Facile green fabrication of hydrophobic-icephobic CoNi-CrAlY nanocomposite coating on St37

A hydrophobic/icephobic MCrAlY (M = Co, Ni) nanocomposite coating was prepared on St37 by way of electrodeposition, while CrAlY nanoparticles (NPs) were synthesised through mechanical alloying. Optimal CrAlY NPs (49 nm, −25.1 mV zeta potential) were achieved with 4 wt.% ethanol for 48-h milling ball (75% cycle), yielding a composition close to 61.3Cr–37Al–1.7Y wt.%. Electrodeposited CoNi–CrAlY coatings, featuring dominant face-centered cubic (E.4 series) and hexagonal close-packed (E.6 series) structures, were characterised to enhance the surface tribology in terms of icephobicity and hydrophobicity. The E.6 series, particularly sample E.610 (10 g/l CrAlY), exhibited superior hydrophobicity, reaching a water contact angle (WCA) of ≈141° ± 1.4 and sliding angle (SA) of ≈9.3° ± 0.5 after 30 days of ageing at room temperature, transitioning from Wenzel to Cassie–Baxter state due to nano/microscale roughness (R_a = 52.76 and 810 nm). The coating, with roughly 1 wt.% CrAlY (inductively coupled plasma mass spectrometry), reduced ice shear stress by 83.3% compared to bare St37 steel. Durability of E.610 was also investigated and its WCAs were reported to be ≈133°  ±  1.9 and ≈141° ± 1.4 after ageing in air in the time periods of 10 and 30 days, respectively. These findings demonstrate the potential of CoNi–CrAlY coatings for hydrophobic and anti-icing applications.