•  
  •  
 

Abstract

The failure process of inorganic zinc-rich/micaceous iron oxide epoxy/aliphatic polyurethane composite coatings in 3.5% NaCl solution under ultraviolet radiation(UV) was studied with Electrochemical Impedance Spectroscopy(EIS).The result shows that the protective property of the coating was enhanced with the increase of total coating thickness,but the degree of improvement reduced gradully as the coating thickness increased.The shielding effect of the micaceous iron oxide epoxy was mainly reflected in the initial period of the service process,while in later period the coating performance largely depended on the zinc-rich primer.The change of the water uptake in the composite coating presented a 'three-stage' characteristic.The thinner the coating,the quicker the water absorption to get saturation,and the faster the protective property of the coating decreased.

Keywords

composite coating, failure, EIS, coating thickness

Publication Date

2010-11-28

Online Available Date

2010-11-28

Revised Date

2010-11-28

Received Date

2010-11-28

References

[1]Mansfeld F.Use of electrochemical impedance spectros-copy for the study of corrosion protection by polymercoatings[J].Journal of Applied Electrochemical,1995,25(3):187.
[2]Colreavy J,Scantlebury J D.Electrochemical impedancespectroscopy to monitor the influence of surface prepara-tion on the corrosion characteristics of mild steel MAGwelds[J].Journal of Materials Processing Technology,1995,55(3/4):206-21.
[3]Fedrizzi L,Rodriguez F J,Rossi S,et al.The use of elec-trochemical techniques to study the corrosion behavior oforganic coatings on steel pretreated with sol-gel zirconiafilms[J].Electrochimica Acta,200l,46:3715-3720.
[4]Yang Li-xia(杨丽霞),Li Xiao-gang(李晓刚),ChengXue-qun(程学群),et al.Diffusion behavior of waterand chloride ion through acrylic polyurethane coating[J].Journal of Chinese Society for Corrosion and Pro-tection(中国腐蚀与防护学报),2006,26(1):6-10.
[5]Song Yi-quan(宋义全),Du Cui-wei(杜翠薇),Li Xi-ao-gang(李晓刚),et al.Effect of thickness of protectivecoating on corrosive characteristic of carbon steel Q235[J].Corrosion&Protection(腐蚀与防护),2003,24(10):432-434.
[6]Li Wei(李玮),Cao Jing-yi(曹京宜),Xiong Jin-ping(熊金平),et al.EIS of corrosion process of steel withzinc-rich epoxy/chlorinated rubber coatings[J].Journalof Chemical Industry and Engineering(China)(化工学报),2007,58(10):2543-2547.
[7]John Mclntyre M,Pham Ha Q.Electrochemcial imped-ance spectroscopy:a tool for organic coatings optimiza-tions[J].Progress in Organic Coatings,1996,27:201-207.
[8]Rammelt U,Reinhard G.Application of corrosion inhibi-tors in water-borne coatings[J].Progress in OrganicCoatings,1992,21:205.
[9]Zhang Jian-qing(张鉴清),Cao Chu-nan(曹楚南).Study and evaluation on organic coatings by electro-chemical impendence spectroscopy[J].Corrosion&Protection(腐蚀与防护),1998,19(3):99-104.
[10]Ochs H,Vogelsang J,Meyer G.Enhanced surfaceroughness of organic coatings due to UV-degradation:an unknown source of EIS-artifacts[J].Progress inOrganic Coatings.2003,46:182-190.
[11]Oliveira C G,Ferreira M G S.Ranking high-qualitypaint systems using EIS(Ι):Intact coatings[J].Cor-rosion Science,2003,45:139-147.
[12]Amirudin A,Thierry D.Application of electrochemicalimpedance spectroscopy to study the degradation ofpolymer coated metals[J].Progress of Organic Coat-ings,1995,26:1-28.
[13]Delucchi M,Turri S,Barbucci A,et al.Investigationon physic-chemical and electrochemical properties offluoropolyether coatings[J].Progress in OrganicCoatings,2002,44(3):227-332.
[14]Yang Li-hong(杨立红),Liu Fu-chun(刘福春),HanEn-hou(韩恩厚).Anti-corrosion performance studiesof the nano-Zno polyurethane coatings[J].ChineseJournal of Materials Research(材料研究学报),2006,20(4):355-361.
[15]Xie De-ming(谢德明),Tong Shao-ping(童少平),Hu Ji-ming(胡吉明),et al.Study on the electro-chemical behaviors of the zinc-rich paints based mul-tilayer organic coatings in NaCl solution[J].ActaMetallurgica Sinica(金属学报),2004,40(7):749-753.

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.