以2A12/45和2A12/40CrNiMoA为研究对象，采用电偶腐蚀实验方法系统研究了溶液浓度、pH值以及材料特性和外力等因素对电偶腐蚀行为的影响。结果表明：pH值不变，随着溶液浓度的升高，两个偶对的电偶电流密度增大；溶液浓度不变，随着溶液pH值的降低，两个偶对的电偶电流密度增大；从腐蚀形态来看，不同浓度下2A12表面的腐蚀形态主要是不均匀的点蚀，pH=2时为均匀腐蚀，而在pH=4和pH=7时为局部的点蚀；应力的变化不仅对电偶电流密度有明显影响，而且承受的应力水平增大，电偶电流密度增加，电偶腐蚀敏感性提高，无应力时，作为阳极的2A12铝合金表面的腐蚀形式是局部的点蚀，且腐蚀产物附着在金属表面，当外加应力增加到75％σs时2A12铝合金表面腐蚀明显加剧，且随着腐蚀产物的脱落，局部区域出现较大的蚀坑。
Galvanic corrosion behaviours of 2A12 aluminum alloy coupled with 40CrNiMoA steel under different solution concentrations and pH value and tensile stress levels were studied by galvanic corrosion test. The experimental results show that the couple current density increases with the decrease of pH for the same solution concentration,and increases with the increase of solution concentration at the same pH. Observing the corrosion appearance,it is found that with changing solution concentration,obvious localized corrosion and pitting corrosion are observed for specimens 2A12. General corrosion plays a key role in acidic solutions(pH=2),and the major corrosion form of specimens 2A12 in both neutral and slight acidic solutions (pH=4 and pH=7)is pitting corrosion. The magnitude of external stress has important effects on couple current density and galvanic corrosion sensitivity. Without the effect of external stress,the corrosion forms of the couple of 2A12/45 steel is the localized corrosion with the corrosion products attaching to the surface of the steel. As stress is applied to specimens 2A12,the pitting corrosion of 2A12 develops into larger dimension,and when the external stress increases to 75%σs,the corrosion product falls from metal surface,the larger pits are distributed on the surface of specimens 2A12.
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