The interaction process between metallic niobium and a melt containing lead dichloride as oxidizer is modeled. For this purpose, the equilibrium potentials of niobium and lead are measured and the thermodynamic parameters are calculated assuming that the reaction 3Pb2+ + 2Nb0 ⇔ 3Pb0 + 2Nb3+ goes on. The calculated values are compared with values directly obtained from experiments.