Thermodynamic modeling of the germanium–manganese system

• A literature review of phase diagram and thermodynamic properties is presented.
• The liquid is modeled with an associated model.
• The parameters of the Gibbs energies of each phase are optimized.
• The calculated phase diagram and thermodynamic properties are compared to experimental review.

Based on a careful review of the literature, the Ge–Mn system is modeled using the Calphad method. The liquid is described using an associate model regarding to physicochemical observations. The phases cub_a13, fcc_a1 and bcc_a2 are modeled as substitution solutions using the Redlich–Kister formalism. The Mn11Ge8, Mn5Ge3, LT_Mn5Ge2 and LT_Mn3Ge are treated as stoichiometric compounds and the non-stoichiometry of Mn3Ge, Mn5Ge2 and Mn2Ge are respectively described as (Mn)0.75(Ge,Mn)0.25, (Ge,Mn)0.714 (Ge,Mn)0.286 and (Ge,Mn)0.667 (Ge,Mn)0.333. The results are in good agreement with the set of experimental data which is carefully selected. Finally, a few experimental data which could be checked are indicated.

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