The evolution of fretting wear in a micro-spherical contact

The effect of surface roughness and materials combination on the evolution of fretting wear in a micro-spherical contact is investigated. The shape of the friction loop, the relative displacement amplitude, the maximum friction coefficient and the dissipated energy were determined as a function of the number of fretting cycles. Wear scars of the interface were analyzed at the completion of each test. It was found that the type of materials combination has a substantial effect on the results while surface roughness effects are small. One of the mating surfaces with a soft coating can provide high wear resistance.

Research highlights
► The evolution of fretting wear in a micro-spherical contact was studied over 10,000 fretting cycles.
► The change in surface roughness of the sphere had little effect on the wear characteristics.
► Substantial differences were observed between a hard flat and a gold coated flat.
► With the soft gold coating the accumulated dissipated energy dropped by about 50% compared to its value without the coating.