Microstructure and Properties of Graphite Embedded SiC Composite by Coating Method

Abstract

Gp/SiC composite was prepared with electrode graphite particle and SiC powders as the raw materials, using coating process and hot-pressing sintering technology. The microstructure and phase constitution was measured by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron energy spectrum (EDS). It was found that the graphite cores are embedded in the SiC matrix as the islands. The apparent porosity increased, density decreased, with graphite particle content increasing, the bending strength decreased, however, fracture toughness increased with the graphite particle content increasing. Increasing hot-pressing sintering temperature imparted Gp/SiC composite characteristic behaviors of better mechanical strength. The apparent porosity, bulk density, bending strength, fracture toughness were 4.0%, 2.58 g•cm-3, 50 MPa, 6.3 MPa•m1/2, respectively, with the size 200 μm graphite core at 2050 °C, while the volume rate of SiC and graphite was 6:4.