Rapid Fabrication of Corrosion Resistant and Superhydrophobic Cobalt Coating by a One-Step Electrodeposition

Abstract

Superhydrophobic cobalt (Co) coating with micro-nanofiber structure was rapidly fabricated by a one-step electrodeposition process. The wettability, microstructure, and corrosion resistance of the as-prepared Co coating were evaluated under different test conditions. The Co coating electrodeposited at 20 V for 5 min displays superhydrophobicity with a contact angle of 160° and a sliding angle of 6.2°. The superhydrophobicity of the coating is derived from the form of the cobalt myristate on its surface and the special micro-nanofiber structure. Excessive electrodeposition time or voltage change the micro-nanofiber structure of the coating and then decrease its superhydrophobicity. The coating surface can be switched from superhydrophobic to hydrophilic by heating in an oven and then dipping in the ethanol solution of 0.1 M myristic acid. In addition, the prepared Co coating displays better corrosion resistance than the bare Cu substrate. The corrosive medium with strong alkalinity or highly acidity decreases the corrosion resistance of the Co coating. The corrosion resistance of the coating is consistent with its hydrophobicity. The superhydrophobicity favored the improvement of the corrosion resistance for the coatings.