Sliding Wear Behavior of the Nanoceria-Doped AlCrFeCoNi High-Entropy Alloy Coatings Deposited by Air Plasma Spraying Technique

In this study, the as-received (AR) and nanoceria-doped (NCD) AlCrFeCoNi high-entropy alloy (HEA) coatings have been applied by the thermal spraying process. In this case, 0.5 wt.% of nanoceria was chosen to obtain NCD-HEA AlCrFeCoNi coating. Microstructural characteristics of the AR- and NCD-HEA AlCrFeCoNi powder and coatings were carried out using transmission electron microscopy, x-ray diffraction analysis, and field-emission scanning electron microscope equipped with energy-dispersive x-ray spectroscopy. Moreover, the microhardness profile and sliding wear behavior of NCD-HEA coatings were examined and compared with the AR-HEA coating. The results indicated that the NCD-HEA coating has a relatively denser microstructure than AR-HEA coating owing to the lower amounts of structural porosity and oxide stringers into the NCD-HEA coating structure. The results also demonstrated that the NCD-HEA coating has a higher sliding wear resistance compared with the AR-HEA coating. These findings were acquired due to the denser structure, higher hardness, and desirable dispersion of hard ceria nanoparticle reinforcements in the lamellar structure of NCD-HEA coating.