氧化时间对2A12铝合金微弧氧化膜层组织及耐腐蚀性能的影响

Effect of Oxidation Time on Microstructure and Corrosion Resistance of Micro-arc Oxidation Coatings on 2A12 Aluminum Alloy

将2A12铝合金置于硅酸钠电解液中进行微弧氧化处理。用扫描电镜、膜层测厚仪和盐雾腐蚀箱等手段研究了不同的氧化时间对2A12铝合金微弧氧化膜层形貌、厚度和耐蚀性能的影响。结果表明,当氧化时间在20min~50min变化时,随着氧化时间的增加,MAO膜层的厚度呈现出不断增大的趋势。不同的氧化时间下MAO膜层表面均形成了“火山堆”形貌,随着氧化时间的增加,“火山堆”数量越来越多,膜层表面越来越凹凸不平。在不同的氧化时间下,MAO膜层呈现出不同的耐蚀性能,这与其厚度、孔隙率和膜层的组织疏松等有关。综合来看,当氧化时间为30min时,MAO膜层获得了最佳的耐腐蚀性能。

The 2A12 aluminum alloy is treated by micro arc oxidation in sodium silicate electrolyte.The effects of different oxidation time on the morphology,thickness and corrosion resistance of micro arc oxidation coatings on 2A12 aluminum alloy were studied by means of scanning electron microscope,film thickness gauge and salt spray corrosion chamber.The results show that,when the oxidation time varies from 20 min to 50 min,the thickness of MAO coatings increases.With the increase of oxidation time,the number of"craters"increased and the surface of MAO coatings became more and more uneven.The MAO coatings show different corrosion resistance under different oxidation time,which is related to the thickness,porosity and structure of the coating.In conclusion,MAO coatings have the best corrosion resistance when the oxidation time is 30 min.