Oxidation ofγ′-Ni3Al andγ′-Ni3Al(Si) intermetallic compounds at low-oxygen pressures

The oxidation behavior of γ′-Ni3Al and γ′-Ni3Al(Si) (Ni75Al20Si5) intermetallic compounds was studied at 1073 K and oxygen partial pressures of 5∼9×10−6 atm, 1.2×10−14 atm, and 1.2×10−19 atm by means of a manometric apparatus, and Rhines packs of NiO/Ni and FeO/Fe, respectively. Oxidation kinetics were determined either by recording weight gains or by measuring the internal-oxidation-zone depths. The structures and morphologies of oxides were …