Fatigue behaviour and mechanical properties of PVD CrSiN coating using cyclic nanoindentation

ABSTRACT In this study, chromium nitride-based CrSiN coatings were deposited by PVD (physical vapour deposition) magnetron sputtering on XC100 steel substrate. Mechanical properties of CrSiN were investigated using monotonic nanoindentation test. It was found that CrSiN coatings had excellent mechanical properties, hardness of 30.52 ± 1.85 GPa and elastic modulus of 338.32 ± 13.5 GPa. Fatigue behaviour of CrSiN thin film was studied using multi-cycles nanoindentation test. Under cyclic nanoindentation, the unloading–reloading paths produced the hysteresis loops which reflect a fatigue effect. In addition, the increase in the number of indentation cycle induced the degradation of the film mechanical proprieties and the evolution of damage mechanism. The similarity between the indentation fatigue depth propagation and the conventional fatigue crack growth was exploited based on Manson–Coffin law to extract the fatigue properties of CrSiN coating. The obtained fatigue ductility coefficient was and the fatigue ductility exponent was c = −0.96.