Phase relations in the system ZnOMgOGeO2 were determined at 1200°C in air. Subsolidus phase relations along the pseudobinary join Zn2GeO4Mg2GeO4 were determined between 700 and 1200°C, the portion below 900°C was obtained hydrothermally. Only one spinel phase is formed at low temperatures; this phase extends from Mg2GeO4 to (Mg0.73Zn0.27)2GeO4 at 820°C. Its highest temperature of stability is 880°C, with a composition of (Mg0.75Zn0.25)2GeO4. The free energies of transformation from the olivine to the phenacite structures at 1200°C are estimated to be + 6 ± 1.0 kcal/mole and - 10 ± 1.5 kcal/mole for Mg2GeO4 and Zn2GeO4, respectively.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry