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.292 北京科技大学学报 第29卷 者关系到产物膜能否在金属基体表面稳定地存在而 膜厚度增大，但对膜保护性能的影响有限，致密度 不被损坏或剥离，在实验中改变C02分压时，腐蚀 的提高是腐蚀产物膜保护性能提高的主要原因， 产物膜都没有脱落现象，也就是说虽然膜的稳定性 和膜一基粘结力的值发生改变，但是都能保证膜不 参考文献 被流体的冲刷破坏；而在任何CO2分压下膜的覆盖 [1]Kermani M B.Matterials Optimization for Oil and Gas Sour Pro 度都为100%，所以覆盖度也不对膜的保护性能产 duction.Houston:NACE International.2000:156 [2]Linter B R.Burstein G T.Reaction of pipeline steels in carbon 生影响，即覆盖度、稳定性与膜一基粘接力都没有影 dioxide solutions.Corros Sci.1999.42:117 响到膜的保护作用，所以致密度是唯一的影响因素， [3]Kermani M B.Carbon dioxide corrosion in oil and gas production- 即CO2分压上升时导致腐蚀产物膜保护性能提高 a compendium.Corrosion.2003,59:659 的根本原因是膜致密度的提高 [4]Videm K.Dugstad A.Lunde L.Parametric Study of CO2 Corro- sion of Carbon Steel.Houston:NACE International,1994:14 3结论 [5]Videm K.Dugstad A.Galvanic Influence of CO2 Corrosion. Houston:NACE International.2000:468 (1)在65℃和90℃时、0.1一1.5MPa范围内， [6]Warrd C D.Lotz U,Dugstad A.Influence of Liquid Flow Veloe- 腐蚀速率随C02分压升高而增大， ity on CO2 Corrosion:A Semi-Empirical Mode.Houston:NACE (2)65℃时形成的腐蚀产物膜的局部缺陷与金 International.1995:128 属的点蚀有重要关联，在0.1~1.5MPa范围内， [7]Moraes F D,Shadley J R,Chen J.Characterization of CO2 Cor rosion Product Scales Related to Environmental Conditions.Hous- C02分压升高有利于减少膜的局部缺陷， ton:NACE International.2000:30 (3)在0.1~1.5MPa范围内，随着成膜时C02 [8]Videm K.Dugstad A.Effect of Flow Rate.pH.Fe concentra- 分压的升高，有膜N80钢的腐蚀电流减小，即高 tion and Steel Quality on the CO2 Corrosion of Carbon Steels- CO2分压下形成的腐蚀产物膜具有更好的保护作 Houston:NACE International,1987:42 [9]陈长风，路民旭，赵国仙，等，N80油套管钢C02腐蚀产物膜特 用.相比65℃，90℃各分压下成膜试样的电化学交 征，金属学报，2002,38：411 流阻抗谱显示出受扩散控制的特征，膜的保护性能 [10]陈长风，赵国仙，路民旭，等.N80钢C02腐蚀产物膜研究 对C02分压的变化更为敏感， 中国腐蚀与防护学报，2002,22：14 (4)在0.1~1.5MPa范围内，C02分压上升时 Influence of CO2 partial pressure on the protection property of corrosion scale formed on N80 steel CHEN Dong,LIU Wei,LU Minxu,WU Yinshun,HOU Shiying,CHEN Yingfeng Materials Science and Engineering School.University of Science and Technology Beijing Beijing Key Laboratory of Corrosion,Erosion,Surface Technology.Beijing 100083.China ABSTRACT Corrosion tests of N80 steel under different CO2 partial pressures at 65C and 90C were carried out by a self-made high-temperature high pressure autoclave.The mass losses of the steel under different CO2 partial pressures were measured.The morphologies of the corrosion scale and the descaled N80 steel were ob- served by SEM,and the thickness of the scale was measured.Electrochemical polarization curve and impedance spectroscopy analysis(EIS)were employed to study the corrosion behavior of N80 pre-corroded under different COz partial pressures at two temperatures.The results show that as the CO2 partial pressure increases,the pro- tection property of the scale becomes better,but the corrosion rate increases because of the increase in solution corrosivity.The local defects of the corrosion scale are responsible for the pitting corrosion of metal matrix,the increase in CO2 partial pressure makes for reducing the defects.Compared with 65C,the protection property of the corrosion scale is more sensitive to the change of CO2 partial pressure at 90C. KEY WORDS N80 steel;corrosion scale:CO2 partial pressure;EIS;polarization curve者关系到产物膜能否在金属基体表面稳定地存在而 不被损坏或剥离在实验中改变 CO2 分压时腐蚀 产物膜都没有脱落现象也就是说虽然膜的稳定性 和膜—基粘结力的值发生改变但是都能保证膜不 被流体的冲刷破坏；而在任何 CO2 分压下膜的覆盖 度都为100％所以覆盖度也不对膜的保护性能产 生影响．