摘要
通过极化曲线、交流阻抗谱和钝化膜半导体特性等电化学测量,研究了经电化学阳极氧化处理的不锈钢钝化膜在0.5mol·L-1NaCl溶液中耐蚀性能与其半导体特性的关系,进一步探索电化学改性处理不锈钢钝化膜的耐蚀机理.结果表明,不锈钢钝化膜在负于平带电位范围表现为p型半导体,在高于平带电位范围表现为n型半导体,这主要与组成钝化膜的Fe和Cr氧化物半导体性质有关.与自然条件下形成的不锈钢钝化膜比较,发现经过电化学阳极氧化后不锈钢钝化膜具有较低的施主与受主浓度,平带电位负移,说明阴离子在钝化膜表面发生吸附.低的施主与受主浓度及钝化膜表面负电荷的增强,可有效排斥侵蚀性Cl-在钝化膜表面的特性吸附,有利于提高不锈钢的耐局部腐蚀性能.
Using polarization scan, electrochemical impedance spectroscopy and capacitance measurement, the correlation of corrosion resistance and semiconductor properties for electrochemically modified passive film formed on stainless steel in 0.5 mol center dot L-1 NaCl solution was investigated, and the mechanism of the corrosion resistance of the electrochemically modified passive film was further studied. The result reveals that the films behave as n-type and p-type semiconductors in the potential range above and below the flat band potential, respectively. This behavior is assumed to be the consequence of the semiconducting properties of the iron oxide and chromium oxide regions which compose the passive film. Compared with natural passive film, electrochemically modified passive film has lower donor and acceptor density. The change of E-FB was discussed as a function of anions adsorption on surface of passive film. With low donor and acceptor density and anion adsorption on surface of passive film, effectively preventing the adsorption of Cl- in passive film, the resistance to localize corrosion of passive film was greatly improved.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2005年第7期740-745,共6页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(59525112)
教育部重点课题资助项目~~
关键词
不锈钢
钝化膜
耐腐蚀性
电化学阻抗谱
半导体特性
stainless steel
passive film
corrosion resistance
EIS
semiconductor property
