Title :
Magnetic properties of coprecipitated barium ferrite powders as a function of synthesis conditions
Author :
Janasi, Suzilene R. ; Rodrigues, Daniel ; Landgraf, Fernando J G ; Emura, Marília
Author_Institution :
Powder Metall. & Magn. Mater. Lab., Inst. for Technol. Res., Sao Paolo, Brazil
fDate :
9/1/2000 12:00:00 AM
Abstract :
Barium ferrite is widely used as a permanent magnet because of its large coercivity and low cost. The usual route to produce barium ferrites is the ceramic method. In order to overcome the detrimental milling effects in the magnetic properties, ferrite powders were obtained by coprecipitation. This method can produce high purity materials with a narrow particle size distribution. In this work, the effects of the pH during coprecipitation, the molar ratio (Fe/Ba), and calcination temperature on the magnetic properties were investigated. The products were characterized by differential thermal analysis, X-ray diffractometry, scanning electron microscopy and thermomagnetic analysis. The magnetic properties were evaluated by vibrating sample magnetometry. Very fine particles with intrinsic coercivities up to 392 kA/m (4.92 kOe) were achieved
Keywords :
barium compounds; coercive force; differential thermal analysis; ferrites; heat treatment; particle size; permanent magnets; powder metallurgy; precipitation; scanning electron microscopy; BaFe12O19; X-ray diffractometry; calcination temperature; coercivity; coprecipitation; differential thermal analysis; ferrite powders; particle size distribution; permanent magnet; scanning electron microscopy; thermomagnetic analysis; vibrating sample magnetometry; Barium; Ceramics; Coercive force; Costs; Ferrites; Magnetic analysis; Magnetic properties; Milling; Permanent magnets; Powders;
Journal_Title :
Magnetics, IEEE Transactions on
