涂层与基体界面结合强度是硬质涂层材料一个关键的性能指标。应用压痕法和十字交叉法测试了硅基/类金刚石(diamond-like carbon,DLC)涂层的界面结合强度。结果表明:利用Vickers压痕法和Hertz压痕法测量所得硅基/DLC涂层的临界载荷分别为0.981N和300N。用Vickers压痕法测量时,载荷达到临界载荷后涂层将产生环状开裂,当载荷进一步增大时,还会产生径向裂纹;对于Hertz压痕法,载荷从300N增加到800N时,涂层环状裂纹从1个增加到4个。通过采用十字交叉法测量得到硅基/DLC涂层界面拉伸强度和剪切强度分别为(8.9±2.7)MPa和(20.1±2.6)MPa,表明该涂层抗剪切性能良好,拉伸分离后界面比剪切分离后界面的均匀性更好。压痕法和十字交叉法评价硬质涂层的界面强度简单易行,结果准确,具有广泛的应用前景。
Interfacial bonding strength is one of mechanical properties for hard coating applications.Indentation and cross-bonded methods were proposed to evaluate the interfacial bonding strength of diamond-like carbon (DLC) coating on a silicon substrate.The critical loads of Vickers and Hertz indentation for the samples were 0.981 N and 300 N,respectively.For Vickers indentation,a circular damage was initiated on the surface of the coatings when the applied load was higher than the critical load.When the applied load was further increased,radial cracks would appear in the coating.For Hertz indentation,the number of the ring cracks increased from 1 to 4 with increasing the load from 300 N to 800 N.The interfacial tensile and the shear bonding strengths of the DLC coatings were (8.9±2.7) MPa and (20.1±2.6) MPa respectively,by the cross-bonded method,indicating that the coatings has a salient shear resistance.Moreover,the uniformity of interface after debonding in tensile test was better than that in shear test.The results show that the indentation and cross-bonded methods are simple and reliable methods to evaluate the interfacial bonding strength of the hard coatings.