MoO_4^(2-)和NO_2^-对碳钢小孔腐蚀的协同抑制作用  

Synergistic Inhibition of MoO_4^(2-) and NO_2^-on Pitting Corrosion of Mild Steel

作　　者：周勇[1] 左禹[1] 

机构地区：[1]北京化工大学材料电化学过程与技术北京市重点实验室,北京100029

出　　处：《腐蚀科学与防护技术》2015年第4期321-326,共6页Corrosion Science and Protection Technology

基　　金：国家自然科学基金项目(51171014和51210001)资助

摘　　要：采用极化曲线、电化学阻抗谱(EIS)、莫特-肖脱基曲线和X射线光电子能谱(XPS)研究了MoO42-和NO2-对碳钢小孔腐蚀的协同抑制作用。结果表明,MoO42-和NO2-联合应用使碳钢的亚稳态孔蚀电位(Em)和孔蚀击穿电位(Eb)发生明显正移,并且显著提高了两者的差值,对抑制亚稳态小孔形核以及亚稳态小孔向稳态小孔转变的效果明显;MoO42-和NO2-联合应用可以在碳钢表面形成一层Fe2O3+Fe2(MoO4)3复合钝化膜,这层复合钝化膜的阻抗较大、缺陷较少,对碳钢的保护作用明显加强。The synergistic inhibition effect of MoO42-and NO2-on pitting corrosion of mild steel was studied by polarization curve, electrochemical impedance spectroscopy（EIS）, Mott-Schottky plot, and X-ray photoelectron spectroscopy（XPS）. The results showed that the metastable pitting potential（Em） and the pitting breakdown potential（Eb） of the mild steel shift significantly to much positive and the value of（Eb-Em） increased markedly when MoO42-and NO2-were applied at the same time, indicating that the combined application of MoO42-and NO2-not only restrained the initiation of metastable pits but also prevented the transition from metastable pits to stable pits, correspondingly where a composite passive film Fe2O3＋Fe2（MoO4）3could form on the mild steel surface.The impedance of the composite passive film Fe2O3＋Fe2（Mo O4）3formed in the solution containing MoO42-and NO2-was larger than that of the single passive films formed in the solutions with individual MoO42-or NO2-, while the defects of the former was less than that of the later one, therefore,the composite passive film could provide better protectiveness for the mild steel.

关 键 词：碳钢 小孔腐蚀 钝化膜 MoO4^2- NO^2- 

分 类 号：TG172[金属学及工艺—金属表面处理]