304奥氏体不锈钢在不同浓度硝酸中的电化学行为

采用动电位极化曲线测量、开路电位测量等技术，研究了304奥氏体不锈钢在不同浓度硝酸溶液中的电化学腐蚀行为，并对304奥氏体不锈钢在硝酸溶液中的电化学反应历程进行了探讨。结果表明：304奥氏体不锈钢在硝酸溶液中具备不锈钢典型的极化曲线特征，有多个钝化区和过钝化区；硝酸浓度升高促进不锈钢表面钝化膜的生成，使开路电位向正电位方向移动，降低了硝酸溶液对不锈钢的腐蚀倾向，同时，随着硝酸浓度的升高，不锈钢的点蚀电位升高，提高了不锈钢耐点蚀能力；在硝酸溶液中，不锈钢的腐蚀速率同时受到酸度和硝酸根浓度的影响，二者相互矛盾，导致硝酸浓度对腐蚀速率的影响呈不规律性。结果表明，在0.5 mol/L硝酸中，不锈钢的腐蚀速率最高。

Electrochemical Corrosion Study of 304 Austenitic Stainless Steel in Different Concentrations of Nitric Acid

The effect of varying concentrations of nitric acid on the electrochemical corrosion of 304 austenitic stainless steel has been investigated. The study was carried out using potentiodynamic cyclic polarization, open-circuit potential measurements. The reaction process of 304 austenitic stainless steel in nitric acid was under discussion. 304 austenitic stainless steel shows the same electrochemical characteristics with other stainless steel, and its polarization curve contains several passive regions and active regions. Electrochemical measurements indicate that nitric acid improves the pitting corrosion resistance capacity of 304 austenitic stainless steel by promoting the formation of passive film on the surface, and shifts the open-circuit potential to more positive values. Furthermore, nitric acid effects the corrosion rates of stainless steel in two contradictory ways. The result shows that 0.5 mol/L nitric acid has the highest corrosion rate.