Oxygen Nonstoichiometry and Permeability of Co-substituted YBa2Cu3O6+δ

The effects of substitution of Cu by Co in YBa2Cu3O6+δ on the oxygen nonstoichiometry and permeability were investigated. The oxygen nonstochiometry δ increased as a result of Co substitution, and its values did not change very much with the changing temperature and oxygen partial pressure. An oxygen permeation flux of 57 μmol/cm2s was observed at 850℃ from YBa2Cu2CoO6+δ disk-shaped dense sample of thickness 1.2 mm with one side exposed to air (PO2=21.2 kPa) and the other side to flowing helium (PO2=101 Pa), but only 31 μmol/cm2s was measured for YBa2Cu3O6+δ. The improved oxygen permeabilty in YBa2Cu2CoO6+δ was attributed to the even distribution of oxygen ions and oxygen vacancacies in the basal plane.