Synthesis of Co-, Co-Zn and Ni-Zn ferrite powders by the microwave-hydrothermal method

Co-, Ni-Zn, and Co-Zn ferrites were prepared with nanosize well-developed spinel phases by the coprecipitation and microwave-hydrothermal (M-H) methods. X-ray diffraction (XRD) and transmission electron microscope (TEM) techniques showed that the average particle size of ferrites obtained by the M-H process is about 10 nm. In the Co-ferrite system, single-phase ferrites with a spinel structure began to form at a relatively low temperature (100 degreesC) in a short holding time (30 min). The lattice parameter of M1-xZnxFe2O4 systems (M = Ni or Co, 0 less than or equal to x less than or equal to 1) increased with an increase of Zn concentration. The crystallization of the spinel ferrites was promoted by the increase in reaction temperature and time. (C) 2001 Elsevier Science Ltd. All rights reserved.