Ceramics-Silikáty 53 (1) 9-14 (2009)

THERMAL BEHAVIOR OF BRANNERITE CERAMICS AND ITS NATURAL ANALOGUE MINERAL BRANNERITE

V. Balek, V. Zeleňák, M. Beneš, J. Šubrt

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.

Keywords: Brannerite ceramics, Brannerite mineral, Emanation thermal analysis, Microstructure, Thermal behavior