Phase Diagram of the System Na 2 O·Ga 2 O 3 ‐Ga 2 O 3 and its Relation to the System Na 2 O·Al 2 O3‐Al 2 O3

A new phase diagram for the system Na 2 O‐Ga 2 O 3 (>50 mol% Ga 2 O 3 ) is presented. It is based on information from differential thermal analysis, X‐ray examination of quenched samples, and a radiochemical technique for determining the compositions of a primary phase and a liquid in equilibrium with it. The diagram provides a guide for the growth of primary crystals of the two ionically conducting sodium gallates that are analogs of the technologically important β‐ and β″‐aluminas.