铁器文物在含氯离子水溶液中局部腐蚀闭塞区化学状态的变化

CHEMICAL CHANGES WITHIN OCCLUDED CELL FOR LOCALIZED CORROSION OF IRON ARTIFACTS IN CHLORIDE SOLUTION

用模拟闭塞电池恒电流实验研究了铁器文物在 3.5 %NaCl水溶液中局部腐蚀闭塞区内化学状态的变化 .对内试件通入阳极电流后 ,闭塞区内溶液pH值随通电时间延长和电流密度的增加而下降 ,pH值与电量的对数成正比 .Cl-向闭塞区内电迁移 ,迁移量和浓集倍数随时间和电流密度的增加而上升 .迁移量与电极上通过的电量呈线性关系 .

The changes of chemical state for localized corrosion of iron artifacts in 3.5% NaCl solution were studied within a simulated occluded cell.As anodic currents passed the cell a series of changes took place,the most important ones were pH fall and Cl - migration within the occluded cell.It was found that as anodic currents passing the cell,the pH value fell quickly at the beginning while slowly after it about 5,which was proportional to the logarithm of quantity of passing electricity.Meanwhile the Cl - migrated into occluded cell.The quantity of Cl - migration and enrichment multiples increased with the time of current flowing.As a rule,a linear relationship existed between the amount of Cl - migration and quantity of electricity passing.Consequently,Cl - concentration was a function of pH in occluded cell.