Tribological Properties of Duplex MAO/Bonded PTFE Coating on Top of Ti Alloy in Vacuμm

Tribological properties of duplex MAO (micro arc oxidation)/bonded PTFE coating were evaluated by ball on disk tribometer in vacuum at different load. The results show that the MAO/bonded PTFE coating had much longer tribological lifetime than that of the sand blasting/PTFE traditional coating. This can be explained by the enhanced deformation resistance by the hard MAO porous and wavy topography. It is found that some " grooves” and " ridges” on surface were produced by machining trace of Ti substrate and in-situ growing mechanism of MAO. During the process of dry sliding on duplex coatings, the soft PTFE located into the grooves as lubricants reduced the friction coefficient, and the hard ridges of MAO coating increased the anti-wear ability of the whole coating.