Liquid-solid diagram for the Na3PO4-GaPO4 system

Differential thermal analysis is used to study the liquid-solid diagram for the Na 3 PO 4 -GaPO 4 system. The compound Na 3 Ga(PO 4 ) 2 is found to form in the system; it decomposes in a solid at 640 ′ 10°C. The eutectic coordinates are 680 ′ 10°C, 44 ′ 4 mol % GaPO 4 . An extensive solid solution based on the high-temperature cubic Na 3 PO 4 phase exists in the system. It contains up to 35 mol % GaPO 4 , which has a high ionic conductivity.