Current density effect on CeO₂-embedded Ni-Co alloy coatings for improved corrosion resistance of mild steel

This study explores the electrodeposition of Ni-Co alloy and Ni-Co-CeO₂ composite coatings on mild steel to enhance its corrosion resistance. The investigation focuses on the influence of varying current densities on key properties such as surface morphology, crystallite size, roughness, and composition. All the deposited coatings exhibited uniform and crack-free surfaces, with distinct structural and morphological features that varied depending on the applied current density. The Ni-Co alloy coatings demonstrated a noticeable improvement in corrosion resistance, which was attributed to the increased nickel content in the alloy. The Ni-Co-CeO₂ system exhibited superior performance among the composite coatings, with the best corrosion resistance observed at a current density of 3 A dm⁻². The composite achieved a remarkably low corrosion rate of 0.075 × 10⁻²mm y⁻¹ at this optimal condition. Conversely, the highest corrosion rate was recorded at a lower current density of 1 A dm⁻². Adding CeO₂ nanoparticles to the Ni-Co matrix significantly enhanced the coatings protective properties, highlighting the composite structure’s synergistic effect in resisting corrosive environments.