Abstract
The effect of plasma beam on the structure of NiCrAlY powders can be a possible source of structural inhomogeneities in plasma spray coatings. Results of structural studies performed with light microscopy, SEM, TEM, and EDX on NiCrAlY metallic powders plasma sprayed and captured in water are presented in this paper. The internal structure was found to consist of a mixture of phases including γ, γ', β-NiAl and martensitic NiAl. Y is bound in the Ni₅Y yttride localized in the grain boundary regions. Spherical caps containing O, Al, Y, and Cr are formed at the surface of powders. The depletion of bulk powders of Al due to surface oxide formation was found to be the cause of a slight decrease of microhardness of plasma sprayed powder.

Key words
plasma sprayed powder , NiCrAlY powders, microstructure, microhardness

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