SONIA REGINA HOMEM DE MELLO CASTANHO

SONIA REGINA HOMEM DE MELLO CASTANHO

(Fonte: Lattes)

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Graduada em Engenharia de Materiais (UFSCar, Universidade Federal de São Carlos), Mestre em Tecnologia Nuclear (IPEN/USP, Universidade de São Paulo) e Doutora em Ciências Químicas-Cerâmicos (UAM/ES -ICV/CSIC, Universidad Autónoma de Madrid, Espanha e Instituto de Ceramica y Vidrio/CSIC de Espanha). Ela é Pesquisadora Senior e atualmente Gestora Adjunta em Pesquisa e Desenvolvimento do Centro de Ciências e Tecnologia de Materiais (CCTM) do Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP). É Professora da Universidade de São Paulo (USP), no programa de posgraduação Tecnologia Nuclear - Materiais. Coordenadora do grupo de pesquisas (GP/CNPq) em Materiais e Meio Ambiente. Principais áreas de atuação: - Energias Renováveis (células a combustível, catalizadores e biomassa), - Ambiental (mitigação, inertização e requalificação de efluentes e subprodutos de processos extrativistas e industriais, diretivas ambientais (RhOS, WEEE)), - Cerâmicas Biocompatíveis (vidros, compósitos multifuncionais para a implantologia). Experiência em gestão de Centro de Pesquisas, gestão ambiental, gestão de projetos, planejamento composicional de materiais, processamento coloidal, reologia, vidros e vitroceramicos, compósitos multifuncionais e nanoestruturas naturais. (Texto extraído do Currículo Lattes em 27 dez. 2021)

