Effect of heating conditions during combustion synthesis on the characteristics of Ni0.5Zn0.5Fe2O4 nanopowders

Ni-Zn ferrite powders were synthesized by combustion reaction. The effect of external conditions of heating on the characteristics of the resulting powders was evaluated. Two synthesis routes were studied. The first involved preheating on a hot plate at 300degreesC and subsequently heating in a muffle furnace at 700degreesC (RCPM). In the second route the powders (RCP) were heated directly to 600degreesC on a hot plate until self-ignition occurred. The resulting RCP products were evaluated before and after attritor milling in order to reduce the size and increase the uniformity of particles and/or agglomerates. The resulting powders were characterized by X-ray diffraction (XRD), BET, scanning electron microscopy (SEM), helium pycnometry, sedimentation and transmission electron microscopy (TEM). The results showed that it was possible to obtain Ni-Zn ferrite powders using both routes and that the second route (RCP) was the most favorable in terms of obtaining powders with high surface area. The efficiency of the grinding was confirmed by the reduction of the size of the particles. (C) 2002 Kluwer Academic Publishers.