The effect of superhydrophobic coating on the electrochemical behavior of carbon steel in chloride and hydrogen sulfide–chloride environments

• V.I. Vigdorovich¹, L.E. Tsygankova^1,2, A.M. Emel’yanenko³, M.N. Uryadnikova² and E.Yu. Shel⁴

¹ All-Russian Scientific Research Institute of Use of Machinery and Oil Products, Novo-Rubezhnyi per., 28, Tambov, 392022, Russian Federation
² Derzhavin State University, ul. Internatsyonalnaya, 33, Tambov, 392000, Russian Federation
³ A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninsky pr. 31, 119071 Moscow, Russian Federation
⁴ Tambov State Technical University, ul. Sovetskaya, 106, Tambov, 392000, Russian Federation

Abstract: Corrosion and kinetics of electrode processes on St3 steel with a superhydrophobic coating based on laser surface texturing followed by hydrophobization with fluoroxysilane (wetting angle 165±2°, rolling angle 3±1°) have been studied in a highly mineralized chloride medium (50 g/L NaCl) in the absence and presence of an additive of hydrogen sulfide (400 mg/L). Similar studies were conducted with uncoated electrodes. The influence of a duration of an exposure of the electrodes in a solution (0.25–96 hours) on kinetics of electrode processes and corrosion rate of steel is considered. In the absence of hydrogen sulfide, a presence of a superhydrophobic coating on steel causes a decrease in the corrosion rate by 67, 13, and 2 times after 0.25, 24, and 48 hours of exposure in a chloride solution. In time, the cathodic process slows down and the anodic one accelerates, especially in a case of electrodes with a hydrophobic coating. In the presence of hydrogen sulfide in a chloride solution, steel with a superhydrophobic coating is characterized by more than an order of magnitude low corrosion rate, compared with unprotected samples during a 96-hour exposure of the electrodes. In this case, there is a slowdown in the anodic reaction and acceleration of the cathodic one compared to the solution without hydrogen sulfide. The corrosion process proceeds with anodic control.

Keywords: steel, superhydrophobic coating, corrosion rate, kinetics, hydrogen sulfide, electrode process

Int. J. Corros. Scale Inhib., 2020, 9, no. 1, 171-181 PDF (558 K)
doi: 10.17675/2305-6894-2020-10-1-10

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