SABRINA GONCALVES DE MACEDO CARVALHO
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Artigo IPEN-doc 29471 Development of stabilized zirconia–alkali salts dual membranes for carbon dioxide capture2023 - MUCCILLO, REGINALDO; CARVALHO, SABRINA G.M.; DENALDI, RAFAEL L.; MUCCILLO, ELIANA N.S.Molten Na2CO3–K2CO3 (NKC, 56–44 mol%) eutectic compositions were vacuum-impregnated, at the eutectic temperature, into two porous ZrO2:8.6 mol% MgO (magnesium-partially stabilized zirconia, MgPSZ) and ZrO2:8 mol% Y2O2 (yttria-fully stabilized zirconia, 8YSZ) ceramics. Thermogravimetric analyses were performed in mixtures of that composition with MgPSZ and 8YSZ ceramic powders. Before impregnation, porosity was achieved in the two compounds by addition and thermal removal of 30 vol.% NKC. To ascertain the carbonates had filled up through the ceramic body, both sides of the parallel and fracture surfaces of the disk-shaped impregnated compositions were observed in a scanning electron microscope and analyzed by energy-dispersive X-ray spectroscopy. The electrical conductivity of the two ceramics, before and after impregnation, was evaluated by electrochemical impedance spectroscopy in the 5 Hz–13 MHz frequency range from approximately 530 to 740°C. The permeation of the carbonate ions through the membranes via the eutectic composition was assessed by the threshold temperatures of the onset of the carbonate ion percolation. The objectives were to prepare dual-phase membranes for the separation of carbon dioxide and for the development of carbon dioxide sensors.Artigo IPEN-doc 28499 Electric field-assisted sintering anode-supported single solid oxide fuel cell2022 - MUCCILLO, REGINALDO; FLORIO, DANIEL Z. de; FONSECA, FABIO C.; CARVALHO, SABRINA G.M.; MUCCILLO, ELIANA N.S.Cosintering (La0.84Sr0.16MnO3 thin-film cathode/ZrO2: 8 mol% Y2O3 thin-film solid electrolyte/55 vol.% ZrO2:8 mol% Y2O3 + 45 vol.% NiO anode, ϕ = 12 × 1.5 mm thick pellet) was achieved by applying an electric field for 5 min at 1200°C. Impedance spectroscopy measurements of the anode-supported three-layer cell show an improvement of the electrical conductivity in comparison to that of a conventionally sintered cell. The scanning electron microscopy images of the cross-sections of electric field-assisted pressureless sintered cells show a fairly dense electrolyte and porous anode and cathode. Joule heating, resulting from the electric current due to the application of the AC electric field, is suggested as responsible for sintering. Dilatometric shrinkage curves, electric voltage and current profiles, impedance spectroscopy diagrams, and scanning electron microscopy micrographs show how anode-electrolyte-cathode ceramic cells can be cosintered at temperatures lower than the usually required.