Subsolidus phase diagram for the Y2O3–Fe2O3–CoOx system and stability boundary of YFe1-xCoxO3

The phase diagram for the ½Y2O3–½Fe2O3–CoOx system is experimentally studied and constructed at 1373 ​K in air. It is also assessed for various temperatures inside 1173–1573 ​K interval based on the homogeneity ranges of YFe1-xCoxO3 and mixed cobalt/iron oxide phases. The stability boundary of YFe1-xCoxO3 oxides in respect to Po2 is estimated. It is shown that the limiting composition of YFe1-xCoxO3 solid solution at 1373 ​K is linearly decreasing from x=0.45 in air down to x=0 corresponding to the decomposition pressure of YFeO3 equal to lg(Po2/atm)= −13.3.