Effect of Y2O3 Particle Size on the Microstructure and Properties of Ni-Co-Y2O3 Composite Coatings

In this study, Ni-Co-Y2O3 composite coating was prepared by electrodeposition, and the effect of Y2O3 particle size on the microstructure and properties of the coating was investigated. The samples were analyzed by XRD, SEM, AFM, EDS, cyclic voltammetry, XPS, hardness, and corrosion resistance test. The results indicate that the diffraction peak of the coating prepared with 50 nm particles exhibits reduced intensity and broadening, whereas the coating prepared with 100 nm particles displays a sharper and more pronounced peak. The onset reduction potential and the performance of the reduction reaction are influenced by particle size. When the particle size is 50 nm, the reduction process is less favorable, with an onset reduction potential of −0.9 V; in contrast, when the particle size is 100 nm, the reduction occurs more readily, with an onset reduction potential of −0.8 V. XPS analysis reveals that the chemical environment of elements varies with particle size. Regarding hardness, the coating prepared by combining different Y2O3 particle sizes exhibits higher hardness compared to that prepared using a single particle size, which can be attributed to the synergistic effect. In terms of corrosion resistance, the coating prepared with 100 nm Y2O3 particles demonstrates superior corrosion resistance, whereas the coating prepared with mixed particle sizes shows reduced stability and is more susceptible to corrosion. The coating prepared by mixing Y2O3 with particle size of 50 nm and 100 nm has a small friction coefficient. In summary, the particle size of Y2O3 has a significant influence on the microstructure, hardness, and corrosion resistance of Ni-Co-Y2O3 composite coatings.