马氏体相变对孔蚀闭塞区化学和电化学行为的影响

Influence of Martensite Transformation on Chemical and Electrochemical Behavior of Pitting Occluded Cell

采用模拟闭塞电池法和模拟闭塞溶液法研究了奥氏体 30 4不锈钢形变诱发马氏体相变对孔蚀闭塞区化学和电化学行为的影响。为了模拟闭塞区内外间的电偶电流 ,对试件通入电流进行阳极极化。结果表明 ,与未形变的 30 4不锈钢的试验结果相比 ,随着马氏体含量的增加 ,闭塞区溶液pH值下降 ,Cl- 迁入闭塞区的量更多。马氏体相的存在增强了材料的电化学活性 ,使其在模拟闭塞溶液中的自腐蚀电位负移 ,维钝电流密度增加 ,加速了闭塞区金属阳极溶解 。

By simulated occluded corrosion cell (OCC) and simulated occluded solution methods, the chemical and electrochemical change within the OCC of austenitic 304 stainless steel which had deformation-induced martensite transformation were studied. Anodic polarizing occluded specimen was used to simulate reaction current between the outer and the interior of OCC. Contrasting to the experiment result of undeformed 304 stainless steel, the more martensite phase of the specimen, the quicker the pH of OCC solution fell and the more Cl - migrated into OCC. Results indicated that the martensite phase increased the electrochemical activity of the material and made corrosion potential changing negative and led to passive current density increase.