Co-electrodeposition of superhydrophobic NiCo/CeO2 coating with hierarchical nano/micro structure for corrosion protection of plain carbon steel

This study aimed to develop an effective corrosion protection strategy for carbon steel by employing a superhydrophobic NiCo coating modified with CeO2 nanoparticles through the co-electrodeposition method. The superhydrophobicity was achieved by adjusting the composite coating's morphology and surface roughness. The synergistic impact of CeO2 and EDA crystal modifier on the coating's morphology, composition, topography, corrosion protection performance, and wetting properties was systematically investigated. The SEM results revealed the formation of a flower-like nano/micro morphology in the presence of EDA, and this morphology was preserved with the addition of 4 g/L CeO2 into the electrolyte. Surface wettability was significantly influenced by the hierarchical nano/micro structure of the deposited coating, with an enhanced superhydrophobicity observed in the presence of CeO2. The increase in surface roughness and compaction, achieved by incorporating CeO2 nanoparticles into the hierarchical structure of the NiCo coating, played a pivotal role in creating a superhydrophobic surface. Furthermore, polarization and EIS tests demonstrated that the superhydrophobic NiCo-EDA/CeO2 coating exhibited excellent anti-corrosion performance for the carbon steel substrate. In this case, Ecorr shifted towards positive values, icorr decreased, and both charge transfer resistance and coating resistance showed a considerable increase compared to other studied coatings. The alteration of metal wettability to a superhydrophobic state, combined with the barrier role of the coating and the presence of ceramic reinforcements (CeO2), offers comprehensive protection to the steel substrate. This approach holds great promise for effectively controlling the corrosion rate of widely used engineering metals.