Fabrication and properties of SiC reinforced graphite composites by hot-pressing sintering

SiC reinforced graphite composites were prepared with natural flake graphite as raw materials and SiC particles as reinforcement phase by hot-pressing sintering process. The effects of SiC contents on microstructures, mechanical properties and friction behavior of SiC reinforced graphite composites were analyzed. The results show that the SiC particles are uniformly distributed in graphite matrix, greatly reducing the porosity of matrix. With the increasing of SiC content, relative density and bending strength of SiC reinforced graphite composites increase, and the open porosity falls significantly. The relative density and flexural strength of composites with 40vol% SiC reach 94.2% and 146 MPa due to the formation of SiC network backbone structure in SiC reinforced graphite composites, 11.8% and 147% larger than those of commodity high-strength pure graphite materials. Matrix graphite keeps the layered structure. The friction coefficients of SiC reinforced graphite composites increase slightly with the content of SiC increasing, which keep the same friction coefficient of pure graphite material when the content of SiC is no more than 40vol%, which shows good friction properties.