Hydrophobicity of Cr3C2-NiCr coating under mechanical abrasion and thermal annealing

Abstract Cr3C2-NiCr coating was fabricated by high velocity oxygen fuel (HVOF) spraying, and its hydrophobic properties under mechanical wear and after exposure to high temperatures were investigated. The as-received coating shows excellent hydrophobicity with a water contact angle of 151 ± 1°. The coating also presents good mechanical wear resistance to retain water contact angle of 150° over a 3.0 m abrasion length under a pressure of 4 kPa against diamond disk (#1500). Further enhancement of the non-wettability of the coating after annealing is achieved by surface modification using epoxy resin, where the secondary nanoscale-rough structure introduced by the resin fiber plays a critical role. Possible mechanisms for the excellent hydrophobicity under abrasion and after high-temperature exposure are discussed. Results of this work demonstrate the hydrophobic cermet coatings prepared by HVOF in combination with surface modification may have practical application in harsh working conditions.