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Kinetics of NiAl3 and Ni2Al3 phase growth on lateral diffusion couples

1988; American Institute of Physics; Volume: 64; Issue: 2 Linguagem: Inglês

10.1063/1.341957

1520-8850

Joyce C. Liu, J. W. Mayer, J. C. Barbour,

Solidification and crystal growth phenomena

The phase formation of NiAl3 and Ni2Al3 is studied on lateral diffusion couples of an Al-rich source on a Ni thin film at temperatures from 375 to 500 °C. Analytical electron microscopy is used to determine the crystal structures, chemical compositions, and the widths of growing phases. Simultaneous growth of NiAl3 and Ni2Al3 is observed at 375 and 450 °C. Al atoms dominate the diffusion process in NiAl3 and Ni2Al3. The growth of Ni2Al3 has a parabolic dependence on annealing time, and the growth constant, X2/t, has an activation energy of 2.0±0.2 eV. The growth kinetics is further studied by comparing the growth rates of NiAl3 in one- and two-phase growth, and by applying the criteria proposed by Gösele and Tu to the simultaneous growth of NiAl3 and Ni2Al3.