高性能CVD金刚石薄膜涂层刀具的制备和试验研究

采用电子增强热丝EACVD法,以WC-Co硬质合金刀具为衬底制备金刚石涂层刀具,研究了提高涂层附着力的衬底预处理新方法,探讨了抑制Co催石墨化作用的有效措施,提出了改善金刚石薄膜表面粗糙度CVD后处理新工艺。研究结果表明,采用了Ar-H_2微波等离子体刻蚀脱碳预处理方法对于提高金刚石薄膜涂层的附着力有明显效果,添加适量粘结促进剂,可有效地抑制CVD沉积过程中钴向表层扩散引起的催石墨化作用。采用分步沉积新工艺是减小金刚石薄膜表面粗糙度的有效方法。所制备的高附着力和低粗糙度的金刚石薄膜涂层刀具切削性能明显改善,对实现高效高精度切削加工具有十分重要的意义。

STUDIES ON FABRICATION AND TEST OF HIGH QUALITY CVD DIAMOND-COATED THIN FILM TOOLS

Diamond coated tools are fabricated using WC-Co cemented carbide inserts as substrates by the electronically aided hot filament chemical vapor deposition(EACVD).The new substrate pretreatment methods are investigated to enhance the adhesion of diamond films. An efficient measure is presented to inhabit the catalytic effect of cobalt. The new CVD processes are proposed to improve the surface roughness of diamond thin films. The research results show that the pretreatment using Ar-H2 etching decarburization by microwave plasma is an effective method to enhance adhesive strength. An adequate amount of additive can effectively prevent the overflow of Co from inner to surface of the substrate and avoid the catalytic effect of Co during CVD. The smooth diamond film with low surface roughness can be deposited by increasing the carbon source concentration and reducing the reactive pressure at the later stage of CVD process. Owing to the fabrication and application of diamond thin films with the low surface roughness and high adhesion strength, it is of great significance for improvement of the cutting performance of diamond-coated tools and development of high efficiency and precision cutting technology.