摘要
目的研究在0.1 mol/L NaCl硼酸缓冲溶液中,研究HCO_3~–对超级13Cr马氏体不锈钢的钝化及点蚀行为的影响。方法采用动电位极化、恒电位极化、Mott-Schottky曲线、电化学阻抗谱等电化学测试手段,并结合3D超景深显微镜进行点蚀形貌观察,研究超级13Cr马氏体不锈钢的电化学腐蚀行为。结果随着HCO_3~–浓度的增加,超级13Cr的钝化区间变宽,点蚀电位向正向移动,稳态点蚀发生的敏感性降低。HCO_3~–减少了超级13Cr亚稳态点蚀数量,降低了亚稳态点蚀电流密度峰值的平均值。随着HCO_3~–浓度的增大,超级13Cr钝化膜电阻Rf升高,电荷转移电阻Rct升高,钝化膜电容Cf逐渐减小。HCO_3~–使得超级13Cr钝化膜半导体特性由n型转变为n+p型双极性,且随着溶液中HCO_3~–浓度的增大,钝化膜中的施主密度ND和受主密度NA减小。结论 HCO_3~–的加入使得超级13Cr不锈钢钝化膜厚度增大,钝化膜内点缺陷密度降低,对基体的保护作用增强,抑制了超级13Cr的亚稳态和稳态点蚀发生。
The work aims to investigate the influence of HCO3^- on the passivation and pitting behavior of super 13Cr martensitic stainless steel in 0.1 mol/L NaCl containing borate acid buffer solution. Potentiodynamic and potentiostatic polarization tests, Mott-Schottky analysis and electrochemical impedance spectroscopy measurements were adopted to observe the pitting morphology and study the electrochemical corrosion behavior of super 13Cr martensitic stainless steel in combination with 3D ultra-depth-of-field microscope. The passive region of super 13Cr was enlarged with the increase of HCO3^- concentration, thus contributing to more positive pitting potential and decreasing the sensitivity of stable pitting. HCO3^- reduced the metastable pitting of super 13Cr and reduced the average value of peak current density of metastable pitting. With the increase of HCO3^- concentration, the passivation film resistance Rf and the charge transfer resistance Rct of super 13Cr increased, but the passivation film capacitance Cf decreased. The presence of HCO3^- changed the semiconductivity of the passive film from n-type to n+p type and the donor density ND and acceptor density NA in passivation film decreased with the increase of HCO3^- concentration. The addition of HCO3^- effectively thickens the passive film of super 13Cr stainless steel and lowers the density of point defects in the passive film, which thereby enhances the protective effect of the passive film on the steel matrix and inhibits the occurrence of metastable and stable pitting corrosion of super 13Cr.
作者
吕乃欣
刘开平
尹成先
付安庆
訾杨
雷晓维
LYU Nai-xin;LIU Kai-ping;YIN Cheng-xian;FU An-qing;ZI Yang;LEI Xiao-wei(School of Material Science and Engineering, Chang'an University, Xi'an 710064, China;State Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials, CNPC Tubular Goods Research Institute, Xi'an 710077, China;School of Metallurgical Engineering, Xi?an University of Architecture and Technology, Xi'an 710055, China;School of Science, Northwestern Polytechnical University, Xi?an 710072, China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2019年第5期36-42,共7页
Surface Technology
基金
国家科技重大专项(2016ZX05051)
中国石油天然气股份有限公司重大科技专项(2018E-1809)
陕西省创新人才推进计划-青年科技新星项目(2017KJXX-03)
陕西省重点研发计划项目(2018ZDXM-GY-171)
