Composite deposits based on titanium aluminide produced by plasma spraying

A Ti–Al–N composite powder is produced by ball-milling of elemental titanium and aluminum powders in a nitrogen atmosphere, and is plasma-sprayed in an Ar gas atmosphere, yielding titanium aluminide-based deposits. The main constituent of the as-sprayed deposit formed on a directly water cooled substrate is Ti3Al(α2), and subsequent heat-treatment of the deposit results in the formation of TiAl (γ), Ti2N and Ti2AlC. There is little difference in hardness between the as-sprayed deposit and the deposits heat-treated at temperatures up to 1473 K. The constituents of the as-sprayed deposit formed on an indirectly water-cooled substrate are α2,γ and Ti2N. This as-sprayed deposit is harder than the deposits formed on a directly water-cooled substrate both in the as-sprayed condition and in the heat-treated conditions.