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

多晶金刚石（PCD）由于烧结性低和高温下转变为石墨，通常通过在约几GPa的超高压下烧结来制备。采用旋转化学气相沉积（CVD）技术，在中等压力（100 MPa以下）下，利用放电等离子烧结（SPS）技术在金刚石粉末表面沉积SiC纳米层，制备致密的金刚石基复合材料。采用SPS烧结技术，以SiO2粉末为原料，制备了金刚石/SiC核壳结构纳米粉体。结果表明，SiC和SiO2复合材料的相对密度高达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.