Influence of Y2O3 Particle Size on the Microstructure, Corrosion Resistance, and Wear Resistance of Electrodeposited Ni-W-Y2O3 Composite Coatings

Ni-W-Y2O3 composite coatings were electrodeposited from a sulfate citrate electrolyte incorporating Y2O3 particles of three different sizes: 50 nm, 1 μm, and 2 μm. This study systematically investigates the impact of Y2O3 particle size on the microstructure, microhardness, corrosion resistance, and wear resistance of the composite coatings. The incorporation of Y2O3 particles leads to notable grain refinement, with the crystallite size decreasing from 31.8 nm for the pure Ni W coating to 17.3 nm, 19.0 nm, and 20.1 nm for the C-50 nm, C-1 μm, and C-2 μm coatings, respectively. Correspondingly, the microhardness increases from 540.2 HV for the unreinforced coating to 732.5 HV, 641.0 HV, and 629.5 HV for the C-50 nm, C-1 μm, and C-2 μm coatings, respectively. In terms of corrosion resistance, the C-50 nm coating exhibits the best performance in both acidic and neutral media, with the lowest corrosion current density of 3.72 μA/cm2 in 10 wt.% H2SO4 and 3.53 μA/cm2 in 3.5 wt.% NaCl. In contrast, micron-sized particles show limited improvement in acidic media and even degrade the corrosion resistance in neutral NaCl solution, where the corrosion current density increases to 7.68 μA/cm2 and 7.74 μA/cm2 for the C-1 μm and C-2 μm coatings, respectively. The wear resistance of the composite coatings is significantly enhanced by the incorporation of Y2O3 particles, with the wear rate decreasing from 17.75 × 10−6 mm3 N−1 m−1 for the pure Ni-W coating to 5.65 × 10−6 mm3 N−1 m−1 for the C-50 nm coating. The presence of Y2O3 particles transitions the wear mechanism from predominantly adhesive wear to a combination of adhesive and abrasive wear. These results demonstrate that the particle size of Y2O3 plays a critical role in determining the microstructure and overall performance of Ni-W-Y2O3 composite coatings, with nano-sized particles offering the most significant improvements.