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The thermochemical behavior of the coordination compound [Fe(urea)6](NO3)3 was studied by simultaneous CG–TG–DTG–DTA and mass spectrometry methods non-isothermal conditions. The compound decomposes at 200 °C into a mixture of spinel-type oxides and hematite. The nature and particle size of the final decomposition products are strongly associated with the conditions during the thermal treatments, in particular the heating rate and the calcination temperature. A certain fraction of the products are formed as nanometric particles; they show superparamagnetic behavior at room temperature. The comparably low temperature of the calcination treatments of this compound is a promising perspective to attain small sized magnetic powders. 相似文献
2.
Thermoanalytical, mass spectrometric and X-ray diffraction data were associated with a reliable assignation of the thermal
transformations of the coordination compound [Mn(urea)6](NO3)2·2H2O.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
Carp O. Patron L. Mindru I. Marinescu G. Diamandescu L. Banuta A. 《Journal of Thermal Analysis and Calorimetry》2003,74(3):789-799
The thermal behaviour of three coordination compounds, potential precursors of nickel ferrite [Fe2Ni(C4H4O5)2.5(OH)2]NO3·5H2O,[Fe2Ni(C4H8O3N2)4](NO3)8·24H2O and (NH4)[Fe2Ni(C4H4O5)3(OH)3]·3H2O has been investigated to evaluate their suitability as precursors for nickel ferrite. For a complete and reliable assignment of the thermal transformations, the isolable solid intermediates and end products were characterized by IR, X-ray diffraction and Mössbauer investigations. A decomposition scheme is proposed. 相似文献
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Oana Carp Luminita Patron Daniela C. Culita Petru Budrugeac Marcel Feder Lucian Diamandescu 《Journal of Thermal Analysis and Calorimetry》2010,101(1):181-187
The thermal stability of two kinds of dextran-coated magnetite (dextran with molecular weight of 40,000 (Dex40) and 70,000
(Dex70)), obtained by dextran adsorption onto the magnetite surface is investigated in comparison with free dextran in air
and argon atmosphere. The thermal behavior of the two free dextran types and corresponding coated magnetites is similar, but
atmosphere dependent. The magnetite catalyzes the thermal decomposition of dextran, the adsorbed dextran displaying lower
initial decomposition temperatures comparative with the free one in both working atmospheres. The dextran adsorbed onto the
magnetite surface decomposes in air through a strong sharp exothermic process up to ~450 °C while in argon atmosphere two
endothermic stages are identified, one in the temperature range 160–450 °C and the other at 530–800 °C. 相似文献
6.
L. Patron O. Carp I. Mandru G. Grasa 《Journal of Thermal Analysis and Calorimetry》1999,56(2):597-602
New Nd-Co based polynuclear coordination compounds containing as ligand polyhydrocarboxylic acid as tartaric, malic and gluconic
acids were prepared, namely: [NdCo(tart)3]·4H2O, (NH4)[NdCo0.5Cu0.5(tart)3]·4H2O, (NH4)[NdCo(malic)3]·4H2O, (NH4)[NdCo0.5Cu0.5(malic)3]·4H2O, [NdCo(gluc)4]·4H2O and [Nd2CoCu(gluc)7]·5H2O. A comparison between the thermal behaviour of the studied polynuclear coordination compounds concerning thermal stability
and thermal decomposition stoichiometry was inferred. Oxalic and malonic intermediates were identified at about 300°C in the
thermal decomposition of tartaric and malic compounds. In all the decomposition processes at about 400°C the presence of oxocarbonate
is shown. The residual products are mixed oxides of perovskite type.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
Pocol V. Patron L. Carp O. Brezeanu M. Segal E. Stanica N. Crisan D. 《Journal of Thermal Analysis and Calorimetry》1999,55(1):143-154
The polynuclear coordination compounds LnCr(tartrate)3·nH2O where Ln(III)=La-Er, obtained through a precipitation method, were characterized on the basis of elemental analysis, their
electronic and vibrational spectra and magnetic susceptibility measurements. The possibility of obtaining chromites through
the transformations of the polynuclear coordination compounds in the solid state was considered. The thermal decompositions
of these compounds, studied by TG and DTA methods, were found to follow an almost uniform pattern. The decompositions occurred
in six-eight steps. The first two steps involved dehydration, and the third the transformation of tartrate anions to oxalate,
followed by conversion to carbonate and oxocarbonate intermediates. The final product in each case was LnCrO3. A non-isothermal kinetic analysis of the first decomposition steps was performed, the most probable decomposition mechanism
being selected and the kinetic parameters evaluated. The final products of the transformations were characterized.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Bogdan Jurca Carmen Paraschiv Adelina Ianculescu Oana Carp 《Journal of Thermal Analysis and Calorimetry》2009,97(1):91-98
Activated carbons (AC), particularly those containing sulphur, are effective adsorbents for mercury (Hg) vapour at elevated
temperatures. Activated carbon-based technologies are expected to become a major part of the strategy for controlling mercury
emission from coal-fired power plants. Understanding the mechanism of mercury adsorption on sulphur impregnated activated
carbons (SIAC) is essential to optimizing activated carbons for better mercury removal efficiency and to developing technologies
for the handling of the spent AC.
In this work thermal analysis before and after mercury uptake was carried out for the SIAC prepared under various conditions
from oil-sand petroleum coke using a simultaneous differential thermal analyzer. Samples were heated at 20°C min−1 under nitrogen in the temperature range from ambient to 1000°C. The DSC curves suggest both endothermic and exothermic changes
during heating. The endothermic processes were attributed to evaporation of moisture and other volatile components. The exothermic
processes existed in a wide temperature range of 150–850°C likely due to the oxidation reactions between carbon and adsorbed
oxygen, oxygen-containing surface groups. The enthalpies of liquid mercury interaction with SIAC at different Hg/AC mass ratio
were also measured at 30, 40 and 50°C using a differential scanning calorimeter. The combination of thermal analysis and calorimetry
techniques enabled confirmation that the interaction of mercury with SIAC involves both physical and chemical processes. 相似文献
10.
Oana Carp E. Segal Maria Brezeanu Luminita Patron R. Barjega N. Stanica 《Journal of Thermal Analysis and Calorimetry》1996,47(3):857-869
The authors analyse the possibility of obtaining manganese-zinc ferrite through the transformations of polynuclear coordination compounds (pcc), either in the solid state or in a reaction medium. Polynuclear coordination compound precursors with the general molecular formula: [Fe(II)xFe(III)y(Mn0.5Zn0.5)(C2O4)2(OH)y+2(H2O)2] with 0.2相似文献