Preparation Of Phenolic-Epoxy Coatings And Corrosion Failure Behavior

Phenolic epoxy anti-corrosion coatings were more widely used in petroleum chemical industry. Based on the industry standard of the inside coating of drill pipe, This paper prepared a novel phenolic epoxy anti anti-corrosion coating according to the SY/T0544-2010technical standards of the drill pipe inside coating technology. A amount of research was doing on the coating film-forming substances, curing agents, additives, pigments and fillers. What’s more, the electrochemical impedance spectroscopy (EIS) technique was used to test the anti-corrosion properties of the coating.1, The different properties of the coating of different curing agent and resin have been studied to choose the best resin and curing agent. It has been found that the phenolic epoxy DEN438resin and epoxy858cured by the curing agent EH7501can basically meet the petroleum the basic coating requirements of the drill pipe.2, Phenolic resin DEN438and epoxy resin858were selected as the main film-forming substance of the premier coating. The coating have the best properties in the heat, adhesion and toughness when the proportion of Phenolic resin DEN438and epoxy resin858is7:33, The appropriate amount of curing agent was30%when the proportion of Phenolic resin DEN438and epoxy resin858is7:3. The curing process is well placed2h in room temperature, then80℃cured for2hours and155℃cured for lh.The FT-IR method is used to study the curing conditions. The basic formulation of phenolic epoxy primer coating is determined by the research.4, The phenolic epoxy primer coating have the best performance when the amount of titanium dioxide is20%, the amount of mica powder is30%, the amount of talcum powder is15%and the amount of quartz powder is20%.5, The phenolic epoxy resin DEN438is selected as the main film-forming substances of the finish coating of the oil drill pipes. The best amount of the curing agent was35%. The reactive diluents X622is used to modify the properties of toughness. When the amount of X622is10%, the properties of the coating were the best.6, The physical performance testing methods and EIS technology are used to research the impact on the corrosion resistance, adhesion and toughness of the coating. Research shows that when15%of titanium dioxide,30%of mica powder,30%of talcum powder and15%of quartz powder were used, physical properties of the coating could meet the basic requirements.7, Studies have shown that both primer and finish coating have good corrosion resistance in the conditions of continuous immersion3.5%NaCl solution. The resistance of the coating declines with the immersion time last, while the capacitance of the coating rises. In contrast, the finish coating has better performance of corrosion resistance...