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

多晶金刚石(PCD)的烧结性较低，在高温下易转变为石墨，一般在几Gpa左右的超高压下烧结。本研究旨在利用旋转化学气相沉积(CVD)技术，以纳米复合粉末为原料，采用放电等离子烧结(SPS)技术，在中等压力(100 Mpa)条件下制备致密的金刚石基复合材料。用SiO_2粉末与SPS复合制备了金刚石/碳化硅核/壳纳米结构粉末。添加SiC和SiO_2的金刚石基复合材料具有高的相对密度(94%)和高的维氏硬度(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.