Comparison of Superhydrophobicity, Anti-Corrosion, Anti-Icing, and Self-Cleaning Properties of Nickel and Cobalt Coatings Fabricated by one-Step Electrodeposition

In this research, superhydrophobic nickel and cobalt coatings with a hierarchical micro-nano structure were deposited on copper substrate by rapid one-step electrodeposition. The microstructure, wettability, corrosion resistance, self-cleaning and anti-icing properties of the coatings were evaluated using a scanning electron microscope (SEM), contact angle measurement, electrochemical impedance spectroscopy (EIS), alumina powder as contaminants and keeping at minus 15 ° C, respectively. According to the obtained results, nickel coating with a higher contact angle of 172.3° delays the freezing of the droplet on the surface by 6 min more than the cobalt coating with a lower contact angle of 155.6°. The surface energies of both coatings were low enough to benefit from oleophobicity and for glycerol and ethylene glycol, both coatings had water contact angles higher than 120°. When the open circuit potentials were atablized in 3.5 wt.% NaCl solution, very high charge transfer resistances of 2370 and 756.3 kΩ.cm 2 were recorded for nickel and cobalt coatings, respectively. After 16 days of immersion in saline solution, the contact angles were still in the hydrophobic range (128.7° and 98.6° for nickel and cobalt coatings, respectively). For cobalt coating with more appropriate surface microstructure and despite its lower water contact angle compared to nickel coating, better self-cleaning properties were observed.