Evaluating and predicting durability of bonded solid lubricant coatings under fretting conditions

Fretting wear is a common failure at contact surfaces of tight assemblies in industries, such as those of transport, power transmission and nuclear power station. Using friction reduction coatings is one of the most effective methods to palliate fretting failure. However, in view of numerous available coatings, it is still a tough task to evaluate them and to select the optimum one for a given application. In this paper, based on the investigation of fretting behaviors of three bonded solid lubricant coatings, an initial maximal dissipated energy density (Ed0 max ini) approach and a local Archard factor (KA0) approach were suggested to evaluate and predict coating durability. The lifetime of each coating under different values of test parameters can be fitted by one master curve. The master curves of a coating may be used to predict the coating lifetime only by running a new test for few cycles under relevant test conditions. For a given test condition, the durability of coatings can be easily evaluated by comparing their KA0 master curves. Ed0 max ini master curves include comprehensive tribological performance, which is helpful for coating selection.

Research Highlights
► Volume–energy wear rate cannot accurately reveal coating durability.
► An initial energy density is suggested to evaluate and predict coating durability.
► A local Archard factor can be easily used to compare the durability of coatings.
► In the approaches, the master curves of coatings are helpful for coating selection.