الملخص
Ferrites are a group of oxides with the general formula MFe2O4, where M is a divalent metal ion. They show great potentials for many technological applications due to their physical and chemical properties. The present study deals with a number of ferrites; namely, Magnesium (Mg), Manganese (Mn), Zinc (Zn), Nickel (Ni), Copper (Cu), Calcium (Ca), Lead (Pb) and Cobalt (Co) ferrites. Results of the preparations, characterizations and catalytic activities of these ferrites are presented. The above mentioned ferrite powders were prepared by two different methods: the sol-gel method and the co-precipitation method, followed by different calcination treatments at 500, 750 and 900 °C. The structural, morphological and thermal properties of the prepared ferrites were characterized using a variety of techniques such as X-ray diffraction (XRD), infra-red spectroscopy (IR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The results confirmed the formation of various spinel ferrite nano-particles consisted of nanocrystallites. The presented results also demonstrated that the formation and crystallinity of ferrite particles depends on their chemical composition, the preparation method and the calcination temperature. Typically, sol–gel methods facilitated the formation of ferrite crystallites more than the co-precipitation method. Moreover, it was shown that the crystallite size of the prepared ferrites increased with increasing the calcination temperature..
