Anticorrosion Property of Black Chemical Oxidation Film on Aluminium Alloy

The anticorrosion properties of the black oxidation film on aluminium alloy were evaluated by means of dropping testing and electrochemical polarization curves.Scanning electron microscopy(SEM) and energy dispersive X-ray detector(EDX) were used to analyze the surface morphology and composition.The results showed that the micro-structure of the oxidation film was network of cracks,and the main composition of the oxidation film were O,Al,Mn,Co and Cr.The potentialdynamic polarization curve results indicated that the corrosion resistance of unsealed alloy in 3.5% NaCl solution was similar to that of the blank sample,and the sample sealed by K2Cr2O7 had a good corrosion resistance.