|
|
|
| EIS STUDY ON THE DETERIORATION PROCESS OF ORGANIC COATINGS UNDER IMMERSION AND CYCLIC WET-DRY CONDITIONS |
| ZHANG Wei1,2, WANG Jia2,3, ZHAO Zengyuan4, LIU Xueqing5 |
1. Qingdao Marine Corrosion Institute, Central Research Institute for Steel and Iron, Qingdao 266071
2. College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266003
3. State Key Laboratory for Corrosion and Protection, Shenyang 110015
4. Offshore Oil Engineering Qingdao Co., Ltd, Qingdao 266555
5. National Oceanographic Center, Qingdao 266071 |
|
|
|
|
Abstract Comparing between immersed and cyclic wet-dry conditions, the deterioration processes of the organic coatings on carbon steel surface have been comparatively studied by using electrochemical impedance spectroscopy (EIS). The wet-dry cycles were carried out in the alternating conditions by immersing in a 3.5% sodium chloride solution and drying at 25° and 50% RH for 4 h respectively. Coating resistance, Rf, coating capacitance, Cf, and double layer capacitance, Cd, were monitored continuously and separately under above two conditions. The percentages of the interface active area, Aw, were estimated from the obtained double layer capacitance, Cd. According to the EIS characteristics, the entire deterioration processes under two above-mentioned conditions can be divided into three main stages, consisting of the medium penetration into coatings, corrosion initiation and corrosion extension underlying coatings. In comparison with the immersed, the wet-dry cycles greatly accelerated the entire deterioration process; especially the corrosion initiation and the corrosion extension periods, leading the paint system lose its anti-corrosive performance in a short period. However, the underlying substrate corrosion of the cyclic coatings was far less serious than the immersed; even the delaminating area was seven times more than the immersed. The acceleration mechanism of the coatings and underlying metal corrosion under wet-dry cycles was discussed based on the above results.
|
|
Received: 13 April 2010
|
|
|
|
Corresponding Authors:
WANG Jia
E-mail: jwang@mail.ouc.edu.cn
|
| [1] Deflorian F, Fedrizzi L, Bonora P L. Influence of the photo-oxidative degradation on the water barrier and corrosion protection properties of polyester paints [J]. Corros. Sci., 1996, 38: 1697-1708[2] Destreri M D G, Vogelsang J, Fedrizzi L, et al. Water up-take evaluation of new waterborne and high solid epoxy coatings [J]. Prog. Org. Coat., 1999,37: 69-81[3] Yang X F, Tallman D E, Croll S G, et al. Morphological changes in polyurethane coatings on exposure to water [J]. Polym. Degrad. Stab., 2002,77: 391-396[4] Park J H, Lee G D, Ooshige H, et al. Monitoring of water uptake in organic coatings under cyclic wet--dry condition [J]. Corros. Sci., 2003,45: 1881-1894[5] Stratmann M, Streckel H, Kim K T, et al. On the atmospheric corrosion of metals which are covered with thin electrolyte layers-Ⅲ.the measurement of polarization curves on metal surfaces which are covered by thin electrolyte layers [J]. Corros. Sci., 1990, 30: 715-734[6] Leng A, Streckel H, Stratmann M. 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.,1999, 41: 599-620[7] Furbeth W, Stratmann M. The delamination of polymeric coatings from electrogalvanised steel--a mechanistic approach.: Part 1: delamination from a defect with intact zinc layer [J]. Corros.Sci., 2001, 43: 207-227[8] Tomashov N D. Development of the electrochemical theory of metallic corrosion [J]. Corrosion,1964, 20: 7t-14t[9] Tsuru T, Nishikata A, Wang J. Electrochemical studies on corrosion under a water film [J]. Mater.Sci. Eng., 1995, A198: 161-168[10] Mansfeld F. Corrosion Processes [M]. London：Applied Science Publishers, 1982[11] Wang J, Tsuru T. An investigation on oxygen reduction under thin electrolyte layer using Kelvin probe reference electrode [J]. J. Chin. Soc.Corros. Prot., 1995, 15(3): 180-188 (王佳，水流彻. 