Abstract: In order to further improve the corrosion resistance of S32750 super duplex stainless steel, the passivation treatment was carried out by nitric acid passivation. The corrosion resistance of S32750 super duplex stainless steel was investigated by electrochemical polarization curve, electrochemical impedance spectroscopy, Mott⁃Schottky curve and immersion method,and the corrosion surface morphology of the sample surface before and after corrosion was observed. The results show that the nitric acid passivation time has a significant effect on the corrosion resistance of S32750 super duplex stainless steel passivation film. When the passivation time is less than 120 minutes, the longer the passivation time, the smaller the corrosion rate is, and the better the passivation film corrosion resistance is.

Key words: S32750 super duplex stainless steel, Nitric acid, Passivation, Passivation film

摘要： 为了进一步提高S32750超级双相不锈钢（S32750 SDSS）的抗腐蚀性能，采用质量分数为40.0%的硝酸对其进行钝化处理，通过电化学极化曲线、电化学阻抗谱、Mott⁃Schottky曲线以及浸泡等方法，考察了硝酸钝化不同时间后S32750超级双相不锈钢的耐蚀性，并观察了腐蚀前后试样表面的腐蚀表面形貌。结果表明，钝化时间对S32750超级双相不锈钢钝化膜耐蚀性有显著影响，当钝化时间小于120 min时，钝化时间越长，腐蚀速率越小，钝化膜耐蚀性越好。

关键词: S32750超级双相不锈钢, 　硝酸, 　钝化, 　钝化膜