Current Density-Dependent Microstructural Evolution and Properties of NiCo-CeO2 Composite Coatings

This study investigates the effects of current density on the microstructure and properties of electrodeposited NiCo-CeO2 composite coatings. Results demonstrate that current density significantly influences coating composition, with higher CeO2 and lower Co content increasing surface roughness (minimum at 30 mA/cm2, maximum at 100 mA/cm2). Microstructural homogeneity improves with optimized Co/CeO2 content, where the A30 coating (30 mA/cm2) exhibits the weakest texture among all coatings due to peak Co incorporation. Texture intensifies at higher current densities (30–100 mA/cm2) as Co and CeO2 contents diminish. Internal stress depends on electrodeposition kinetics and particle dispersion, ranging from −2.22 MPa (A20) to 651 MPa (A50). Hardness correlates with (111) plane dominance and Co/CeO2 content, reaching 449.8 HV for A30 but dropping to 288.8 HV for A100. Optimal current density tuning refines grains, enhances (111) texture, and improves compositional uniformity, endowing the A30 coating with balanced hardness and corrosion performance (corrosion potential: −224 mV; current density: 0.225 μA/cm2). These findings provide guidelines for tailoring high-performance NiCo-CeO2 coatings through current density regulation.