采用摸拟缝隙的闭塞电池研究了0Cr18Ni9Ti 奥氏体不锈钢在3%氯化钠溶液中闭塞区内溶液的变化和 Cr(Ⅲ)存在的形态。当电流通过闭塞区时,随电量的增加,溶液的 pH 值迅速下降,Cl~-离子浓集。合金元素 Cr 是导致该体系中缝内阳极液低 pH 值的主要因素。用分光光度法和电化学分析法研究了阳极液,发现 Cr(Ⅲ)是以稳定而可溶的羟氯络合物形态存在于缝内闭塞液中,没有观察到 Cr(Ⅲ)因水解而形成的难溶 Cr(OH)_3沉淀物。根据上述实验结果推断:由于 Cl~-离子在缝内不锈钢表面的特性吸附,并进一步与膜中主要成份 Cr 形成可溶性的羟氯络合物而淡钝化膜遭到破坏,从而使腐蚀加剧。 The occluded cell of 0Cr18Ni9Ti austenitic stainless steel in 3% sodium chloride solution and the morphology of Cr (Ⅲ) were studied using a closed cell with simulated gap. When the current through the occlusion zone, with the increase of power, the pH value of the solution decreased rapidly, Cl ~ - ion concentration. The alloying element, Cr, is a major contributor to the low pH of the anolyte in the system. The anolyte was studied by spectrophotometry and electrochemical analysis. Cr (Ⅲ) was found to be stable and soluble hydroxychloro complex in occlusion liquid, and no Cr (Ⅲ) was observed due to hydrolysis The formation of insoluble Cr (OH) _3 precipitate. Based on the above experimental results, it is concluded that the corrosion of the passive film is exacerbated due to the adsorption of Cl ~ - ions on the surface of the stainless steel and the further formation of soluble hydroxychloro complex with Cr as the main component in the film.