Preparation of nickel-ferrites from complex compounds with acetylacetonato-ligands in different atmosphere conditions

Ultrafine nickel-ferrite materials were prepared from complex compounds with acetylacetonato-ligands, according to a previously developed method. The influence of different atmospheres (air, oxygen and nitrogen) applied during thermal decomposition of precursors was studied. Thermal decomposition was carried out with the heating rate of 10 degrees C/min and the cooling rate of 20 degrees C/min. Characterization of the final products was performed by X-ray and TEM analysis. Reviewing the products, we concluded that the optimal temperatures for the preparation of pure ultrafine ferrite materials were 400 degrees C for air atmosphere, and 500 degrees C for O-2 and N-2 atmospheres. All samples prepared at lower temperatures show the presence of the nickel-phase, while all samples prepared at higher temperatures show the presence of the hematite-phase.