即覆盖度、稳定性与膜—基粘接力都没有影 响到膜的保护作用所以致密度是唯一的影响因素 即 CO2 分压上升时导致腐蚀产物膜保护性能提高 的根本原因是膜致密度的提高． 3 结论 （1） 在65℃和90℃时、0∙1～1∙5MPa 范围内 腐蚀速率随 CO2 分压升高而增大． （2）65℃时形成的腐蚀产物膜的局部缺陷与金 属的点蚀有重要关联在0∙1～1∙5MPa 范围内 CO2 分压升高有利于减少膜的局部缺陷． （3） 在0∙1～1∙5MPa 范围内随着成膜时 CO2 分压的升高有膜 N80钢的腐蚀电流减小即高 CO2分压下形成的腐蚀产物膜具有更好的保护作 用．相比65℃90℃各分压下成膜试样的电化学交 流阻抗谱显示出受扩散控制的特征膜的保护性能 对 CO2 分压的变化更为敏感． （4） 在0∙1～1∙5MPa 范围内CO2 分压上升时 膜厚度增大但对膜保护性能的影响有限．致密度 的提高是腐蚀产物膜保护性能提高的主要原因． 参 考 文 献 ［1］ Kermani M B．Matterials Optimization for Oil and Gas Sour Production．Houston：NACE International2000：156 ［2］ Linter B RBurstein G T．Reaction of pipeline steels in carbon dioxide solutions．Corros Sci199942：117 ［3］ Kermani M B．Carbon dioxide corrosion in oil and gas productiona compendium．Corrosion200359：659 ［4］ Videm KDugstad ALunde L．Parametric Study of CO2Corrosion of Carbon Steel．Houston：NACE International1994：14 ［5］ Videm KDugstad A．Galvanic Influence of CO2 Corrosion． Houston：NACE International2000：468 ［6］ Warrd C DLotz UDugstad A．Influence of Liquid Flow Velocity on CO2Corrosion：A Sem-i Empirical Mode．Houston：NACE International1995：128 ［7］ Moraes F DShadley J RChen J．Characterization of CO2Corrosion Product Scales Related to Environmental Conditions．Houston：NACE International2000：30 ［8］ Videm KDugstad A．Effect of Flow RatepHFe 2＋ concentration and Steel Quality on the CO2 Corrosion of Carbon Steels． Houston：NACE International1987：42 ［9］ 陈长风路民旭赵国仙等．N80油套管钢 CO2 腐蚀产物膜特 征．金属学报200238：411 ［10］ 陈长风赵国仙路民旭等．N80钢 CO2 腐蚀产物膜研究． 中国腐蚀与防护学报200222：14 Influence of CO2 partial pressure on the protection property of corrosion scale formed on N80steel CHEN DongLIU WeiLU MinxuW U Y inshunHOU ShiyingCHEN Y ingfeng Materials Science and Engineering SchoolUniversity of Science and Technology Beijing ＆ Beijing Key Laboratory of CorrosionErosionSurface TechnologyBeijing100083China ABSTRACT Corrosion tests of N80steel under different CO2partial pressures at 65℃ and90℃ were carried out by a self-made high-temperature high-pressure autoclave．The mass losses of the steel under different CO2 partial pressures were measured．The morphologies of the corrosion scale and the descaled N80steel were observed by SEMand the thickness of the scale was measured．Electrochemical polarization curve and impedance spectroscopy analysis （EIS） were employed to study the corrosion behavior of N80pre-corroded under different CO2partial pressures at two temperatures．The results show that as the CO2partial pressure increasesthe protection property of the scale becomes betterbut the corrosion rate increases because of the increase in solution corrosivity．The local defects of the corrosion scale are responsible for the pitting corrosion of metal matrixthe increase in CO2partial pressure makes for reducing the defects．Compared with65℃the protection property of the corrosion scale is more sensitive to the change of CO2partial pressure at 90℃． KEY WORDS N80steel；corrosion scale；CO2partial pressure；EIS；polarization curve ·292· 北 京 科 技 大 学 学 报 第29卷