Nanocrystalline Structure
Mostrando 1-12 de 21 artigos, teses e dissertações.
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1. Tribological behavior of hydrogenated W-C/a-C:H coatings deposited by three different sputtering techniques
Abstract The evolution of structure, mechanical properties and friction behavior of DC magnetron sputtered (DCMS), high power impulse magnetron sputtered (HiPIMS) and high target utilization sputtered (HiTUS) W-C:H coatings was investigated as a function of the addition of acetylene and hydrogen into Ar atmosphere. The gradual addition of reactive gases caus
Cerâmica. Publicado em: 2019-01
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2. Influencia de los tratamientos térmicos en recubrimientos anódicos nanotubulares de TiO2
ABSTRACT TiO2 is a semiconductor widely used in heterogeneous photocatalysis processes for water decontamination. Several studies indicate that ordered nanostructures in anatase phase improve the photocatalytic properties with respect to other morphologies and crystal structures of TiO2. The aim of the present work is to evaluate the influence of different t
Matéria (Rio J.). Publicado em: 19/07/2018
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3. Effect of Urea Excess on the Properties of the MgAl2O4 Obtained by Microwave-Assisted Combustion
In this paper, magnesium aluminate spinels were prepared by microwave-assisted combustion, using urea as fuel. In order to evaluate the effect of the urea excess used in the synthesis, its mass was added in a range of 1.0 to 2.5 times the stoichiometric amount required. The materials produced were characterized by TGA, FTIR, XRF, XRD, BET, SEM and TEM. The r
Mat. Res.. Publicado em: 23/10/2017
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4. Series of Nanocrystalline NiCoAlFe(Cr, Cu, Mo, Ti) High-Entropy Alloys produced by Mechanical Alloying
Abstract The mechanical alloying technique was employed to produce series of high entropy alloys, combining in equiatomic percentage Al, Co, Cr, Cu, Fe, Mo, Ni and Ti. Milling times were 0, 10, 20 and 30 h, and experiments were performed in a high energy ball mill (SPEX-8000M) under argon atmosphere. The structural and microstructural changes due to mechanic
Mat. Res.. Publicado em: 08/08/2016
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5. Microwave Assisted Combustion Synthesis and Characterization of Nanocrystalline Nickel-doped Cobalt Ferrites
Abstract Nanoparticles nickel-doped cobalt ferrites [NixCo1-xFe2O4 (x = 0.0, 0.25, 0.50, 0.75 and 1.0 of Ni2+)] were prepared by the microwave combustion synthesis, using a stoichiometric mixture of metal nitrates and urea as the oxidizer and fuel to drive the reaction. The effect of microwave irradiation on the phase composition was favorable to promote the
Mat. Res.. Publicado em: 01/08/2016
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6. Synthesis by coprecipitation of india-stabilized zirconia and codoping with MoO3, WO3, TaO2.5, or NbO2.5 for application as thermal barrier coatings
Coprecipitation synthesis of nanocrystalline india-stabilized zirconia with high surface area and codoping with MoO3, WO3, TaO2.5, or NbO2.5 is reported. The concentration of codopants was defined by the charge-compensating mechanism. Ethanol washing followed by azeotropic distillation and freeze drying were compared as dehydration techniques for the gels. A
Mat. Res.. Publicado em: 05/02/2016
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7. Development and Applications of Highly Functional Al-based Materials by Use of Metastable Phases
This paper reviews the features of alloy components, structure and mechanical properties, physical and chemical properties of metastable Al-based alloys developed by use of various liquid or vapor quenching-induced phases such as amorphous, quasicrystalline, nanocrystalline, nanocomposite, supersaturated solid solution and structure gradient phases. As advan
Mat. Res.. Publicado em: 04/12/2015
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8. Phase Separation in Rapid Solidified Ag-rich Ag-Cu-Zr Alloys
The microstructure and phase formation of rapid solidified Ag-rich Ag-Cu-Zr alloys were investigated. Two types of structure; interconnected- and droplet-type structures, were obtained due to phase separation mechanisms. The former was spinodal decomposition and the later was nucleation and growth mechanism. Depending on the alloy compositions, three crystal
Mat. Res.. Publicado em: 17/11/2015
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9. Síntese de manganita dopada com estrôncio e cobaltita dopada com antimônio e caracterização microestrutural
The great variety of properties of oxides with the perovskite structure allows their application in several fields of technology. Specially, the electrochemical properties and the thermal stability of some of these compounds make these materials the most used in devices for energy generation such as the solid oxide fuel cells (SOFC). SOFC¿s are devices the
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2012
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10. Caracterização estrutural e eletrônica da zircônia pura e com defeitos e impurezas / Structural and electronic characterization of zirconia, pristine and with impurities
In this investigation we studied the electronic properties and the structural stabilities of zirconia (ZrO2), as well as oxygen vacancy and Ce substitutional impurity. The investigations were carried by computational simulations using ab initio methods, based on the density functional theory and the APW + lo (Aumengted Plane Waves plus local orbitals) method
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 09/12/2011
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11. Development of granular structure in Cu/sub 90/Co/sub 10/ ribbons through furnace and current annealing
On-line measurements of resistance and temperature in melt-spun Cu90Co10 ribbons are made using two different annealing techniques: conventional furnace annealing, and linearly varying current Joule heating. The aim of this paper is to consider the electrical current, flowing through the sample during the annealing, as a possible parameter to control thermal
Publicado em: 2011
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12. Study of diamond film interface structure and contacting area
High purity diamond film has been grown by refined Combustion Flame method with high oxygen proportion. Snapshots of time series of the diamond film forming were taken and a model was derived. By observing the period of seeding to coalescing of diamond crystals to form film, it is realized that the contacting area is small and the calculated value was less t
Materials Research. Publicado em: 2009-03