نتایج جستجو برای: spinel
تعداد نتایج: 3807 فیلتر نتایج به سال:
Electron energy-loss spectroscopy (EELS) attached to current transmission electron microscopes can probe not only element-selective chemical information, but also site-selective information that depends on the position that a specific element occupies in a crystal lattice. The latter information is exploited by utilizing the Bloch waves symmetry in the crystal, which changes with its orientatio...
in this paper we present our studies using pauling electrostatic bond strength (esb) rules forstructural behaviour, cation vacancies, relation between x, y, and the valence of cations and coordinationin spinel compounds lixmn2o4, 0
Two Cu-Co and Co3O4 oxides were synthesized by the conventional sol-gel auto-combustion and their physical-chemical properties were characterized by XRD, FTIR, SEM, TPR and XPS. The XRD results indicated that copper-cobalt oxide appeared in a mixture form of Cu0.15Co2.85O4 spinel and CuO phases, whereas the cobalt oxide exhibited in the pure form of Co3O4 spinel. The FTIR approved the formation...
A general model is presented to enable the calculation of the cation distribution and thermodynamic properties of any binary solid solution between oxide spinels containing 2*, 3* and 4* cations. The model includes the effect ofdisordering enthalpy which depends linearly on the degree of disorder. In addition there are important contributions to the thermodynamic properties from the size mismat...
A solvothermal method was used to prepare zinc ferrite spinel oxide (ZnFe₂O₄) using ethylene glycol and 1,4 butanediol as solvent diols, and the influence of diols on the physical properties of ZnFe₂O₄ particles was investigated. The produced particles were characterized by X-ray powder diffraction (XRD), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR) and nitrogen...
Ten chromite ores from ophiolite complexes in SE Iran were analyzed mineralogically by XRD, chemically by XRF, and mineral chemistry by EPMA. The identified paragenesis of silicate minerals of chromite ores with the X-ray diffraction is pronounced differently. It consists of secondary phases formed as serpentine, Cr-containing chlorite (kaemmererite), chromic garnet (uarovite) with preserved pa...
Nanocrystalline undoped and 5% Mn doped ZnO powders are synthesized by sol-gel route using constituent nitrate and citrate precursors. The physico-chemical characterizations of powders calcined at various temperatures (400-1100 ̊C), are performed using techniques (XRD and SQUID) to study structural, nano/microstructural, and magnetic properties. XRD patterns clearly revealed the evolution of ma...
A spinel ferrite of the system NiSixFe2-xO4 with (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) were studied via IR, Xray spectra and cation distribution. The X-ray pattern confirmed the spinel cubic structure of all Si contents. The lattice parameters estimated as a function of Si contents indicated a slight decrease of lattice parameter up to 0.2. The grain size increases with increasing Si content up t...
Modified Li-rich layered cathode Li(Li0.2Mn0.54Ni0.13Co0.13)O2 has been synthesized by a simple strategy of using surface treatment with various amounts (0-30 wt.%) of Super P (carbon black). Based on detailed characterizations from X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy...
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