研究了Fe-Al合金在500℃空气中ZnCl2-KCl盐膜下的腐蚀行为。结果表明,与无盐膜氧化实验相比,合金在盐膜下发生了加速腐蚀,表面生成了疏松多孔的腐蚀产物,基体产生内腐蚀,其中Fe-25Al合金表面氧化铝膜甚至发生退化。合金加速腐蚀是由于腐蚀过程中氯化物沉积盐与合金表面的氧化膜反应产生氯所致。腐蚀随合金中Al含量的增加而减轻。基于热力学相图预测了合金在盐膜下可能发生的反应,并解释了合金发生加速腐蚀的机制。
The corrosion behavior of Fe-Al alloys below KCl-ZnCl2 deposits in air was investigated at 500℃. Compared to their oxidation in air without salt deposits, all the examined alloys below chloride deposits experienced accelerated corrosion characterized by formation of porous corrosion products plus internal attack of matrix, particularly the degradation of alumina on Fe-25Al alloy. The enhanced corrosion was attributed to then formation of chlorine from the reaction of chlorides in the deposit with the oxide scale of alloy. The corrosion rate decreased with increasing Al content. The possible reactions between alloy component and chloride compounds were predicted on basis of phasestability diagrams and the mechanism on accelerated corrosion was also interpreted.
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