SHIRLEY LEITE DOS REIS
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Artigo IPEN-doc 21671 Microstructure and electrical conductivity of fast fired Sr- and Mg-doped lanthanum gallate2016 - REIS, S.L.; MUCCILLO, E.N.S.La0.9Sr0.1Ga0.8Mg0.2O3−δ solid electrolytes were consolidated by fast firing aiming to investigate the effects of the sintering method on densification, microstructure and ionic conductivity. Powder mixtures were prepared by solid state reaction at 1250 and 1350 °C for 12 h, and fast fired at 1450 and 1500 °C temperatures for 5 and 10 min. The content of impurity phases was found to be quite low with this sintering method. Relatively high density (>90% of the theoretical value) and low porosity (<1.5%) were readily obtained for powder mixtures calcined at 1250 °C. The activation energy for conduction was approximately 1 eV. Specimens fast fired at 1450 °C for 10 min with a mean grain size of 2.26 µm reached the highest value of total ionic conductivity, 22 mS cm−1, at 600 °C.Artigo IPEN-doc 21303 Phase composition, densification and electrical conductivity of Lasub(0.9)Srsub(0.1)Gasub(0.8)Mgsub(0.2)Osub(3-'delta') consolidated by the two-stage sintering method2015 - REIS, S.L.; MUCCILLO, E.N.S.The influence of the method of sintering on densification, phase assemblage and electrical conductivity of Sr- and Mg-doped lanthanum gallate was investigated aiming to optimize the sintering process of this solid electrolyte. Powder mixtures were prepared by solid state reactions, and the sintering of green compacts was carried out by the two-stage method varying the temperature of the first stage (T1) and the isothermal temperature (T2) and time (t2) profile. The type and content of predominant impurity phases depend on specific parameters of the sintering process. In the first stage of sintering, the content of impurity phases, such as LaSrGaO4 and La4Ga2O9, decreases with increasing temperature. The relative density of sintered specimens reaches 99% whenever T1 is 1500 1C. The mean grain size varies from 1.45 to 4.9 mm. At 600 1C the electrical conductivity attains 12 mS cm 1 for T1 1400 1C and T2 1350 1C for 5 h, with activation energy of approximately 1 eV.Artigo IPEN-doc 17257 Solid solution formation, densification and ionic conductivity of Gd- and Sm-doped ceria2011 - REIS, S.L.; SOUZA, E.C.C.; MUCCILLO, E.N.S.