Effect of some additions on the sinterability and magnetic properties of barium hexaferrite

The effect of additions on the densification of previously prepared stoichiometric barium hexaferrite, during the initial and intermediate stages of sintering, as well as on the coercivity and remanence were studied. The effect of non-stoichiometry, SiO₂, Al₂O₃, Cr₂O₃, TiO₂, SnO₂, MnO₂, MgO, NiO and Bi₂O₃ is included.While SiO₂ and Bi₂O₃ form liquid phases that increase the density, Al₂O₃, Cr₂O₃ and MnO₂ form a limited solid solution and are generally beneficial when added in the proper amounts. At 1300 SiO₂ up to 0.55% and Al₂O₃ up to 1% gave better magnetic properties. On the other hand addition of TiO₂, MgO, NiO or SnO₂ has a deleterious effect.