化学气相沉积MT-TiCN和HT-TiCN涂层的摩擦磨损性能

Friction and wear properties of MT-TiCN and HT-TiCN coatings deposited by chemical vapor deposition

采用中温化学气相沉积（Medium Temperature Chemical Vapor Deposition MT-CVD）和高温化学气相沉积（High Temperature Chemical Vapor Deposition HT-CVD）在WC-Co硬质合金基体上沉积TiCN涂层。利用X射线衍射仪、扫描电镜表征涂层的显微组织结构,采用纳米压痕仪测试涂层的硬度,采用往复式多功能摩擦磨损试验机（UMT-3T）和表面轮廓仪研究MT-TiCN和HT-TiCN涂层的摩擦磨损性能。结果表明：HT-TiCN涂层比MT-TiCN涂层C/N比大,晶粒尺寸较小,硬度较高。MT-TiCN涂层表面晶粒呈透镜状,表面较为粗糙,摩擦系数较大。HT-TiCN涂层由透镜状晶粒和细小的等轴晶组成,表面较为光滑,摩擦系数较小。MTTiCN涂层磨损机制除磨粒磨损外,还包括粘着磨损和氧化磨损;HT-TiCN涂层磨损机制主要是磨粒磨损。HT-TiCN涂层晶粒形貌特殊、硬度较高、摩擦系数较小,因此,耐磨性比MT-TiCN涂层更好。

TiCN coatings were deposited on WC-Co cemented carbides surface by medium temperature chemical vapor deposition （MT- CVD） and high temperature chemical vapor deposition （HT-CVD）. Microstructure of the coatings was studied by means of scanning electron microscopy （SEM） and X-ray diffraction （XRD）, the hardness and friction and wear properties of the coatings were analyzed by means of nanoindetation test, reciprocating muhi-function friction and wear tester （UMT-3T） and surface profilometer. The results show that compared with MT-TiCN coating（prepared by MT-CVD） , HT-TiCN coating （prepared by HT-CVD） has a larger C/N ratio, smaller grain size and higher hardness. The friction coefficient of the MT-TiCN coating is high because of lenticular-like grains and rough surface, while the friction coefficient of the HT-TiCN coating is low due to the lenticular-like grains and fine equiaxed grains and smooth surface. In addition to abrasive wear, the wear mechanism of the MT-TiCN coating includes adhesive wear and oxidation wear. By contrast, the wear mechanism of the HT-TiCN coating is mainly abrasive wear. Compared with the MT-TiCN coating, the HT-TiCN coating possesses better wear resistance because of special grain morphology, higher hardness and smaller friction coefficient.