Study on corrosion resistance and photocatalysis of cobalt superhydrophobic coating on aluminum substrate

A textured flower-like cobalt superhydrophobic surface (SHS) with a water contact angle of 160° and a sliding angle of less than 1° was fabricated on aluminum substrate by immersing the processed aluminum sheets perpendicularly into cobalt (II) nitrate aqueous solution and followed by annealing treatment. The morphology and chemical composition of the SHS were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray diffraction pattern (XRD), Energy-dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). The corrosion resistance of the samples was characterized via polarization, Nyquist and bode modulus plots. The photocatalysis of samples was also studied by catalytic degradation of methyl orange under a UV lamp (λ = 365 nm) with a light intensity of 8 W. The cobalt superhydrophobic sample not only exhibited excellent catalytic properties, but also substantially improved the corrosion resistance of aluminum substrate.