Application of a novel lateral force-sensing microindentation method for evaluation of the bond strength of thermal sprayed coatings

A novel lateral force-sensing microindentation method was applied to evaluate the interfacial bond strengths of regularly grained and nanograined Al2O3/TiO2 composite coatings. The interfacial bond strength, i.e., the bond between a coating and its substrate (steel), was determined by performing microindentation tests, on a cross section near the interface. By monitoring changes in lateral force during indentation, the critical indentation force at interfacial debonding was determined. The interfacial bond strength was then determined based on this critical indentation force and interfacial stress analysis using the finite element method. The results were compared to those obtained from a pull-off test and showed consistency with them.