Sintered SrFe12O19/Fe-B composites: Precipitation of α-Fe and magnetic properties

SrFe12O19 (SrM) and Fe-B powders obtained via a hydrothermal and a molten salt method, respectively, were uniformly mixed with different mass ratio (R-m) and sintered at different sintering temperatures (T-s), attempting to prepare SrM/Fe-B composites. The structural and magnetic properties of sintered composites are systematically studied. It is found that the composite only consists of SrM and Fe-B powders after sintering at 500 degrees C. However, the precipitation of alpha-Fe begins after sintering at a temperature of 600 degrees C, and attains the severest at about 690 degrees C. Both the saturation magnetization and coercivity of composites change irregularly with the increase of R-m, while they keep a marked increasing and decreasing tendency, respectively, with the increase of T-s. All the above changes of magnetic properties could be ascribed to the precipitation of alpha-Fe and the formation of new phase(s). (C) 2015 Elsevier B.V. All rights reserved.