Niobium Oxide
Mostrando 1-12 de 44 artigos, teses e dissertações.
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1. Influence of the addition of niobium oxide on the properties of fused aluminum oxide used in abrasive tools
Abstract Fused alumina is a material used in the manufacturing of abrasive tools, due to its high fusion point, great hardness, and mechanical toughness. In this context, this study addressed the influence of niobium addition on the properties of fused alumina for abrasive applications. A comparison was also made between this oxide and the brown fused alumin
Cerâmica. Publicado em: 2022
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2. Metal-Supported Niobium Catalysts Investigation for Conversion of Bio-Renewable Glycerol to Organic Compounds
The glycerol oxidative dehydration to organic compounds, especially acrolein and acrylic acid, was studied over vanadium, molybdenum, and cobalt oxides supported on niobium oxide and niobium phosphate catalysts. At 300 °C, the glycerol conversion was 100% over all catalysts tested, and acrolein was the main product observed, without significant deactivation
Journal of the Brazilian Chemical Society. Publicado em: 2022
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3. Study of the Nb2O5 Insertion in ZnO to Dye-sensitized Solar Cells
Dye-sensitized solar cells (DSSC) have received much attention as an alternative to silicon-based solar cells, due to various advantages. Zinc oxide (ZnO) is an n-type semiconductor employed as photoanode on DSSC. The decrease of charge recombination is an efficient strategy capable of improving the photovoltaic performance of the device. In this perspective
Mat. Res.. Publicado em: 01/07/2019
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4. Methyl Esters Production by Heterogeneous Catalyst Mixtures of CaO/Nb2O5 with Simulation of Analysis of Environmental Impacts
The conventional biodiesel process, although it reaches high conversion yields and productivity, faces problems related to the use of homogeneous catalysts. This work aims to study mixtures of calcium oxide (CaO) and niobium oxide (Nb2O5) as the heterogeneous catalyst. It was used a full 23 factorial design with four central points to analyze how the mass pe
J. Braz. Chem. Soc.. Publicado em: 2019-03
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5. Nb-doped Ti2O3 Films Deposited Through Grid-Assisted Magnetron Sputtering on Glass Substrate: Electrical and Optical Analysis
Abstract Niobium doped dititanium trioxide (Ti2O3:Nb) films were deposited on glass substrates, through grid-assisted magnetron sputtering. The Ti2O3:Nb films were characterized by X-ray diffraction (XRD), electrical conductivity and optical properties. Film deposition was carried out in two different substrate bias modes: DC and unipolar pulsed. Results sho
Mat. Res.. Publicado em: 24/01/2019
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6. Production of Ba2AlNbO6 Ceramics and Study of their Stability in Crude Petroleum for the Conservation of Metallic Sensing Elements Used in Petroleum Extraction
In the present work niobium based complex cubic perovskite oxide Ba2AlNbO6 ceramics were produced, characterized and their stability in crude petroleum environment was studied for inert ceramic embedding used in petroleum extraction. Ba2AlNbO6 ceramic powder was prepared by means of thermo-mechanical processing. Structural characteristics of calcined materia
Mat. Res.. Publicado em: 26/07/2018
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7. A Model for the Formation of Niobium Structures by anodization
The fluoride use for anodizing electrolytes has been primarily responsible for the formation of nanoporous oxides at valve metals, except aluminum, since it causes a dissolution process. This study presents the formation of an oxide model according to the following anodizing parameters: 100 V, 12.73 mA/cm2, room temperature and the niobium samples anodized i
Mat. Res.. Publicado em: 25/05/2017
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8. Crystallization of Anatase TiO2 in Niobium Potassium Phosphate Glasses
In this work, the glass forming ability was studied in potassium phosphate glasses with increasing amounts of TiO2 in order to obtain a glass-ceramic with photocatalytic properties. The first studied series has been the binary system (100-x) KPO3-xTiO2. Homogeneous and transparent glasses could be obtained with x varying from 10 to 30 mole%. Since the photoc
Mat. Res.. Publicado em: 16/02/2017
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9. Cytotoxicity and Bioactivity of Calcium Silicate Cements Combined with Niobium Oxide in Different Cell Lines
Resumo O objetivo deste estudo foi avaliar a citotoxicidade e bioatividade de cimentos à base de silicato de cálcio associados com óxido de nióbio (Nb2O5) micro e nanoparticulados, e comparar a resposta em diferentes linhagens celulares. Foram utilizadas quatro linhagens celulares: duas culturas primárias (células da polpa dentária humana - hDPCs e c�
Braz. Dent. J.. Publicado em: 2017-02
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10. Synthesis and Characterization of CuNb2O6 from an Oxalic Precursor Via Solid State Reaction
The present paper's objective was to synthesize and characterize both the oxalic niobium precursor (NH4)3NbO(C2O4)3.H2O, and the product of its doping with Cu and calcining, CuNb2O6. In order to obtain the niobium precursor, commercially available niobium oxide (Nb2O5) was subject to fusion with potassium bisulfate (KHSO4). Once leached with water, the powde
Mat. Res.. Publicado em: 07/07/2016
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11. Thermal, Structural and Crystallization Study of Niobium Potassium Phosphate Glasses
New glass compositions were investigated in the binary system KPO3-Nb2O5. The glass forming domain was determined by melt-quenching of the starting nominal compositions and it has been experimentally observed that glass samples can be obtained between the molar compositions 95KPO3-5Nb2O5 and 50KPO3-50Nb2O5. Chemically stable compositions from 80KPO3-20Nb2O5
Mat. Res.. Publicado em: 23/10/2015
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12. Radiopacity and cytotoxicity of Portland cement associated with niobium oxide micro and nanoparticles
Objective Mineral Trioxide Aggregate (MTA) is composed of Portland Cement (PC) and bismuth oxide (BO). Replacing BO for niobium oxide (NbO) microparticles (Nbµ) or nanoparticles (Nbη) may improve radiopacity and bioactivity. The aim of this study was to evaluate the radiopacity and cytotoxicity of the materials: 1) PC; 2) White MTA; 3) PC+30% Nbµ; 4) PC
J. Appl. Oral Sci.. Publicado em: 2014-12