Effect of Nano‐CeO 2 Powder on Microstructure and Wear Resistance of Deloro 40 Coating Prepared by Laser Additive Manufacturing

In this study, a series of Deloro40 + x CeO 2 ( x = 0, 0.5, 1, 2, and 5 wt%) coatings were fabricated on SS316L stainless steel by laser additive manufacturing. The microstructure evolution, mechanical properties, and tribological behaviors of the deposited coatings were systematically investigated. SEM and XRD analyses reveal that the coatings mainly consist of a dendritic γ‐Ni matrix, interdendritic γ‐Ni + Ni 3 B eutectic structures, Cr‐rich carbides, and Ni 3 B hard phases. The Ce distribution evolves from a relatively dispersed state at low CeO 2 addition (0.5 wt%) to pronounced segregation at higher contents (2–5 wt%). Appropriate CeO 2 addition promotes microstructural refinement and hard‐phase precipitation, resulting in a maximum microhardness of 570.9 HV. Furthermore, CeO 2 ‐modified coatings exhibit enhanced wear resistance under different temperature conditions (20, 300, 500, and 700 °C). The wear mechanism analysis indicates that abrasive wear dominates at low temperatures, while oxidative wear becomes increasingly significant at elevated temperatures. The improved tribological performance is attributed to the synergistic effects of grain refinement, oxide film stabilization, and particle distribution regulation induced by CeO 2 .