The Influence of Calcination Temperature in Ni-Zn Ferrite Doped with Al3+

Ferrites are ceramic materials whose magnetic properties are very interesting used in various applications. This study evaluates the calcination on the characteristics of Ni0.5Zn0.5Fe1.97Al0.3O4 ferrites synthesized by combustion reaction. The samples as synthesized and after calcination at 700 oC/1h in a muffle type furnace were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, magnetic measurements and determination of carbon content. The results showed the formation of the Ni0.5Zn0.5Fe2O4 ferrite phase for samples with and without calcination. The infrared spectra showed characteristic vibrations of HO and NO bonds, possibly attributed to the adsorbed water and residual nitrate. Morphologically there was the formation of soft agglomerates with interparticule porosity for both samples. The Ni-Zn ferrite doped with 0.3 mol of Al3+ showed superparamagnetic behavior without calcination and after calcination observing its behavior as a soft magnetic material (easy magnetization and demagnetization). Samples showed very low carbon content, indicating that urea used as a fuel was nearly completely consumed in the reaction and after calcination it wasnt observed the presence of carbon.