High temperature in situ investigations of Y1+xBa8Cu4Oy x nCO2 phase

Thermogravimetric and x-ray diffraction methods have been used for studying physical and chemical processes accompanying the heating of phase Y1+xBa8Cu4Oy x nCO2 (where x=0; 0.33) in the air at T=20-1200 deg C. These processes are based on the interaction of the phase with atmospheric CO2, on the one hand, and a partial loss of oxycarbonate groupings in the process of heating, on the other. In consequence, the initial rhombic phase transforms into the tetragonal one, stable within the range of 900-1080 deg C. The composition of the latter features a reduced by half value of n. 16 refs., 2 figs., 6 tabs