The ternary system Na2O-ZnO-WO3:: Compounds and phase relationships

The subsolidus phase relationships of ternary system Na2O-ZnO-WO3 have been investigated by X-ray diffraction (XRD) and differential thermal analyzer (DTA). All the samples were synthesized in the temperature range from 530 to 850 degrees C in air. There are one ternary compound and five binary compounds in the Na2O-ZnO-WO3 System, which can be divided into eight three-phase regions. The crystal structure of the ternary compound Na3.6Zn1.2(WO4)(3) is determined by single-crystal structure analysis method. It belongs to triclinic system with space group P1 and lattice constants a = 7.237 (5) angstrom, b = 9.172 (6) angstrom, c = 9.339 (6) angstrom and alpha = 94.920 (4)degrees, beta = 105.772 (9)degrees, gamma = 103.531 (8)degrees, Z = 2. DTA analyses indicate that the compound Na2WO4 is not suitable to be the flux for ZnO crystal growth below 1250 degrees C, since no liquidus was observed in the system before 1250 degrees C. (c) 2007 Published by Elsevier B.V.