Hydrophobic and corrosion-resistant composite (BiVO4/TiO2) hot-dip zinc coating with enhanced self-cleaning ability

Abstract

The modification of zinc coating through the integration of BiVO4/TiO2 composite is an effective strategy to improve the hydrophobicity, corrosion resistance, and self-cleaning performance along with the photocatalytic performance of the coating. The incorporation of the optimum composition of BiVO4/TiO2 composite facilitates the formation of sharp protrusions, which can enhance and retain air pockets on the surface. Thereby, the real contact between corrosive electrolyte and coating can be significantly suppressed. Thus, the coating becomes hydrophobic in nature with a water contact angle of 120.2° and exhibits good self-cleaning ability. High charge transfer resistance (248.47 Ω cm2) and high inhibition efficiency (91.68%) of the Zn-0.2BVT-1 coating reveal the excellent corrosion resistance characteristics of the coating. The developed hydrophobic coating exhibits excellent chemical stability and durability under both acidic and alkaline environments. Also, the developed coating retains its hydrophobic nature after 21 days of immersion in NaCl solution. A plausible mechanism for the corrosion-resistant characteristics of the coating is proposed based on the electrochemical analysis results. The electrochemical evaluations of the coating confirm that the developed hydrophobic coating, even after 21 days of immersion in NaCl solution, possesses excellent corrosion resistance, durability, chemical stability, and long-term stability to find wide application in marine and industrial fields.