The oxygenation kinetics of YBa2Cu3O7-δ-(0-30%)Ag superconductors

Oxygenation kinetics of YBa2Cu3O7-δ superconductor with silver (0%, 10% and 30% Ag by weight) have been studied by using thermogravimetric analysis at annealing temperatures ranging from 350 deg. C to 850 deg. C in air. The results show that both the silver addition and annealing temperature greatly influence the oxygenation processes of the YBa2Cu3O7-δ superconductor. The amounts of the oxygen loaded into Y123-Ag compounds increase with decreasing temperature. The silver additions also increase the saturation oxygen contents, increase the maximum oxygenation rates and slow down the accelerations and deceleration of the oxygenation rates. It is believed that there are two types of diffusion that affect the oxygenation kinetics: oxygen transfer through grain boundaries and pores and oxygen diffusion through Y123 lattice. Added silver changed the microstructures of Y123 specimens by segregating itself onto the grain boundary areas and therefore affecting the oxygen transfer processes and oxygenation kinetics. (author)