钨酸根对不锈钢局部腐蚀的作用  

A study on the mechanism of localized corrosion of stainless steel by tungstate

作　　者：许淳淳[1] 吴小梅[1] 刘幼平[1] 

机构地区：[1]北京化工大学材料科学与工程学院,北京100029

出　　处：《北京化工大学学报（自然科学版）》2001年第2期49-51,55,共4页Journal of Beijing University of Chemical Technology(Natural Science Edition)

基　　金：国家自然科学基金项目! (5 970 10 0 9) ;国家重点基础研究发展规划项目 !(19990 6 5 0 )

摘　　要：采用模拟闭塞电池恒电流实验研究了 30 4不锈钢在 0 5 (mol·L-1)NaCl(pH =7)溶液中及添加不同浓度钨酸钠后局部腐蚀闭塞区内化学状态的变化。结果表明 ,主体溶液中添加一定浓度的WO2 -4 离子后 ,随着时间的延长 ,闭塞区的 pH值下降明显减缓 ,Cl-离子浓集倍数降低。WO2 -4 离子与Cl-离子向闭塞区内竞争迁移。当添加的WO2 -4 离子浓度较低时 ,Cl-离子的电迁移量仍然随时间的延长而增加 ;WO2 -4 离子浓度达到一定值后 ,WO2 -4离子能有效地阻止Cl-离子向闭塞区的迁移 ,钨酸根浓度越高效果越显著。闭塞区内WO2 -4 离子浓度随主体溶液中WO2 -4 离子浓度的增加而增大。对一定浓度WO2 -4 的主体溶液 ,WO2 -4 离子向闭塞区的迁移量随时间延长而增大 。Simulated Occluded Corrosion Cell(OCC) was used to study the changes of chemical state within the OCC of 304 stainless steel in neutral solution of 0.5 mol/L NaCl containing various tungstate ion concentration at 50 °C. Anodic polarizing occluded specimen to simulate reaction current between outside and inside of OCC. It was found that when WO42- anion was added into the bulk solution, it migrated into OCC, and the migration quantity increased with the concentration and the time, the migration rate decreased with the time. WO42- 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 efficient it is. WO42- can retard pH fall and decrease the multiples of Cl- enrichment effectively.

关 键 词：闭塞电池 304不锈钢 局部腐蚀 钨酸根 缓蚀剂 

分 类 号：TG174.3[金属学及工艺—金属表面处理] TG174.42[金属学及工艺—金属学]