Phase transition during sintering process before nucleation of TFA-MOD YBa2Cu3O7-δ films

Abstract

In order to bring new insights to the transformation mechanism of intermediate phase and its dependence on processing conditions via trifluoroacetate metal organic deposition (TFA-MOD) method, a series of quenching experiments with different annealing temperature and atmospheres were designed. It was revealed that the transformation temperature of Ba-Y-F solid solution was lower with increasing the partial pressure of water. Calculation results of the Gibbs free energy change with different partial pressure of HF and H 2 O illustrated that the intermediate process is dominated by the exit diffusion of fluorine and the higher concentration of HF will inhibit the hydrolysis of barium fluoride.

Effect of Chlorine Addition on Texture and Superconducting Performance of YBa2Cu3O7−δ-Coated Conductors

“…where J P is the pressure quotient, let J 0 = P 2 HCl /P H 2 O , then the J 0 values of chemical reaction Equations ( 1) and (2) are J 0 3 and J 0 , respectively. The Gibbs free energy changes of the reaction Equations ( 1) and ( 2) are plotted for three different pressure quotients J 0 = 1, 1 × 10 −8 , 1 × 10 −13 [19], as shown in Figure 8. As the partial pressure of HCl decreases gradually, the free energy is driven below the negative value and the reaction will proceed from left to right.…”