Voltage-time synergy in brass anodization in NaOH: Unraveling corrosion resistance and hydrophilicity

An adherent oxide layer was synthesized on yellow brass (CuZn35.5) via one-step anodization in a strong alkaline electrolyte (0.1 M NaOH) under varying voltages and times. The morphology and composition of the anodic films, characterized by FE-SEM, EDS, and XRD, revealed the formation of CuO, Cu 2 O, and ZnO. Electrochemical Impedance Spectroscopy and Tafel analysis demonstrated a significant improvement in total corrosion resistance for specific anodizing parameters. Notably, the sample anodized at 1 V for 60 minutes exhibited the highest total corrosion resistance (R total = 2480 Ω.cm 2 ) and the lowest corrosion current density (1.14 μA.cm -2 ) outperforming bare brass. Most anodized samples exhibit hydrophilic character (WCA < 70°), though the practical significance of this classification varies across the parameter space. This study identifies the critical synergy between low voltage and prolonged time to achieve a superior protective oxide layer on brass, offering a cost-effective route for enhancing its durability in corrosive environments