Tyschenko J. Рhase equilibria in the systems invoving alumina, hafnia with lanthana, gadolinium, erbia and yttria oxides

For the first time phase equilibria in the ternary systems Al2O3-HfO2-Ln2O3 (Ln = La, Gd, Er, Y) were systematically studied in all range of concentrations and 1250-2820 С temperature range. The phase diagrams of these systems are presented as projections of liquidus and solidus surfaces, isothermal at 1250/1650 С and polythermal sections, melting diagrams and reactions schematics. Solidification in the systems is completed in eutectic reactions. New 8 quasibinary and 13 ternary eutectics were found for the first time. Found that a number of eutectic crystallizes the mechanism of cooperative crystallization phases, which opens the possibility to obtain composite materials by directional solidification The established regularities allowed specifying the phase diagrams shape forecast including other members of the lanthanides. For the first time on the basis of the experimental data elements specified forecast charts of several other systems Al2O3-HfO2-Ln2O3 and experimentally confirmed forecast results for three-phase alumina-rich eutectics.