Oxygen Permeation and Electrical Transport Properties of 70 vol. Bi_(1.6)Y_(0.4)O_3 and 30 vol. Ag Composite

摘要

Oxygen permeability and electrical conductivity of a composite material constituted of 70 volume% of Bi_(1.6)Y_(0.4)O_3 and 30 volume% of Ag (70BYO) have been measured as functions of temperature and normalized oxygen partial pressure difference. Different conduction paths of oxide ions and electrons were found to be formed in the composite ceramics by the Bi_(1.6)Y_(0.4)O_3 and metallic silver, respectively from the combined results of total conductivity and oxygen permeability. The oxygen permeation flux is limited by the migration of oxide ions in Bi_(1.6)Y_(0.4)O_3 paths with the sample thickness between 0.81mm and 1.57mm. The effective oxide ion conductivity calculated from the oxygen permeation flux shows the same temperature dependence of the oxide ion conductivity of non-composite Bi_(1.6)Y_(0.4)O_3, and the values of 70BYO are almost the same with those for 60 vol.% Bi_(1.6)Y_(0.4)O_3 -40 vol.% Ag composite, regardless of the difference in the volume fraction of the oxide ion conduction paths.