304不锈钢晶间腐蚀发展过程的阻抗谱分析

Electrochemical Impedance Spectroscopy of 304 Stainless Steels During Intergranular Corrosion

研究了敏化态304不锈钢在10%草酸溶液中电解浸蚀不同时间的腐蚀形貌及产生晶间腐蚀后的电化学阻抗谱特征并拟合了电化学阻抗谱。结果表明:钝化膜表面界面电容Cc及晶间腐蚀活性区界面电容Cd随敏化态不锈钢晶间腐蚀程度的加剧呈上升趋势,电荷传递电阻Rt呈现下降趋势,与晶间腐蚀的发生和发展有一定的对应关系。研究结果为运用电化学阻抗谱技术检测不锈钢晶间腐蚀提供了必要的依据。

The corrosion morphology of sensitized 304 stainless steels in 10% oxalic acid for different time was studied. The electrochemica impedance spectroscopy（EIS） of cracked 304 stainless steel in 10% oxalic acid and 5% sulphuric acid was measured and simulated. Electrochemical equivalent circuit parameters, such as Cc and Cd increase, Rt decreases, as the intergranular corrosion of sensitized stainless steel increases, which is somewhat relative to occurrence and development of intergranular corrosion. The results provide the knowledge base for intergranular corrosion detection using EIS technique to some extent.