Effect of Citric Acid Passivation on the Marine Atmospheric Corrosion Resistance of L80 - 13Cr Stainless Steel

13Cr stainless steel is commonly used as the material of downhole tools in the field of offshore oil &gas exploitation,but it is prone to be corroded when stored in marine atmospheric environment.In order to improve the corrosion resistance of 13Cr stainless steel in marine atmosphere,the single citric acid passivation and citric acid-hydroxide composite passivation were selected to deal with the surface of L80-13Cr stainless steel,and their effects on the corrosion resistance of L80-13Cr stainless steel were investigated by polarization curve,FeCl3 pitting corrosion test,neutral salt spray test,outdoor exposure test in marine atmospheric environment and etc.Additionally,the reasons for the improvement of the corrosion resistance of L80-13Cr stainless steel resulting from citric acid passivation treatment were analyzed.Results showed that the two citric acid type passivation methods could significantly improve the marine atmospheric corrosion resistance of L80-13Cr steel and could ensure that the L80-13Cr ste