냉간압연된 Ni3Al 박판재의 내산화 특성 개선을 위한 NiAl-Ti-Y 코팅의 증착

Abstract

Since the intermetallic compound Ni_(3)Al has attractive high-temperature properties, Ni_(3)Al thin foils could be used as lightweight, high-temperature structural materials. The floating zone (FZ) method makes it possible to fabricate the thin foils with smooth and crack-free surface by cold rolling up to 96% without any intermediate annealing steps. For the practical application of Ni_(3)Al foils, the other properties such as oxidation resistance, wear resistance and friction resistance should be considered. The 3-NiAl, which is one of the important intermetallic compound in Ni-Al systems together with γ-Ni_(3)Al, have been used as coating materials of Ni-base superalloys because of its excellent oxidation resistance. In this study, the NiAl-based coating was intended to deposit on the Ni_(3)Al foils through RF magnetron sputtering. The binary Ni-50Al coating, however, was not able to form the stable α-Al_(2)O_(3) oxide. Moreover, the rapid Al diffusion between coating layer and substrate was occurred. On the contrary, it was found that the Ni-47Al-3Ti-0.1Y coating showed superior oxidation resistance due to stable α-Al_(2)O_(3) formation and good retardation of Al diffusion from coating layer.