TEM analysis of the hafnium-doped aluminide coating deposited on Inconel 100 superalloy

• The coating consists of the β-NiAl phase, M23C6 and M6C carbides.
• No hafnium rich particles were observed.
• Hafnium has dissolved in the coating.
• 1% at. of hafnium in the coating improves oxidation resistance of superalloy.

Hafnium-doped aluminide coating was deposited on Inconel 100 superalloy by the CVD method. The coating consists of two layers: the additive and the interdiffusion one. The coating was formed by the predominant outward diffusion of nickel from the substrate. The additive layer consists of the β-NiAl phase and the interdiffusion layer consists of the β-NiAl phase with M6C and M23C6 carbides. No hafnium rich particles were observed. It is the evidence, that hafnium has dissolved in the coating. The oxidation resistance of hafnium-doped and undoped coatings was tested. Hafnium significantly improved oxidation resistance of coated Inconel 100 superalloy.