Comparative Investigation on Wear Properties of Composite Coatings with Varying CeO2 Contents

Several innovative mixed powders of Ti6Al4V and NiCr-Cr3C2 with different CeO2 contents (0, 1, 2, 3, and 4 wt.%) were designed, and Ti2C-reinforced CrTi4-based composite coatings were prepared on the Ti6Al4V surface via laser cladding technology. The effects of CeO2 amount on the forming quality, microstructure, hardness, and wear resistance of the composite coatings were studied. The results showed that the CeO2 amount had a significant influence on the forming quality of the composite coatings. The cracks were eliminated completely when the CeO2 content was 2 wt.%; furthermore, the lowest porosity was obtained with the addition of 3 wt.% CeO2. The primary phase constituents of the coatings were non-stoichiometric Ti2C and a β-type solid solution (CrTi4) as the reinforcement and matrix, respectively. CeO2 and a low quantity of Ce2O3 were re-precipitated at the Ti2C/CrTi4 interface and CrTi4 grain boundary in the coatings with CeO2 addition. In addition, the average hardness of the composite coatings was 1.28–1.34 times higher than that of the Ti6Al4V substrate. The wear resistance of the composite coatings was significantly higher than that of the substrate. However, both the composite coatings and the Ti6Al4V substrate exhibited a mixed-wear mode, i.e., abrasive and adhesive wear.