Preparation of diamond/RB-SiC composite with low residual silicon and high diamond content by infiltration

The infiltration has the advantages of high efficiency and near net forming, making it the mainstream method for preparing diamond/SiC composite. However, no pressure was applied during the infiltration and the SiC matrix originated from the silicon-carbon reaction, resulting in a low diamond content and a large amount of residual silicon. This makes it difficult to further improve the properties of the composite, especially the thermal conductivity. Therefore, reaction bonded SiC (RB-SiC) was proposed as the matrix to reduce silicon content, and composition design was carried out to obtain high content of diamond. The results showed that in the prepared composite, the diamond content (61.14 vol%) reached the theoretical maximum of 90.43 %, and the silicon is only 4.79 vol%. Therefore, the thermal conductivity of composite can reach up to 665.47 W/mK. In addition, the influence of SiC particle size on phase composition, microstructure, and properties was analyzed.