KINETICS OF OXYGEN LOSS IN SOME (RE)BA2CU3O7-X COMPOUNDS

Thermogravimetric in situ measurements of the oxygen loss in(RE)Ba2Cu3 O7-x samples (RE = Y, Nd, Eu, Er) isothermally heated in relatively hi gh vacuum (approximately 10(-4) Pa) are performed. The decomposition c urves are reasonably good described by the sum of three exponential te rms corresponding to quick, medium and slow first order processes in w hich small, medium and large grains of the powder samples are involved . The activation energies estimated from appropriate Arrhenius plots a re for all preparations close to each other and equal to 0.92 +/- 0.02 eV.