Effect of CeO2 Content on Microstructure and Tribological Properties of TiC‐Inconel 718 Composite Coatings by Laser Cladding

In this work, CeO 2 /TiC‐Inconel 718 composite coatings are fused on Inconel 718 substrate by laser cladding method. The effects of adding different rare earth CeO 2 (0–4 wt%) contents on the phase composition, microstructure, microhardness, and wear resistance of the composite coatings are investigated. The findings show that the addition of small amounts of CeO 2 does not affect the phase composition of the coating, which mainly contains γ(Ni,Fe), TiC, Cr 7 C 3 , and Laves phases, and the Ce 2 O 3 phase appears in the coating at 3 wt% CeO 2 . The addition of CeO 2 refines the coating's microstructure and promotes the columnar to equiaxial grains transition (CET). The adsorption and pinning effects of Ce atoms lead to spheroidization and refinement of TiC particles upon precipitation, particularly at a CeO 2 mass fraction of 3%, while also improving the segregation of the Laves phase. The coatings exhibit a marked improvement in hardness as the CeO 2 concentration increases. The coating demonstrates optimal wear resistance at a CeO 2 content of 3 wt%. The wear mechanism is mainly abrasive wear, accompanied by oxidative wear and adhesive wear.