Interaction between lanthanum oxide and yttrium oxide

Abstract

This paper studies the phase equilibria in the La/sub 2/O/sub 3/-Y/sub 2/O/sub 3/ system in a wide range of temperatures (1350-2450 degrees C) and concentrations (0-100 mole % Y/sub 2/O/sub 3/). The phase-field boundaries were determined by the method of annealing and quenching with the help of DTA, during the course of which the samples were heated in an inert atmosphere up to 2450 degrees C. The phase composition of the samples was investigated by x-rays and petrographic analysis. The phase diagram of the system was constructed, for which the existence of wide regions of solid solutions based on A-, B-, C-, H-, and X-forms of rare-earth-element oxides, the decrease in the phase-transformation temperature of La/sub 2/O/sub 3/ and Y/sub 2/O/sub 3/ upon introducing a second element, and the presence of a compound of the perovskite structure with a region of homogeneity, formed by a solid-state reaction at 1585 degrees C, are typical.