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A. M. George N. C. Mishra M. S. Nagar N. C. Jayadevan 《Journal of Thermal Analysis and Calorimetry》1996,47(6):1701-1708
Thermal decomposition of the amorphous coprecipitate of yttrium and aluminium hydroxides forming yttrium aluminium garnet has been investigated employing thermal analyses, X-ray diffraction and IR spectroscopy. On heating, the coprecipitate progressively loses water forming a stable but highly disordered hydroxy garnet which crystallizes at 1180 K and decomposes to YAG at 1290 K. Nucleation of the crystalline phase appears to begin at 800 K.The authors thank Dr. P. V. Ravindran of the Analytical Chemistry and Shri N. K. Kulkarni of the Fuel Chemistry Divisions of BARC for their assistance in the thermoanalytical experiments. 相似文献
2.
Chung-King Hsu Jinn-Shing Lee Chin-Wang Huang 《Journal of Thermal Analysis and Calorimetry》1998,51(1):295-305
The kinetics of the decomposition of Y, Ba and Cu oxalates and coprecipitanted Y-Ba-Cu oxalate was investigated under a nitrogen
atmosphere on the basis of dynamic thermogravimetric data, the average activation energies of the decomposition of Y, Ba and
Cu oxalates were obtained from the slopes of the T. Ozawa plot.
The average activation energies for the dehydration of these oxalate and coprecipitated Y-Ba-Cu oxalate were also evaluated
from the thermogravimetric curves. 相似文献
3.
Popa M. Calderon-Moreno J. M. Crisan D. Zaharescu M. 《Journal of Thermal Analysis and Calorimetry》2000,62(3):633-645
This work introduces results obtained during the preparation of a Bi-based material with superconducting properties by oxalate
coprecipitation.
The influence of Fe presence on the precursors thermal stability and on the superconducting phases formation mechanism are
presented. The thermal decomposition and the stability in air of FeC2O4×2H2O and also of the components mixture were studied by DTA/TG. It was evidenced that iron oxalate decomposes at the lowest temperature
compared to the decomposition temperatures of the individual oxalates.
XRD, IR and TEM/ED studies were approached to investigate the individual oxalates and the mixture coprecipitates for the high-T
c superconducting material synthesis.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
4.
Donia A. M. Radwan N. R. E. Atia A. A. 《Journal of Thermal Analysis and Calorimetry》2000,61(1):249-261
Mixed oxides were prepared by the thermal decomposition of the oxalates of cobalt(II) and copper(II) coprecipitated from aqueous
solution or made by mechanical mixing. The compositions and structures of the oxides were confirmed by means of TG and X-ray
powder diffraction spectroscopy. The catalytic behaviour of the oxides obtained was studied by using the decomposition of
H2O2 as a model reaction. The results were compared with those on the oxides produced from the thermal decomposition of mechanically
mixed oxalates. The catalytic activities of the mixed oxides were found to be lower than that of pure cobalt oxide, but higher
than that of copper oxide. This result was interpreted in terms of the relative standard reduction potential of the catalyst
as compared with that of H2O2. The catalytic activity of the mixed oxides obtained from the coprecipitate was found to be lower than that of the oxides
obtained from the mechanical mixture at the same temperature. As the temperature of preparation was increased, the catalytic
activities of the oxides obtained decreased. This was attributed to the solid-solid interactions, which gave a new phase with
lower catalytic activity than those of the interacting phases.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
E. A. Evsei V. R. Pupkevich A. M. Kirillov E. A. Telushchenko M. N. Kopylovich A. K. Baev 《Journal of Applied Spectroscopy》2001,68(5):736-742
A range of coprecipitated Fe(III)-Me(II) (Me(II) = Ni, Cu) hydroxides and of the products of their thermolysis have been investigated by the IR spectroscopy method. The basic absorption bands has been assigned, and the chemistry of the process of formation of coprecipitated hydroxides has been discussed from the standpoint of generation of heteronuclear hydrococomplexes. 相似文献
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