Behaviors of Fretting Wear of Microarc Oxidation Coating

LD11 aluminium alloy surface was treated with microarc oxidation(MAO).Fretting wear tests of the microarc oxidation coating and its substrate were carried out under different displacement amplitudes.Dynamic analyses in combination with microscopic examinations through Laser Confocual Scanning Microscope and Scanning Electric Microscope were performed.Results show that fretting regimes of such MAO coating were changed,i.e.the mixed and slip regime shifted to the smaller displacement.Compared with the substrate material,friction coefficient was higher in initial stage due to its coarse surface,and was lower in steady stage.Wear of material reduced greatly for the MAO coating specimens.In the fretting regime of partial slip,damage was very slight,but the wear increased with the increase of the displacement amplitude.In mixed and slip regime,the damage mechanism of the MAO coating was mainly delamination.