Spinel Phase
Mostrando 37-40 de 40 artigos, teses e dissertações.
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37. Synthesis, characterization and study of catalytical properties of mixed layered hydroxides containing Cu(II)/Mg(II)/Al(III) / Síntese, caracterização e estudo de propriedades catalíticas de hidróxidos mistos lamelares contendo Cu(II)/Mg(II)/AI(III)
In this work it was investigated the preparation and spectroscopic characterization of layered hydroxides of composition [Mg3-xCuxAl(OH)8](CO3)0.5.yH2O (x = 0.3; 0.6; 0.9; 1.2; 1.5; 1.8; 2.1; 2.4; 2.7 and 3.0), as well the reactivity of these materials towards phenol hydroxylation, using hydrogen peroxide as oxidizing agent. The solids had been prepared thro
Publicado em: 2005
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38. Preparation and characterization of Nickel-and cobalt-doped magnetites
Nickel- and cobalt-doped magnetites were prepared by a co-precipitation method and studied in some detail, in an effort to identify some effects of the doping cations on the magnetic, crystallographic and morphological properties of the resulting spinel. The synthetic samples were characterized by conventional chemical analysis, powder X-ray diffractometry,
Materials Research. Publicado em: 2003-06
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39. Electrical characterization by impedance spectroscopy of Zn7Sb2O12 ceramic
Impedance spectroscopy technique was used to investigate the electric properties of Zn7Sb2O12, an electroceramic with inverse spinel type structure. The electric characterization of the Zn7Sb2O12 semiconducting ceramic was performed at temperature from 250 to 550 °C, in the frequency range from 5 Hz to 13 MHz. Zinc antimoniate phase was synthesized by the p
Materials Research. Publicado em: 2003-06
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40. Natural occurrence and synthesis of two new postspinel polymorphs of chromite
A high-pressure polymorph of chromite, the first natural sample with the calcium ferrite structure, has been discovered in the shock veins of the Suizhou meteorite. Synchrotron x-ray diffraction analyses reveal an orthorhombic CaFe2O4-type (CF) structure. The unit-cell parameters are a = 8.954(7) Å, b = 2.986(2) Å, c = 9.891(7) Å, V = 264.5(4) Å3 (Z = 4)
National Academy of Sciences.