Phase relations and flux research for zinc oxide crystal growth in the ZnO-K2O-P2O5 system

The subsolidus phase relations of the ternary system ZnO-K2O-P2O5 were investigated by means of X-ray diffraction (XRD). There are 7 binary compounds, 6 ternary compounds and 20 three-phase regions in this system. The phase diagram of the pseudo-binary system KZn4(PO4)3-ZnO was also investigated by means of XRD and differential thermal analysis (DTA) methods. KZn4(PO4)3-ZnO is a eutectic system with eutectic temperature about 952 °C and eutectic point at about 2 mol% ZnO. Only narrow composition range in the KZn4(PO4)3-ZnO system is suitable for the growth of ZnO crystals.