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| Degradation Processes of Organic Coating with Artificial Defects in Flowing Seawater |
| Received:July 04, 2018 Revised:November 25, 2018 |
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| DOI：10.7643/ issn.1672-9242.2018.11.019 |
| KeyWord:organic coating with artificial defects electrochemical impedance spectroscopy static seawater flowing seawater equivalent circuits |
| Author | Institution |
| WANG Xiao-hui |
1. Southwest Technology and Engineering Research Institute, Chongqing , China |
| LI Shou-biao |
2. SunRui Marine Environment Engineering Co., Ltd, Qingdao , China |
| LI Zhao |
3. Yantai University, Yantai , China |
| LIU Jie |
3. Yantai University, Yantai , China |
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| Abstract: |
| Objective To study the degradation processes of organic coating with artificial defects in flowing seawater. Methods The degradation behaviors of organic coating with artificial defects in flowing seawater and static seawater were in-vestigated with electrochemical impedance spectroscopy (EIS) technology; and the evolutions of macroscopic morphology of the coatings was observed. Results According to the EIS response characteristics, the degradation of organic coating with artificial defects in flowing seawater was faster; and the diffusion impedance did not appear during the late immersion. According to evolutions of macroscopic morphology of the coatings, it was found that some small rust spots and bubbling appeared around the artificial defect for the coating immersed in static seawater; while more large-area rust spots and bubbling appeared on the whole surface of the organic coating immersed in flowing seawater. Conclusion During immersion of the organic coating in static seawater and flowing seawater, the degradation of the coating firstly happens around the artificial defect. The defect position of the coatings becomes the main anode region of local corrosion reactions, and the artificial defects and the inherent defects of the coatings becomes the cathode area of the extended corrosion reactions. Corrosion products at the artificial defects position accumulated and fell off more frequently in flowing seawater, which accelerates the degradation of coating and corrosions of matrix metal. |
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