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

Abstract

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 γ^°_{Mg(s)in solid Si}=193,000(±52,000)-69.8(±34)T (J/mol)

RT ln γ^°_{Ca(s)in solid Si}=140,000(±35,000)-72.6(±23)T (J/mol)