铸铁文物在碱性溶液中的电化学脱氯研究

采用模拟闭塞电池恒电流法和恒电位法研究在碱性溶液中阴极极化对模拟铸铁文物局部腐蚀闭塞区内溶液化学和电化学状态的影响以及电化学脱氯的效果。试验结果表明，对试样进行恒电流或恒电位阴极极化，闭塞区内溶液的pH值随着阴极极化时间的延长而升高；氯离子向闭塞区外迁移，迁移率随阴极极化时间的延长而增高。由于Cl^-的迁出及外部OH^-的迁入，闭塞区内的腐蚀受到抑制。阴极极化能加速闭塞区内Cl^-的迁出，比铸铁文物通常采用的碱性溶液浸泡脱氯法更为有效，是一种快速的电化学脱氯方法。

ELECTROCHEMICAL DECHLORINATION OF CAST IRON IN ALKALINE SOLUTION

A simulated galavanstatic and potentiastatic occluded cell was used to investigate the effect of cathodic polarization on chemical and electrochemical states inside occluded cell (OC) of localized corrosion for cast iron in alkaline solution and the effect of electrochemical dechlorination. It has been found that the pH value of the OC solution rised with the prolonging of treatment time and the ratio of Cl~- migrating out from the OC also rised with prolonging of treatment time. Because of Cl~- migrating out from OC and OH~- immigrating into OC, localized corrosion was retarded. Cathodic polarization in alkaline solution can make Cl~- migrating more quickly and is more efficient than the cast iron immersed in alkaline solution without cathodic polarization.