Observation on the Interface of α-Al2O3/Cr2O3: Prepared by oxidation of Al45Cr7

► α-Al2O3 film was prepared by oxidation of Al45Cr7. ► Cr2O3 was found to be the nuclei core of α-Al2O3. The nucleation and growth of α-Al2O3 on Cr2O3 surface was observed and discussed. ► The interface of α-Al2O3/Cr2O3 was found to be (0 0 1)α-Al2O3/(0 0 1)Cr2O3 when α-Al2O3 nucleate on a fresh Cr2O3 facet. ► The influence of temperature for the formation and growth of α-Al2O3 on Cr2O3 surface was investigated.