Abstract: Porcelain insulator corrosion seriously threatens the safe and stable operation of transmission lines. In this work, the corrosion behavior of porcelain insulator steel caps in NaHCO3 solution, NaCl solution, and dust filtrate was investigated by electrochemical method, and the electrochemical impedance spectroscopy and polarization curve analysis showed that the electrochemical corrosion rates of NaHCO3 and NaCl solution on porcelain insulator steel caps were positively correlated with the solution concentration, the corrosion rate of steel caps was the largest in NaCl solution, and the corrosion rate in the dust filtrate increased with the increase of pollution equivalent salt density. Among them, the corrosion rate of the filtrate of contamination in the highly polluted degree area was close to that of the low concentration NaHCO3 solution. Through the comparison of the color and micromorphology of the corrosion experimental solution, it can be found that there was a deposition of corrosion products and oxidation products on the surface of the sample in NaHCO3 solution and dust filtrate, while comprehensive corrosion occurred on the corrosive surface in NaCl solution, and no obvious brown-red Fe(OH)3 deposition occurred. Therefore, the anti-corrosion of insulator metal accessories in highly polluted areas was of great significance to prevent insulator failure and pollution flashover.

Key words: electrochemical corrosion, electrochemical impedance spectroscopy, polarization curve, industrial pollution, metal accessories

摘要： 瓷绝缘子钢帽腐蚀严重威胁输电线路的安全稳定运行。采用电化学方法考察了瓷绝缘子钢帽在NaHCO3溶液、NaCl溶液和污秽滤液中的腐蚀行为，电化学阻抗谱和极化曲线分析表明，NaHCO3和NaCl溶液对瓷绝缘子钢帽产生的电化学腐蚀速率与溶液浓度呈正相关，钢帽在NaCl溶液中腐蚀速率最大，在污秽滤液中的腐蚀速率随污秽等值盐密增大而增大，其中在高污秽度地区的污秽滤液中腐蚀速率与在低浓度NaHCO3溶液中的腐蚀速率接近；通过腐蚀实验溶液颜色及微观形貌对比可以发现，试样在NaHCO3溶液和污秽滤液中，表面存在腐蚀产物和氧化产物的沉积，而在NaCl溶液中腐蚀表面发生全面腐蚀，且没有出现明显的棕红色Fe(OH)3沉积。因此，高污秽地区绝缘子金属附件的防腐对预防绝缘子失效及防污闪具有重要意义。

关键词: 电化学腐蚀, 电化学阻抗谱, 极化曲线, 工业污秽, 金属附件