Estrutura e propriedades de filmes finos ferroelétricos do sistema PZT

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo da cerâmica PZT sob o ponto de vista microestrutural e propriedades eletro-ópticas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Filmes finos de LaNiO3 e PZT preparados pelo métodos das soluções precursoras poliméricas e depositados em substratos de silício

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Síntese de PZT puro, dopado com níquel e tungstênio, com propriedades fotoluminescentes à temperatura ambiente

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Structural refinement, optical and electrical properties of [Ba1-x Sm-2x/3](Zr0.05Ti0.95)O-3 ceramics

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of Sm3+ doping on the dielectric properties of CaCu3Ti4O12 ceramics synthesized via autocombustion

Ca-1 -xSmxCu3Ti4O12 (x = 0.0, 0.2, 03) electronic ceramics were fabricated via the chemical route using metal nitrate solutions in order to improve the dielectric properties of this ceramic. X-ray diffraction (XRD) analysis indicated the formation of a single CaCu3Ti4O12 (CCTO). Grain size of the samples doped with Sm3+ was in the range of 1-2 mu m, as opposed to 50-100 mu m in the pure samples of CCTO. The cutoff frequency with the doping was remarkably shifted, from 1 MHz (pure CCTO) to 10 MHz (doped CCTO). Meanwhile, the real dielectric (epsilon(r)) and imaginary dielectric (epsilon '') constants showed a decrease as the doping was increased. (C) 2013 Elsevier B.V. All rights reserved.

Fabrication and Characterization of PZT-PAni/PVDF Based Nanocomposite

This work presents the preparation and characterization of PZT ceramic obtained by the polymeric precursor method (PPM). The influence of the synthesis method on the grain size and the morphology are also object of study. The fabrication and characterization of composite films with 0-3 connectivity, immersing nanoparticles of PZT into the non-polar poly(vinylidene fluoride) -PVDF as the polymer matrix were presented. For comparison there are results obtained with composite samples made of ceramic particles unrecovered and recovered with a conducting polymer, the polyaniline (PAni).

Effect of Composition on the Physical Properties at Nanoscale of PZT Thin Films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo de sensores PZT aplicados à detecção de danos em tubulações

Pós-graduação em Engenharia Elétrica - FEIS

Lead-free BaBi4Ti4O15 ceramics: Effect of synthesis methods on phase formation and electrical properties

The processing of ferroelectric BaBi4Ti4O15 (BBT) ceramics from powders prepared by conventional solid state reaction (SSR) and mechanochemical activation (MA) has been investigated. It was shown that MA synthesis reduces the synthesis temperature of BBT powders, leading to smaller particles with reduced anisotropy and consequently to smaller grain size of ceramics. Dielectric properties were investigated in a wide range of temperatures (20-800 degrees C) and frequencies (1.21 kHz to 1 MHz). The relative dielectric permittivity at Curie temperature was higher for solid state obtained ceramics than for the mechanically treated ones. The conductivity of sintered samples was studied, suggesting decreasing of conductivity of BBT-MA in comparison with BBT-SS ceramics. The influence of the grain and the grain boundaries contribution to the dielectric behavior in both ceramics was analyzed through impedance spectroscopy. A well-defined ferroelectric hysteresis loop was obtained for both samples. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Quantitative phase analysis from X-ray diffraction in Y-TZP dental ceramics: A critical evaluation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Polishing for glass ceramics: Which protocol?

Purpose: The execution of adjustments on ceramic restorations is sometimes necessary for either correction of occlusion and/or inadequate contours or esthetical improvements. Clinically, the surfaces undergo weariness through fine grinding diamond burs which remove the superficial glazing layer. Several materials for ceramic polishing have been used in an attempt to reach a satisfactory surface smoothness. The aim of this study was to perform a literature review on different polishing protocols of several dental ceramics. Study selection: This is a literature review performed through scientific articles published between 2004 and 2012, indexed in MEDLINE, PubMed and Scielo databases. The study selected and analyzed a total of 20 relevant articles that evaluated different types of ceramics, polishing treatment and surface roughness.Results: After an extensive literature review, this study observed: 1 - after the rupture of the glazing layer due to the adjustments of the restorations, the best choice for the polishing of the surface will depend on the type of ceramics used; 2 - glazing procedure provide excellent results regarding to the superficial smoothness; however, if reglazing is impossible, either abrasive rubber cups/points or sandpaper discs followed by the use of diamond polishing pastes results in a satisfactory superficial smoothness; 3 - clinical studies that take into account the behavior of the protocols polishing are scarce and should be encouraged; 4 - the large number of variables influence the final outcome of polishing should be considered. Conclusions: The necessity in standardization of methodologies to enable a comparison among researches. (c) 2014 Japan Prosthodontic Society. Published by Elsevier Ireland. All rights reserved.

Investigation of the dielectric relaxation processes in PbZr0.65Ti0.35O3-BaFe12O19 multiferroic ceramic composites

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of surface treatment on the bond strength between yttria partially stabilized zirconia ceramics and resin cement

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Translucent tin dioxide ceramics obtained by natural sintering

Dense SnO2-based ceramics (relative density >95%) have been obtained by natural sintering at a moderate temperature (less than or equal to 1300 degrees C) with the help of a small amount of manganese, Further thermal treatments above 1500 degrees C result in grain growth and transport of manganese toward the sample surface. If the ceramic is embedded inside alumina powder, the diffusion of Mn out of the sample and into alumina during such heat treatments leads to a manganese-free body (<40 ppm) which is translucent. The transmission in the visible region depends on sample thickness; 61% was achieved for a 0.05 mm thick sample.