Ceramics-Silikáty 53, (1) 9 - 14 (2009) |
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THERMAL BEHAVIOR OF BRANNERITE CERAMICS AND ITS NATURAL ANALOGUE MINERAL BRANNERITE
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Balek Vladimír 1,2, Zeleňák Vladimír 2,4, Beneš Martin 2,
Šubrt Jan 3
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1 Nuclear Research Institute Řež , plc , 250 68 Řež , Czech Republic
2 Research Center Řež , Ltd., 250 68, Řež, Czech Republic
3 Institute of Inorganic Chemistry, ASCR, 250 68, Řež, Czech Republic
4 Faculty of Sciences, P.J. Šafárik University, Moyzesova 11, 041 54 Košice, Slovak Republic
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Keywords: Brannerite ceramics, Brannerite mineral, Emanation thermal analysis, Microstructure, Thermal behavior
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Thermal behavior of brannerite ceramics (uranium titanate of chemical composition UTi₂O₆) was characterized in the range
30-1250°C. By using emanation thermal analysis (ETA) the temperatures of the microstructure changes were indicated
as a decrease of radon release rate, the onset of healing subsurface microstructure irregularities is supposed at 250°C,
whereas the onset of sintering at 800°C. The intensity of microstructure changes in the temperature intervals 250-500°C and
800-950°C was assessed by a mathematical model. From the ETA results of metamict brannerite mineral (from locality
El Cabril near Cordoba, Spain) it followed that in the range 970-1020°C the crystallization of the metamict mineral took
place. Relative changes in the amount of microstructure irregularities during heating of the metamict brannerite mineral
were assessed from the ETA results measured on heating and subsequent cooling to temperatures of 300, 550, 750, 880, 1020
and 1150°C, respectively. |
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