Tribo-corrosion Investigation of Electroplated Nanocoating for Automobile Application

Abstract Ni–TiO 2 /hBN nanocoating was performed on a mild steel substrate by electrodeposition from Watts Nickel bath solution. The three-level design of the Taguchi method of the L9 orthogonal array has been chosen, and the experimentation was carried out in the run order of this L9 orthogonal array. The surface morphology of the coating was investigated using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM/EDS). X-ray Diffraction analysis confirms the presence of material (Ni–TiO 2 ) on the substrate. Electrochemical corrosion testing in 3.5 wt% NaCl solution demonstrated that the optimized coating (ED7: 1.5 V, 15 min, 1.3 g TiO 2 ) achieved a ~ 358 mV positive shift in corrosion potential (Ecorr) and an 81% reduction in corrosion current density (Icorr) compared with the least-performing sample (ED6). Similarly, electrochemical impedance spectroscopy revealed that the polarization resistance of ED7 increased by more than fivefold (23.01 kΩ vs. 4.36 kΩ for ED6), confirming superior corrosion resistance. Tribological testing using a pin-on-disc tribometer revealed a reduction in the coefficient of friction (COF) from 0.84 (ED2) to 0.16 (ED9), corresponding to a decrease of ~ 76% under optimal deposition conditions. Taguchi analysis identified voltage as the most significant factor influencing COF, followed by deposition time and TiO 2 concentration. The synergistic effect of TiO 2 (hardness enhancer) and hBN (solid lubricant) produced a refined microstructure with enhanced wear resistance and durability, making the Ni–TiO₂/hBN composite a promising candidate for automotive applications requiring improved tribo-corrosion performance.