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在含有不同浓度NaHSO_3的模拟海水溶液中系统考察了2205双相不锈钢的腐蚀行为。利用动电位极化曲线和电化学阻抗谱测试,研究模拟海水中不同浓度HSO_3~-对2205双相不锈钢腐蚀行为的影响。通过Mott-Schottky和XPS测试,分析了2205不锈钢在不同浓度HSO_3~-模拟海水溶液中钝化膜的缺陷浓度和成分。结果表明,模拟海水溶液中HSO_3~-的存在会提高2205不锈钢钝化膜中金属氧化物的含量。在含有0.01 mol/L HSO_3~-的模拟海水溶液中,2205双相不锈钢表现出较差的耐蚀性,其表面钝化膜中的缺陷浓度计算结果也与电化学测试结果相吻合。主要是由于HSO_3~-在溶液中极易被氧化为HSO_4~-,电离出H~+,会对2205不锈钢钝化膜产生破坏作用;而当模拟海水中HSO_3~-浓度低于0.01 mol/L时,材料阻抗呈上升趋势,HSO_3~-会在2205不锈钢表面和Cl~-产生竞争吸附,阻碍Cl~-在不锈钢表面的吸附,从而减少点蚀发生的可能。
The corrosion behavior of 2205 duplex stainless steel was systematically investigated in a simulated seawater solution containing different concentrations of NaHSO_3. The potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS) were used to study the effects of different concentration of HSO_3 ~ - on the corrosion behavior of 2205 duplex stainless steel. Through the Mott-Schottky and XPS tests, the defect concentration and composition of 2205 stainless steel passivation film in different concentrations of HSO_3 ~ - simulated seawater were analyzed. The results show that the existence of HSO_3 ~ in simulated seawater solution will increase the metal oxide content in 2205 stainless steel passivation film. In simulated seawater containing 0.01 mol / L HSO_3 ~ -, 2205 duplex stainless steel showed poor corrosion resistance, and the calculated results of the defect concentration on the surface passivation film also coincided with the electrochemical test results. It is mainly due to HSO_3 ~ - can easily be oxidized to HSO_4 ~ - in solution and ionized out of H ~ +, which will destroy the passivation film of 2205 stainless steel. When the concentration of HSO_3 ~ - in simulated seawater is less than 0.01 mol / L , The material resistance is on the rise. HSO_3 ~ - will compete with Cl ~ - on 2205 stainless steel surface and hinder the adsorption of Cl ~ - on the stainless steel surface, thus reducing the possibility of pitting corrosion.