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Oxidation behavior of NiCrAl and NiCrAl-Y alloys has been studied at various temperatures in the present work.Thermogravimetric analysis has been carried out at 900,1000,1100 ℃ for 210 h in order to investigate oxidation kinetics.Phase constitution of surface scales was determined by using X-ray diffraction,and microstructure was examined by using scanning electron microscope with energy dispersive spectra.Oxidation resistance of NiCrAl alloy has been found to be improved substantially by adding trace amount of rare earth element yttrium at all the three experimental temperatures.Two different types of mechanisms of enhancing anti-oxidation property at different temperatures have been proposed based on experimental observations-selective formation of oxides at 900 ℃ and providing nucleation sites at 1000 and 1100 ℃.