Study on a hydrophobic nano-TiO2 coating and its properties for corrosion protection of metals

A uniform TiO2 nanoparticle film has been coated on the surface of 316L stainless steel by using sol-gel and dip-coating technology. A hydrothermal post-treatment method has been developed to eliminate the crack defects in the coatings, and to improve the structure and property for the coating. A self-assembly of fluoroalkylsiane (FAS-13) has been conducted to enhance the surface hydrophobic property of the nano-TiO2 coatings. The distribution of particle sizes of TiO2 sol has been analyzed by zeta-potential analysis, and the surface morphology and structure have been characterized by contract angle, XRD, and SEM measurements. The results indicate that the surface of coatings is uniform and dense, with approximately 375 nm thickness. The diameter of particles of TiO2 anatase is in the range of 15-18 nm. The contact angle of the super-hydrophobic surface is 150 +/- 1 degrees. It shows, from the electrochemical tests, that the super-hydrophobic coatings on 316L stainless steel exhibit an excellent corrosion resistance in chloride containing solution at the room temperature. (C) 2005 Elsevier Ltd. All rights reserved.