Fretting behaviour of low‐friction coatings

The choice of an appropriate low-friction coating for an industrial application is generally a difficult task. As many parameters are involved and are often unknown, selection criteria are hard to define. In order to elucidate the case of fretting conditions, a simulator has been used to reproduce the degradation mechanisms observed for real situations. Numerous experiments performed with this machine permit one to define endurance life criteria. The evolution of the life observed has been analysed as a function of the contact pressure and the film thickness. Using a Wohler approach, endurance curves have been plotted that give useful information for selecting appropriate coatings. As other parameters may be of some interest, performance indices have been associated with them, and the results can be presented on a multi-axis (polar) diagram.