The effect of porous substrate on the tribological performance of a MoS2 based coating in fretting by statistical analysis

Coatings are used to protect surfaces subject to fretting wear in many contacts under oscillating motions. In all these contacts, the failure of the coating is a concern. Accordingly, the durability and wear properties of coatings are widely investigated for various coatings sliding against different metal counterfaces. Most studies focus only on the coating properties. In contrast, this study is devoted to the research of substrate effect (including porous substrate, materials and shape) on the tribological performance of a given coating by various statistical analyses. In this study, six factors (including the porous substrate, contact configuration, coating position, coating thickness, contact force and displacement amplitude) are selected. The factorial analysis is used to give a quantitative description for the contribution of each factor on the tribological performance of the coating. The porous substrate can effectively improve the coating lifetime under cylinder-on-flat configuration, while it has no significant effect on the friction coefficient Friction coefficient is always dependent on the contact pressure. With the increase of contact pressure, the friction coefficient is decreased. When the coating is only 10 mu m, coating on spherical surface can effectively improve the coating lifetime for non-porous surface. Besides, it proves that the Weibull distribution can be used as an effective way to distinguish the different wear mode. (C) 2015 Elsevier B.V. All rights reserved.