THE EFFECT OF Nb ON THE OXIDATION BEHAVIOR OF TiNiAl ALLOYS
Nb对TiNiAl合金高温氧化行为的影响

The cyclic oxidation behaviors of Ti50Ni44Al6 and Ti50Ni41Al6Nb3 alloys at 1073 K in air showed that the addition of Nb could improve the oxidation resistance of the alloys. After 100 h oxidation the outer oxide scale of Ti50Ni44Al6 alloy consists of TiO2 and a few of Al2NiO4, and the internal scale is TiNiO3. The oxidation kinetics of the Ti50Ni44Al6 alloy obeys a linear law. For the TisoNi41Al6Nb3 alloy under the same oxidation condition, the oxide scale mainly consisted of TiO2 as well as Nb, Al riched complex oxide beneath the TiO2 layer, and the oxidation kinetics obeys parabolic law. The improvement of the oxidation by Nb addition results from that the Nb, Al complex oxide impedes the inward diffusion of oxygen and outward diffusion of metallic elements, which decreases the oxidation rate of the Nb containing alloy.