Résumé
Literature data of the Mn-Si system is analyzed and discordances are pointed out. First principles calculations are performed to clarify the enthalpies of formation of the intermetallic phases. Especially the enthalpies of formation of the various possible structures of the MnSix are discussed. On the basis of these new data, a thermodynamic description of the Gibbs energy of the phases is performed using the Calphad method. The system Ge-Mn is also assessed using the Calphad method for the first time. The mixing enthalpy in the D88 solid solution is calculated between Mn5Ge3 and Mn5Si3 by DFT calculations. Finally a thermodynamic description of the ternary system is suggested. Especially the solubility of germanium in MnSix is modeled.