Establishment of the equilibrium phase diagrams in fluorite-related systems, ZrO2-CeO2 and SrF2-LaF2, by hydrothermal techniques

The equilibrium solidus phase diagrams in fluorite-related systems of ZrO2-CeO2 and SrF2-LaF3 are established by hydrothermal techniques in aqueous LiCl solution at below 1400 C and 750 C, respectively. The solid solutions of cubic, tetragonal and monoclinic phase are produced in the system ZrO2-CeO2. the tetragonal phase decomposes to monoclinic and cubic phase at the eutectoid temperature of 1050 C±50 C. The coexistent boundary of the tetragonal and cubic phase are about 18 and 70 mol% CeO2, 16 and 80 mol% CeO2, at 1400 C and 1200 C, respectively. The coexistent boundary of the monoclinic and cubic phase are about 1.5 and 88 mol% CeO2, 1.5 and 98 mol% CeO2, at 1000 C and 800 C, respectively. The solid solutions and cubic and hexagonal phases are produced in the system SrF2-LaF3. The coexistent boundaries of the cubic and hexagonal phases are about 47 and 94 mol% LaF3, 47 and 96 mol% LaF3, and 46 and 98 mol% LaF3 at 750 C, 650 C and 500 C, respectively. 15 refs.; 8 figs.; 1 table