It has been found that HVOF-sprayed Cr3C2–NiCr coatings exhibit good wear-resistance and corrosion resistance in various high-temperature service environments. Previous research shows that rare earth oxides as additives for coatings lead to excellent high-temperature wear resistance. However, little attention has been paid to the sliding wear behavior of Cr3C2–NiCr coating doped with rare earth oxide at elevated temperature up to 800℃, which is greatly important in tribological field and surface engineering area.

　  Recently, the research (Tribol Lett (2010) 37:463–475) carried out by the State Key Laboratory of Solid Lubrication, LICP, CAS, has investigated the friction and wear behavior of Cr3C2–NiCr/CeO2 coatings at elevated temperature up to 800℃. It is hoped that the Cr3C2–NiCr coating containing proper content of CeO2 additive could function as the promising candidate coating material to substitute for pure Cr3C2–NiCr coating, which is commonly used in various high-temperature environments.

　  Results show that the composite coatings doped with CeO2 had better wear-resistance than that without CeO2, and the coating containing 4wt% CeO2 showed the best wear-resistant property. The improved wear-resistant properties of the composite coatings doped with CeO2 were attributed to the refined microstructure and improved mechanical properties induced by CeO2. The Cr3C2–NiCr/CeO2 coatings with the refined microstructure and improved hardness possess the high load capacity, resulting in the high stability of Cr2O3-lubricious film and the excellent friction and wear properties at elevated temperatures as compared with coating without CeO2 additive. Thus, HVOF sprayed Cr3C2–NiCr/CeO2 composite coatings might serve as promising surface coatings for engineering components in aggressive working environments involving elevated temperatures.

SEM images of wear debris of HVOF sprayed (a, b and c) coating 1 and (d, e and f) coating 3 sliding against Si3N4 at various temperatures