Triangulation and Liquidus Surface in the Al2O3 ― ZrO2 ― La2O3 Phase Diagram

A projection has been constructed for the liquidus surface in the phase diagram for the Al2O3 ― ZrO2 ― La2O3 system on to the plane of the concentration triangle. There are found to be two partially quasibinary sections LaAlO3 ― (98.5 mole% ZrO2 ― 1.5 mole% La2O3) and La2O3·11Al2O3 ― (98.5 mole% ZrO2 ― 1.5 mole% La2O3) together with one quasibinary LaAlO3 ― La2Zr2O7 section, which triangulate the ternary system, and the phase diagrams have been constructed for them. There are nine fields of primary crystallization for phases based on the T and F forms of ZrO2, the X, H, and A forms of La2O3, and also the phases La2Zr2O7, LaAlO3, La2O3·11Al2O3, and Al2O3, together with two quasibinary eutectics and three ternary ones. It is not found that there are any ternary phases and solid-solution regions based on the components and the binary compounds. The minimum temperature in the system is 1665°C. The interactions are basically of eutectic type.