Abstract

PENA-RODRIGUEZ, Gabriel et al. Effect of the concentration of magnetite on the structure, electrical and magnetic properties of a polyester resin-based composite. TecnoL. [online]. 2018, vol.21, n.41, pp.13-27. ISSN 0123-7799.

Abstract This study reports the effect of the concentration of magnetite powders (Fe₃O₄) on the electrical and magnetic properties of a resin-based composite of thermoset polyester. The samples were prepared by the casting method at different concentrations: 60-40, 70-30, 80-20, 90-10 and 100-0 (% in weight), where the primary phase was resin and the secondary, Fe₃O₄ powders. The crystalline structure was studied using X-ray diffraction and surface characterization was carried out applying the scanning electron microscopy technique. The electrical response was measured by electric polarization curves as a function of the electric field; and the volumetric electrical resistivity, by an electrometer. The magnetic response was determined by magnetization curves as a function of temperature and intensity of the applied magnetic field. The structural analysis indicates that crystallinity increases as higher concentrations of Fe₃O₄ are added to the samples. The electrical characterization of the material reveals that the volumetric resistivity decreases as the content of magnetite increases. These reactions indicate an insulation-conductor transition with increasing dielectric constant values. The magnetic characterization presents a linear increase of the saturation of magnetization and magnetic moment as a function of the amount of magnetite added to the polymer matrix, whereas the coercivity shows behaviors of soft magnetic materials for T > T_V and for T < T_V, where Tv represents the temperature of Verwey.

Keywords : Composite materials; magnetite; electric polarization; volumetric resistivity; magnetic behavior; XRD.

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