摘要
采用模拟装置研究３０４不锈钢在０．５ｍｏｌ／ＬＮａＣｌ溶液中缝（孔）内外间电流与闭塞腐蚀电池及外表面电位的关系。表明缝（孔）内外间电流的方向对闭塞区溶液是否酸化以及Ｃｌ－是否浓集起着决定作用。测得该体系缝内外间电流换向电位ＥＴ为－２６０～－２３０ｍＶ（ＳＣＥ），当外表面电位正于ＥＴ时，流向闭塞区的电流为阳极电流，缝内溶液ｐＨ值下降，Ｃｌ－浓集，产生自催化加速腐蚀效应。当外表面电位负于ＥＴ时，阴极电流流向闭塞区，缝内溶液的ｐＨ值增大到碱性，Ｃｌ－向外电迁移，腐蚀受到抑制。因而局部腐蚀的保护电位实质上是缝（孔）内外间电流换向电位。
Artificial cells were used to study the relationship between occluded corrosion cell(OCC) and potential of external surface for the system of AISI 304 stainless steel and 0.5 mol / L NaCl solution (50℃). It was shown that the direction of current between the and the external surface decided whether the occluded solution was acidified and enriched with Cl-. The transition potential of the current direction (ET) was found in the range of -260～-230 mV(SCE). Above ET, the anodic current flowed into OCC, the pH value of occluded solution decreased and the Clconcentration of occluded solution increased so that the autocatalytic acceleration efTect occurred inside OCC. While below ET, the cathodic current flowed into OCC, the pH .value of occluded solution increased and Cl-migrated from OCC to the outside, thereby stifling the occluded cell corrosion. It was indicated that ET was actually the protection potential of localized corrosion.
出处
《北京化工大学学报（自然科学版）》
CAS
CSCD
北大核心
1996年第2期66-70,共5页
Journal of Beijing University of Chemical Technology(Natural Science Edition)
关键词
局部腐蚀试验
缝隙腐蚀
闭塞电池
保护电位
电流
localized corrosion tests
crevice corrosion
occluded corrosion cell
protection potential
current
