Superhydrophobic graphite/TiO2 micro-nano composite coatings: Fabrication and properties

Abstract

Superhydrophobic surfaces play an important role in applications such as self-cleaning, anti-corrosion and anti-icing due to their unique wettability. In this work, a one-step spraying method was developed to fabricate superhydrophobic coatings on the surface of 304 stainless steel (SLS). To enhance surface roughness, TiO₂ was deposited on graphite particles via sol-gel method. Hydrophobic modification of epoxy resin was then achieved using KH550 to graft perfluorodecyltriethoxysilane (PFDTES). Orthogonal experiments were employed to investigate the optimal preparation parameters for modified particles, while the components ratios in the coatings were determined via the control variable method. The prepared coating exhibited a water contact angle (WCA) of up to 162.6 ± 1.5° and a sliding angle (SA) as low as 2.0 ± 0.2°, along with strong adhesion to the substrate and remarkable impact resistance. Moreover, it demonstrated long-term stability under harsh conditions, including both strong acid (pH = 1) and strong alkali (pH = 14) environments, as well as high temperatures up to 350 °C. Electrochemical tests revealed that the superhydrophobic SLS achieved an ultrahigh corrosion inhibition rate (η_CIR) of 99.89 % compared to the raw SLS. The developed one-step spraying method offers a simple, scalable, and versatile fabrication approach, demonstrating significant potential for enhancing the long-term durability and corrosion resistance of metallic surfaces in practical applications.