Document Type : Original Article
1 School of New Energy and Materials, Southwest Petroleum University, Chengdu, 610500, Sichuan, P.R. China
2 State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, Sichuan, P. R. China
In order to solve the corrosion and wax deposition problem of X80 steel used in oil pipelines, a hydrophobic surface layer was prepared by ferric chloride pre-etching followed by hydrochloric acid etching and finally surface modification with fluorosilane. The study revealed that the best hydrophobic effect was obtained when the concentration of ferric chloride was 0.21 g/ml, the concentration of hydrochloric acid was 1.5mol/L, and the etching time was 30min. The X80 steel etched with the above process has excellent hydrophobicity and demonstrated a contact angle value of 158º and only change to 150º even exposed to air for three months. The X80 steel etched with the above process also has anti-waxing properties and the wax-proof rate was more than 66%. The corrosion resistance properties of such formed surfaces of X80 steel was also analyzed by EIS analysis and the results of which demonstrated that the impedance of the etched X80 steel is much higher than that of the non-etched X80 steel. Scanning electron microscopy (SEM) results indicated that the etched X80 steel has excellent anti wax and corrosion resistant properties because of its unique structure, similar to lotus leaf surface, which is comprised of micro and nano pits.