【摘要】 微观结构对金刚石涂层硬质合金的结合性能具有重要影响。本文采用酸碱二步腐蚀法预处理WC-Co基体,使用热丝化学气相沉积（HFCVD）设备,分别在CH₄浓度为2%,3%,4%的CH₄/H₂/Ar气氛体系中,沉积得到不同微观结构的金刚石薄膜。采用SEM和Raman分别对薄膜的表面形貌、截面形貌及sp³/sp²相成分进行表征,采用划痕法评估薄膜的膜基结合性能。结果表明:提高甲烷浓度可有效细化金刚石晶粒,有利于纳米晶金刚石的生长;当金刚石薄膜的晶粒尺寸从几百纳米降低至几十纳米时,薄膜的sp²相增多,晶粒的形核密度随之提高;各样品所沉积的金刚石薄膜在剥落时所受的临界载荷分别为15.2,6.9和9.1 N,结合薄膜的微观结构,可得出结论:高纯度、高形核密度的金刚石有利于提高纳米尺寸薄膜与WC-Co基体的结合性能。更多还原

【Abstract】 Diamond structure has an important effect on the adhesion of diamond film coated cemented carbides. In this paper, the WC-Co substrate was pretreated by two-step method, and the hot-filament chemical vapor deposition（HFCVD） actor was used to fabricate nano-scale diamond films under the condition of 2%, 3% and 4%CH₄ concentration in CH₄/H₂/Ar atmosphere, respectively. The surface morphology, section morphology and the sp³/sp² phase of the films were analyzed by SEM and Raman, respectively. The adhesion properties of the films were evaluated by scratch test. The results show that increasing the concentration of methane can effectively refine the grain of the diamond, which is beneficial to obtain nanocrystalline diamond. As the the grain size of diamond decreases from hundreds of nanometers to tens of nanometers, the sp² phase in the film and the nucleation density increases. The critical loads of diamond films deposited on each sample are 15.2, 6.9 and 9.1 N, respectively. Combined with the microstructure of the films, it can be concluded that the diamond film with high purity and high nucleation density contributes to the improvement of the adhesion of the nano-scale diamond film.更多还原