Air Oxidation of a Ni₅₃Nb₂₀Ti₁₀Zr₈Co₆Cu₃ Glassy Alloy at 400–550 °C

Air-oxidation behavior of a Ni₅₃Nb₂₀Ti₁₀Zr₈Co₆Cu₃ amorphous ribbon was studied at 400–550 °C. The oxidation kinetics of the amorphous alloy followed a two-stage parabolic rate law with its oxidation rates steadily increasing with temperature. The steady-state oxidation rate constants of the alloy were faster than those of pure Ni. Triplex scales formed on the glassy alloy, containing an outer layer of NiO. The scales formed in the intermediate layer consisted of Nb₂O₅, NiO, and uncorroded α-Ni, while an additional Nb₂Zr₆O₁₇ phase was also detected in the inner layer. The formation of multilayered scales is responsible for the faster oxidation for the Ni6-AR.