Mechanical characterization of a CVD diamond coating by nanoindentation test

A FEM analysis was carried out to study the mechanical behavior of a hard coating subjected to a nanoindentation test performed with a Berkovich indenter. The nanoindentation test was simulated by, FEM code MSC Marc. The case study is a coating of CVD (Chemical Vapor Deposition) diamond. By the simulation it is possible to obtain the load-displacement curve by which Young modulus and hardness may be evaluated. The paper also analyzes the residual stresses developed at the end of the unloading phase and the influence of the strengthening law to determine the hardness and the elastic modulus of the CVD diamond. The analysis has demonstrated, by the comparison with the experimental results, that the numerical model well describes the behavior of the coating of CVD diamond in the nanoindentation test; in addition it was pointed out that the choice of the hardening law is a crucial aspect in the simulation.