Synthesis and characterization of barium hexaferrite nanoparticles

This investigation dealt with the synthesis of nanocrystalline barium hexaferrite (BaFe12O19) powders through the co-precipitation-calcination route. The ferrite precursors were obtained from aqueous mixtures of barium and ferric chlorides by co-precipitation of barium and iron ions using 5 M sodium hydroxide solution at pH 10 in room temperature. These precursors were calcined at temperatures of 800-1200 degrees C for constant 2 h in a static air atmosphere. The effect of Fe3+/Ba2+ mole ratio and addition of surface active agents during co-precipitation step on the structural and magnetic properties of produced ferrite powders were studied. It is found that the formation of single phase BaFe12O19 powders was achieved by decreasing the Fe3+/Ba2+ molar ratio from the stoichiometric value 12-8 and increasing the calcination temperature >= 1000 degrees C. In addition, the Fe3+/Ba2+ mole ratio of 8 the surface active agents promoted the formation of homogeneous nanopowders (ca. 113nm) of BaFe12O19 at a low-temperature of 800 degrees C with resultant good magnetic saturations (50.02 emu/g) and wide intrinsic coercivities (642.4-4580 Oe). (c) 2006 Elsevier B.V. All rights reserved.