氧等离子体对以石墨为碳源合成的CVD金刚石颗粒的影响

In this paper, a new method for preparing diamond particles was introduced. Microwave plasma chemical vapor deposition (MPCVD) technology was used to deposit diamond particles in the reaction chamber. Solid graphite sheets are used as carbon source and substrate simultaneously. The synthesized micro-crystalline diamond particles can be employed as abrasive, polishing agent and nucleating agent. However, the synthesized diamond particles still contain a small amount of amorphous carbon, and the particle size uniformity needs to be improved. In order to solve the above problems, oxygen plasma was introduced in different stages of the reaction (initial, intermediate and final stages), and the effects of oxygen plasma on the morphology, size, quality and purity of diamond particles were studied. The results show that oxygen plasma treatment makes diamond particle surface smoother compared to the untreated that, and it can improve the consistency of diamond particle size. Laser particle size measurement demonstrates that the size of diamond particles is mainly 25-29 μm. The addition of oxygen plasma is conductive to eliminate amorphous carbon in diamond and improve the purity of diamond. Additionally, the diamond particles with the best quality can be obtained by adding oxygen plasma at the initial stage of the reaction.