Effect of annealing atmosphere on the kinetics and mechanism of low-temperature decomposition of the nonstoichiometric Ba2YCu3O7-δ ceramics

The effect of heat treatments in helium, nitrogen, and vacuum (P = 10(-2), 20, and 100 mmHg) on the kinetics of low-temperature decomposition (T < 400 degrees C) of the nonstoichiometric Ba2YCu3O7-delta ceramics has been studied. The decomposition in the vacuum was found to be very slow; the rate of the decomposition in both helium and nitrogen is substantially higher. The results obtained indicate the strong effect of the nature of gas absorbed on the grain surface. Possible mechanisms of the effect of absorption on the kinetics of low-temperature decomposition are considered.