ABSTRACT
Plasma electrolytic oxidation (PEO) coatings were produced on AZ31 magnesium alloy in a phosphate-based electrolyte with current density varying from 5 to 20 A dm−2. The influences of the current density on the PEO process and resulting coating characteristics were discussed. The coating morphology and phase composition were studied by scanning electron microscopy and X-ray diffraction technique, respectively. The corrosion performance of the coatings was evaluated in 3.5 wt-% NaCl solution using potentiodynamic polarisation scans. The electrochemical corrosion results proved that the coating produced at current density of 10 A dm−2 shows the best corrosion resistance. The tribological test suggested that the ceramic coating produced at 10 A dm−2 exhibited the most superior wear resistance.
Acknowledgements
The financial aids of the National Natural Science Foundation of China under grant No. 51371039, the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) and the Opening Project of Jiangsu Key Laboratory of Materials Surface Science and Technology, Changzhou University are gratefully acknowledged.