Structure and electrochemistry corrosion behaviors of microarc oxidation on aluminum

The thick, dense and ultra-hard ceramic coating was obtained on the aluminum surface in a silicate electrolyte by microarc oxidation.The surface morphology and cross section of ceramic coating were observed by SEM, the hardness and Young's modulus of ceramic coating were estimated by nano-hardness tester, and the electrochemistry corrosion behaviors of ceramic coating were evaluated using polarization curves.The results show that the highest surface hardness of ceramic surface coating is 25.3 GPa;the hardness and Young's modulus of cross section of coating distribute similarly, both of them decrease from interface to surface of the coating; from the results of electrochemistry, microarc oxidation is effective method to form an anti-corrosion protective film on aluminum.