ISSN:
1573-8663
Keywords:
mixed-conductor
;
oxygen permeation
;
diffusivity
;
ceramic membrane
;
Sr-Fe-Co oxide
Source:
Springer Online Journal Archives 1860-2000
Topics:
Electrical Engineering, Measurement and Control Technology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Single phase SrFe1.2Co0.3Ox sample with layered crystal structure was prepared using a solid state reaction method. Electrical conductivity and apparent oxygen diffusion coefficients of the SrFe1.2Co0.3Ox sample were measured as functions of temperature in atmospheres of various oxygen partial pressures $$({\text{P}}_{{\text{O}}_{\text{2}} } )$$ . Total and ionic conductivities were determined by using the conventional four-probe and electron blocking four-probe methods, respectively. The apparent oxygen diffusion coefficient was derived from the time-dependent conductivity relaxation data of the reequilibrium process after abruptly changing the $$({\text{P}}_{{\text{O}}_{\text{2}} } )$$ in the surrounding atmosphere. Several atmospheres of different $$({\text{P}}_{{\text{O}}_{\text{2}} } )$$ were established by the use of premixed gas cylinders. The conductivity of SrFe1.2Co0.3Ox increases with increasing temperature and $$({\text{P}}_{{\text{O}}_{\text{2}} } )$$ . At 900°C in air, the total conductivity and ionic conductivity are 10 and 8 S · cm-2, respectively. The ionic transference number (≈ 0.8 in air) does not have strong temperature dependence. The activation energy increases with decreasing $$({\text{P}}_{{\text{O}}_{\text{2}} } )$$ . In air, the activation energy has a low value of ≈ 0.37 eV. The apparent oxygen diffusion coefficient was $$ \approx 2 \times 10^{ - 6} {\text{ cm}}^{\text{2}} \cdot {\text{s}}^{{\text{ - 1}}}$$ at 950°C over a wide range of $${\text{P}}_{{\text{O}}_{\text{2}}} (1 \leqslant {\text{P}}_{{\text{O}}_{\text{2}}} \leqslant 10^{ - 18} {\text{atm}})$$ .
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1009939309781
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