(武汉工业大学 材料复合新技术国家重点实验室, 武汉 430070)
摘 要: 采用自制2 450 MHz, 5 kW不锈钢谐振腔型微波等离子体设备, 研究了超声处理、 细砂纸研磨、 1 μm和0.5 μm金刚石粉研磨等Si3N4 基底预处理方法对MPCVD金刚石涂层质量的影响, 用SEM和Raman光谱仪检测和分析了金刚石成核和生长质量, 分析了金刚石的应力情况, 用对比切削实验检测了金刚石涂层的附着情况。 结果表明,经0.5μm金刚石粉研磨后, 在7.0kPa压力、 1.5%的CH4/H2气体流量比、1.5 kW微波功率下, 沉积4 h可得到高质量的金刚石涂层, 在切削18.0%SiAl合金时, 金刚石涂层Si3N4刀具比未涂层Si3N4刀具的加工光洁度提高一级, 使用寿命提高10倍以上。
关键字: 金刚石涂层; 微波等离子CVD; Si3N4基底;干切削
(State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, P.R.China)
Abstract:The effects were studied of Si3N4 tool substrate pretreatment in ultrasonic, polishing of fine gained SiC emery paper, 1.0 μm and 0.5 μm diamond powder on the quality of MPCVD diamond coating in a domestic 2 450 MHz, 5kW stainless steel resonant cavity microwave plasma CVD (MPCVD) equipment. The qualityof diamond nucleation and growth was measured, then the stress condition was analysed, at last the adhesion of diamond coating in contrast cutting test was determined. The results show that high quality diamond coating can be obtained under 4 h MPCVD with 7.0 kPa pressure, 1.5%CH4/H2 gas volume rate, 1.5 kW microwave power after pretreatment of 0.5 μm diamond power polishing, diamondcoated Si3N4 tool can increase its precision about one order compared with uncoated Si3N4 tool when it cut the 18.0%SiAl alloy, moreover, the service life of diamondcoated tool increases by 10 times.
Key words: diamond coating; microwave plasma CVD; Si3N4 substrate; dry cutting