Study on wear behavior of plasma electrolytic oxidation coatings on aluminum alloy

Thick and hard ceramic coatings were fabricated on A356 aluminum alloy by using plasma electrolytic oxidation (PEO) technique. The microstructure and phase composition of the PEO coatings were examined by using SEM and XRD method. It is found that the PEO coatings are mainly composed of crystalline alpha-Al2O3 and mullite. The dry sliding wear test of PEO coatings were carried out on a ring-on-ring wear machine. Results shows that there is hardly no wear loss of polished PEO coatings while the wear rate of uncoated aluminum alloy is 4.3 x 10(-5) mm(3 .) (N (.) m)(-1) at a speed of 0.52 m (.) s(-1) and a load of 40 N.