MEASUREMENT AND THERMODYNAMIC EVALUATION OF PHASE-EQUILIBRIA IN THE FE-TI-O SYSTEM

The stability of pseudobrookite type solid solutions in the binary sec tion FeTi2O5-Ti3O5 is investigated in the temperature range 1060 degre es to 1360 degrees C by the quench method combined with chemical analy sis and X-ray diffractometry. These data are then combined with all ot her available phase equilibrium and thermodynamic data in order to obt ain a set of optimized thermodynamic equations for the phases in the F eTiO3-TiO2-Ti2O3-Fe system. Models for the ilmenite and pseudobrookite solutions are developed. The good agreement between the calculated ph ase equilibria and the measurements indicates the essential correctnes s of the thermodynamic data and the phase diagrams.