Fluorine-free superhydrophobic Ni/Mn-TiO₂ composite coatings on carbon steel via one-step electrodeposition for enhanced durability and corrosion resistance

The application of superhydrophobic coatings on carbon steel (CS) surface represents an effective strategy for mitigating corrosion in these materials. This study presents the preparation of superhydrophobic Ni/Mn-TiO₂ composite (SNMT) coatings on CS substrates through a facile one-step electrodeposition technique. The formation mechanism of SNMT coatings was meticulously analyzed under varying conditions of nanoparticle types and concentration levels. The inclusion of TiO₂ nanoparticles, with an optimal additive concentration of 1 g, facilitated the formation of numerous low surface energy, cauliflower-like microstructures on CS interface. Surprisingly, the results indicate that SNMT coatings maintained commendable superhydrophobicity even post-exposure to superficial damages such as tape peeling, sandpaper wear, and knife-scratch, as evidenced by a static contact angle (CA) exceeding 158° and a sliding angle (SA) below 2°. Furthermore, the corrosion inhibition efficacy of SNMT coatings was quantitatively assessed via dynamic potential polarization curves in a simulated seawater environment. The results demonstrated that SNMT coatings exhibited excellent corrosion inhibition performance in simulated seawater solution, with a protection efficiency (PE) reaching 96.5 %. In conclusion, superhydrophobic surfaces can effectively inhibit the penetration of corrosive liquids. The durability and robustness of such superhydrophobic surfaces advocate for their potential widespread application in enhancing the longevity and reliability of CS in corrosive environments.