High temperature oxidation behavior and interface diffusion of Cr3C2-NiCrCoMo/nano-CeO2 composite coatings

The high-temperature oxidation resistance of chromium carbide cermet coating was improved by developing a novel Cr3C2-NiCrCoMo/nano-CeO2 (NCE) composite coating based on the collaborative modification of the multielement alloy adhesive phase. The present study aimed to investigate the influence of nano-CeO2 on the high-temperature oxidation resistance, interfacial element diffusion and oxidation mechanism of the coating deposited by the high-velocity oxygen fuel spraying technology (HVOF). The results showed that the novel NCE coating with the addition of 4 wt% nano-CeO2 resulted in lower oxidation rates of 0.10, 0.23 and 0.39 mg/cm2 at 700–900 °C and superior oxidation resistance compared with the original Cr3C2-NiCrCoMo (NCC) coating because of the improvement of the thickness and denseness of the oxide film. The addition of nano-CeO2 promoted the reaction between oxides and the content of spinel phases generated in the NCE coating oxide film. The oxide film of NCE coating with high content of spinel phases strongly inhibited on the ion diffusion, thus reducing the decarburization of the Cr3C2 particles at the coating-oxide film interface. The present study will contribute to improving the service life of chromium carbide cermet coatings in high-temperature oxidation environments and extending the application of coating.