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采用铝酸盐为主的碱性电解液,在2024铝合金表面制备微弧氧化涂层。通过表面形貌、涂层厚度与生长速率,研究了氧化时间对涂层结构的影响;通过动电位极化曲线及电化学阻抗谱研究了微弧氧化涂层在NaCl溶液中的腐蚀行为。结果表明:微弧氧化涂层表面形成了许多大小不一的微孔,表面的陶瓷颗粒以搭桥的方式在表面不同部位堆积。随着氧化时间的延长,该微弧氧化涂层的厚度逐渐增大,生长速率减慢;经过不同氧化时间的处理,与铝合金基体相比,涂层的腐蚀电压升高,腐蚀电流密度有不同程度的减小;氧化时间20 min的微弧氧化涂层的腐蚀电流密度低、腐蚀电压高,膜层的耐蚀性能较好。
Using aluminate-based alkaline electrolyte, micro-arc oxidation coating was prepared on the surface of 2024 aluminum alloy. The influence of oxidation time on the structure of the coatings was investigated by surface morphology, coating thickness and growth rate. The corrosion behavior of the coatings on NaCl solution was investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy. The results show that many micro-pores are formed on the surface of MAO coating, and the ceramic particles on the surface are piled up in different parts of the surface. With the extension of the oxidation time, the thickness of the MAO coating gradually increases and the growth rate slows down. After different oxidation time, the corrosion voltage of the coating increases compared with the aluminum alloy substrate, and the corrosion current density has The corrosion current density of micro-arc oxidation coating with oxidation time 20 min is low, the corrosion voltage is high, and the corrosion resistance of the coating is better.