STRUCTURAL-CHANGES OF TL OXIDE SYSTEM ON NONISOTHERMAL THERMOGRAVIMETRY WITH SLOW HEATING RATES

The oxygen desorption processes of Ta2Ba2CuO6 and TI0.5Pb0.5Sr2CuO5 wi th double and single TI layer structures, respectively were studied by non-isothermal thermogravimetry (TG) with slow heating rates of 10-30 degrees/h in Ar and O-2 streams. The structural changes and the valen ce changes of the metals caused by the oxygen desorption were examined . The TG curve of TI2Ba2CuO6 gave an inflection point around at 600 de grees C, indicating that the oxygen desorption occurred separately fro m decomposition. In this course, the tetragonal unit was kept and the cell dimension (a) over bar increased. TI0.5P0.5Sr2CuO5 had no labile oxygen which is released separately from decomposition and can change (a) over bar.