Microstructure and oxidation behaviour of an AlSiY/NiCrAlYSi composite coating at 1150 °C

A composite coating consisting of an outer AlSiY layer and an inner NiCrAlYSi layer has been prepared by a two-step arc ion plating method. The isothermal and cyclic oxidation behaviour of the composite coating at 1150 °C, including the growth of oxide scale and the microstructure transformation of the coatings, have been investigated comparing with the reference coating, NiCrAlYSi. The results show enhanced oxidation performance of the composite coating, which is concerned with its abundant possession of β-NiAl phase reservoirs, providing it the long term healing capacity of re-growing the α-Al2O3 scale.

Research highlights
► One duplex composite coating AlSiY/NiCrAlYSi was prepared by AIP process.
► Isothermal and cyclic test were performed on the as-annealed samples at 1150 °C.
► The oxide scale on the composite coating was of double-layer microstructure.
► Y was incorporated in the scale during oxidation as Y–Al–O and Y-doped Al2O3.