Ce和W对444铁素体不锈钢耐点蚀性的影响

采用浸泡失重法和电化学方法研究Ce和W对铁素体不锈钢在含Cl-溶液中耐点蚀性能的影响,并通过恒电位极化法测定不同Ce和W含量的铁素体不锈钢临界点蚀温度(CPT)。结果表明,W和Ce都可显著抑制铁素体不锈钢在FeCl₃溶液中的腐蚀溶解,且含W的不锈钢蚀坑坑底有W元素富集。Ce和W的添加提高了不锈钢在5%NaCl溶液中的临界点蚀温度,并且当W的质量分数达到1%时,可以显著增强蚀坑的再钝化能力。添加Ce和W可提高不锈钢的点蚀电位,降低腐蚀电流密度,提高不锈钢的耐点蚀性能。不同成分的铁素体不锈钢在中性氯溶液中都表现出稳定的钝态,而Ce和W的添加可以提高钝化膜的稳定性,扩大钝化区范围。

Effect of Ce and W on pitting corrosion resistance of 444-type ferritic stainless steel

The effect of Ce and W addition on pitting corrosion resistance of ferritic stainless steel in the solution containing Cl- was studied by electrochemical and gravimetric tests. The critical pitting temperature (CPT) of ferritic stainless steel with different Ce and W contents was measured by potentiostatic polarization method. The results show that addition of both Ce and W can inhibit the corrosion dissolution of ferritic stainless steel in FeCl₃, and W element is enriched on corrosion pits bottom of stainless steels containing W. Both Ce and W increase the critical pitting temperature value of ferritic stainless steel in 5%NaCl solution. When the mass fraction of W element reaches 1%, the repassivation ability of corrosion pits can be significantly enhanced. The addition of Ce and W can increase the pitting potential of ferritic stainless steel, decrease the pitting current density, and improve the pitting resistance of the stainless steel. Ferritic stainless steels with different components show stable passivation in neutral solution containing chlorine, while the addition of Ce and W can improve the stability of passivation film and expand the range of passivation zone.