The purpose of the present study is to investigate and compare the oxidation behaviour of conventional and nanocrystalline CoNiCrAlY bond coats. The nanocrystalline feedstock powder is produced from the conventional feedstock powder using the cryogenic milling process. Conventional and nanocrystalline bond coats are produced using the Cold Spray (CS) process in order to avoid the onset of thermally induced grain growth and minimize the inclusion of oxides in the bond coat microstructure. The oxidation behaviour of free-standing CoNiCrAlY coating samples is determined by means of isothermal oxidation experiments consisting of heat treatments in air at 1000°C for various periods of time. Characterization of the feedstock powders and resulting CS coatings, as well as investigation of the oxide scale growth dynamics, is achieved by means of SEM, XRD and TEM analyses. Mass gain measurements were also carried out throughout the oxidation tests to evaluate oxide growth rates.

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