Experimental Investigation of Influence of Thickness on Contact Fatigue Lifetime of Sprayed Coatings

The aim of this paper was to address the influence of thickness on contact fatigue lifetime of sprayed coatings. Two Fe-based coatings with different thickness were deposited by plasma spraying. The microstructures of coating and interface between coating and substrate were characterized by scanning electron microscopy (SEM). The contact fatigue behaviors of the two kinds of coating were investigated by a ball on disk tester. The comparison of the RCF lifetime of the coatings was conducted by using a Weibull distribution. The results showed that the thick coating prevented the occurrence of catastrophic delamination, and prolonged the contact fatigue lifetime. Finite element method (FEM) was employed to analysis stress distribution within the coating. It is revealed that the magnitude of shear stress on the thicker coating interface was less than the half on thinner coating interface. Therefore the contact fatigue performance of thick coating was excellent owing to remarkable reduction of shear stress on the interface.