Thermodynamic modelling of Li–Sn liquid alloy based on Knudsen effusion mass spectrometric measurements

• The experimental KEMS data fit well with the Redlich–Kister sub-regular solution model applied to Li–Sn melt.
• The Redlich–Kister binary interaction L-parameters of the Li–Sn melt were provided in this work.
• The experimental KEMS data fit well with the ideally associated mixture model, too.
• The quantitative associate composition of the Li–Sn melt was given.
• The thermodynamic properties of the associate-forming reactions were also provided.

The mixing thermodynamic properties of liquid Li–Sn system, determined previously by Knudsen effusion mass spectrometry (KEMS), were successfully fitted to both Redlich–Kister (RK) sub-regular mixture and ideally associated mixture (IAMT) models. The RK binary interaction L parameters, as a function of temperature in the CALPHAD-type functional form, were obtained as follows: L(0)=-(108580±0.00171)+(16.4±1.6·10-5)·T+(1.96496·10-9±2.03133·10-6)·T·ln(T)L(0)=-(108580±0.00171)+(16.4±1.6·10-5)·T+(1.96496·10-9±2.03133·10-6)·T·ln(T)L(1)=-(96600±4700)+(3.3±43.0)·T+(4.4±5.6)·T·ln(T)L(1)=-(96600±4700)+(3.3±43.0)·T+(4.4±5.6)·T·ln(T)L(2)=-(64670±190)-(44.4±1.7)·T+(8.44±0.22)·T·ln(T)L(2)=-(64670±190)-(44.4±1.7)·T+(8.44±0.22)·T·ln(T)L(3)=-(20900±1500)-(29±14)·T+(4.3±1.8)·T·ln(T)L(3)=-(20900±1500)-(29±14)·T+(4.3±1.8)·T·ln(T) The former literature data provided only qualitative information on possible liquid associates but no quantitative associate composition was given as a function of the sample composition and temperature. The experimental KEMS data in the composition range XLi = 0 to ∼0.7 fit well with the Li(l) + Sn(l) + LiSn(l) + LiSn2(l) + Li2Sn(l) associate model. At XLi > 0.7 no associate variations – including further associate variants such as Li4Sn(l) etc. – could be fitted to the KEMS data. Nevertheless, in this work the Li(l) + Sn(l) + LiSn(l) + LiSn2(l) + Li2Sn(l) + Li4Sn(l) + Li9Sn(l) associate model was successfully fitted to the thermodynamic data of a selected literature study over the complete composition range. The thermodynamic data of the associate-forming reactions were also given in this paper.