负脉冲电压对A356铝合金双脉冲微弧氧化膜组织与耐蚀性的影响

Effect of Negative Pulse Voltage on the Microstructure and Corrosion Resistance of Microarc Oxidation Film on A356 Aluminum Alloy

采用SEM、覆层测厚仪等研究了负脉冲电压对A356铝合金双脉冲微弧氧化处理膜的组织微观结构及耐腐蚀性能的影响。结果表明,负脉冲电压通过其电极反应对膜层的组织与耐蚀性有重要影响,随负脉冲电压由0增加到160 V,膜层厚度随负脉冲电压的升高而增加;膜层表面粗糙度先减小后增加,表面微孔孔径与数量先减小后增加,在负脉冲电压为40 V时膜层表观上最致密;微弧氧化处理明显提高了合金的耐蚀性能,负脉冲电压为0 V时最佳。

The effect of negative pulse voltage on the microstructure and corrosion resistance of microarc oxidation film on A356 aluminum alloy treated by double pulse microarc technique was investigated by SEM, coating thickness gauge etc. The results show that the negative pulse voltage by its electrode reaction greatly influences the microstructure and corrosion resistance of microarc oxidation film： the film thickness increases obviously when the negative pulse voltage varies from zero to 160 V; Size of pore and roughness of film surface firstly decreases then follows by a vital in creasing, coating has the optimal compactness when negative pulse voltage is 40 V; The microarc oxidation treatment obviously improves the corrosive resistance of alloy, the best corrosion resistance of the film is achieved when negative pulse voltage is 0V.