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The influence of various amounts of Y addition on the isothermal oxidation behavior of sputtered Ni-based superalloy K38 nanocrystalline coating at 1273 K was investigated. The result indicated that the addition of 0.05 and 0.1 wt.% Y in nanocrystalline coating enhanced the selective oxidation of Al, reduced scale growth rate and retarded the phase transformation from metastable to stable alumina. In contrast, 0.5 wt.% Y addition significantly increased the oxidation rate of the coating, the incorporation of Ti in the external alumina scale accelerated the phase transformation to stable alumina. (C) 2007 Elsevier B.V. All rights reserved.