p O 2 stability of Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ
p O 2 stability of Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ
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Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ 的 p O 2 稳定性
DOI：
10.1557/opl.2011.419
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
E. Ivers
中科院分区：
文献类型：
--
作者：
S. Wagner;Simon Taufall;C. Niedrig;H. Götz;W. Menesklou;S. Baumann;E. Ivers
混合导电钙钛矿氧化物Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF)由于其优异的氧离子和电子输运性能，被认为是一种很有前途的高温氧输运膜材料。然而，它在运行条件下的长期稳定性仍然是一个重要问题。虽然BSCF与含CO 2的大气的不相容可以通过适当的方法（在没有二氧化碳的情况下进行氧燃料过程）来避免，但BSCF本身的热稳定性和化学稳定性仍在深入研究中。这项工作的重点是BSCF在OTM应用的目标温度范围（700…900°C）和低氧含量大气中的稳定性。先前的文献研究表明，在大约10 -6巴的氧分压po2下，化学稳定性有限。采用基于氧化锆“氧气泵”装置的库伦滴定法，可将氧分压po2精确控制在1 ~ 10 ~ 18 bar之间。结合对致密陶瓷体样品的电学测量与不同o2处理下单相BSCF粉末的XRD相组成研究，可以评估BSCF的化学稳定性与氧分压的关系。因此可以证明，二氧化碳的稳定极限比以前文献中假设的要低得多。
The mixed-conducting perovskite oxide Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3-δ (BSCF), given its outstanding oxygen ionic and electronic transport properties, is considered a promising material composition for oxygen transport membranes (OTM) operated at high temperatures. Its long-term stability under operating conditions is, however, still an important issue. Although the incompatibility of BSCF with CO 2 -containing atmospheres can be avoided by appropriate means (oxyfuel processes in the absence of carbon dioxide), the thermal as well as the chemical stability of BSCF itself are still under thorough investigation. This work is focused on the stability of BSCF in the targeted temperature range for OTM applications (700…900 °C) and in atmospheres with low oxygen contents. Previous studies in literature suggest limited chemical stability below oxygen partial pressures p O 2 of around 10 -6 bar. By using a coulometric titration method based on a zirconia “oxygen pump” setup, precise control of the oxygen partial pressure p O 2 between 1 bar and 10 -18 bar was facilitated. Combining electrical measurements on dense ceramic bulk samples performed as a function of p O 2 with an XRD phase composition study of single phase BSCF powders subjected to various p O 2 treatments, an assessment of the chemical stability of BSCF is facilitated as a function of oxygen partial pressure. It could thus be shown that the p O 2 stability limit is considerably lower than previously assumed in literature.