Fabrication of superhydrophobic cauliflower-like Cu-Co coating with anti-corrosion and anti-fouling properties on B10 copper-nickel alloy welded joint

A superhydrophobic Cu-Co coating is successfully applied to the surface of a B10 copper-nickel (Cu-Ni) alloy welded joint via electrodeposition and modification using a low-surface-energy material (stearic acid). The static water contact angle is measured to be 162.2 +/- 1 degrees, and the roll off angle is 2.1 degrees. Various techniques, including scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier-transform infrared absorption spectroscopy are employed to characterize the chemical composition and phase structure of the samples before and after electrodeposition and modification. The corrosion resistance of the superhydrophobic samples is evaluated via electrochemical impedance spectroscopy, potentiodynamic polarization, and scanning Kelvin probe microelectrochemistry. The results indicate that the superhydrophobic coating exhibits greater charge transfer resistance, lower self-corrosion current density, and higher surface work function, thus effectively enhancing the corrosion resistance of the B10 Cu-Ni alloy welded joint. Furthermore, the micro-nano rough structure with low surface energy on the superhydrophobic sample surface traps air and forms an air layer, thereby reducing the contact between the corrosive medium and welded joint as well as minimizing corrosion. The superhydrophobic coating demonstrate thermal stability as well as excellent self-cleaning and mechanical properties, based on comprehensive testing and analysis.