EFFECT OF CYCLIC PRESSURE ON DEGRADATION BEHAVIOR OF EPOXY COATING IN SIMULATED DEEP OCEAN ENVIRONMENT

The effect of cyclic pressure on the degradation behavior of the epoxy coating on carbon steel surface in 3.5%NaCl solution in a simulated deep-ocean environment was studied using electrochemical impedance spectroscopy(EIS)and weight method.The results showed that the EIS characteristics displayed a periodic variation under the cyclic pressure condition.The coating capacitance at high pressure was higher and the coating resistance was lower than that at atmospheric pressure during immersion periods,respectively.With increasing the cyclic pressure,the corrosion medium such as water had diffused to the coating/metal interface more easily.As a result,the increase of the water absorption capacity of the epoxy coating and the decrease of coating resistance were observed.The coating protection properties were obviously deteriorated.