The influence of pH electrolyte on the electrochemical deposition and properties of cerium oxide thin films

Thin cerium oxide layers cathodically deposited on zinc were studied. These electrochemically deposited coatings provide effective corrosion protection and require less deposition time compared to chemical conversion coatings. The kinetics of their formation depend on various factors, such as temperature, applied current density, electrolyte composition, pH, and agitation. In this study, the effect of bath solution pH was investigated, with coatings produced at room temperature from aqueous cerium nitrate solutions. Chronopotentiometry, linear sweep voltammetry, and electrochemical impedance spectroscopy (EIS) were used to monitor the deposition process, while scanning electron microscopy and energy-dispersive spectroscopy were performed to characterize the deposits. Corrosion resistance was evaluated through potentiodynamic tests in a 3.5% NaCl solution. The results indicate that the electrolyte pH significantly influences the cerium electrodeposition process. Based on the findings, the cerium oxide coating obtained from a pH 4 solution exhibited lower corrosion current density, higher polarization resistance, and superior anti-corrosion performance.