A3钢在碱性NaCl体系中闭塞电池腐蚀的研究

用模拟闭塞电池法研究了A3钢在0.01 (mol·L^-1)NaCl( pH =12.00 )溶液中闭塞区内化学状态的变化。结果表明, 随着阳极极化时间的延长, 闭塞区溶液的pH值下降,开始时下降较快 ,Cl^- 向闭塞区内迁移 ,闭塞溶液的Cl^- ]与极化时间成直线关系。在不同 pH值下的NaCl溶液中的极化曲线测试结果表明 ,当 pH值大于11时, A3钢极化曲线阳极区出现明显的钝化, 可见, 在pH值大于11的体系中, A3钢发生局部腐蚀的倾向更大。

Study of occluded cell corrosion of A3 steel in alkali NaCl solution

A simulated occluded corrosion cell (OCC) was used to study chemical changes within corrosion cracks or crevices of mild steel (A3) in 0 01(mol·L^-1 ) NaCl solution at 50 ℃. It has been found that as the anodic current passes through the cell,the pH value falls quickly at the beginning, then slowly down to about 4 55. Meanwhile Cl^- migrates into the occluded cell,and the Cl^- concentration is proportional to polarization time. Polarization curves show that in solutions with a pH value above 11, obviously visible localized corrosion occurs to A3 steel.