Polycrystalline Ceramics
Mostrando 1-12 de 21 artigos, teses e dissertações.
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1. Fracture strength of monocrystalline and polycrystalline ceramic brackets during archwire torque
Resumo Introdução A demanda por tratamentos estéticos tem crescido nos últimos anos, sendo cada vez mais forte a preocupação com a estética por parte dos pacientes que buscam o tratamento ortodôntico. Objetivo Este estudo avaliou a resistência à fratura de bráquetes cerâmicos monocristalinos e policristalinos de diferentes fabricantes quando su
Rev. odontol. UNESP. Publicado em: 03/10/2019
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2. The Contribution of Mechanical Spectroscopy to Understanding Grain Boundary Sliding
This review paper shows that grain boundary sliding (GBS) is a general phenomenon occurring in all classes of inorganic materials: ceramics, metals and composite materials. The occurrence of relaxations attributed to GBS is also quite general and therefore the mechanical spectroscopy constitutes a sensitive and universal technique to study such phenomenon. G
Mat. Res.. Publicado em: 25/10/2018
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3. Fatigue strength of several dental ceramics indicated for CAD-CAM monolithic restorations
Abstract This in vitro study evaluated the fatigue strength of different ceramic materials indicated for monolithic restorations. Disc-shaped specimens were made according to ISO 6872 from five different ceramic materials: feldspathic ceramic (FC), polymer-infiltrated ceramic network (PIC), lithium disilicate glass-ceramic (LD), zirconia-reinforced lithium s
Braz. oral res.. Publicado em: 11/06/2018
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4. Impedance and Modulus Spectroscopy Characterization of Tb modified Bi0.8A0.1Pb0.1Fe0.9Ti0.1O3 Ceramics
In this paper we present the impedance spectroscopy of ternary solid solutions of BiFeO3, TbFeO3 and PbTiO3, prepared by solid-state reaction method. The preliminary structural studies were carried out by x-ray diffraction technique, showing the formation of polycrystalline sample with ABO3 type of perovskite structure with hexagonal symmetry for Bi0.8Tb0.1P
Mat. Res.. Publicado em: 16/02/2016
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5. Development and test of a small resistive fault current limiting device based on Hg, Re-1223 and Sm-123 ceramics
Several reports describing Superconducting Fault Current Limiter (SFCL) containing members of the bismuth or yttrium ceramics were already described. However, none of these included the mercury and samarium cuprates. Consequently, we have conducted a study of a resistive-type superconductor fault current limiter based on Hg0.82Re0.18Ba2Ca2Cu3O8+d samples and
Mat. Res.. Publicado em: 03/06/2014
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6. Influence of the interposition of ceramic spacers on the degree of conversion and the hardness of resin cements
This study evaluated: I) the effect of photo-activation through ceramics on the degree of conversion (DC) and on the Knoop hardness (KHN) of light- and dual-cured resin cements; and II) two different protocols for obtaining the spectra of uncured materials, to determine the DC of a dual-cured resin cement. Thin films of cements were photo-activated through c
Braz. oral res.. Publicado em: 2013-09
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7. Effect of pH-induced nanopowder deagglomeration on sintering, microstructure and dielectric properties of Ba0.77Ca0.23TiO3 ceramics
Ba0.77Ca0.23TiO3 ceramics were produced in this work starting from nanopowders synthesized via a polymeric precursor method. By adjusting the pH values of the precursor solutions above 7, it was possible to prepare powders weakly aggregated and with a smaller particle size, both facts which traduced into an enhanced nanopowders' sintering process at comparat
Materials Research. Publicado em: 17/07/2012
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8. Propriedades mecânicas de cerâmicas de zircônia tetragonal policristalina contendo ítrio (Y-TZP) após aplicação de cerâmica / Mechanical properties of different stabilized tetragonal zirconia polycrystalline (Y-TZP) ceramics after veneering with ceramic
Objetivo: Quantificar e comparar propriedades mecânicas, tais como resistência ao cisalhamento da interface de aderência zircônia/cerâmica, microdureza e resistência à flexão de corpos-de-prova confeccionados com diferentes cerâmicas de zircônia tetragonal policristalina contendo ítrio (Y-TZP) e cerâmica de revestimento aplicada. Método: Foram c
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/04/2010
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9. Efeito do envelhecimento por ciclagem mecânica ou ciclagem em autoclave na resistência à flexão de cerâmicas odontológicas / Mechanical and autoclave cycling effect on flexural strength of dental ceramics
The aims of this study were: to perform a microestrutural analysis of dental ceramics and correlate the results with the flexural strength obtained; to evaluate two aging process (mechanical cycling and autoclave cycling) on the flexural strength of the materials and to evaluate the specimen configuration (bar or disc) on the flexural strength of mechanical
Publicado em: 2010
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10. Spectroscopies of photoluminescence and excitation of MgGa2O4 samples doped with Mn2+. / Espectroscopia de fotoluminescência e excitação de amostras MgGa2O4 dopadas com Mn2+
This work presents the room temperature photoluminescence and excitation spectroscopes data of MgGa2O4 samples doped with 0.5% and 10.0% Mn2+. The polycrystalline samples were produced by solid-state reaction at high temperature and characterized with X ray Diffraction and SEM. The photoluminescence spectra showed emission at green and red spectral regions,
Publicado em: 2009
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11. Simulações por dinâmica molecular de compostos do tipo ABO3 (SrTiO3 e CaTiO3)
Using the classical molecular dynamics simulations, Perovskites systems composed by oxides (ABO3), in particular SrTiO3 and CaTiO3, were performed. The titanates are easily prepared as polycrystalline ceramics; chemically and mechanically stable they can be characterized in various temperature and pressure conditions. These provide us reliable experimental r
Publicado em: 2009
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12. Performance of 3Y-TZP bioceramics under cyclic fatigue loading
In this work, the static mechanical properties and cyclic fatigue life of 3 mol. (%) Y2O3-stabilized tetragonal zirconia polycrystalline (3Y-TZP) ceramics were investigated. Pre-sintered samples were sintered in air at 1600 °C for 120 minutes, and characterized by X ray diffraction and scanning electronic microscopy. Hardness and fracture toughness were det
Materials Research. Publicado em: 2008-03