摘要
通过开路电位、动电位极化、电化学阻抗谱、X射线光电子能谱(XPS)、扫描电镜(SEM)等分析手段研究了酸性含氯溶液pH的变化对汽轮机末级叶片用钢14Cr12Ni3WMoV电化学腐蚀行为的影响。结果表明:随着酸性含氯溶液pH的减小,材料表面阻抗减小,腐蚀速率和点蚀敏感性均增大;点蚀发生时,pH的减小会导致蚀坑沿纵向的发展减缓,而在无明显均匀腐蚀时其沿径向的发展加快;当溶液pH5时,不锈钢钝化膜主要由Fe和Cr相应的氧化物和氢氧化物组成,pH2时,钝化膜主要由Cr的氢氧化物、氧化物和高价态Mo6+的相应化合物组成,含氯溶液pH的减小,会显著加速不锈钢钝化膜中Fe的溶解,从而钝化膜的稳定性降低,材料的耐蚀性下降。
The effect of pH value on the electrochemical corrosion behavior of 14Cr12Ni3WMoV steel,which is often used for steam turbine final blade,in acidic chlorine-containing solutions was investigated by open circuit potential measurement,potentiodynamic polarization,electrochemical impedance spectroscopy,X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy(SEM).The results show that with the decrease of pH value of acidic chlorine-containing solutions,the impedance of the steel surface decreases,while the corrosion rate and pitting sensitivity increase.When pitting occurs,the vertical growth of pits on the steel surface slowed down,while their lateral growth accelerated without obvious uniform corrosion.The passivation film of 14Cr12Ni3WMoV stainless steel is mainly composed of oxides and hydroxides of Fe and Cr in the solution of pH5,while the passivation film is mainly composed of hydroxides and oxides of Cr and corresponding compounds of high valence state Mo6+in the solution of pH2.With the decrease in pH value of the acidic chlorine-containing solution,the dissolution of Fe in the passivation film on the steel is accelerated significantly,so that the stability of the passivation film decreases,thereby the corrosion resistance of the stainless steel decreases.
作者
冉斗
孟惠民
刘星
李全德
巩秀芳
倪荣
姜英
龚显龙
戴君
隆彬
RAN Dou;MENG Huimin;LIU Xing;LI Quande;GONG Xiufang;NI Rong;JIANG Ying;GONG Xianlong;DAI Jun;LONG Bin(Institute of Advance Materials and Technology,University of Science and Technology Beijing,Beijing 100083,China;State Key Laboratory of Long-life High Temperature Materials,Deyang 618000,China;Dongfang Turbine Co.,LTD.,Deyang 618000,China)
出处
《中国腐蚀与防护学报》
CAS
CSCD
北大核心
2021年第1期51-59,共9页
Journal of Chinese Society For Corrosion and Protection
基金
四川省科技计划应用基础研究项目(2019YJ0699)
长寿命高温材料国家重点实验室开放课题(DTCC28EE190230)。
关键词
电化学腐蚀
不锈钢
汽轮机叶片
PH
钝化膜
点蚀
electrochemistry corrosion
stainless steel
steam turbine blade
pH
passivation film
pitting corrosion
