SO3^2-浓度对5052铝合金在交变电场、干湿交替条件下腐蚀行为的影响

Effect of SO3^2- Concentration on Corrosion Behavior of 5052Aluminum Alloy in Alternating Electric Field with Cyclic Wet-Dry Condition

采用pH为4.0的含氯腐蚀液及400kV·m-1交变电场模拟工业输电环境,研究了SO3^2-浓度(0.005,0.01,0.02,0.05,0.1mol·L-1)对5052铝合金在交变电场中干湿交替环境下腐蚀行为的影响。结果表明:随着SO3^2-浓度增加,5052铝合金的腐蚀质量增加、自腐蚀电位、溶液电阻、电荷转移电阻先增大后减小,自腐蚀电流密度、腐蚀速率则先减小后增大;当SO3^2-浓度为0.005~0.01mol·L-1时,合金以点蚀为主,点蚀坑内开始出现成分为Al2O3、Al2O3·3H2O的龟裂状腐蚀产物;随SO3^2-浓度继续增加,合金表面腐蚀坑减少,与基体结合紧密的龟裂状腐蚀产物增多;SO3^2-浓度为0.02mol·L-1时,合金腐蚀速率最小,腐蚀程度最低。

The corrosive solution containing chlorine with pH 4.0 and 400 kV·m-1 alternating electric field were used to simulate the industrial transmission environment.The effect of SO3^2-concentration(0.005,0.010,0.020,0.050,0.100 mol·L-1)on corrosion behavior of 5052 aluminum alloy in alternating electric field with cyclic wet-dry condition was studied.The results show that with the increase of SO3^2-concentration,the corrosion mass increment,free-corrosion potential,solution resistance,and charge transfer resistance of 5052 aluminum alloy increased first and then decreased,while the free-corrosion current density and corrosion rate decreased first and then increased.When the concentration of SO3^2-was from 0.005 to 0.020 mol·L-1,the main corrosion was the pitting corrosion,and cracked corrosion products of Al2O3 and Al2O3·3H2O began to appear in pitting pits.When the concentration of SO3^2-continued to increase,the corrosion pits on the surface of the alloy were reduced,and the cracked corrosion products being tightly bound to the substrate with composition of Al2O3·3 H2O were increased.The corrosion rate and degree of the alloy were both the smallest when the concentration of SO3^2-was 0.020 mol·L-1.