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为了降低2024铝合金在海水中的缝隙腐蚀敏感性,采用浸泡和动电位极化、电化学阻抗等研究了氯化镧(LaCl3)对该铝合金缝隙腐蚀行为的影响,并通过原子力显微镜对缝隙试样内、外腐蚀产物膜的形貌进行了观察.结果表明:当海水中LaCl3的质量浓度超过2.0 g.L-1以后,它能有效地减缓2024铝合金在海水中的缝隙腐蚀.这主要是因为LaCl3减缓了缝隙的阴极反应速率,降低了缝隙内、外的氧浓度差,且缝隙内、外生成的均匀致密的腐蚀产物膜降低了Cl-侵蚀性,这些因素抑制了缝隙的萌生与扩展,提高了2024铝合金在海水中的抗缝隙腐蚀能力.
In order to reduce the crevice corrosion susceptibility of 2024 aluminum alloy in seawater, the effect of LaCl3 on the crevice corrosion behavior of the aluminum alloy was studied by immersion, potentiodynamic polarization and electrochemical impedance. The effects of LaCl3 on the crevice corrosion The morphology of the corrosion film inside and outside the sample was observed.The results showed that when the mass concentration of LaCl3 in seawater exceeds 2.0 gL-1, it can effectively reduce the crevice corrosion of 2024 aluminum alloy in seawater, which is mainly Because LaCl3 slows down the cathodic reaction rate of the gap and reduces the difference of oxygen concentration inside and outside the gap, and the uniform and dense film of corrosion products formed inside and outside the gap reduces Cl-erosion, these factors inhibit the initiation and propagation of the gap , Which improves the crevice corrosion resistance of 2024 aluminum alloy in seawater.