通过极化曲线和电化学阻抗谱的测试，分别对不锈钢焊缝附近不同区域在硝酸中的腐蚀电化学特性进行了研究。结果表明：不锈钢敏化后腐蚀电流密度增大，表面钝化膜的反应电阻减小；焊缝各非敏化区的腐蚀电流密度和表面反应电阻差别不大；焊缝金属的耐硝酸腐蚀性能优于敏化区的，但弱于非敏化区的。区域1、3、5、7未发生晶间腐蚀，在Nyquist图中均呈单一容抗弧，且各自的阻抗值差别不大；发生严重晶间腐蚀的区域6的阻抗在Nyquist图中呈现两个容抗弧，极化电阻明显小于其他区域。

The corrosion electrochemical characteristics of the materials from different areas near the weld in nitric acid solution were studied through the testing of polarization curves and electrochemical impedance spectroscopy (EIS). The results show that the corrosion current density increased and the reaction resistance of surface passivation film reduced after stainless steel sensitization. The corrosion current density and surface reaction resistance of the non-sensitized areas of the weld had few differences. The corrosion resistance of weld metal was better than that of the sensitized area, but worse than that of the non-sensitized area. Intergranular corrosion didn't occur in the areas of No. 1, 3, 5 and 7, which showed a single capacitance arc in Nyquist diagram, and each resistance value was close. Serious intergranular corrosion occurred in the area of No. 6, whose Nyquist diagram presented two capacitive arcs, and the polarization resistance of this area was significantly less than that in othe ther areas.