Development of superhydrophobic and corrosion resistant coatings on carbon steel by hydrothermal treatment and fluoroalkyl silane self-assembly

Superhydrophobic polysiloxane coatings was prepared on the surface of carbon steel by combining the hydrothermal method and self-assembly. The results show that when the hydrothermal reaction time is 6 h, the temperature is 140 °C, and the ethylenediamine concentration is 3.00 mol L−1, the surface achieves super-hydrophobicity with a water contact angle of 152°. The rough regular octahedral and flower-like structures were formulated on the hydrothermal treat surface. The fluorosilane molecules are bonded to the surface of the carbon steel through Fe–O–Si bonds. The superhydrophobic coating with the thickness of 15–17 μm is dense and uniform. During the first 4 h of corrosion test in the simulated marine atmospheric environment, the superhydrophobic coating hindered the diffusion and migration of the corrosive medium on the metal interface, thus decreased the standard deviation of the current noise by 40%, increased the noise resistance by 5 times, showing a good corrosion resistance.