The Co-Ta system has been reviewed and the thermodynamic description was re-assessed in the present work.
DFT (density functional theory) calculations considering spin polarization were performed to obtain the energies
for all end-member configurations of the C14, C15, C36 and μ phases for the evaluation of the Gibbs energies of
these phases. The phase diagram calculated with the present description agrees well with the experimental and
theoretical data. Considering the DFT results was essential for giving a better description of the μ phase at lower