硬质合金复合涂层的结合强度与失效机理  

Bonding strength and failure mechanism of cemented carbide with multilayer coatings

作　　者：陈响明[1,2] 易丹青[1] 李秀萍 王以任 刘会群[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]株洲钻石切削刀具股份公司,株洲412007

出　　处：《粉末冶金材料科学与工程》2011年第3期464-470,共7页Materials Science and Engineering of Powder Metallurgy

基　　金："高档数控机床与基础制造装备"科技重大专项(2009ZX04012-021)

摘　　要：通过4种硬质合金基体和3种TiN/TiCN/Al2O3/TiN复合涂层的组合,采用化学气相沉积(CVD)法制备12种涂层/硬质合金样品,借助划痕试验机、扫描电镜和能谱仪测定涂层与基体的结合强度,观察划痕的形貌,测定划痕的微区成分。结果表明,基体成分和WC的晶粒度,以及涂层的成分和厚度对涂层与基体的结合强度有明显影响,增大基体中WC的晶粒度和Co含量、或减少基体中立方碳化物的含量均可提高基体与复合涂层的结合强度。随着涂层层数和厚度增加,涂层之间结合强度有所降低,含TiCN涂层样品的结合强度高于含Al2O3涂层样品的结合强度。此外,结合划痕试验和扫描电镜观察结果,讨论了复合涂层逐层破损的失效机理。Multilayer coatings were designed with four kinds of cemented carbides and three TiN/TiCN/Al2O3/TiN coatings,twelve samples of cemented carbide with multilayer coatings were prepared by chemical vapor deposition（CVD） technique.Bonding strength between the coating and substrate,scratch morphology and composition of failure microzone were investigated by scratch testing machine,scanning electron microscope（SEM） and energy dispersion spectrum（EDS）.The results show that the bonding strength between the coating and substrate depends closely on the composition of substrate,grain size of WC,composition and thickness of the coating.The increase of WC grain size and Co content,and the decrease of the content of cubic carbide phase are effective ways to improve the bonding strength between the coating and substrate.With the increase of number of layer and thickness of the coating,the bonding strength between coatings decreases.The bonding strength of TiCN coating is higher than that of Al2O3 coating.The failure mechanism was also discussed based on the scratch and microstructure results.

关 键 词：硬质合金 复合涂层 结合强度 划痕试验 

分 类 号：TF125.4[冶金工程—粉末冶金]