Mass spectrometric investigation of vaporization in the Bi 2O 3-Fe 2O 3 system

The thermodynamics of vaporization in the Bi 2O 3-Fe 2O 3 quasibinary system was studied by hightemperature mass-spectrometry. The partial pressures of the constituents of a saturated vapor over the system at 1100 K were determined. Based on the experimental data, the following parameters were calculated: the activities of the components of the Bi 2O 3-Fe 2O 3 system condensed phase, the standard enthalpies of some heterogeneous reactions, and standard enthalpies of formation and enthalpies of formation for crystalline BiFeO 3 and Bi 2Fe 4O 9 from individual oxides. An optimal temperature for the solid-phase synthesis of bismuth ferrites from simple oxides is recommended. © Pleiades Publishing, Ltd., 2011.