高压输电线路用耐张线夹用铝的电化学腐蚀行为研究

Electrochemical Corrosion Behavior of the Aluminum used for High Voltage Transmission Line Strain Clamps

通过测定极化曲线和交流阻抗谱,并借助于扫描电镜、能谱分析和X射线光电子能谱仪研究了腐蚀液的浓度、pH和温度等因素对高压输电线路耐张线夹用铝在NaHSO_3+NaCl溶液中的电化学腐蚀行为,即对腐蚀产物的形貌、成分和分布等的影响。结果显示:耐张线夹用铝在NaHSO_3+NaCl溶液中的腐蚀产物为Al(OH)_3和Al_2O_3,随着溶液的pH增加浓度增大或温度升高,耐张线夹的EIS半圆弧形半径减小,自腐蚀电位Ecorr负向移动,自腐蚀电流增大,阳极极化斜率增大,阴极极化斜率减小。此外,随着溶液的浓度增大、温度升高和pH减小,耐张线夹用铝的线性极化电阻减小,腐蚀加快,耐腐蚀性能降低。

It was investigated how electrochemical corrosion behavior of aluminum used for strain clamp of high-voltage transmission line in a solution consisting of NaHS03 and NaCl,namely,morphology,composition and distribution of corrosion products,was affected by concentration,pH and temperature of the corrosion liquor through measurements of polarization curve and AC impedance spectra as well as by means of SEM,EDS AND XPS.The results showed that the corrosion products of the aluminum for strain clamp developed in the solution consisting of NaHS03 and NaCl were A1(0H)3 and A1203,and that as pH or concentration or temperature increased,radius of EIS semicircle arc decreased,self-corrosion potential Econr moved negatively,both the self-corrosion current and the anodic polarization slope increased,whereas the cathodic polarization slope decreased.Also,with the increase in both concentration and temperature of the solution and decrease in its pH the aluminum for strain clamp exhibited less linear polarization resistance,greater corrosion rate,and relatively poor corrosion resistance.