亚硝酸钙阻锈剂对钢筋钝化膜的影响

Influence of Calcium Nitrite on Passive Films of Rebar in Simulated Concrete Pore Solution

为深入揭示亚硝酸盐阻锈剂提高钢筋混凝土结构耐久性的机理,采用动电位极化技术、X射线光电子能谱(XPS)和原子力显微镜(AFM)研究了亚硝酸钙阻锈剂对钢筋表面生成的钝化膜的影响。动电位极化研究结果表明:未添加阻锈剂时,钢筋发生点蚀的临界氯离子浓度在0.05~0.06 mol/L之间,添加亚硝酸钙阻锈剂后,钢筋发生点蚀的临界浓度增大至0.18~0.20 mol/L,表明亚硝酸钙阻锈剂提高了钢筋表面钝化膜的抗点蚀能力。X射线光电子能谱的研究结果表明:钢筋表面生成的钝化膜的成分均是由铁的氧化物(Fe_(ox))和铁的氢氧化物(Fe_(hydrox))组成,亚硝酸钙阻锈剂降低了钝化膜中Fe_(hydrox)的含量。原子力显微镜的研究结果表明:亚硝酸钙阻锈剂的添加使得钝化膜的表面更加光滑平整。

The effect of calcium nitrite inhibitor on the passive films of rebar was studied by potentiodynamic polarization measurements,X-ray photoelectron spectroscopy （XPS）,and atomic force microscopy（AFM）.The results from potentiodynamic polarization measurements showed that the critical chloride ion concentration for pitting took place in the range of 0.05～0.06 mol/L without the inhibitor,while the critical chloride ion concentration for pitting to occur in the solution with calcium nitrite inhibitor was in the range of 0.18 ～ 0.20 mol/L,which indicated that calciun nitrite inhibitor improved the resistance to pitting corrosion of the passive films.The research results from X-ray photoelectron spectroscopy showed that the components of the passive films of the rabar were composed of Feox and Fehya and the calcium nitrite inhibitor decreased the content of Fehydrox in the passive films of the rabar.Moreover,the results from atomic force microscopy showed that the surface of the passive films became more smooth and flat with the addition of calcium nitrite inhibitor.