摘要
应用动电位极化、电化学阻抗谱与电容电位法等方法研究了Cr8Ni2合金耐蚀钢筋在不同pH值(13.5~9.0)模拟混凝土孔溶液中的钝化行为.结果表明:在相同pH值下,随着钝化时间延长,合金耐蚀钢筋钝化不断强化,3 d后钝化趋于稳定;随着pH值下降,合金耐蚀钢筋钝化并未弱化,反而显著增强,表明新型合金耐蚀钢筋在较低p H下亦能保持良好致钝性能.采用XPS分析合金耐蚀钢筋钝化膜组成结构,分析结果表明:合金耐蚀钢筋钝化膜为双层结构,外层主要为Fe3O4,Fe2O3及FeOOH(Fe(OH)3),内层为Cr2O3和CrOOH(Cr(OH)3).随着环境溶液pH值降低,合金耐蚀钢筋钝化膜Fe氧化物含量逐渐减少,而铬氧化物含量明显增大,低pH值下高含量Cr氧化物维持了合金耐蚀钢筋钝化膜良好稳定性和优越耐蚀性,从而使耐蚀钢筋钝化强化.
The passive behaviour of Cr8Ni2 alloy corrosion-resistant steel which was immersed in simulating concrete pore solutions with different pH values( 13. 5 to 9. 0) was investigated by various electrochemical techniques including potentiodynamic polarization,electrochemical impedance spectroscopy and capacitance measurements. The results showthat the passivity of the alloy corrosion-resistant steel enhances gradually with the increase of the immersion time,and tends to stability when immersed for 3 days with the same pH values. The passivity is not declined but increases significantly with decrease of pH values,indicating excellent passive performance of the alloy corrosion-resistant steel at lower pH values. The chemical composition of passive films was investigated using XPS( Xray Photoelectron Spectroscopy). The analytical results showthat the passive film formed on the alloy corrosion-resistant steel presents a bilayer structure composed of Cr and Fe oxides / hydroxides. The out layer contains mainly Fe3O4,Fe2O3 and FeOOH( Fe( OH)3),and the inner layer has Cr2O3 and CrOOH( Cr( OH)3). The films on the alloy corrosion-resistant steel become enriched obviously in Cr oxides while depleted in Fe species as p H values dropping. High chromium oxides provide the films favourable stability and superior corrosion resistance,strengthening the passivity of the alloy corrosionresistant steel at lower p H values.
出处
《东南大学学报(自然科学版)》
EI
CAS
CSCD
北大核心
2016年第1期152-159,共8页
Journal of Southeast University:Natural Science Edition
基金
国家自然科学基金资助项目(51278098)
国家重点基础研究发展计划(973计划)资助项目(2015CB655100)
江苏省产学研联合创新资金资助项目(BY2013091)
关键词
合金耐蚀钢筋
PH值
钝化行为
钝化膜
alloy corrosion resistant steel
pH values
passive behaviour
passive film