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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New approach to niobia-modified borosilicate glasses for Cs waste immobilization
2024 - COSTA-SILVA, D.L.; ARAUJO, M.S.; FUNGARO, D.A.; SILVA, P.S.C.; MELLO-CASTANHO, S.
The use of nuclear materials is increasing in energy production, medicine, and environmental sectors. Following this trend, the generation of radioactive wastes is also increasing in the whole production cycle and use of this kind of materials. Among these, the 137Cs radionuclide presents a potential risk to human health due to its half-life time (30,2 years), high-level activity (1 TBq) and easiness to contaminate rivers, soil, and air. The immobilization of 137Cs in solid matrices has been an available option researched by several countries. In this context a new glass composition based on aluminoborosilicate glass modified with niobium (Nb) was used for the immobilization of cesium through adding Cs-loaded zeolite. Homogeneous vitreous wasteforms were improved with the growth of Nb content in the compositions. All compositions were able to keep up to 5.9 wt% Cs2O, previously adsorbed by zeolite A, and the immobilization efficiency was around 53%. Their structural analyses by Raman revealed a depolymerized and complex network structure, due to the presence of several cations including Cs. In turn, Nb reflected positively on the chemical resistance and thermal properties, by changing the distribution of silicate species. The wasteforms presented good glass forming ability and thermal stability up to 520 °C. Through the thermal treatment for devitrification, Cs atoms were stabilized into the Pollucite phase (CsAlSi2O6). Besides that, the wasteforms, preferably the one containing 8.0 mol% Nb, showed low elemental releases and leaching rates for Cs (1 × 10−3 g m2.day−1), after the leaching experiments at 90 °C for 7 days in static conditions, verified by the neutron activation analysis (NAA).
Structural and thermal influence of niobia in aluminoborosilicate glasses
2022 - COSTA-SILVA, D.L.; BARTOLOME, J.F.; SILVA, A.C.; MELLO-CASTANHO, S.
The addition of small amounts of niobia (Nb2O5) in borosilicate glasses was explored. By analysis on thermal and structural changes, we found evidences that niobium integrates the glass structure in octahedral NbO6 coordination. Adding up to 8.0 mol% of Nb2O5, the oxide partially ruptured the glass structure, interfering in the BO3/ BO4 ratio, but the predominant network configuration was maintained. Thermally, there was an increase in the processing interval and the glasses became more resistant against crystallization, with the presence of niobia. Also, the oxide contributed to a notable decrease in the viscosity of the melts. The improvement of such properties were obtained by the controlled dispersion of the oxide in the glass network structure, avoiding large areas of phase-to-phase separation to preserve the desired ability of these glasses to incorporate a wide range of elements.
In vitro bioactivity and antibacterial capacity of 45S5 Bioglass®-based compositions containing alumina and strontium
2021 - ARAUJO, M.S.; SILVA, A.C.; CABAL, B.; BARTOLOME, J.F.; MELLO-CASTANHO, S.
A modified 45S5 Bioglass® containing 2 mol% alumina and 2 mol% strontium oxide was prepared. In vitro bioactivity in powder and monolithic samples was conducted. Fourier transform infrared analysis and pH change in simulated body fluid were investigated for powder samples after 480 min of immersion. Additionally, X-ray diffraction and scanning electron microscopy after 7 and 14 days of immersion in simulated body fluid were investigated for monolithic samples. The formation of phosphate and carbonate phase precursors of hydroxycarbonate apatite was observed after 480 min for powder samples, and the hydroxycarbonate apatite pattern and morphology were confirmed after 7 days of immersion for monolithic samples. It seems that changes in composition did not affect reactivity but caused a decrease in the maxima of pH. Cytotoxicity and cell viability obtained by using the NCTC clone 929 cell line did not show any significant loss of cell viability or cytotoxicity. Moreover, after overnight incubation, the samples demonstrated safe disinfection for Escherichia coli. For these reasons, the use of these new bioactive glasses can be considered a promising alternative for the reconstruction of bone defects and even for the treatment and suppression of bone infections.
Tribological and mechanical behaviour of 45S5 Bioglass®-based compositions containing alumina and strontium
2020 - ARAUJO, M.S.; BARTOLOMÉ, J.F.; MELLO-CASTANHO, S.
Although bioactive glasses have been widely used for the surfaces of orthopaedic and dental implants, its limited mechanical strength, low toughness and wear resistance have prevented their use as load-bearing devices. Considering that even a small variation in the composition of such materials can deeply modify their features, inducing very different physicochemical or mechanical properties, the present research was conducted by modifying the glass network of 45S5 Bioglass® by adding Al2O3 and SrO to obtain a highly bioactive glass with improved mechanical and tribological performance for biomedical applications. The addition of 2% Al2O3 and 2% SrO produced a dense material with the same elastic modulus as 45S5 (~50 GPa). Moreover, the bending strength increased by 60% and the toughness doubled. The wear rate obtained against steel was found to be three times lower than that of 45S5. From the results, it can be assumed that both alumina and strontium synergistically play crucial roles in the mechanical and tribological properties of these new bioactive glasses.
