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A novel Ni-6Cr-7Al (wt.%) nanocomposite was developed by co-electrodeposition of Ni with nanoparticles of Cr and Al from a sulphate bath.The as-deposited nanocomposite consisted of a nanocrystalline Ni matrix and dispersed second phase nanoparticles of Cr and Al.The initial oxidation of the nanocomposite at 900℃ in air was investigated by SEM/EDAX, AFM, TEM and XPS.For comparison, the initial oxidation of an arc-melted Ni-6Cr-7Al alloy was also studied.It was found that an Al-rich oxide scale with fine-grained structure formed on the nanocomposite, whereas a Ni-rich oxide scale with larger-grained structure formed on the alloy during oxidation for 5 minutes.The results indicated that the unique structure of the nanocomposite favored a quick formation of Al2O3 scale.The reason lies in three aspects: first, the numerous dispersed Cr and Al nanoparticles as well as abundant grain boundaries act as the easy nucleation sites of Al2O3 when oxidation starts, second, initially-formed Cr2O3 serve as the catalyst for the nucleation and growth of Al2O3, third, the abundant grain boundaries in the nanocrystalline Ni matrix, as "short-circuit" diffusion path of Al to oxidation front, promote fast formation of Al2O3.