Ti(CN)/TiC/Al_2O_3/TiN多层涂层的结构和界面结合力研究

Microstructure and interfacial adhesion of Ti(CN)/TiC/Al_2O_3/TiNmultilayer ceramic coatings

采用中温、高温复合化学气相沉积技术(MHCVD)在WC-(6%wt)Co硬质合金基体表面制备了Ti(CN)/TiC/Al2O3/TiN多层陶瓷涂层。通过光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)和数显显微硬度计等手段分析多层陶瓷涂层的表面及断面形貌、物相组成、显微硬度;采用表面划痕实验,结合形貌观察及X射线能谱分析(EDS)研究多层陶瓷涂层/硬质合金基体的界面结合力及其影响因素。结果表明:Ti(CN)/TiC/Al2O3/TiN多层陶瓷涂层结构均匀致密,涂层后硬质合金的显微硬度明显提高,约2600 HV,多层陶瓷涂层与基体界面结合良好,划痕实验显示临界载荷高达105 N,多层陶瓷涂层界面间的原子扩散作用对涂层/基体界面附着力有较大贡献,而涂层内部少量Ti2O3、W6Co6C等物相的存在对提高界面结合力也有帮助。

Ti （CN）/TiC/Al2O3/TiN muhilayer ceramic coatings were deposited on the WC-（6%wt）Co cemented carbide substrates by a composite of medium and high temperature chemical vapor deposition （MHT-CVD）. Optical microscope （OM）, SEM, XRD and microhardness tester were used to analyze the surface and cross-section morphology, phase composition and mierohardness. Scratch test and energy dispersive spectrometer （EDS） were applied to investigate the interracial adhesion and its influencing factors. The results show that the Ti（CN）/TiC/Al2O3/TiN coating is Compact and uniform with obviously enhanced hardness which is about 2600HV. The adhesion of multilayer ceramic coating to the substrate is good under the critical load up to 105N. The adhesion mechanisms are understood as follows： the atom diffusion has important contribution to the adhesion. A small amount of Ti2O3, W6Co6C in the coatings is the miner factors resulting in high binding states of the coatings simultaneously.