Microstructure and oxidation behaviour of an AlSiY/NiCrAlYSi composite coating at 1150 degrees 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 degrees 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 beta-NiAl phase reservoirs, providing it the long term healing capacity of re-growing the alpha-Al(2)O(3) scale. (c) 2011 Elsevier Ltd. All rights reserved.