Preparation and Properties of Barium Ferrite Using Hot-Rolled Mill Scale

Commercial-quality barium ferrite was made on a laboratory scale by the solid-state reaction of raw hot-rolled mill scale and barium carbonate. The quality of the isotropic magnets reached coercivity H _c 1750 Oe, remanence B _r 2200 G, and maximum energy product ( BH )_max 1.0 × 10⁶ G · Oe and that of the anisotropic magnets formed by dry powder die pressing H _c 2000 Oe, B _r 3500 G, and ( BH )_max 2.6 × 10⁶ G · Oe. The amount of the additives was in the range 0.4 to 0.8 wt%. The processing parameters were reported. The mechanism of ferrite formation was proposed.