Processamento e caracterização de nanoferritas Ni-Zn para desenvolvimento de dispositivos magnéticos moles.

Abstract

The Ni-Zn ferrite are materials that exhibit magnetic and electrical properties very useful to applications in electronic materials industry, medicine, telecommunications and catalysis. Their properties are dependent on the type of crystalline structure, of the chemical composition and processing method for obtaining it. This work proposes prepare the system of ferrite Ni0,5Zn0,5Fe2O4 by combustion reaction in large scale (200 grams / batches), and posterior sintering in oven resistive type. The structural morphological and magnetic characterization ferrites of aimed at obtaining material with characteristics suitable for application such as soft magnetic devices was investigated. The samples were initially obtained in receptacles with different volumetric capacities. As from the structural analysis by X-ray diffraction, of these samples was selected which was presented crystal clear and with higher yield. Based on these data was selected the most suitable container and reproduced in the batches Ni-Zn ferrite in order to ensure reproducibility of the synthesis. The samples were characterized by X-ray diffraction (XRD), nitrogen adsorption (BET), X-ray fluorescence by energy dispersive (EDX), scanning electronic microscopy (SEM) and magnetic characterization (VSM). The results of X-ray diffraction showed that the samples reproduced exhibited similar structural characteristics. For comparative effects a sample of Ni-Zn ferrite commercial, obtained by the conventional method of mixing oxides, provided by the Industry and Commerce of Electronic Components Ltd - IMAG was used as reference. The two samples of the ferrite, both the reproduced by combustion reaction how much the commercial sample were submitted to compaction sintering and subsequent characterizations. The results of X-ray diffraction of the reproduced sample and commercial sample were presented crystalline, with crystallite sizes of 34 and 45 nm and 65 and 78 nm before and after sintering, respectively. The micrographs of both samples revealed a homogeneous morphology, consisting of porous agglomerates, and after sintering the reproduced sample showed hexagonal format particles, and the commercial sample of irregular shape particles. As for magnetic characterization behavior of presented soft magnetic materials with low coercive field (0.016 kOe), low hysteresis loss (1293 emu.g-1 x kOe) and elevated magnetization values of (68 emu.g-1), enabling the use of Ni-Zn ferrite reproduced in soft magnetic devices, for presenting characteristics similar to commercial ferrite provided. These results showed that the ferrite obtained by combustion reaction in large scale laboratory is promising for the applications commercial ferrite.