Effect of interlayer on maximum contact stresses of hard coating under sliding contact

Abstract

In order to prevent surface damage or spalling of a coating with an interlayer under sliding contact, the understanding of the effect of the interlayer on the maximum contact stresses (maximum tensile stress, maximum shearing stress, maximum von Mises stress) is necessary, Because the damage or the spalling of coating initiates usually from the positions of these maximum stresses. Therefore, in this paper, the sliding contact problem of a hard coating with an interlayer was analyzed using the finite element method. The results show the effect of four typical elastic moduli of the interlayer, i.e., E inter = 2 E topp, ( E top + E base)/2, E base and E inter = E base/2 (here E inter is the elastic modulus of interlayer, E top is the elastic modulus of the hard coating and E base is the elastic modulus of the base) on these maximum stresses. In the case of maximum tensile stress on the surface, E inter = 2E top is most useful for decreasing the stress as compared to other interlayers, while in the case of maximum shearing stress on the interface between the coating and the substrate, E inter = E base/2 is most useful for decreasing the stress. In the case of maximum von Mises stress, E inter = 2 E top shows the largest effect of interlayer on the stress. In addition, the effect of the coating thickness and the friction coefficient on these maximum stresses are also presented in the paper.