Oxygen permeation measurement of La1-xCaxCrO3-delta by using an electrochemical method

Oxygen permeation current density (J(O2-)) through La0.9Ca0.11CrO3-delta was measured by using an electrochemical method under an oxygen potential gradient, P(O-2)=1 similar to 1x10(-13) bar. The oxygen vacancy diffusion coefficient (D-V) is estimated 1.5x10(-10) m(2) s(-1) in the P(O-2) range from 10(-5) to 10(-10) bar. The oxygen permeation current density through 1 mm thick plate is estimated as 10 mA cm(-2) in SOFC operation condition. The oxygen tracer diffusion coefficients via bulk (D*) and via grain boundary (D-gb*) were estimated by SIMS for La1-xCaxCrO3-delta (x=0.1, 0.2). The contribution of grain boundary diffusion on permeation was considered in the oxidizing atmosphere, however, the bulk diffusion is dominant in a large oxygen potential gradient.