THE CHARACTERISTICS OF OXIDE SCALE FORMED ON LOW PRESSURE PLASMA SPRAYED NiCrAIY COATING IN THE PRESENCE OF 5% WATER VAPOR

The oxidations of low pressure plasma sprayed (LPPS) NiCrAlY coating on nickelbase superalloy were studied at 1050C in flows of O2, and mixture of O2 and 5%H2 Ounder atmospheric pressure. Oxide formed on the surface of LPPS NiCrAlY coatingafter oxidation at 1050℃ in pure O2 consisted of NiCr2 O4, whereas oxide formed onthe surface of LPPS NiCrAlY coating after oxidation at 1000℃ in a mixture of O2 and5%H2 O is mainly composed of NiO. The effect of water vapor on the characteristicsof the oxide scale is attributed to the increase in Ni cation transport.