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Degradation Behavior of Solvent-free Epoxy Coatings in Simulated Flowing Sea Water with Sand by Different Flow Rates |
Hongtao ZHAO, Weizhong LU(), Jing LI, Yugui ZHENG |
Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China |
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Abstract The degradation behavior of three solvent-free epoxy coatings on carbon steel Q345E in simulated flowing sea water with 1% (mass fraction) sand by different flow velocities (2, 4 and 6 m/s respectively) was investigated at 60 ℃ by means of open circuit potential (OCP) measurement and electrochemical impedance spectroscopy (EIS) as well as confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS). Results showed that the failure process of the three coatings was greatly shortened in the flowing slurry, and the reason for the accelerated degradation of the coatings may be ascribed to the facts that: on one hand, the wear effect of sends, which led to the generation and development of pits or holes on/in coatings which shorten the diffusion path of the corrosive medium from the outside environment to the coating/metal interface, on the other hand, the high flow rate of the slurry could accelerate the transmission of Cl- to the coating.
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Received: 23 June 2016
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Fund: Supported by Strategic Priority Research Program of Chinese Academy of Sciences (XDA13040500) |
About author: These authors contributed equally to this work. |
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