Thermodynamics of Titanium and Boron in Molten Aluminum

Abstract

Solubilities of Al₃Ti at 1273-1623 K and TiB₂ at 1373-1573 K in molten Al were measured, and the excess partial molar Gibbs energies of titanium and boron in molten Al of liquid standard state at infinite dilution were determined as follows.
G^e_T^x_i^*_(l) = RT ln γ°_Ti(l) = 95800(±790)+24.5(±0.70)T (J/mol) [943∼1623 K]
G^e_B^x*_(l) = RT ln γ°_B(l) = 18600(±1100) (J/mol) [1373∼1573 K]
Also, solubility of AlB₁₂ at 1273-1573 K in molten aluminum was measured, and the standard formation energy of AlB₁₂ was evaluated as a following equation with the determined thermodynamic property of boron in molten aluminum.
Al(l) + 12B(s) = AlB₁₂(s)
ΔG°^f_AlB12 = −379000(±23000) + 177(±15)T (J/mol) [1273∼1573 K]