Reassessment of Solid Solubilities and Thermodynamic Properties of Magnesium and Calcium in Silicon

To obtain fundamental knowledge on the behavior of magnesium (Mg) and calcium (Ca) in solid silicon ( Si) during solidification, the solid solubilities of Mg and Ca in Si were reinvestigated by temperature-gradient zone melting method. Solubilities were measured to be 0.0016-0.0041 mol% for Mg and 0.0006-0.0021 mol% for Ca at 1373-1623 K. The excess Gibbs energies of Mg and Ca in solid Si were determined from their solid solubilities as follows: RT ln gamma degrees(Mg(s) in solid Si) = 193,000(+/- 52,000) - 69.8(+/- 34) T ( J/mol) RT ln gamma degrees(Ca(s) in solid Si) = 140,000(+/- 35,000) - 72.6(+/- 23) T (J/mol)