SILAS CARDOSO DOS SANTOS

SILAS CARDOSO DOS SANTOS

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Yttria nettings by replica processing
2014 - SANTOS, S.C.; YAMAGATA, C.; ACCHAR, W.; MELLO-CASTANHO, S.R.H.
In the context of green economy supported and widespread by United Nations (UN), the renewable energy sources are the unique mechanism to universalize the access to energy. Face to this strategic direction of change is essential to develop efficient components for saving energy such as porous ceramics that associate light with mechanical strength. Thus, the objective of this work concerns to improve the homogeneity of porous size distribution of yttria porous ceramics by evaluating their morphology during replica processing. Samples were subject to immersion into 30vol% yttria aqueous suspensions during an interval from 1min to 120min and sintered through careful thermal conditions. Based on the results, the weight and morphology of porous structure samples were directly influenced by immersion time, whereby intervals from 30-120min showed the best final products.
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.
Processing and thermoluminescent response of porous biomorphic dysprosium doped yttrium disilicate burner
2016 - SANTOS, S.C.; YAMAGATA, C.; CAMPOS, L.L.; MELLO CASTANHO, S.R.H.
Bio-prototyping and thermoluminescence response of cellular rare earth ceramics
2016 - SANTOS, S.C.; YAMAGATA, C.; CAMPOS, L.L.; MELLO CASTANHO, S.R.H.
The use of renewable materials is essential toward green economy. Vegetable structures are abundant, exhibit complex hierarchically built shape and an architecture that is promising to form functional materials. In this work using a mixture of rare earth oxides, which contain around 57 wt% yttrium oxide, cellular ceramics by bio-prototyping from the vegetable sponge Luffa cylindrica were produced and the thermoluminescence response was evaluated. By colloidal processing aqueous suspensions with 25 vol% solids content, pH 10, 1 wt% deffloculant and 0.2 wt% binder exhibited shear thinning behavior and apparent viscosity suitable for replica method. By thermal treatment at 1600 ◦C for 2 h in air biomorphic rare earth ceramics with dense microstructure and reticulated architecture were produced.
Lighting by biogas burners: Perspectives on development in Brazil
2014 - SANTOS, SILAS C.; YAMAGATA, CHIEKO; MELLO CASTANHO, SONIA
Rheological behaviour of yttria aqueous suspensions for impregnation method
2010 - SANTOS, S.C.; YAMAGATA, C.; MELLO CASTANHO, S.R.H.
Yttrium disilicate stability in aqueous medium
2013 - SANTOS, S.C.; ACCHAR, W.; SILVA, A.C.; YAMAGATA, C.; MELLO CASTANHO, S.R.H.
Rheological study of yttrium oxide aqueous suspensions
2009 - SANTOS, S.C.; SETZ, L.F.G.; YAMAGATA, C.; MELLO CASTANHO, S.R.H.
Rheological study of yttrium oxide aqueous suspensions
2010 - SANTOS, S.C.; SETZ, L.F.G.; YAMAGATA, C.; MELLO-CASTANHO, S.R.H.
Yttria (Y2O3) has been used in many technological applications areas as luminescence material, high temperature and strength structural material, owing to its excellent optical and refractory characteristics. Applying conformation techniques using Y2O3 concentrated suspensions is adequated, if it is well controlled, so that assisting to obtain homogeneous ceramic bodies, reproductive and with complex geometry. Studies involving superficial behavior, stability conditions of suspensions and the behavior related to conformation give important information to control the processes in manufacturing ceramic components. In this work is presented a rheological study of Y2O3 aqueous suspensions, which concerns to solids and dispersant concentration and pH of media. Preparation of Y2O3 aqueous suspensions with solids concentration of 30vol% was possible, using 1wt% of ammonium polyacrylate (PAA) that was enough to gain the lowest viscosity of the suspensions.