Thermodynamic assessment of the La–Zn system

A thermodynamic optimization of the La–Zn system is carried out using the CALPHAD (CALculation of the PHAse Diagram) method. This new assessment takes into account the latest experimental values of enthalpies of formation reported in literature. The solution phases (liquid, bcc-La, fcc-La, dhcp-La and hcp-Zn) are modelled as substitution solutions using the Redlich–Kister equation. Nine intermediate phases are considered in this assessment, namely LaZn, LaZn2, LaZn4, LaZn5, LaZn7, La3Zn22, La2Zn17, LaZn11 and LaZn13 and are treated as stoichiometric compounds.

► Literature data is presented.
► Previous assessments results are described.
► Assessed parameters are listed.
► Calculated data are compared with experimental data.
► LaZn7 phase added in spite to fit e.m.f. measurements.