| The various analytical expressions for the free energies of pure metals, binary and ternary solution phases were discussed. The methods of obtaining parameters in the expressions from experimental data were also described in detail. The methods were used to optimize thermodynamic data of eight binary systems and activities of components of the Ag-Sn-Pb system at 1073˚K, the Bi-Cd-Pb and Sn-Cd-Pb systems at 773˚K. The correction terms added to the ternary model equations such as the Kohler, Toop, and Muggianu equations improved the calculated values within the experimental error, in which the correlation coefficients were larger than 0.98 for the three ternary systems. The published activities of Ag and Pb in the Ag-Sn-Pb were found to be erroneous because wrong equations were used. The corrected activities were calculated using the above method without the Darken integration. |
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