金刚石表面的膜层沉积处理及其感应钎焊的研究

将热丝化学气相沉积(HFCVD)处理的金刚石作为磨料感应钎焊制作金刚石工具。HFCVD处理试验中,混合气为H2和CH4(体积流量比为100∶1.5),炉内压力为2.0kPa,700℃下处理45min后,在金刚石表面沉积了一层非晶碳膜。感应钎焊HFCVD处理的金刚石显示,出露部分的金刚石棱边能保持良好的锋利性;浸没在钎料层下面的金刚石表面形成了有均匀孔隙且形状不规则的铬碳化合物,液态钎料充填这些化合物孔隙之间,能够增强钎料对金刚石的把持强度。3种金刚石磨料感应钎焊制作的金刚石磨盘的高效重负荷石材磨削试验显示,HFCVD处理的金刚石的整体破碎率和脱落率最低。

Research on Treatment of Diamond Surface by Film Deposition and Induction Brazing

Diamond grits were deposited by hot filament chemical vapor deposition(HFCVD) and they were used to fabricate the brazed diamond tools by induction brazing.The gas ratio(H2/CH4) used was 100∶1.5(standard cubic-centimetres per minute),the total gas pressure was maintained at about 2.0 kPa,and the substrate temperature was heated to 700℃ for 45 minutes during HFCVD.As a result,amorphous carbon film is deposited on the diamond surface.The diamond edges exposed out of the filler alloy keeps good sharpness after induction brazing of HFCVD deposited diamond.Chromium-carbides with uniform porosity and irregular shapes were formed on the diamond grits immersed into the brazing filler alloy.The liquid brazing filler metal filled in porosity can enhance the bonding strength between the brazing filler metal and the diamond grits.The heavy-load grinding tests of the brazed diamond wheels fabricated by three kinds of diamond grits show that there is a low percentage of pullout from matrix and whole grain fracture for the deposited diamond grits brazed by induction heating.