使用Kelvin探头参比电极技术研究液层厚度对氧还原速度的影响 [J]. 中国腐蚀与防护学报, 1995, 15(3): 180-188)[12] Yadav A P, Nishikata A, Tsuru T. Electrochemical impedance study on galvanized steel corrosion under cyclic wet--dry conditions influence of time of wetness [J]. Corros. Sci., 2004, 46: 169-181[13] Veracruz R P, Nishikata A, Tsuru T. Pitting corrosion mechanism of stainless steels under wet-dry exposure in chloride-containing environment [J]. Corros. Sci., 1998, 40(1): 125-139[14] Zhang J Q, Cao C N Study and evaluation on coatings by electrochemical impedance spectroscopy [J]. Corros. Prot., 1998, 19(3): 99-104 (张鉴清, 曹楚南. 电化学阻抗谱方法研究评价有机涂层 [J]. 腐蚀与防护, 1998, 19(3): 99-104)[15] Gao Z M, Song S Z, Xu Y H. Electrochemical impedance spectroscope analysis of coating deterioration process with Kohonen neural networks [J]. J. Chin.Soc. Corros. Prot., 2005, 25(2): 106-109 (高志明, 宋诗哲, 徐云海. 涂层失效过程电化学阻抗谱的神经网络分析 [J]. 中国腐蚀与防护学报, 2005, 25(2): 106-109)[16] Zhao X, Wang J, Wang Y H, et al. Analysis of deterioration process of organic protective coating using EIS assisted by SOM network [J].Electrochem. Commun., 2007, 9: 1394-1399[17] Zhang W, Wang J, Zhao Z Y, et al. Study on deterioration process of organic coatings by EIS and SKP [J]. Chem. J. Chin. Univ., 2009,30: 762-766 (张伟，王佳，赵增元等. 有机涂层失效过程的电化学阻抗和电位分布响应特征 [J]. 高等学校化学学报, 2009, 30: 762-766)[18] Howard R L, Lyon S B, Scantlebury J D. Accelerated tests for prediction of cut edge corrosion of coil-coated architectural cladding.Part II: Cyclic immersion [J]. Prog. Org.Coat., 1999, 37: 99-106[19] Gamal A, El-Mahdy, Nishikata A, et al. Electrochemical corrosion monitoring of galvanized steel under cyclic wet--dry conditions [J]. Corros.Sci., 2000, 42: 183-194[20] Gamal A, El-Mahdy. Atmospheric corrosion of copper under wet/dry cyclic conditions [J].Corros. Sci., 2005, 47: 1370-1383[21] Lendvay-Gyorik G, Pajkossy T, Lengyel B. Corrosion-protection properties of water-borne paint coatings as studied by electrochemical impedance spectroscopy and gravimetry [J].Prog. Org. Coat., 2006, 56: 304-310[22] Deflorian F, Fedrizzi L, Rossi S, et al.Organic coating capacitance measurement by EIS:ideal and actual trends [J]. Electrochim.Acta, 1999, 44: 4243-4294[23] Morcillo M. Soluble salts: their effect on premature degradation of anticorrosive paints [J].Prog. Org. Coat., 1999, 36: 137-147[24] Amirudin A, Thierry D. Application of electrochemical impedance spectroscopy to study the degradation of polymer-coated metals [J]. Prog. Org. Coat., 1995, 26: 1-28[25] Battocchi D, Tallman D E, Bierwagen G P. Electrochemical behavior of a Mg-rich primer in the protection of Al alloys [J]. Corros Sci.,2006, 48: 1292-1306[26] Poelman M, Olivier M G, Gayarre N, et al. Electrochemical study of different ageing tests for the evaluation of a cataphoretic epoxy primer on aluminium [J]. Prog. Org.Coat., 2005, 54: 55-62[27] Deflorian F, Rossia S, Fedrizzi L, et al. EIS study of organic coating on zinc surface pretreated with environmentally friendly products [J]. Prog. Org. Coat., 2005, 52: 271-279 |
| No Suggested Reading articles found! |
|
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
