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研究了不同Cr含量的Fe-x Cr-5Al合金(x=10%,15%,20%,原子分数)在KCl-Zn Cl2盐膜下在600℃空气中的腐蚀行为。结果表明,与无盐膜条件下合金的氧化相比,3种材料在KCl-Zn Cl2盐膜下均发生了加速腐蚀,其表面氧化铬膜在氯化物盐中发生溶解,且合金中较高Cr含量并没有有效提高合金抗氯化腐蚀的能力。在氯化盐中合金发生快速腐蚀主要是由于氧化铬溶解生成了铬酸盐,使得合金表面形成疏松的富Fe氧化产物。基于热力学相图讨论了合金在氯化物盐中的腐蚀机制,并揭示了Cr的作用机制。
The corrosion behavior of Fe-x Cr-5Al alloys with different Cr contents (x = 10%, 15%, 20%, atomic fraction) under air of KCl-Zn Cl2 salt film at 600 ℃ was investigated. The results showed that all the three materials accelerated corrosion under the KCl-Zn Cl2 salt film compared with that of the alloy without salt film. The chromium oxide film on the surface dissolved in the chloride salt and the content of Cr Cr content does not effectively improve the corrosion resistance of the alloy. Rapid corrosion of the alloy in the chloride salt is mainly due to the formation of chromate dissolved chromium oxide, making the alloy surface to form loose Fe-rich oxidation products. Based on the thermodynamic phase diagram, the corrosion mechanism of the alloy in chloride salt was discussed and the mechanism of action of Cr was revealed.