含Cu、Nb铁素体不锈钢在硫酸溶液中的电化学行为及表面组成

ELECTROCHEMICAL BEHAVIOR AND SURFACE COMPOSITION OF FERRITIC STAINLESS STEELS CONTAINING Cu AND Nb IN SULFURIC ACID SOLUTION

一、前言关于铁素体不锈钢中添加合金元素铜、铌的作用和效果,至今仍不很清楚。有的工作认为添加铜对提高不锈钢的耐蚀性是有益的,但也有报告提出了不同的结果。在某些铁素体不锈钢中加入了稳定化元素铌,对于铌及铌、铜的复合作用也尚待研究。本工作应用电化学方法及俄歇能谱法,对含Cu、含Nb及含Cu+Nb的铁素体不锈钢在1.0mol/dm^3硫酸溶液中的电化学行为及表面组成进行了研究,并探讨添加铜及铌的效果与作用。

Electrochemical behavior and surface composition of ferritic stain- less steels containing Cu and Nb in 1.0 mol.din^(-3) sulfuric acid solution have been investigated to evaluate the effects of alloying elements Cu and Nb on the corrosion resistance of ferritic stainless steel.The ac- tive dissolution current density of copper added steel is suppressed significantly because of the surface enrichment of metallic copper. From the measurements of the reactivation potential by a cathodic potential sweep of the passivated steel,it is found that the copper addition has a detrimental effect on the passivity.On the other hand, the addition of niobium improved the passivity of ferritic stainless steel. Auger Spectroscopy revealed that the niobium existed in the inner layer of passive film.Therefore with both niobium and copper added,the ferritic stainless steel shows excellent corrosion resistance,because active disolution is decelerated by copper addition and because passive film is improved by niobium addition.