The method of phase diagrams related to design of single crystal growth

New approaches are used for the phase diagram investigation of the oxide systems, which include phases with the non-linear properties. The phase diagram of K2O-Nb2O5 system is studied by the differential thermal analysis (DTA) and vibration phase-shift analysis in the interval of 30-65 mol% Nb2O5. Position the liquidus and coordinates of invariant points are studied more correctly than earlier. It is proposed to determine the topology of the liquidus surface of ternary system over the sub-solidus section of phase diagram. This procedure is realized for the fragment of the phase diagram of B2O3-K2O-Nb2O5 system.