Preparation and oxidation behaviour of NiCrAlYSc coatings on a Ni-based single crystal superalloy.

• NiCrAlYSc coatings were prepared by arc ion plating. • Minor addition of Sc in the coating shortened the transient oxidation stage. • Minor addition of Sc in the coating promoted the transformation from θ-Al 2 O 3 to α-Al 2 O 3. • Minor addition of Sc in the coating significantly improved the scale adhesion. The NiCrAlYSc coatings with different Sc content were prepared on the Ni-based superalloy by arc ion plating. Cyclic and isothermal oxidation behaviours of all the coatings were investigated. The results show that an appropriate addition of Sc in the coating can significantly improve the scale adhesion, shorten the transient oxidation stage and promote the transformation from θ-Al 2 O 3 to α-Al 2 O 3. The effects of Sc addition on the oxidation performance of the coating as well as the mechanism of oxide adherence were discussed. [ABSTRACT FROM AUTHOR]