Effects of Element Distribution on Interfacial Damage of CoNiCrAlY Coatings

Abstract

The CoNiCrAlY coated Ni-base superalloy was exposed at 1000 and 1100°C for up to 1000h. The morphology and residual stresses in the Thermally Grown Oxide (TGO) layer on the CoNiCrAlY coating were examined by microscopic observation and luminescence spectroscope. The low pressure plasma sprayed CoNiCrAlY coating (LPPS) shows the thinnest TGO layer and lowest residual stress. Residual stress declined the longer the thermal exposure time, it was found that depending on the morphology of TGO layer. Further, the morphology of the TGO layer is likely to depend on the distribution of elements Yttrium to generate the Alumina layer / mixed oxide layer interface was found.