Ceramics-Silikáty 57, (2) 83 - 86 (2013) |
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THERMAL PROPERTIES AND HOMOGENITY RANGE OF Bi24+xCo2-xO39 CERAMICS
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Jankovský O. 1, Sedmidubský D. 1, Sofer Z. 1,
Čapek J. 2,
Růžička K. 3
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1 Department of Inorganic Chemistry, Institute of Chemical Technology Prague,
Technicka 5, 166 28 Prague 6, Czech Republic
2 Department of Metals and Corrosion engineering, Institute of Chemical Technology Prague,
Technicka 5, 166 28 Prague 6, Czech Republic
3 Department of Physical Chemistry, Institute of Chemical Technology Prague,
Technicka 5, 166 28 Prague 6, Czech Republic
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Keywords: Cobalt sillenite, Thermal properties, Heat capacity
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Samples with different Bi2O3/Co2O3 ratio were prepared by ceramic route. Based on the results of DTA, XRD and SEM – EDX
a section of phase diagram of the Bi–Co–O diagram in air atmosphere was calculated using the FactSage software. The
sillenite structure of Bi24+xCo2-xO39 was confirmed and described. The Rietveld analysis confirmed SEM – EDX results. The
heat capacity and enthalpy increments of Bi24Co2O39 were measured by differential scanning calorimetry (DSC) from 258 K
to 355 K and by the drop calorimetry from 573 K to 973 K. Above room temperature the temperature dependence of the molar
heat capacity in the form Cpm = (1467.87 + 0.299410 · T – 15888378 · T-2) J K-1 mol-1 was derived by least-squares method
from the experimental data. |
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