材料期刊网

目的：评估缓蚀剂更换过程对核电厂冷冻水系统管材防腐的影响。方法采用线性极化、交流阻抗、强极化等电化学方法以及扫描电镜、X 射线衍射等表面分析技术,研究在从原缓蚀剂( NaNO2-Na2MoO4介质)向新缓蚀剂(LiOH-联氨介质)置换过程中,A106B碳钢及B10铜镍合金等两种主体管材的耐蚀性能变化。结果电化学测量表明,缓蚀剂置换过程中,两种管材的极化电阻Rp 和传递电阻Rt总体上逐渐增大,腐蚀电流Jcorr逐渐减小。表面分析表明,金属在原缓蚀剂中表面较光滑,换水过程中逐渐生成锈层,在新缓蚀剂中锈层未见明显发展。结论原NaNO2-Na2 MoO4介质可抑制金属阳极腐蚀过程,对金属材质有良好的保护效果。换水阶段,A106B碳钢发生均匀腐蚀,表面积聚有锈层；B10铜镍合金腐蚀程度较轻微,两种材质的耐蚀性能均未见明显降低。新LiOH-联氨介质可继续对带锈层金属起保护作用,可增强锈层致密性,使金属材质的耐蚀性进一步提高。以LiOH-联氨介质置换NaNO2-Na2 MoO4介质,作为核电厂冷冻水的缓蚀剂具有可行性及可操作性。

ABSTRACT:Objective To assess the influence of replacing inhibitors on the anti-corrosion treatment of chilled water system. Methods This paper studied the changes of corrosion resistance of A106B and B10 in the replacement process from the original in-hibitor ( NaNO2-Na2 MoO4 ) to a new inhibitor ( LiOH-N2 H4 ) by the means of electrochemical tests and surface analysis methods, such as linear polarization and AC impedance tests, SEM and XRD. Results The electrochemical results showed that the Rp value and Rt value of two pipe materials increased gradually while the Icorr value decreased in the replacement process of inhibitors. The surface analysis results showed that there was little rust on metal surfaces in original inhibitor solution, the rust layers were formed during the replacement process of inhibitors, and the rust layers were not thickened in the new inhibitor solution. Conclusion The original NaNO2-Na2 MoO4 medium had a good protective effect on the metal above by inhibiting anodic corrosion process. A106B carbon steel suffered a uniform corrosion and a rust layer formed on its surface, while B10 copper-nickel ally had a lesser degree of corrosion when the inhibitor was replacing, indicating the anti-corrosion property of the two materials was not decreased. The novel LiOH-N2 H4 medium, which can enhance the compactness of rust, was able to reduce the corrosion rate of rusted metal and increase the corrosion resistance of metals. It is feasible and operable to replace NaNO2-Na2 MoO4 with LiOH-N2 H4 medium for the anti-cor-rosion treatment of chilled water system of nuclear power plant.