NO_2^-及其浓度对混凝土模拟孔隙液中碳钢早期孔蚀的作用  

Inhibition Effect of NO_2^- and Its Concentration on Metastable Pitting Corrosion of Carbon Steel in a Simulated Concrete Pore Solution

作　　者：唐聿明[1] 牛犇[1] 林冰[1] 赵旭辉[1] 左禹[1] 

机构地区：[1]北京化工大学材料科学与工程学院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2期123-128,共6页Corrosion Science and Protection Technology

基　　金：国家自然科学基金项目(51171014和5121001)资助

摘　　要：应用动电位极化、Mott-Schottky曲线测试和XPS测试等方法研究了含0.05 mol/L Cl-,p H值为11的混凝土模拟孔隙液中常用缓蚀剂亚硝酸盐对Q235碳钢小孔腐蚀早期行为的影响。结果显示,NO2-对稳定孔蚀和亚稳态孔蚀均有很好的抑制作用,亚稳态孔蚀电位和稳定孔蚀电位均随着NO2-浓度的增加而增大,且影响趋势接近。NO2-浓度较低时,对孔蚀的抑制作用很明显,超过0.03 mol/L后抑制作用变化不大。这是因为,NO2-浓度增大,钝化膜中更多的Fe2+被氧化为Fe3+,膜中的氧空位缺陷浓度降低,因此小孔的形核受到抑制。The Effect of NO2-on the early stages of pitting corrosion of Q235 carbon steel in a simulated concrete pore solution(p H=11) was studied by means of polarization curves, Mott-Schottky curves and XPS methods. It was found that, NO2-inhibits both the stable pitting corrosion and the metastable pitting corrosion. The metastable pitting corrosion potential and the stable pitting corrosion potential increase with the increase of NO2-concentration and follow the similar trend. The nucleation process of pits can apparently be inhibited by a low content of NO2-, however this effect increases only slightly as the NO2-content higher than a critical value about 0.03 mol/L. With the increase of NO2-concentration, more Fe2 +in the passive film can be oxidized into Fe3 +and thereby,the defect density related with oxygen vacancies decreases, so the nucleation process of pits may be inhibited.

关 键 词：碳钢 混凝土模拟孔隙液 孔蚀 亚稳态孔蚀 NO2- 

分 类 号：TG172[金属学及工艺—金属表面处理]