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 (P-O2 = 21278.25 Pa) have been experimentally determined at temperatures between 1430 degrees C and 1690 degrees 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 degrees C and 0.52 +/- 0.01 mole fraction of ZnO, and at 1497 +/- 2 degrees C and 0.71 +/- 0.01 mole fraction of ZnO, respectively. The results were compared with the earlier studies available for this system. (C) 2015 Elsevier Ltd. All rights reserved.