Effect of the Coating Type on Retaining SiC Particles in the Composite During Grinding

The problem of retaining coarse (150 μm) SiC particles in the composite during grinding with a cup diamond wheel with fine grains (20/14 μm) is considered. SiC particles are coated with Co, Ni, Cu, and WC and are referred to as SiC(Co), SiC(Ni), SiC(Cu), and SiC(WC), respectively. The prepared powders are pressed in a steel die with a diameter of 8.15 mm. The compacts are 5–8.5 mm in height. The compacts are sintered in hydrogen at 980–1470°C with holding for 1–2 h. In addition, the samples containing SiC(WC) particles are impregnated with WC + Ni eutectic melt (VN65). Metallographic analysis shows that in the samples containing SiC(Co), SiC(Ni), and SiC(Cu), SiC particles cannot be retained during grinding because of the formation of brittle silicides, when sintering. In case of WC-coated SiC particles, most of the SiC particles do not leave the composite during grinding. When SiC(WC) samples are impregnated with TN65 eutectic mixture, most of the SiC particles do not leave during grinding.