Tribo-corrosion and mechanical performance of electro-deposited nano-composite h-BN/epoxy coating

In this work, mild steel as a substrate was coated by electrodeposition in a bath mixed with nickel sulfate (NiSO₄·6H₂O), nickel chloride (NiCl₄·6H₂O), and boric acid (H₃BO₃) using nanocomposite cetyltrimethylammonium bromide, hBN, and epoxy with hardener. The experiments were designed using the Taguchi method through the L9 orthogonal array to reduce the number of experiments. The input parameters for the design of experiments were taken: the time (min), voltage (V), and the hBN concentration (wt-%). The coated samples were tested for their tribological, corrosion, and adhesion performance using pin-on-disc, electro-impedance spectroscopy, and cross hatch tester, respectively. The tribological results reveal that the coated sample of 3 wt-% hBN concentration at 3 mV voltage and 30-minute deposition time shows the lowest friction coefficient (∼0.42) among all the samples, indicating its superior wear resistance and corrosion resistance. Further, the same sample also outperformed the others, demonstrating the high adhesion (adhesion scale of 5 B) of coating with the substrate. Moreover, the surface was characterized using X-ray diffraction, Fourier transforms infrared, goniometer, and scanning electron microscopy.