采用真空感应熔炼法制备铝电解用Fe-40Cr-2Ce合金阳极。研究了合金阳极900℃下的氧化和电解腐蚀行为。电解测试采用900℃的NaF-AlF3低温电解质体系,阳极电流密度为0.5 A/cm2,电解时间10 h。结果表明：合金的氧化动力学曲线遵循抛物线规律;合金中高浓度的Ce形成晶界沉淀,造成Ce的＂活性元素效应＂失效。电解后的阳极表面生成连续的FeCr2O4尖晶石相氧化膜。根据热腐蚀酸-碱溶解机理,氧化物在氧化物/电解质界面上的溶解度负梯度造成了阳极表面氧化物的持续的溶解。电解质中高浓度的氧化铝有利于减缓氧化膜的酸性溶解,降低合金阳极的电解腐蚀速率。
Fe-40Cr-2Ce alloy anodes for aluminium electrolysis were prepared by a vacuum induction melting process.The thermal oxidation and electrolysis corrosion behavior of the alloy anodes at 900 ℃ were investigated.The electrolyzing tests were conducted in a NaF-AlF3 electrolyte system at 900 ℃,and at an anodic current density of 0.5 A/cm2 for 10 h.The results indicated that the oxidation kinetics of the alloys followed a parabolic law.High concentration of Ce in the alloys induced the failure of ＂reactive element effect＂,due to the formation of precipitates along grain boundaries.A continuous FeCr2O4 spinel film was formed on anode surface after electrolysis.Followed the hot corrosion mechanism of basic-acidic fluxing,the negative solubility gradient of oxide at oxide/electrolyte interface resultsed in continuous dissolution of the oxide formed on the alloy anode surface.The high concentration of alumina in electrolyte was favorable for reducing the acidic dissolution of oxide film and decreasing the electrolysis corrosion rate of alloy anode.
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