Q345钢预热时间对熔结环氧粉末涂层防护性能的影响Ⅱ:涂层体系失效行为分析
|
摘要
通过EIS研究了210℃下基体的预热时间对熔结环氧粉末涂层/Q345钢体系失效行为的影响,利用SEM和EDS对涂层底部金属表面的腐蚀产物进行了分析,探讨了涂层体系结合性能与涂层下金属基体腐蚀过程的相关性。结果表明,基体的预热时间对涂层体系结合性能影响显著,结合性能的差异导致涂层下金属基体腐蚀过程不同。基体预热时间为0和2 h时,涂层体系结合性能差,涂层/金属界面处富氧,涂层下金属腐蚀反应开始较早,阴极反应主要为O_2还原反应,金属基体腐蚀向纵深发展速率快,金属基体易发生点蚀;基体预热时间为6和12 h时,涂层体系结合性能好,涂层下金属腐蚀反应开始较晚,涂层/金属界面处贫氧,铁氧化物参与阴极反应,金属基体腐蚀横向发展快,更接近于均匀腐蚀行为。
The effect of substrate preheating time at 210 ℃ on the degradation behavior of fusion bonded epoxy powder coating/Q345 steel system was studied by electrochemical impedance spectroscopy(EIS). The corrosion products of the substrate beneath the coating were characterized by means of scanning electron microscopy(SEM) and energy dispersive spectrometer(EDS). Results showed that the substrate preheating time had a significant effect on the adhesion of the coating to the substrate,which led to the different corrosion behavior of the metal substrate beneath the coating. The coating exhibited poor bonding performance when the substrate preheating time was less than 2 h, which resulted in the occurrence of premature corrosion of the substrate metal. This might be due to the oxygen enrichment in the interface gap of coating/metal and the cathode reaction was mainly O_2 reduction reaction. In this case, the corrosion of the substrate metal developed rapidly along the depth and the substrate metal was prone to pitting. When the substrate preheating time was 6 and 12 h, the coating showed good bond-ing performance and the corrosion reaction of the substrate metal beneath the coating happened much later. This could be supposed that the excellent adhesion of the coating made the oxygen deprivation at the interface of coating/metal and iron oxide was reduced in the cathode reaction. The corrosion of the substrate metal developed laterally and the corrosion behavior was closer to be uniform corrosion.
The effect of substrate preheating time at 210 ℃ on the degradation behavior of fusion bonded epoxy powder coating/Q345 steel system was studied by electrochemical impedance spectroscopy(EIS). The corrosion products of the substrate beneath the coating were characterized by means of scanning electron microscopy(SEM) and energy dispersive spectrometer(EDS). Results showed that the substrate preheating time had a significant effect on the adhesion of the coating to the substrate,which led to the different corrosion behavior of the metal substrate beneath the coating. The coating exhibited poor bonding performance when the substrate preheating time was less than 2 h, which resulted in the occurrence of premature corrosion of the substrate metal. This might be due to the oxygen enrichment in the interface gap of coating/metal and the cathode reaction was mainly O_2 reduction reaction. In this case, the corrosion of the substrate metal developed rapidly along the depth and the substrate metal was prone to pitting. When the substrate preheating time was 6 and 12 h, the coating showed good bond-ing performance and the corrosion reaction of the substrate metal beneath the coating happened much later. This could be supposed that the excellent adhesion of the coating made the oxygen deprivation at the interface of coating/metal and iron oxide was reduced in the cathode reaction. The corrosion of the substrate metal developed laterally and the corrosion behavior was closer to be uniform corrosion.
