9S75铝合金的电化学腐蚀行为及阳极氧化工艺

Electrochemical Corrosion Behavior and Anodic Oxidation Process of 9S75 Aluminum Alloy

采用极化曲线测试了9S75铝合金在不同pH的3.5% NaCl溶液中的电化学腐蚀行为,介绍了一种硫酸阳极氧化工艺并通过正交试验的方法确定了硫酸恒压阳极氧化的最优工艺条件。结果表明:在酸性溶液中,铝合金的腐蚀速率随着pH的增大而减小;在碱性溶液中,铝合金的腐蚀速率随着pH的增大而加剧。9S75铝合金的最佳阳极氧化电压为20V,氧化时间为35min,硫酸质量分数为184g/L,采用此方法制得的氧化膜为非晶态的氧化铝,呈蜂窝状结构,膜厚约为16μm,该氧化膜对铝合金表面起到了很好的防护作用。

The electrochemical corrosion behavior of 9S75 aluminum alloy in 3.5% NaCl solution with different pH was tested using polarization curves.An anodizing process of sulfuric acid was introduced and the optimum conditions of constant voltage anodization of sulfuric acid were determined by orthogonal test.The results showed that the corrosion rate of aluminum alloy decreased with the increase of pH in acidic solution.In alkaline solution,the corrosion rate of aluminum alloy increased with the increase of pH.The optimum anodic oxidation voltage of 9S75 aluminum alloy was 20 V,the oxidation time was 35 min,and the mass concentration of sulfuric acid was 184 g/L.The oxide film obtained by this method was amorphous alumina,which had a honeycomb structure and a film thickness of about 16μm.The oxide film plays an important role in protecting the surface of the aluminum alloy.