脉冲频率对A7N01P-T4铝合金微弧氧化膜微观结构和耐蚀性的影响

Effects of Pulse Frequency on Microstructure and Corrosion Resistance of Micro-arc Oxidation Coating on A7N01P-T4 Aluminum Alloy

在硅酸盐和磷酸盐复合体系下,利用微弧氧化技术对A7N01P-T4铝合金进行微弧氧化处理。利用扫描电镜、EC-770涡流涂层测厚仪、sj-210便携式粗糙度仪和CS310电化学工作站等仪器研究了脉冲频率对A7N01P-T4铝合金微弧氧化膜微观结构和耐蚀性的影响。结果表明,随频率的增加,微弧氧化膜层表面孔径减小,熔融凝固物更加细小均匀,相应膜层表面粗糙度降低。厚度随脉冲频率的增加先增加后减少,500 Hz频率对应44μm最厚膜层。微弧氧化膜层能明显提高试样的耐腐蚀性,500Hz频率制备的膜层试样耐腐蚀性能最好。

In the composite system of silicate and phosphate, A7N01P-T4 aluminum alloy was treated by micro-arc oxidation(MAO). The effects of pulse frequency on the microstructure and corrosion resistance of A7N01P-T4 aluminum alloy micro-arc oxidation coating were studied by scanning electron microscopy, EC-770 eddy current coating thickness meter, sj-210 portable roughness meter and CS310 electrochemical workstation. The results show that the surface pore size of the MAO coating decreases with the increase of frequency, the melt solidification becomes smaller and more uniform, and the surface roughness of the film decreases accordingly. The coating thickness first increases and then decreases with the increase of pulse frequency. The frequency of 500 Hz corresponds to the thickest coating, which is 44 μm. The MAO coating can significantly improve the corrosion resistance of the sample, and the coating sample prepared at the frequency of 500 Hz has the best corrosion resistance.