引文
[1]Cao H J,Wei Y H,Zhao H T,et al.Effect of preheating time on protective performance of fusion bonded epoxy powder coating on Q345 steel I:Analysis of interface bonding[J].J.Chin.Soc.Corros.Prot.,2018,38:124(曹海娇,魏英华,赵洪涛等.Q345钢预热时间对熔结环氧粉末涂层防护性能的影响I:界面结合性能分析[J].中国腐蚀与防护学报,2018,38:124)
[2]Liu D,Wu F,Zhao W J,et al.Advance in anticorrosion performance of epoxy resin[J].Mater.China,2015,34:852(刘丹,伍方,赵文杰等.环氧树脂防腐性能研究进展[J].中国材料进展,2015,34:852)
[3]Elsner C I,Cavalcanti E,Ferraz O,et al.Evaluation of the surface treatment effect on the anticorrosive performance of paint systems on steel[J].Prog.Org.Coat.,2003,48:50
[4]Jamali S S,Mills D J.Steel surface preparation prior to painting and its impact on protective performance of organic coating[J].Prog.Org.Coat.,2014,77(12):2091
[5]Vakili H,Ramezanzadeh B,Amini R.The corrosion performance and adhesion properties of the epoxy coating applied on the steel substrates treated by cerium-based conversion coatings[J].Corros.Sci.,2015,94:466
[6]Wielant J,Posner R,Hausbrand R,et al.Cathodic delamination of polyurethane films on oxide covered steel-Combined adhesion and interface electrochemical studies[J].Corros.Sci.,2009,51:1664
[7]Cho K,Cho E C.Effect of the microstructure of copper oxide on the adhesion behavior of epoxy/copper leadframe joints[J].J.Adhes.Sci.Technol.,2000,14:1333
[8]Zhao H T,Lu W Z,Li J,et al.Electrochemical behavior of solventfree epoxy coating at simulated flowing sea water in erosion condition[J].J.Chin.Soc.Corros.Prot.,2016,36(4):295(赵洪涛,陆卫中,李京等.无溶剂环氧防腐涂层在模拟海水冲刷条件下的电化学行为[J].中国腐蚀与防护学报,2016,36(4):295)
[9]Zhang J T,Hu J M,Zhang J Q,et al.Studies of impedance models and water transport behaviors of polypropylene coated metals in Na Cl solution[J].Prog.Org.Coat.,2004,49:293
[10]Guan M R.The action mechanism of anion Cl-on pitting corrosion[J].J.Qingdao Inst.Arch.Eng.,1997,18(3):95(管明荣.Cl-离子对孔蚀的作用机理[J].青岛建筑工程学院学报,1997,18(3):95)
[11]Cao C N,Zhang J Q.An Introduction to Electrochemical Impedance Spectroscopy[M].Beijing:Science Press,2002(曹楚南,张鉴清.电化学阻抗谱导论[M].北京:科学出版社,2002)
[12]Leng A,Streckel H,Stratmann M.The delamination of polymeric coatings from steel.Part 1:Calibration of the Kelvinprobe and basic delamination mechanism[J].Corros.Sci.,1998,41:547
[13]Lai C X.Water induced mechanism of protective film peeling and its prevention[J].Corros.Sci.Prot.Technol.,1992,4:127(赖春晓.水引起保护涂膜剥离的机理及防止方法[J].腐蚀科学与防护技术,1992,4:127)
[14]Hoffmann K,Stratmann M.In-situ M??bauer spectroscopic investigations of phase transformations in iron oxide layers below organic coatings[J].Ber.Bunsenges.Phys.Chem.,1989,93:1389
[15]Leng A,Streckel H,Hofmann K,et al.The delamination of polymeric coatings from steel.Part 3:Effect of the oxygen partial pressure on the delamination reaction and current distribution at the metal/polymer interface[J].Corros.Sci.,1998,41:599
[16]Deflorian F,Rossi S.An EIS study of ion diffusion through organic coatings[J].Electrochim.Acta,2006,51:1736
