Corrosion behaviour of super-hydrophobic electrodeposited nickel-cobalt alloy film

Hierarchical super-hydrophobic Ni-Co film with enhanced corrosion resistance was fabricated on a copper substrate by one-step electrodeposition process. The contact angle and water repellence properties of the Ni-Co film were measured to determine its wettability. The Ni-Co film exhibited excellent super hydrophobic properties with a static water contact angle of 158 and a sliding angle of <=degrees 5. The corrosion performance of the super-hydrophobic surface (SHS) was investigated by electrochemical potentio-dynamic measurements and electrochemical impedance spectroscopy in NaCl solution (3.5 wt.%). Moreover, to study the long-term stability of the super -hydrophobic film, SHS samples were immersed into NaCl solution and their corrosion behaviour was investigated by the electrochemical impedance spectroscopy. Additionally, the changes of surface wettability were also monitored over the whole immersion time up to 11 days. Experimental results indicated that super -hydrophobic samples had much more corrosion resistance in comparison with freshly prepared samples or the bare substrate. (C) 2015 Elsevier B.V. All rights reserved.