Synergistic enhancement of wear and corrosion resistance in Ni-W-Si₃N₄ composite coatings via tailored ultrasonic power during electrodeposition

Abstract A Ni-W-Si₃N₄ composite nanocoating was deposited on a copper substrate via direct current electrodeposition. The influence of ultrasonic power on the microstructure, mechanical properties, corrosion resistance, and wear resistance of the composite coating, along with the underlying mechanisms, was systematically examined. The results demonstrate that the introduction of ultrasound significantly refines the grains of the composite coating and improves the distribution of Si₃N₄ nanoparticles. At an ultrasonic power of 90 W, the sample C2 exhibits optimal overall performance. It achieves the highest hardness of 554.2 HV, whilst also having the lowest average friction coefficient and wear rate, at 0.59 and 0.093 μ m 3 (N∙m) −1 , respectively. The wear mechanism shifts from a combination of adhesive wear and abrasive wear of the coatings prepared without ultrasound to predominantly abrasive wear. Furthermore, the sample C2 shows superior corrosion resistance, with the lowest self-corrosion current density of 0.8 × 10 − ⁷A·cm −2 and the highest self-corrosion potential of −0.28 V. The enhancement in performance is primarily attributed to grain refinement, dispersion strengthening and lubricating effects contributed by the nanoparticles. This study elucidates the regulatory role of ultrasonic power on the microstructure and performance of composite coatings during electrodeposition, providing theoretical insights and process references for the development of high-performance coatings.