[17]Zhao Z Y,Wang J.Progresses in cathodic delamination of organic coatings from metals[J].J.Chin.Soc.Corros.Prot.,2008,28:116(赵增元,王佳.有机涂层阴极剥离作用研究进展[J].中国腐蚀与防护学报,2008,28:116)
[2]Liu D,Wu F,Zhao W J,et al.Advance in anticorrosion performance of epoxy resin[J].Mater.China,2015,34:852(刘丹,伍方,赵文杰等.环氧树脂防腐性能研究进展[J].中国材料进展,2015,34:852)
[3]Elsner C I,Cavalcanti E,Ferraz O,et al.Evaluation of the surface treatment effect on the anticorrosive performance of paint systems on steel[J].Prog.Org.Coat.,2003,48:50
[4]Jamali S S,Mills D J.Steel surface preparation prior to painting and its impact on protective performance of organic coating[J].Prog.Org.Coat.,2014,77(12):2091
[5]Vakili H,Ramezanzadeh B,Amini R.The corrosion performance and adhesion properties of the epoxy coating applied on the steel substrates treated by cerium-based conversion coatings[J].Corros.Sci.,2015,94:466
[6]Wielant J,Posner R,Hausbrand R,et al.Cathodic delamination of polyurethane films on oxide covered steel-Combined adhesion and interface electrochemical studies[J].Corros.Sci.,2009,51:1664
[7]Cho K,Cho E C.Effect of the microstructure of copper oxide on the adhesion behavior of epoxy/copper leadframe joints[J].J.Adhes.Sci.Technol.,2000,14:1333
[8]Zhao H T,Lu W Z,Li J,et al.Electrochemical behavior of solventfree epoxy coating at simulated flowing sea water in erosion condition[J].J.Chin.Soc.Corros.Prot.,2016,36(4):295(赵洪涛,陆卫中,李京等.无溶剂环氧防腐涂层在模拟海水冲刷条件下的电化学行为[J].中国腐蚀与防护学报,2016,36(4):295)
[9]Zhang J T,Hu J M,Zhang J Q,et al.Studies of impedance models and water transport behaviors of polypropylene coated metals in Na Cl solution[J].Prog.Org.Coat.,2004,49:293
[10]Guan M R.The action mechanism of anion Cl-on pitting corrosion[J].J.Qingdao Inst.Arch.Eng.,1997,18(3):95(管明荣.Cl-离子对孔蚀的作用机理[J].青岛建筑工程学院学报,1997,18(3):95)
[11]Cao C N,Zhang J Q.An Introduction to Electrochemical Impedance Spectroscopy[M].Beijing:Science Press,2002(曹楚南,张鉴清.电化学阻抗谱导论[M].北京:科学出版社,2002)
[12]Leng A,Streckel H,Stratmann M.The delamination of polymeric coatings from steel.Part 1:Calibration of the Kelvinprobe and basic delamination mechanism[J].Corros.Sci.,1998,41:547
[13]Lai C X.Water induced mechanism of protective film peeling and its prevention[J].Corros.Sci.Prot.Technol.,1992,4:127(赖春晓.水引起保护涂膜剥离的机理及防止方法[J].腐蚀科学与防护技术,1992,4:127)
[14]Hoffmann K,Stratmann M.In-situ M??bauer spectroscopic investigations of phase transformations in iron oxide layers below organic coatings[J].Ber.Bunsenges.Phys.Chem.,1989,93:1389
[15]Leng A,Streckel H,Hofmann K,et al.The delamination of polymeric coatings from steel.Part 3:Effect of the oxygen partial pressure on the delamination reaction and current distribution at the metal/polymer interface[J].Corros.Sci.,1998,41:599
[16]Deflorian F,Rossi S.An EIS study of ion diffusion through organic coatings[J].Electrochim.Acta,2006,51:1736
[17]Zhao Z Y,Wang J.Progresses in cathodic delamination of organic coatings from metals[J].J.Chin.Soc.Corros.Prot.,2008,28:116(赵增元,王佳.有机涂层阴极剥离作用研究进展[J].中国腐蚀与防护学报,2008,28:116)