The changes of Ba0.5Sr0.5Co0.8Fe0.2O3-δ perovskite oxide on heating in oxygen and carbon dioxide atmospheres

In the first part of this study, the oxygen deficiency, delta, in Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) was measured by means of thermogravimetry as a function of the oxygen partial pressure, p(O-2), in the range of 1.1 x 10(-6) - 41.67 % at elevated temperatures in the range 873-1073 K. It was shown that delta becomes more pronounced with increasing T and with decreasing p(O-2). The isotherms delta vs. p(O-2) were determined. The second part of this study relates to the reaction of CO2 with Ba0.5Sr0.5Co0.8Fe0.8O3-delta perovskite oxide in the absence and presence of O-2 at temperatures ranging from 673 to 973 K, also by thermogravimetry. The reactivity of CO2 with BSCF increased with increasing temperature and increasing exposure to CO2. The reaction of CO2 with BSCF was described by equilibrium reaction isotherms. The results of X-ray diffractometry evidenced that exposure to CO2 leads to the formation of carbonates.