Interfacial fracture induced by cross-sectional nanoindentation in metal–ceramic thin film structures Original Research Article

The cross-sectional nanoindentation (CSN) technique is extended to examine the fracture properties of thin film metal–ceramic interfaces. The methodology includes the selection of appropriate indentation parameters to achieve controlled interfacial delamination together with finite element modelling to estimate the contribution of plasticity of the metallic film to the overall interfacial fracture process. The results show good agreement with four-point bending, a method commonly used to measure thin film interfacial toughness, provided that mode mixities are similar. In addition, CSN allows observation of the interfacial crack by scanning electron microscopy and a local measurement of adhesion, with debonded areas in the range of 100–1000 μm2. The numerical modelling of the test provides an estimate of the intrinsic interfacial adhesion energy, separating the effects of metal plasticity.