|Microstructure of plasma sprayed NiCrAlY coating isothermally exposed at 850 °C for 1, 10 and 100 hours|
IZDINSKY, K., IVAN, J., ZEMANKOVA, M.
vol. 39 (2001), no. 5, pp. 316 - 330
Results of structural studies performed with light microscopy and transmission electron microscopy on plasma sprayed NiCrAlY coatings isothermally exposed at 850 °C for 1, 10 and 100 hours are presented in this paper. The applied thermal treatment led to the decomposition of initial phases and to precipitation of α-Cr and γ'-Ni3Al. It is shown that the precipitation of α-Cr in the γ/γ' matrix obeys orientation relationships.
Complete transformation of amorphous oxides into crystalline structures takes place within the 100 hour exposure. Spinel structures with spacings close to γ-Al2O3 are mostly formed, however, Cr2O3 and CrO3 oxides were found too. No transformation to stable α-Al2O3 oxide has been observed.
NiCrAlY coatings, microstructure, thermal treatment, TEM studies
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