Protection of carbon steel against corrosion with a superhydrophobic coating

Abstract

Under atmospheric conditions at 100% humidity, a surface phase film of moisture is formed on the surface of metals, in which air microimpurities NH3, CO2, H2S, etc. are dissolved and almost completely hydrated with the formation of NH4OH and acids H2CO3 and H2S. The method of potentiodynamic polarization has been used to study the protective efficiency of a superhydrophobic coating on carbon steel in NaCl-based model media simulating saturation of the surface moisture film with carbon dioxide (IV) and/or ammonia under atmospheric conditions. Similar studies were carried out with uncoated electrodes. The superhydrophobic coating was obtained on the basis of laser texturing of the steel surface followed by hydrophobization with fluoroxysilane (wetting angle 165±2°, rolling angle 3±1°). The influence of the duration of exposure of electrodes in solution (0.25 - 168 h) on the kinetics of electrode processes, the rate of steel corrosion and the protective effectiveness of the superhydrophobic coating is considered. It has been shown that the presence of ammonium hydroxide or ammonium carbonate in solution increases the protective effectiveness of the coating compared to a purely chloride medium simulating harsh atmospheric conditions.