Structural and thermal behavior of 45S5 Bioglass®-based compositions containing alumina and strontium
2020 - ARAUJO, MARIANA S.; SILVA, ANTONIO C.; BARTOLOMÉ, JOSÉ F.; MELLO-CASTANHO, SONIA
The present research exposes the influence of 2 mol% of Al2O3 and 2 mol% SrO in 45S5 Bioglass®-based compositions. Four compositions were produced to elucidate the difference in how both oxides influence structure and thermal behavior separately and their synergy when together. Thermal properties, crystallization tendency, and sintering behavior was evaluated by differential scanning calorimetry, hot stage microscopy, and dilatometry. Changes of medium-range structures were characterized by Qn distribution of Raman spectroscopy and evaluation of 31P, 27Al, 23Na, and 29Si environment obtained by magic angle spinning nuclear magnetic resonance. Despite Qn distribution was predominantly Q2 in all samples, the composition criteria used enabled improved processing and stabilibity characteristics. The addition of Al2O3 and SrO promoted larger sinterability parameter (Sc) which indicates better sintering behavior, the glass stability against crystallization doubled (KH) compared to 45S5 and the processing window enlarged from 106 to 171.
Editorial
2019 - MELLO-CASTANHO, SONIA R.H.; MORENO, RODRIGO
Use of waste water glass as silica supplier in synthesis of pure and Mg-doped lanthanum silicate powders for IT-SOFC application
2019 - YAMAGATA, C.; LEME, D.R.; CASTANHO, S.R.H.M.
Water glass in alkali solution (Na2SiO3/NaOH) an abundant effluent, generated in the alkaline fusion of zircon sand, represents a potential silica source to be converted in useful silica technological application. Actually, the generation of energy by environmental-friendly method is one of the major challenges for researchers. Solid Oxide Fuel Cells (SOFC) is efficient and environmentally clean technique to energy production, since it converts chemical energy into electrical power, directly. Apatite-type lanthanum silicates are promising materials for application as an electrolyte in intermediate temperature SOFC (IT-SOFC) because of their higher ionic conductivity, in temperatures of range 600–700 °C, than conventional zirconia electrolytes. In this work, pure (La9,56(SiO4)6O2,34) and Mg-doped (La9,8Si5,7Mg0,3O26,4) lanthanum silicate were synthesized, from that rich effluent. Using the sol-gel followed by precipitation method, the single crystalline apatite phase of both silicates was obtained by thermal treatment at 900 °C of their precursors. Sintered ceramic samples reached density of higher than 90%.
Micrograded ceramic-metal composites
2019 - RESTIVO, THOMAZ A.G.; BECCARI, RAFAEL F.; PADILHA, WELLINGTON R.; DURAZZO, MICHELANGELO; TELLES, VICTOR B.; COLETI, JORGE; YAMAGATA, CHIEKO; SILVA, ANTONIO C. da; SUZUKI, EDUARDO; TENORIO, JORGE A.S.; MELLO-CASTANHO, SONIA R.H.
The article shows new designed cermets and processes concerning primary to applications as thermal insulation materials with low emissivity. A new projected microstructure was obtained where dense regions (micropellets) rest inside the main porous pellet. The feature resembles a frozen hypercube, therefore such architecture is called hyper-pellet/ cermet. The processing method to obtain the hyper-cermet is based on sequential tape castings and sintering techniques. Ni-zirconia lamellae were prepared by a special mechanochemical process followed by sintering, which remain inside the main pellets as a dense region. The whole pellet is turned to be porous by employing pore-forming additives. All the constituents and porosity shapes are aligned along the disc/ flake planes. Thermal conductivity is estimated for the materials up to 800 °C by a flash diffusivimeter. Ceramographic analyses show graded density regions with directional constituents and pores. Applications of such materials are foreseen as temperature insulation materials and thermal radiation shields.
Processing, microstructure and thermoluminescence response of biomorphic yttrium oxide ceramics
2016 - SANTOS, S.C.; YAMAGATA, C.; CAMPOS, L.L.; MELLO-CASTANHO, S.R.H.
The present work reports a fast-direct bio-prototyping process using Luffa Cylindrica vegetable sponge to produce biomorphic yttrium oxide ceramics with reticulated-porous architecture and thermoluminescence response. Processing parameters as rheology of yttrium oxide suspensions, bio-template surface treatment and thermal decomposition of bio-template were investigated. Shear thinning suspensions of 30 vol% yttrium oxide with apparent viscosity of 243mPa.s provided a successful impregnation of samples, whereby bio-templates with smooth ceramic layer and hierarchical reticulated architecture were formed. By thermal treatment at 1600 degrees C for 2 h biomorphic yttrium oxide ceramics with porous microstructure and TL response at 150 degrees C and lambda=550 nm were produced. The proposed fast direct bio-prototyping process is suitable for the production of ceramic components with complex shape and demonstrates potential for general applicability to any bio-template. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
Glass ceramic sealants belonging to BAS (BaO-Alsub(2)Osub(3)-SiOsub(2) ternary system modified with Bsub(2)Osub(3) addition
2016 - SILVA, MAVIAEL J. da; BARTOLOME, JOSE F.; AZA, ANTONIO H. de; MELLO CASTANHO, SONIA
Four compositions in the BaO–Al2O3–SiO2 system modified with B2O3 were investigated with regard to their use as glassy seals in anode supported SOFC or iT-SOFC. The glassy system studied contains varying percentages of SiO2, Al2O3, B2O3, and high content of BaO as modifier (67–74%-wt). Their glass transition (Tg) and maximum densification point lies between 630 and 680 ◦C, and 734 ◦C to 828 ◦C, respectively. The viscosities of the four glasses are situated between 107 to 109.5 Pa.s, in the sealing range (730–830 ◦C). Heat treatment at 850 ◦C, revealed crystalline phases identified as BaAl2Si2O8 (hexacelsian) and BaSiO3. The thermal expansion coefficient (TEC) of the obtained glasses (8.8–10.5 ppm/K) was comparable to zirconia (YSZ) electrolyte, and shows chemical compatibility and high characteristic bond strength (up to 33 ± 7 MPa). The compositions with higher BaO contentin the system studied seem to be good candidates for iT-SOFC sealant application.