In this paper, hierarchical surface structures were developed to achieve the superhydrophobicity on AZ31 magnesium alloys. The uniform nodular microstructure was constructed by laser processing, and the subsequent cobalt electrodeposition fabricated a nanostructured needle-like morphology onto the surface nodules. The superhydrophobic surfaces prepared under varied electrodeposition current densities were characterized. When applying 7 mA/cm2 current density, the sample revealed the best superhydrophobic performance. The chemical stability of superhydrophobic samples was tested, which confirmed excellent superhydrophobicity was hardly affected by the corrosion environment. The results showed the samples still possessed the hydrophobic ability after tests. The developed fabrication method combines the advantages of laser processing and electrodeposition, which serves as a fast and cost-effective pathway to manufacture superhydrophobic surfaces.

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This investigation proposes the use of sol-enhanced electrodeposition to create a range of Co−Ni−TiO2 films. The addition of TiO2 sol controls the nucleation process and the properties of the composite films by generating TiO2 nanoparticles in situ in the electrodeposition process. The transmission electron microscopy (TEM) and zeta potential analyses revealed a relatively homogenous distribution with particle size in the range below 100 nm for the TiO2 nanoparticles produced. Microstructure, phase composition, hardness, friction, and corrosion resistance of Co−Ni−TiO2 films were thoroughly investigated in relation to TiO2 sol concentration. The results show that the addition of a limited content of TiO2 sol upgraded Co−Ni films by producing a Co−Ni−TiO2 film with a high dispersion of TiO2 nanoparticles. On the other hand, too much TiO2 sol could cause agglomeration and hinder the metal deposition process, resulting in surface pores and the deterioration of film performance.

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