氯离子杂质对304和316L奥氏体不锈钢在熔融硝酸盐中腐蚀行为的影响

Effect of Chloride Ion Impurities on Corrosion Behavior of 304and 316L Austenitic Stainless Steel in Molten Nitrate Salt

采用恒温全浸腐蚀试验方法,研究了304和316L奥氏体不锈钢在565℃含不同质量分数(0,0.6%,1.0%,1.4%)氯离子杂质熔融硝酸盐(60%NaNO_(3)+40%KNO_(3),质量分数)中的腐蚀行为。结果表明:在4种熔融硝酸盐中,304和316L不锈钢的腐蚀动力学曲线均呈抛物线型;随着氯离子含量增加,304和316L不锈钢的腐蚀速率均显著提升,腐蚀程度逐渐加重,腐蚀产物层在与基体结合处的裂纹增多,氯离子杂质通过活性氧化腐蚀作用加速了不锈钢腐蚀;与316L不锈钢相比,304不锈钢对氯离子杂质的腐蚀作用更敏感。

The corrosion behaviors of 304and 316Laustenitic stainless steel immersed in molten nitrate salt(60%NaNO_(3)+40%KNO_(3),mass fraction)with different mass fraction(0,0.6%,1.0%,1.4%)of chloride ion impurity at 565℃were studied using constant temperature immersion corrosion test method.The results show that 304and 316Lstainless steel in four types of molten nitrate salts exhibited parabolic corrosion kinetic.With increasing chloride content,the corrosion rate of 304and 316Lstainless steel increased significantly,the corrosion degree gradually increased,and the cracks of the corrosion product layer at the junction with the substrate increased.Chloride ion impurities accelerated the corrosion of stainless steel through active oxidative corrosion.Compared with 316Lstainless steel,304stainless steel was more sensitive to the corrosive effect of chloride ion impurities.