The long-term isothermal oxidation and cyclic oxidation performance of anodized Ti48Al2Nb2Cr alloy

The long-term isothermal oxidation and cyclic oxidation performance of the Ti48Al2Nb2Cr alloy anodized in NH4F containing electrolyte were investigated. After isothermal oxidation at 1000 °C and cyclic oxidation at 900 °C for 1000 h, the weight gains of the anodized Ti48Al2Nb2Cr alloys are 1.12 mg cm−2 and 0.48 mg cm−2, respectively. The excellent oxidation performance is ascribed to the fluorine effect. Raman and photo-stimulated luminescence spectra revealed that anodization impedes the formation of rutile and promotes the generation of α-Al2O3 at high temperatures. The Al2O3 and TiO2 formed during anodization act as crystal nucleus for the generation of α-Al2O3-based scale. Al2O3 and TiO2 formed at the anodization process, together with the fluorine effect, promote the generation of protective α-Al2O3 scale. [Display omitted] •A fluorine-enriched region can be found beneath the anodic film.•The anodized Ti48Al2Nb2Cr alloy exhibits excellent oxidation performance.•Al2O3 and TiO2 formed during anodization promote the generation of α-Al2O3-based scale.•The improved oxidation resistance can be ascribed to the fluorine effect.