Effect of microcrystallization on the cyclic oxidation behavior of β-NiAl intermetallics at 1000 °C in air

The cyclic oxidation behavior of a magnetron sputtered NiAl microcrystalline coating was investigated at 1000 °C in air by TGA, and SEM in comparison with cast NiAl and NiAlY alloys. Results indicate that, for the cast NiAl alloy, mass loss is observed at about 40 cycles, implying the serious spallation occurred, while no spallation is detected for NiAlY alloy and NiAl coating for the whole test period. It is evident that, the scale adhesion is improved by the microcrystallization and the addition of Y.