Spinel Phase
Mostrando 13-24 de 40 artigos, teses e dissertações.
-
13. Synthesis and Characterization of LiCoO2 from Different Precursors by Sol-Gel Method
Lithium cobalt oxide, LiCoO2, widely used as cathode in lithium ion batteries was synthesized and their structural and electronic properties investigated. The crystalline powders were prepared by the sol-gel method with four complexing agents: citric acid, glycine, starch and gelatin. These syntheses were compared with the blank test (without complexing agen
J. Braz. Chem. Soc.. Publicado em: 2017-11
-
14. 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
-
15. Impact of Ni Substitution on Structural, Electrical and Thermoelectrical Properties of Zinc Alluminium Chromites Synthesized by sol-gel Route and their Photocatalytic Investigation
Nanostructured nickel substituted zinc alluminium chromites (Zn1-xNixAlCrO4, where, x= 0.0, 0.25, 0.50, 0.75, 1.0) were prepared by simple, cost effective, sol-gel autocombustion method. Temperature of phase formation was analyzed by thermogravimetric and differential thermal analysis (TGA/DTA). Crystallographic studies of all the samples show formation of s
Mat. Res.. Publicado em: 17/08/2017
-
16. Phase Diagram Study for the PbO-ZnO-CaO-SiO2-"Fe2O3" System in Air with CaO/SiO2 in 1.1 and PbO/(CaO+SiO2) in 2.4 Weight Ratios
An experimental study on the phase equilibrium and the liquidus isotherms for the PbO-ZnO-CaO-SiO2-"Fe2O3" system with CaO/SiO2 in 1.1 and PbO/(CaO+SiO2) in 2.4 weight ratios, respectively, was carried out in the temperature range 1100-1300ºC (1373-1573 K). High temperature phases were determined by the equilibrium-quenching method. Results are presented in
Mat. Res.. Publicado em: 05/06/2017
-
17. Al and PEG Effect on Structural and Physicochemical Properties of CoFe2O4
In this work, pure and Alumina doped cobalt ferrite nanoparticles CoFe2−xAlxO4 (for x = 0.44) have been synthesized by the sol gel method. The influence of alumina doping on the morphological and mechanical properties of CoFe2O4 nano-particles were investigated by means of X-ray powder diffraction (XRD) and rietveld analysis. XRD analysis confirmed that th
Mat. Res.. Publicado em: 06/03/2017
-
18. Investigation of Structural, Morphological, Magnetic Properties and Biomedical applications of Cu2+ Substituted Uncoated Cobalt Ferrite Nanoparticles
ABSTRACT In the present work, Cu2+ substituted cobalt ferrite (Co1-xCuxFe2O4, x = 0, 0.3, 0.5, 0.7 and 1) magnetic nanopowders were synthesized via chemical co-precipitation method. The prepared powders were investigated by various characterization methods such as X-ray diffraction analysis (XRD), scanning electron microscope analysis (SEM), vibrating sample
Braz. arch. biol. technol.. Publicado em: 23/01/2017
-
19. 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
-
20. Influence of magnesia in the infiltration of magnesia-spinel refractory bricks by different clinkers
Abstract In cement production, which involves the production of cement clinker in rotary kilns, the main refractories used are magnesia-spinel bricks. These bricks may suffer infiltration by the clinker liquid phase, resulting in the corrosion of the spinel and the formation of low refractoriness mineralogical phases, such as the Q phase (C20A13M3S3), which
Rem: Rev. Esc. Minas. Publicado em: 2015-12
-
21. Combustion synthesis of Co-Cu-Mn oxides deploying different fuels
ABSTRACTTernary spinel-like oxides such as CuFeMnO4, CoCuMnOxand CuCr2O4 are attractive materials due to their absorbent properties when used as pigments for selective surfaces thus improving solar heaters efficiency. These materials are obtained through sol-gel and sol-gel-combustion methods. This work proposes the synthesis of mixed oxides of Co, Cu and Mn
Matéria (Rio J.). Publicado em: 2015-09
-
22. Thermal stability and microstructure characterization of MgAl2O4 nanoparticles synthesized by reverse microemulsion method
Magnesium aluminate (MgAl2O4) spinel nanoparticles were synthesized by reverse microemulsion process in cyclohexane by using two kinds of surfactants, n-amyl alcohol as cosurfactant and mixture of aluminic/magnesic salt aqueous solution as basic reagents. The effects of surfactant types and titration methods on the morphologies and sizes of the MgAl2O4 nanop
Mat. Res.. Publicado em: 07/05/2013
-
23. Microstructural changes and effect of variation of lattice strain on positron annihilation lifetime parameters of zinc ferrite nanocomposites prepared by high enegy ball-milling
Zn-ferrite nanoparticles were synthesized at room temperature by mechanical alloying the stoichiometric (1:1 mol%) mixture of ZnO and α-Fe2O3 powder under open air. Formation of both normal and inverse spinel ferrite phases was noticed after 30 minutes and 2.5 hours ball milling respectively and the content of inverse spinel phase increased with increasing
Mat. Res.. Publicado em: 11/10/2012
-
24. Ce - promoted catalyst from hydrotalcites for CO2 reforming of methane: calcination temperature effect
Ce-promoted Ni-catalysts from hydrotalcites were obtained. The effect of calcination temperature on the chemical and physical properties of the catalysts was studied. Several techniques were used to determine the chemical and physical characteristics of oxides. The apparent activation energies of reduction were determined. Catalytic experiments at 48 L g-1h-
Química Nova. Publicado em: 2012