Evaluation of Mechanical and Electrical Properties of Diamond Synthesized from Gas Phase

点击翻译按钮获取中文摘要

YAG laser cutting and planing of diamond films synthesized by arc discharge plasma jet CVD have been described. As a result, by controlling the energy density, cutting of a CVD diamond is possible. As for etching of CVD diamond in oxygen gas, preferentially amorphous carbon, grain boundary and fault in grain are vaporized and then diamond grains are oxidized. In the case of cutting, diamonds are removed by oxidization and Vaporization in the oxygen gas or by graphitization in the argon gas. Therefore by laser irradiation in the oxygen gas, clear cross sections were grained without graphite deposition. Moreover by controlling the incident angle, the surface planing is possible. The roughness of diamonds surface after planing by parallel incident laser beam was about 3um Rmax.Polishing is a essential technique to apply diamond films to industrial uses. It has been cleared that diamond film can be polished by using thermochemical reaction. The optimum condition of diamond film polishing u … More sing hot metallic plates is determined experimentally. Although diamond films deposited by microwave plasma CVD are not firmly connected to the surface of substrates, under low applied pressure and slow spinning speeds, diamond film can be polished smooth without peeling off the substrate by using hot metals. In this study, the effects of polishing conditions on polishing rate are xamined by changing the polishing plate materials, temperatures, atmospheric gases, applied pressures and spinning speeds. As an optimum polishing condition, a 7x7 mm diamond film with a surface of 2.5um Rmax is polished at 950C in vacuum for 15 minutes, using an iron polishing plate under an applied pressure 40kPa and a spinning speed 7mm/s. A smoothly polished surface of 2.5nm Ra is obtained.In order to estimate the toughness of diamond films, diamond coating on a ceramic and a PCD substrate were carried out. And by using these deposits as cutting tools, Al-Si alloys were turned. Though small peeling-off was observed on a ceramic substart diamond films did not wear even if 5452m of the cutting distance. It shows that the diamond films have good wear-resistance. Less