Corrosion protection of superhydrophobic/amphiphobic cobalt coating with anti-icing and self-cleaning properties fabricated by a one-step electrodeposition method

Fabrication of superhydrophobic cobalt-based coatings is a useful way to provide metals, including copper, with corrosion protection, anti-icing, and self-cleaning properties to enhance their industrial applications. A one-step electrodeposition process was applied to synthesize a cobalt coating on a copper substrate. Superhydrophobicity, amphiphobicity, anti-freezing, self-cleaning, corrosion protection, and long-term stability of the coating were investigated. The coating surface was studied using SEM and the water contact angles (CAs) were measured by an optical tensiometer. The coating showed a water CA of 155.6 ± 0.6° with a sliding angle of 4.8 ± 0.3°, denoting its superhydrophobicity. Also, it was amphiphobic with CAs over 120° for glycerol and ethylene glycol. The coating was highly corrosion resistant with a high charge transfer resistance of 756.3 kΩ.cm2. This was compatible with the stability of coating during 16 days of immersion in 3.5 wt% NaCl solutions (pH 1 and 14), when it remained hydrophobic with CA over 90°. The 23 min longer freezing time of water droplets on the coating at − 15° compared to the copper substrate was a proof of its excellent anti-icing. Only three rolling water drops were required to remove the alumina powder from 1.13 cm2 of the coating area, denoting excellent self-cleaning with a rare superiority over other similar research.