Consolidation of Diamond-Based Composite by Rapid Sintering Using CVD-Coated Powder

多晶金刚石（PCDs）由于烧结性低且在高温下向石墨转变，一般采用几GPa左右的超高压烧结制备。本研究旨在利用旋转化学气相沉积（CVD）技术，在中压（低于100 MPa）条件下，采用火花等离子烧结（SPS）技术制备致密金刚石基复合材料。采用旋转CVD法在金刚石粉末表面涂覆SiC纳米层。采用SPS和SiO2粉末对金刚石/碳化硅核壳纳米结构粉末进行固结。合成的SiC和SiO2金刚石基复合材料相对密度高达94%，维氏硬度高达39 GPa。

Polycrystalline Diamonds (PCDs) are generally prepared by sintering at ultra-high pressure about several GPa because of low sinterability and transformation to graphite at high temperatures. This research aimed to prepare dense Diamond-based composites under moderate pressures (below 100 MPa) by Spark Plasma sintering (SPS) using nano-composite powders via a rotary chemical vapor deposition (CVD) technique.SiC nano-layers were coated on Diamond powder by rotary CVD. The Diamond/SiC core/shell nano-structured powder was consolidated by SPS with SiO2 powder. The resultant Diamond-based composite with SiC and SiO2 exhibited the high relative density of 94% and the high Vichers hardness of 39 GPa.