The phase boundaries of the solid phases of the Ni-Ta system at 1473 K, 137
3 K and 1173 K were determined using the diffusion couple and EPMA techniqu
es. The Ni-Ta binary system was then assessed by means of the CALPHAD metho
d. Considering the crystallographic and the phase stability information, a
new model, (Ni,Ta),(Ta), (Ni,Ta)(2)(Ni)(6), was used to describe the NiTa p
hase. A set of parameters describing the Gibbs energy of each phase was obt
ained. Calculated quantities were compared with experimental data, and they
are in good agreement. Using a thermodynamic approach, the crystallization
temperatures T-x and the glass forming range of Ni-Ta system were calculat
ed. In most cases, the calculation represented the experimental data well.