An EIS Study of Failure Process of Zinc-rich Epoxy/ Bituminous Epoxy Coatings in Accumulated Water in Crude Oil Storage Tank

The studied coating system consists of two parts, i.e., epoxy zinc-rich coating as a primer and bituminous epoxy coating as finish. The EIS of the coating system in accumulated water in crude oil storage tank was studied, and the equivalent circuit models of the coatings during the course of immersion was put forward. The relationship between characteristics of EIS and structure properties of coating system was discussed. The results show that EIS can reflect the corrosion stage of the coating system from the characteristics of EIS and provide reference for the maintenance of the coatings on the bottom of the crude oil storage tank.