Direct use of celestite to prepare presintered SrFe12O19 powders

Mineral celestite was directly used to prepare presintered single-phase Sr-ferrite powders for fabrication of sintered permanent magnets. The starting materials were high-purity domestic celestite, modified iron oxide and sodium carbonate. The role of sodium carbonate is firstly to promote the displacement solid-state reaction and secondly to lower the temperature during calcining stage. A vibrating sample magnetometer was used to measure magnetic parameters of the powders. The results were compared with those of the powders prepared by conventional ceramic process. Lower reaction temperature of 1000degreesC and low-cost celestite show that this process is more economical for production of presintered SrFe12O19 powders than the conventional One. (C) 2002 Elsevier Science B.V. All rights reserved.