High characteristic Sr-ferrite magnetic powders made by new direct-spray roasting

We have studied the process of new direct-spray roasting; SrCO₃ powders were directly added into the 12FeCl₂·4H₂O solution first, and then α-Fe₂O₃ powders with the particle size of 210∼620 nm was made after spray roasting in the low temperature of 400∼700 °C. The direct-spray roasting enables us to get the uniform mixing of α-Fe₂O₃ and SrCO₃ powders, and to lower the calcination temperature of Sr-ferrite, compared to that of the conventional dry method. Also, the magnetic properties of the powders made by direct-spray roasting are very higher than that made by the dry method. We suggest that the Sr-ferrite powders by the direct-spray roasting act as useful high-Br magnetic powders for high characteristic resin-bonded magnet.