Effect of mullite formation on densification of SiC-coated diamond and SiO2-mullite composites fabricated by SPS

摘要

Diamond has the highest hardness and excellent wear resistance, so it has been widely employed in cutting tool applications. However, diamond possesses the strong covalent bond and it readily transform to graphite which are the main problems to consolidate under atmospheric pressure. The diamond compact and diamond composites are generally prepared at high pressure and high temperature sintering condition but it is expensive then limits the wide use of diamond. Previously, we coated the diamond particles surface with a SiC layer by rotary chemical vapor deposition (RCVD) to improve the wettability of diamond and enable diamond particles to be consolidated with SiO2 at lower pressure. In this study, Al2O3-SiO2 was used as an additive for the SiC-coated diamond particle to promote the viscos sintering by spark plasma sintering (SPS). The effect of Al2O3 content on the formation of mullite and densification behavior of SiC-coated diamond and SiO -mullite composite were investigated.