采用模拟闭塞电池恒电流实验研究了304不锈钢在0.5 mol/L NaCl(pH =7)溶液中及在该溶液 中添加不同浓度十二烷基硫酸钠（C12H25SO4Na）后局部腐蚀闭塞区内化学 状态的变化.结果表明，对内试件通入阳极电流后，随着时间的延长，闭塞区内的pH值下降 ，C12H25SO-4离子基本上不影响闭塞区溶液pH值的变化，C12H 25SO-4离子与Cl-离子向闭塞区内竞争迁移.当在主体溶液中添加0.01 mol/L C 12H25SO4Na时，C12H25SO-4离子能有效地阻止Cl-离子 向闭塞区的迁移，闭塞区内Cl-离子增浓倍数降低.闭塞区内C12H25SO- 4浓度随主体溶液中C12H25SO-4离子浓度的增加而增大.对含一定浓度C 12H25SO-4的主体溶液，C12H25SO-4离子向闭塞区的 迁移量随时间延长而增大，而迁移速率则随时间的延长而降低.极化曲线测试结果表明十二 烷基硫酸钠为阴极型缓蚀剂，添加一定浓度后能有效抑制孔蚀的发展.
Simulated occluded corrosion cell(OCC) was used to stud y the changes of chemical state within the OCC of 304 stainless steel in neutra l solution of 0.5 mol/L NaCl containing various SDS(sodium dodecyl sulphate) ion concentration at 50℃.Anodic polarizing occluded specimen to simulate reaction current between outer and inter of OCC.It was found that,when C12H25 SO-4 anion added into the bulk solution,it migrated into OCC,and the migrati on quantity increased with the concentration and the time,the migration rate dec reased with the length of the time.C12H25SO-4 was in competition with Cl- on migration,It can retard the migration of Cl- effectively above a certain concentration,The higher the concentration,the more the efficiency.C 12H25SO-4 can not retard pH fall but fell multiples of Cl- enric hment effectively above a certain concentration.SDS was anioning inhibitor,E b and Ep were shifted towards positive potentials by the addition of C 12H25SO-4,indicating suppression of pit propagation.
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