کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1295576 | 1498282 | 2014 | 4 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Stability and oxygen transport property of La0.8Sr0.2Cr0.5Fe0.5O3 -δ Stability and oxygen transport property of La0.8Sr0.2Cr0.5Fe0.5O3 -δ](/preview/png/1295576.png)
• La0.8Sr0.2Cr0.5Fe0.5O3 -δ maintains perovskite structure in diluted hydrogen at 950 °C.
• Its decomposition oxygen partial pressure at 950 °C is calculated to be 6.3 × 10− 28 atm.
• It exhibits appreciable oxygen permeation flux indicative of oxygen ionic conduction.
The stability of La0.8Sr0.2Cr0.5Fe0.5O3 -δ (LSCrF) in reducing atmosphere was investigated by examining the extent of its reaction with hydrogen at elevated temperature. LSCrF powder exposed to diluted hydrogen was found to loss a weight of only ~ 0.5%, corresponding to the formation of oxygen vacancies in the lattice. LSCrF powder exposed to flowing concentrated hydrogen for 30 h was found to decompose partially. The decomposition oxygen partial pressure of LSCrF at 950 °C was estimated to be 6.3 × 10− 28 atm from thermodynamic calculations. The stability of LSCrF under an oxygen chemical potential gradient was also examined by exposing a disk-shaped dense sample to air at one side and to reducing atmosphere (CO) at the other side at elevated temperatures. A thin, porous layer was found to form on the CO side surface. An oxygen permeation flux of 2.5 × 10− 7 mol cm− 2 s− 1 was observed at 950 °C under given air/CO gradient. The occurrence of oxygen permeation revealed the presence of mixed oxygen ionic and electronic conductivity. The oxygen ionic conductivity was estimated to be ~ 0.01 S/cm at 950 °C.
Journal: Solid State Ionics - Volume 260, 1 July 2014, Pages 86–89