Experimental determination of the liquidus temperatures of the binary (SiO2–ZnO) system in equilibrium with air

The phase equilibria and liquidus temperatures in the binary SiO2–ZnO system in equilibrium with air (PO2 = 21278.25 Pa) have been experimentally determined at temperatures between 1430 °C and 1690 °C. Equilibration at target temperature in an appropriate container material was achieved, followed by rapid quenching. The microstructure of the specimen was observed by a scanning electron microscope from polished sections. The phase compositions were collected by an energy-dispersive X-ray spectroscopy (EDS), and confirmed by an electron probe X-ray microanalysis (EPMA). The only binary compound was found to be Zn2SiO4. Two binary eutectics were determined at 1442 ± 2 °C and 0.52 ± 0.01 mole fraction of ZnO, and at 1497 ± 2 °C and 0.71 ± 0.01 mole fraction of ZnO, respectively. The results were compared with the earlier studies available for this system.