通过缝隙腐蚀浸泡实验考察了钼酸铵((NH4)6Mo7O24)和氯化铈(CeCl3)对2024铝合金在海水中缝隙腐蚀行为的影响,采用扫描电子显微镜(SEM)及能谱EDAX对腐蚀试样表面形貌进行了观察，并分析了试样表面膜成分；结合动电位极化和交流阻抗对其抗缝隙腐蚀机理进行了讨论.结果表明：钼酸铵不能有效地抑制2024铝合金在海水中的缝隙腐蚀,虽然钼酸铵可以在缝隙外表面形成保护膜,但缝隙内的腐蚀却更为严重；而在含氯化铈的海水中,由于Ce3+的还原性降低了缝隙内外氧的浓度差,有效抑制了缝隙腐蚀的发生.
The influence of addition of(NH4)6Mo7O24 and CeCl3 on crevice corrosion behavior of 2024 aluminum alloy was investigated in this paper.The surface morphology of the alloy after immersion was observed by scanning electron microscopy(SEM),and the corrosion product was analysed by EDAX.The corrosion mechanism was discussed in terms of the measurement results of potentiodynamic polarization and electrochemical impedance spectroscopy(EIS).The results revealed that(NH4)6Mo7O24 could not inhibit the crevice corrosion of 2024 aluminum alloy in seawater.A protective film was formed outside the crevice in the presence of(NH4)6Mo7O24,but the corrosion rate of inside the crevice was accelerated.However,Ce3+ improved the crevice corrosion resistance,due to the effect of reduction characteristic of Ce3+ the concentration difference of oxygen inside and outside the crevice wao reduced.
参考文献
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