Effect of water vapor on thermally grown alumina scales on bond coatings

► Study of alumina scale formed after exposure in various environments (dry O2, air + 10%, 50% and 90% H2O). ► Study of β-(Ni,Pt)Al and two phase (γ + γ′) bond coatings on Ni-base superalloy René N5. ► With and without water vapor, the β-(Ni,Pt)Al coatings showed a martensitic structure with 10-50 nm α-Cr(Re) precipitates. ► Compared to dry O2, the addition of 10%H2O increased the alumina scale thickness especially for the γ + γ′ bond coating.