interface conductance can be estimated for the SiC diamond interface. This value is similar to the values determined for diamond/Si interfaces. An increasing graphitization of the interface leads to a strong reduction of the thermal conductivity of the composites.