REDOX EQUILIBRIA IN WUSTITE DOPED WITH CAO, SRO AND BAO

This study was performed to obtain the concentration of defects and activities of components in wustite doped with MeO(Me: Ca, Sr and Ba). The composition as FeO-Fe//2/////3O-MeO for wustite in equilibrium with CO-CO//2 gas mixtures of P//C//O(2)/P//C//O equals 30/70, 50/50 and 60/40 at temperatures of 1273, 1373 and 1473 K was determined utilizing the weight loss during reduction. The concentration of cation vacancies is estimated as one-third of the mole fraction of Fe//2/////3O. The value increases with an increase in the amount of MeO and in the ionic radius of Me except for higher concentrations of CaO. The activities of FeO and MeO were estimated by Schuhmann's method from the oxygen pressure contours for wustite doped with CaO at 1273 K.