Preparação e caracterização de compósitos de galato de lantânio contendo estrôncio e magnésio/galato de estrôncio

Abstract

PAULA, P. P. d. . Preparation and characterization of strontium and magnesium doped lanthanum gallate/strontium gallate composites. 2021. 68 p. Dissertação (Mestrado em Tecnologia Nuclear), Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, São Paulo. Ceramic composites based on strontium-and magnesium-doped lanthanum gallate (LSGM), and strontium gallate (SG) were prepared by the conventional solid-state synthesis method. The LSGM and SG compounds as well as the LSGM-xSG (x=05, 0.75, 1.0, 1.5 and 2.0% mol) composites were characterized by X-ray diffraction, scanning electron microscopy and impedance spectroscopy techniques. The main purpose of this work was to verify the effects of the minor phase (SG) on those properties. The base compounds investigated were La0.9Sr0.1Ga0.8Mg0.2O3- (LSGM10) and La0.85Sr0.15Ga0.8Mg0.2O3- (LSGM15).Sintering experiments allowed for determining an ideal sintering temperature of 1400 ºC resulting in compacts with high relative densities (> 92%). Linear shrinkage measurements evidenced that the SG phase slows down the LSGM densification. The microstructure of the base compounds (LSGM10 and LSGM15) along with that of composites is heterogenous, Dispersive energy spectroscopy coupled to scanning electron microscopy evidenced obtaining the composites.Results of electrical conductivity determined by impedance spectroscopy revealed that SG addition to LSGM10 and LSGM15 promoted increase of the bulk conductivity. This increase was higher for LSGM10 containing 1 mol% SG.