摘要
采用恒电位模拟闭塞电池装置研究外部电位对局部腐蚀闭塞区的影响．在蚀孔或裂缝的扩展阶段，即当闭塞区溶液的ｐＨ值已经降到临界值以下时，外表面阴极极化使闭塞区电位负移，腐蚀率变小，闭塞区电位与外部电位呈线性关系，闭塞区腐蚀率与外部电位呈指数关系．对外表面施加阳极极化时，闭塞区的电位和腐蚀率不随极化电位而变化．闭塞区内外的电位差主要来自内外溶液的扩散电位差和离子的电迁移欧姆降．
An apparatus with the occluded specimen connected to the potentiostatically polarized external specimen was used to study the effects of the external potential on corrosion of the occluded cell simulating the propagating cracks or pits. A series of equations describing the relationships between corrosion rates and potentials were derived for systems of type 1Cr13 and OCr18Ni9 stainless steel in 0.5mol/L NaCl solution. Results demonstrated that cathodic polarization of the external specimen caused a reduction in corrosion rate and a decrease in potential of the occluded specimen. It was also found that both corrosion rate and potential with propagating pits or cracks maintained constant even if anodic polarization was applied to the external surface. The potential difference between pit bottoms or crack tiPS and the external surface could be attributed to a summation of a diffusion potential difference and the ohm drop of the ion migration.
出处
《中国腐蚀与防护学报》
CAS
CSCD
1995年第1期43-48,共6页
Journal of Chinese Society For Corrosion and Protection
基金
国家自然科学基金
关键词
腐蚀
电位
电化学保护
蚀孔
裂缝
Localized corrosion, Potential, Electrochemical protection, Occluded corrosion cell
