Influence of Voltage on the Corrosion and Wear Resistance of MicroArc Oxidation Coating on Mg-8Li-2Ca Alloy

Bing-Yu Qian¹，Wei Miao²，Min Qiu³，Fan Gao³，Dong-Hui Hu³，Jian-Feng Sun¹，Rui-Zhi Wu^2,3，Boris Krit⁴，Sergey Betsofen⁴

1. College of Material Science and Engineering, Heilongjiang University of Science and Technology2. Key Laboratory of Superlight Materials and Surface Technology, Ministry of Education, Harbin Engineering University3. College of Science, Heihe University4. Moscow Aviation Institute, National Research University

摘 要：Calcium phosphate（CaP） coatings were prepared on Mg–8Li–2Ca magnesium alloy by micro-arc oxidation（MAO） in an alkaline Na₃PO₄–Ca[C₃H₇O₆P] base solution at the different applied voltages. Scanning electron microscope and X-ray diffraction were employed to characterize the microstructure and phase composition of the coatings, respectively. The corrosion resistance of the coatings was assessed by potential dynamic polarization curves, electrochemical impedance spectroscopy and hydrogen evolution experiment in simulated body fluids solution. The friction and wear properties were evaluated by friction and wear testing machine. The results demonstrate that the coating surface is porous and mainly composed of MgO, Ca₅（PO₄）₃（OH） and CaH₂P₂O₅. With the increase in voltage, the corrosion resistance and wear resistance of the MAO coating are both enhanced. The corrosion current density of the MAO coating decreases about two orders of the magnitude compared to the substrate. Additionally, wear and corrosion mechanisms are discussed.

关键词：