Degradation of mechanical proprieties of TiN coatings under cyclic nanoindentation

Abstract

TiN thin film was deposited on 100C6 steel (AISI 52100) substrate with the PVD technique using magnetron sputtering. Morphological examination showed the presence of domes and craters which are uniformly distributed over the entire surface. Mechanical properties, plastic and elastic deformation resistance of TiN coating were studied using conventional indentation method. Cyclic nanoindentation technique, with variation of loading rate, was used to analyze the failure modes and depth profile of mechanical proprieties of TiN thin film. Cyclic nanoindentation technique was performed with a Berkovich indenter at maximum loads of 100 mN, then unloaded to 100% of the maximum load and repeatedly reloaded. The indentation cycles were 200 cycles. When the loading rate was increased from 200mN/mn to 400mN/mn, the mechanical proprieties were decreased. For the highest loading rate (400 mN/mn), hardness and Young’s modulus falling have reached to 50, 50% and 71, 28% respectively.