掺B金刚石膜的电火花抛光实验研究

Polishing of B-Doped Diamond Films by Electrical Discharge Machining

通过化学气沉积过程中掺B,制备的金刚石膜电阻率下降10-19,导致金刚石膜整体导电,可采用电火花抛光。用扫描电镜和Raman分析了金刚石膜电加工表面的形貌和成分。金刚石膜的电火花抛光是多种效应综合作用的结果,即金刚石膜熔化、汽化、碳的氧化和蒸发、爆炸抛出、界面的化学反应以及金刚石的石墨化。通过实验研究了电加工参数对表面粗糙度和加工速度的影响,通过回归分析得到电火花抛光表面粗糙度和加工速度的经验公式,其相关系数的平方分别为0.91和0.99,表明拟合精度高。试验结果表明,放电电流和脉冲宽度对加工面的表面粗糙度和加工速度影响很大。放电电流为5 A、脉冲宽度为380μs时,抛光后表面粗糙度Ra<1μm。

A novel technique was developed to polish the boron-doped diamond films,grown by chemical vapor deposition.The newly-developed,electrical discharge machining polishing technique involves various processes,such as the melting,vaporization,oxidation,and graphitization of diamond grains,chemical reaction at the interface.The impacts of the polishing conditions on the surface microstructures and contents were studied.The results show that the discharge current and the pulse width significantly affect the polishing.For instance,under optimized polishing conditions：at a discharge current of 5 A,a pulse width of 380 μs,the electrical discharge machining polishing is capable of reducing the surface roughness of the diamond films to less than 1 μm