2004 Volume 45 Issue 6 Pages 1847-1851
Thermodynamic properties of the SiO2-GeO2 melt were investigated from the measurement of the GeO2 activity in the SiO2-GeO2 melt by equilibrating it with solid platinum under controlled oxygen partial pressure. The excess Gibbs energy for the SiO2-GeO2 melt was evaluated as the following equation in the quasi-regular solution formalism.
ΔGM,ex = (−47600 + 18.2T)XGeO2XSiO2.
Also, by equilibrating solid platinum with the GeO2 melt under controlled oxygen partial pressure and investigating the phase equilibrium between solid platinum and the liquid Pt-Ge alloy, thermodynamic properties of Pt-rich Pt-Ge system above the eutectic temperature of Pt3Ge was clarified.