Síntesis y evaluación de la morfología, estructura y parámetros electroquímicos de un material magnetocalórico (MMC) fabricado por autocombustión.

The magnetocaloric effect (EMC) is defined as the heating or cooling of magnetic material when the applied magnetic field changes. Various types and families of magnetocaloric materials (MMC) have been developed around the theme of EMC, within which are ceramic magnetocaloric materials (MMCC), and w...

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Autores:: Muñoz Mizuno, Andrea Lucía

Tipo de recurso:

Fecha de publicación:: 2020

Institución:: Universidad Nacional de Colombia

Repositorio:: Universidad Nacional de Colombia

Idioma:: spa

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Summary:	The magnetocaloric effect (EMC) is defined as the heating or cooling of magnetic material when the applied magnetic field changes. Various types and families of magnetocaloric materials (MMC) have been developed around the theme of EMC, within which are ceramic magnetocaloric materials (MMCC), and within these, lanthanum manganites. The last one has become a focus of research interest, due to the good properties that have been obtained for technological applications in the area of solid state refrigeration. In studies on magnetic refrigeration, a point that must be taken into account; but that is poorly evaluated, is the interaction of the working fluid with the magnetocaloric material, that is, the chemical stability and degradation of the material when exposed to the corrosive/erosive action of the working fluid. The manganites synthesized in this work, have the general formula La0.7Ca0.3Mn1-xNixO3 (x = 0; 0,02; 0,07; 0,1), which were made by solution combustion method. Morphological and structural characterization was performed by Field Emission Scanning Electron Microscopy (FE-SEM) and X-ray diffraction, respectively. Electrochemical behavior was evaluated by Electrochemical Impedance Spectroscopy and Potentiodynamic Polarization curves in a 3.5% NaCl solution. The electrochemical results indicated that the Ecorr values were 2; 87; 79 and 88 mV and for the icorr were 0,78; 0,55; 0,48 and 0,39 µA/cm2 for x = 0; 0.02; 0.07 and 0.1, indicating that doping with nickel could improve the electrochemical resistance of the material. On the other hand, the possible mechanism of degradation of the MMC is the dissolution, evidenced in the overpotential curves, the SEM micrographs and in the color change observed in the electrolyte at the end of the polarization tests.

Síntesis y evaluación de la morfología, estructura y parámetros electroquímicos de un material magnetocalórico (MMC) fabricado por autocombustión.

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