Subsolidus phase relations in the BaO-TiO2-Fe2O3 system

The subsolidus phase equilibrium relation in the BaO-TiO2-FeO3 system at 1240 degrees C in air has been investigated by conventional solid state reaction techniques and X-ray powder diffraction. Twelve quaternary compounds were recognized, BaTi1-xFexO3-z (0.1 less than x less than 0.75) (N), Ba3TiFe10O20 (K), BaTi2Fe4O11 (R), Ba2Ti4Fe2O13 (J), Ba4Ti4-2xFe2xO8 (0.55 less than x less than 0.67) (H), Ba12Ti16Fe30O89 (I), Ba3.5Ti5Fe23O48 (O), Ba1.8Ti4.4Fe13.6O31 (L), BaTi2O5 (0.2 mol percent Fe2O3) (Q), Ba2Ti4.73Fe0.27O11.865 (P), Ba5Ti13Fe2O34 (A), and Ba8Ti16Fe6O49 (B). The phases J, I, O, L, Q, P, A and B are new compounds found in this study. Oxidation of Fe3+ to Fe4+ was observed in the BaO rich region (50 mol percent). Ba12Ti16Fe30O19 (I) is a ferrimagnet with a T-c around 130 degrees C.