摘要
采用动电位极化曲线和电化学阻抗谱等测量方法,研究了Cl-浓度、溶解氧含量以及pH对核电汽轮机25Cr2Ni2MoV转子钢焊接接头电偶腐蚀性能的影响。结果表明:在不同环境变量下,转子钢焊接接头均存在一定程度的电偶腐蚀效应,Cl-浓度的增大显著地增强了焊接接头的电偶腐蚀效应,而溶解氧含量的升高却降低了焊接接头的电偶腐蚀效应,但是酸性条件下pH变化对电偶腐蚀效应的影响并不明显。
The effect of chloride ion concentration, dissolved oxygen(DO) concentration and pH value of the water on the galvanic corrosion performance of the weld joint of 25Cr2Ni2MoV steel used for nuclear steam turbine rotor were investigated by means of potentiodynamic polarization measurements and electrochemical impedance spectroscopy. The results reveal that under different environmental variables selected, the welded joints of rotor steel exhibit a certain degree of galvanic corrosion effect, in which weld metal(WM) is preferentially corroded as the anode, and the corrosion resistance of WM and base metal(BM) decreases with the increasing chloride ion concentration, increasing dissolved oxygen content and decreasing pH value. In the environment of low chloride ion concentration(0.035 and 35 mg/L), the electrode process of WM and BM is controlled by ion diffusion, while in other environments, the electrode process is controlled by electrochemical activation. In addition, the increase of chloride ion concentration significantly enhances the galvanic corrosion effect of welded joints. The increase of dissolved oxygen concentration reduces the galvanic corrosion effect of welded joints, while the change of pH value under acidic conditions has no obvious effect on galvanic corrosion effects.
作者
苍雨
黄毓晖
翁硕
轩福贞
CANG Yu;HUANG Yuhui;WENG Shuo;XUAN Fuzhen(East China University of Science and Technology,Key Laboratory of Pressure System and Safety of Ministry of Education,Shanghai 200237,China;University of Shanghai for Science and Technology,Shanghai 200093,China)
出处
《中国腐蚀与防护学报》
CAS
CSCD
北大核心
2021年第3期318-326,共9页
Journal of Chinese Society For Corrosion and Protection
基金
国家自然科学基金(51875202)。
关键词
焊接接头
电偶腐蚀
动电位极化
电化学阻抗谱
welded joint
galvanic corrosion
potentiodynamic polarization
electrochemical impedance spectroscopy
