高氮奥氏体不锈钢耐点蚀性能研究

目前产于高氮不锈钢的研究多集中于理论基础、制造工艺和力学性能等方面,有关耐蚀性方面的研究有限。通过循环极化、Mott-Schottky曲线以及电化学阻抗(EIS)等方法,研究了Cr23Mo1N奥氏体不锈钢(高氮钢,HNSS)和316L不锈钢在Cl-溶液中的耐点蚀性能。结果表明:与316L不锈钢相比,高氮钢具有更正的自腐蚀电位,更小的维钝电流密度。阻抗谱表明高氮钢的钝化膜比316L更加稳定,且电荷转移电阻更大。Mott-Schottky曲线表明高氮钢的点缺陷施主浓度比316L不锈钢低一个数量级,钝化膜的绝缘性更好。循环极化曲线表明高氮钢的点蚀敏感性更小,钝化膜的自修复能力更强,耐蚀性能更加优越。

Study on Pitting Corrosion of High Nitrogen Austenitic Stainless Steels

The pitting corrosion resistance of Cr23Mo1N austenitic stainless steels (HNSS) and ordinary 316L stainless steels in Cl-solution was studied by cyclic polarization,Mott-Schottky curve,electrochemical impedance spectroscopy (EIS),and other methods.Results showed that compared with 316L,HNSS had much higher free corrosion potential and much smaller passive current density.EIS analysis showed that passivating film of HNSS was more stable than that of 316L,and the charge transfer resistance was larger.Moreover,Mott-Schottky curve showed that point defect donor concentration of HNSS was one order of magnitude lower than that of 316L,and insulation of passive film was better.Cyclic polarization curves showed that the HNSS possessed smaller pitting sensitivity,stronger self-healing ability of passive film and superior corrosion resistance than 316L.