MICROSTRUCTRAL EFFECT ON OXYGEN PERMEABILITY OF MIXED CONDUCTING OXIDES

摘要

Microstructural dependence on oxygen permeability of perovskite-type mixed conductor, La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ), has been discussed. Electrochemical properties such as electrical conductivity and oxygen permeability have been evaluated as a function of temperature. Increase in grain size of the membrane results in higher oxygen permeability, which implies that the grain boundary of the membrane has a negative effect on oxygen permeation. The effect of surface modification with a reactive phase has been investigated, which confirms that overall oxygen permeability of 1.7 mm-thick La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ) membrane is determined by bulk transport process at elevated temperature.