Effect of Sm, Gd, Yb, Sc and Nd as reactive elements on oxidation behaviour of β-NiAl at 1200 °C

• Oxidation behaviour of Sm, Gd, Yb, Sc and Nd doped NiAl alloys was investigated.
• The REs reduced the oxidation rate and improved the oxide scale adhesion to NiAl.
• Yb and Sc greatly inhibited the formation of interfacial voids and scale rumpling.
• Nb and Ta had no effect on the oxide scale adhesion to NiAl.

Cyclic oxidation of NiAl alloys doped by the elements of Sm, Gd, Yb, Sc, Nd, Nb and Ta was investigated at 1200 °C. All the dopants effectively reduced the oxidation rate. Sm, Gd and Nd contributed to improved oxide scale adhesion, whereas Nb and Ta had no effect on scale adhesion. The Yb and Sc doped alloys exhibited not only improved oxide scale adhesion but also lower oxidation rates. The mechanism of action of these dopants is discussed.