Effects of current density on microstructure and properties ofplasma electrolytic oxidation ceramic coatings formed on 6063 aluminum alloy
(1. School of Materials Science and Engineering, Changzhou University, Changzhou 213164, China;
2. Jiangsu Key Laboratory of Materials Surface Science and Technology,Changzhou University, Changzhou 213164, China;
3. Ningbo Ruilong Surface Technology Co., Ltd., Ningbo 315177, China)
2. Jiangsu Key Laboratory of Materials Surface Science and Technology,Changzhou University, Changzhou 213164, China;
3. Ningbo Ruilong Surface Technology Co., Ltd., Ningbo 315177, China)
Abstract: Plasma electrolytic oxidation (PEO) ceramic coatings were fabricated in a silicate-based electrolyte with the addition of potassiumfluorozirconate (K2ZrF6) on 6063 aluminum alloy, and the effects of current density on microstructure and properties of the PEO coatings were studied. It was found that pore density of the coatings decreased with increasing the current density. The tribological and hardness tests suggested that the ceramic coating produced under the current density of 15 A/dm2 showed the best mechanical property, which matched well with the phase analysis. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves proved that the coating obtained under 15 A/dm2 displayed the best anti-corrosion property, which was directly connected with morphologies of coatings.
Key words: 6063 aluminum alloy; ceramic coating; plasma electrolytic oxidation (PEO); current density; microstructure; mechanical property