镁合金微弧氧化及涂装耐电偶腐蚀的研究

Galvanic Corrosion Resistance of Magnesium Alloy with Microarc Oxidation Film and Coating

在大气环境中,镁合金与碳钢偶接后腐蚀状况严重,将微弧氧化及涂装技术组合进行防腐蚀简易有效。通过中性盐雾试验、湿热试验和模拟潮工业大气试验,研究了镁合金微弧氧化和涂装组合对镁合金电偶腐蚀的抑制作用,分析了不同涂装体系耐蚀性的差异。结果表明:微弧氧化膜/有机涂层的防护体系对镁合金的电偶腐蚀有良好的抑制作用,可使耐蚀性有进一步的提高,其原因是微弧氧化膜与有机涂层具有良好的吸附和嵌合作用;在比较苛刻的腐蚀环境中,微弧氧化与涂装的组合对腐蚀的抑制作用有限。

The magnesium alloy coupled with carbon steel experiences serious corrosion in atmosphere environment. Fortunately, it is simple and effective to increase the corrosion resistance of the Mg alloy by combining microarc oxidation (MAO) with coating. Thus the galvanic corrosion resistance of the Mg alloy treated by MAO and organic coating was studied making use of neutral salt spray test, humidity cabinet test, and simulated wet industrial atmosphere test. The corrosion resistance of various organic coating systems was compared as well. It was found that the combined system of MAO film/organic coating had good galvanic corrosion resistance for the Mg alloy. The increase in the corrosion resistance of the Mg alloy was closely related to the characteristics of the MAO film having good adsorption and interlocking effect with the organic coating. However, further work is needed to realize the satisfactory protection of the Mg alloy in severe corrosive environment by combining the MAO film and organic coating.