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用失重法和电化学方法研究2A12,5A06和7A04铝合金在中性和酸性(pH≈5)连续盐雾环境下的腐蚀过程。通过金相显微镜和接触角表面分析仪观察其金属相界面处的腐蚀形貌和表面状态,分析腐蚀机理。结果表明:失重法、极化曲线Tafel外推法和电化学阻抗谱法均显示3种铝合金在中性盐雾中腐蚀速率的大小关系为7A04>2A12>5A06;在酸性盐雾中腐蚀速率的大小关系为7A04>5A06>2A12;铝合金表面与中性和酸性盐溶液的接触角分别为70.9°和52.6°,酸性盐溶液的接触角小于中性盐溶液的接触角,可能是因为氢离子增多使阴极反应右移,加速阳极溶解,破坏了铝合金表面的氧化膜。
The corrosion process of 2A12, 5A06 and 7A04 aluminum alloys under neutral salt and acidity (pH≈5) continuous salt spray was studied by weight loss method and electrochemical method. The corrosion morphology and surface state at the interface of metal phase were observed by optical microscope and contact angle surface analyzer, and the corrosion mechanism was analyzed. The results show that: the weight loss method, polarization curve Tafel extrapolation and electrochemical impedance spectroscopy showed that the relationship between the corrosion rate of the three kinds of aluminum alloy in neutral salt spray was 7A04> 2A12> 5A06; the corrosion rate in acid salt spray 7A04> 5A06> 2A12. The contact angle between the surface of Al alloy and the neutral and acidic salt solution is 70.9 ° and 52.6 °, respectively. The contact angle of acid salt solution is smaller than the contact angle of neutral salt solution, probably because hydrogen The increase of ions causes the cathode reaction to shift to the right, accelerates the anodic dissolution, and destroys the oxide film on the surface of the aluminum alloy.