几种有机阴离子的电迁移及其对闭塞区的影响

MIGRATION OF VARIOUS ORGANIC ANIONS AND THEIR EFFECTS ON OCCLUDED CORROSION CELL

用模拟闭塞电池方法研究了低碳钢 /碱性NaCl水溶液体系中三种有机阴离子十二烷基硫酸根 (C12 H2 5SO- 4)、十二烷基苯磺酸根 (C12 H2 5C6H4 SO- 3 )和月桂酸根 (C12 H2 3OO- )向闭塞区的电迁移规律及其对闭塞区的影响 .结果表明 :对内试件通入阳极电流后 ,在所选阴离子浓度范围内 ,C12 H2 5SO- 4、C12 H2 5C6H4 SO- 3 和C12 H2 3OO- 均能向闭塞区内迁移 ,且遵循相同的规律 ,即电迁移量随其浓度的提高和通电时间的延长而增大 .当有机阴离子的浓度为 0 0 1mol·L- 1时 ,三者迁移量的顺序为 :C12 H2 3OO- >C12 H2 5C6H4 SO- 3 >C12 H2 5SO- 4;而在浓度为 0 0 0 2、0 0 0 5mol·L- 1时 ,三者的电迁移量接近 .C12 H2 5SO- 4、C12 H2 5C6H4 SO- 3 和C12 H2 3OO- 均能阻止Cl- 向闭塞区的迁移 ,当有机阴离子的浓度为 0 0 0 2、0 0 0 5mol·L- 1时 ,三者对抑制Cl- 向闭塞区迁移的效果相差不大 ,当浓度为 0 0 1mol·L- 1时 ,抑制Cl- 向闭塞区迁移作用最明显的是C12 H2 3 OO- ,其次是C12 H2 5C6H4 SO- 3 ,C12 H2 5SO- 4的效果最差 .这三种阴离子的迁入对闭塞区溶液pH值影响不大 .

Simulated occluded cells were used to study organic anions such as C 12 H 25 SO - 4、 C 12 H 25 C 6H 4SO - 3 、C 12 H 23 OO - migration and their effects on occluded corrosion of mild steel (A3) in 0 01mol·L -1 NaCl solution at 50℃ It was found that they migrated into the occluded cell as anodic current passing the cell, the quantity of migration increased with the time and the concentration, the order of migration quantity was:C 12 H 23 OO - >C 12 H 25 C 6H 4SO - 3 >C 12 H 25 SO - 4 at a concentration of 0 01mol·L -1 ,while the migration quantity of them were same when the concentration were 0 002 and 0 005 mol·L -1 They all can retard the migration of Cl -,and had the same effects on the migration of Cl - at the concentration of 0 002 and 0 005mol·L -1 ,but it was the best when the concentration was 0 01mol·L -1 ,C 12 H 23 OO -,and C 12 H 25 C 6H 4SO - 3 was the better They had no effect on the pH fall of the OCC solution.