Study on corrosive electrochemical behaviors of zinc-rich and graphite-filled epoxy coatings in 3.5 wt% NaCl solution
✍ Scribed by J. Liu; F. Wang; K. C. Park
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- German
- Weight
- 548 KB
- Volume
- 62
- Category
- Article
- ISSN
- 0947-5117
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✦ Synopsis
Abstract
Environment behaviors and degradation mechanisms of two organic epoxy coatings coated on carbon steel sheets in 3.5 wt% NaCl neutral solution were studied by electrochemical impedance measurements and atomic force microscopy (AFM). The results showed that the coating resistance (R~p~) of the graphite‐filled epoxy coating tested, which presents the film barrier performance, is higher than those of 6101 epoxy resin for initial seawater immersion, but the coating resistance of the zinc‐rich epoxy coating was lower than that of 6101 epoxy resin. After salt spray tests, zinc‐rich epoxy coating coated on the metal still has good anti‐corrosion performances due to the existence of protection effects called “electrochemical” and “chemical” protection. Those behaviors and degradation mechanisms of two coatings can be explained by a series of measured electrochemical impedance spectroscopy measurements, and two equivalent circuit models were proposed to explain the degradation processes of the two organic coatings.