Development and Evaluation of Corrosion Resistance and Hydrophobic Properties of Thermal Sprayed Coatings over Carbon Steel

Abstract

Various industrial parts and equipment made of steel need to withstand demanding conditions. In order to increase performance and lifetime, surface processing and functional coatings can be applied. In this study we report on the evaluation of coated carbon steel with commercial corrosion-resistant powders Diamalloy 4276 and Woka 7502 by Oerlikon Metco, using thermal spraying. Further functionalization is performed by rendering thermal sprayed surfaces syperhydrophobic via gas phase deposition of trichloro-1H,1H,2H,2H-perfluorooctyl silane, (PFOTS). Electrochemical impedance spectroscopy, contact angle and water condensation studies reveal the protective properties of coatings prepared by both materials as well as the superiority of Diamalloy 4276 based coatings. Corrosion was evaluated under a harsh 20% w/w H2SO4 environment. Rendering the coating superhydrophobic improves water condensation under the tested conditions of high (80%) relative humidity.