Abstract
Equilibrium experiments were performed to determine thermally stable ranges of BaO⋅2FeO⋅8Fe2O3 (W) and BaO⋅FeO⋅7Fe2O3 (X) under various oxygen pressures. Ferrous contents of W and X compounds increas-ed with increasing temperature and with decreasing oxygen pressure. No significant changes in saturation magnetization were observed with variation of ferrous contents of W and X compounds. Upper and lower limits of the stablility ranges for W and X compounds were found to be expressed as follows:
(1) W compound; W=Magnetite+Liq. RTlnPo2=-1030×103+578T(1622-1728 K), 2W+O2=2M (BaO⋅Fe2O3)+6Fe2O3 RTlnPo2=-444×103+255T (1448-1622K)
(2) X compound; X=W+Liq. RTlnPo2=-967×103+553T (1587-1697K), 2X=W+M (BaO⋅6Fe2O3) RTlnPo2=-682×10;3+402T (1510-1633K)
Here, Po2: the oxygen pressure in atm unit, T: temperature in K unit, and R: 8.3145J/mol⋅K.
