温度对Cr26Mo1超纯高铬铁素体不锈钢在3.5%NaCl溶液中耐点蚀性能的影响

通过循环极化曲线、Mott-Schottky曲线以及电化学阻抗谱等方法研究了温度对Cr26Mol超纯高铬铁素体不锈钢在3.5%NaCl溶液中耐点蚀性能的影响.结果表明:随着温度升高,Cr26Mol超纯高铬铁素体不锈钢的自腐蚀电位降低,腐蚀电流密度增大,点蚀电位下降,钝化膜阻抗降低.Cr26Mol不锈钢钝化膜的半导体类型和性质在不同温度下发生改变.Cr26Mol不锈钢发生点蚀的孕育期随着温度的升高而缩短,点蚀敏感性增加,已发生点蚀的试样不能够自修复.

INFLUENCE OF TEMPERATURE ON PITTING CORROSION RESISTANCE OF Cr26Mol ULTRA PURE HIGH CHROMIUM FERRITE STAINLESS STEEL IN 3.5%NaCl SOLUTION

The remarkable uniform corrosion resistance of ultra pure high chromium ferrite stainless steel in various rigorous corrosive environments is based on the formation of a passive film on its surface.However,it is suspected that this stainless steel was easy to suffer from pitting corrosion.In this work,the influences of temperature on the pitting corrosion resistance of Cr26Mol ultra pure high chromium ferrite stainless steel were studied by electrochemical methods such as cyclic polarization curves,Mott-Schottky curves and electrochemical impedance spectroscopy in 3.5%NaCl solution.The results showed that with the increase of the temperature,open-circuit corrosion potential and pitting corrosion potential decreased,corrosion current density increased,the impedance of passive film decreased. The semi-conductive styles and properties of passive film changed at different temperatures. Also,the pregnancy time of pitting shortened and the sensitivity of pitting increased remarkably as the temperature increased.In addition,the cyclic polarization curves indicated that the repassivation of existing pits was more difficult when the potential was swept toward the negative direction.