Study on Tribological Behavior of Microarc Oxidation Ceramic Coating of Aluminum Alloy with Different Thickness

The tribological performance of the microarc coatings with different thickness was evaluated using pin-on-disk tribometer,and surface morphology,cross-section structure and abrasive morphology before and after the test were analyzed by scanning electron microscope(SEM),and phase constituents were studied by X-ray diffraction(XRD).The results show that the thickness on the cross section becomes same and the film/substrate interface even with MAO time.The results of XRD reveal that the content of γ-Al2O3 in the ceramic coatings decreases,while α-Al2O3 increases with oxidation time,and so the average hardness increases with the oxidation time.The abrasive wear mass loss and wear rate increase with the oxidation time for the unpolished MAO films,while that decrease for the polished MAO films.The abrasive trace shows scales,grooves and there are not any cracks observed.