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Strontium and cobalt doped-lanthanum chromite
2015 - SETZ, L.F.G.; SANTACRUZ, I.; LEON-REINA, L.; TORRE, A.G. De la; ARANDA, M.A.G.; MELLO CASTANHO, S.R.H.; MORENO, R.; COLOMER, M.T.
Perovskite powders prepared by combustion synthesis with a nominal composition of La0.800Sr0.200Cr0.920Co0.080O3.000 δ were obtained from the corresponding metal nitrates, and characterised in terms of in-situ phase development (crystalline structure and thermal behaviour). Synchrotron X-ray powder diffraction (SXRPD) and Rietveld analyses demonstrated that the as-prepared powder showed an orthorhombic perovskite structure with an estimated composition of La0.803Sr0.197Cr0.966Co0.034O3.000 δ. Second phases present in the as-prepared powder were m-LaCrO4, CoLa1.250Sr0.750O4.000, c-CoCr2.000O4.000 and m-SrCrO4.000. Sintering processes, including phase transition (from orthorhombic to rhombohedral) of the main phase and, melting/evaporation of second phases have been studied by DTA/TGA and dilatometric studies; the results were in full agreement with those detected by High-Temperature Synchrotron X-ray powder diffraction (HT-SXRPD). The transition temperature was determined to be 1380 1C by dilatometric studies, and between 1240 and 1405 1C by HT-SXRPD. Dye-pressed samples sintered at 1600 1C/4 h showed a density of 98.9 dth%. The phase transition is an irreversible process since the sintered perovskite, measured at room temperature after cooling, only showed the rhombohedral phase as main phase. The evaluation of the linearity of the conductivity versus the inverse of temperature and the activation energy values of the sintered material indicated that the electrical conduction occurs via the non-adiabatic small-polaron mechanism in either air or hydrogen atmosphere. In the reducing environment, the perovskite shows significantly reduced electrical conductivity compared with that in air, as it is expected for a p-type conductor. & 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Surface behaviour and stability of strontium and cobalt doped-lanthanum chromite powders in water
2009 - SETZ, LUIZ F.G.; MELLO CASTANHO, SONIA R.H. de; COLOMER, MARIA T.; MORENO, RODRIGO
In this paper, the surface behaviour and stability in water of a powder with the composition La0.8Sr0.2Cr0.92Co0.08O 3 prepared by combustion synthesis were studied. The isoelectric point of as-prepared suspensions occurs at pH near 8, while the maximum zeta potentials of 40 to 50 mV are reached at pH 3, but suspensions are not stable as the pH tends to move towards the isoelectric point. Solubility of ions occurs at acidic pH, although chromium and strontium are detected at basic pH, also. If the pH of the suspensions is periodically readjusted, the highest solubility is reached at very acidic conditions and only chromium is detected at basic pH. The effect of 1 wt.% of an anionic polyelectrolyte (ammonium polyacrylate, PAA) on suspension stability shifted down the isoelectric point to pH 6 and very high zeta potentials (> |- 50| mV) were attained at pH 9-10, where the moderate pH assures that the solubility is low.
PhysicoChemical characterization of strontium- and cobalt-doped lanthanum chromite powders produced by combustion synthesis
2009 - SETZ, LUIZ F.G.; MELLO CASTANHO, SONIA R.H.; MORENO, RODRIGO; COLOMER, MARIA T.
Doped lanthanum chromites are investigated as ceramic interconnect materials to be used in high-temperature solid oxide fuel cells (SOFCs). In this work, a La0.80Sr0.20Cr0.92 Co0.08O3 powder was produced by combustion synthesis and characterized in terms of phases and crystalline structure, thermal evolution, particle size, and surface behavior. The effects of milling time on the particle size distribution and the agglomeration factor were also studied. The physicochemical characterization was completed with ζ potential measurements in order to establish the isoelectric point and the best pH conditions because slurry-processing techniques are mostly used for the manufacture of the SOFC devices.
Tape casting of strontium and cobalt doped lanthanum chromite suspensions
2010 - SETZ, LUIZ F.G.; SANTACRUZ, ISABEL; COLOMER, M.T.; MELLO CASTANHO, SONIA R.H.; MORENO, RODRIGO
Lanthanum chromite (LaCrO3) is currently the most widely studied material as interconnector layers for solid oxide fuel cells (SOFC). The complexity of microstructures and geometries of SOFC devices, which are usually built-up by lamination of the different constitutive layers, make it necessary a precise control of processing parameters to achieve the desired combination of properties. Much effort has been devoted to the processing of electrodes and electrolytes but the other layers, such as that of interconnecting material, have received scarce attention. This work deals with the preparation and optimisation of the rheological behaviour of concentrated suspensions of Sr- and Co-doped LaCrO3 and the subsequent tape casting to produce homogeneous thin sheets to be used in the SOFC stack. The starting powder was produced by combustion synthesis from the corresponding nitrates and urea as a fuel, and had a final composition of La0.80Sr0.20Cr0.92Co0.08O3. These powders were dispersed in ethanol with commercial copolymers (Hypermer, KD6) to solids loading of up to 58wt%. The binding system (BS) consisted of a mixture of a binder, polyvinyl butyral-co-vinyl alcohol-co-vinyl acetate (PVA-PVAc), and two plasticizers, polyethyleneglycol (PEG400) and benzylbutylphthalate (BBP). The effect of the binding system content and the binder-to-plasticizer ratio on the tape casting performance and the characteristics of the green and the sintered tapes, were studied, as well as the influence of the casting parameters (casting speed and blades height).
Fabrication of Sr- and Co-doped lanthanum chromite interconnectors for SOFC
2011 - SETZ, L.F.G.; SANTACRUZ, I.; COLOMER, M.T.; MELLO CASTANHO, S.R.H.; MORENO, R.
A viscoelastic approach from 'alfa'-Alsub(2)Osub(3) suspensions with high solids content
2013 - SETZ, LUIZ F.G.; SILVA, ANTONIO C.; SANTOS, SILAS C.; MELLO CASTANHO, SONIA R.H.; MORELLI, MARCIO R.