Oxygen Content and Thermodynamic Stability of YBaCo2O6−δ Double Perovskite

Autor: Anton L. Sednev, Andrey Yu Zuev, Dmitry S. Tsvetkov
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Advances in Materials Science and Engineering, Vol 2018 (2018)
Druh dokumentu: article
ISSN: 1687-8434
1687-8442
DOI: 10.1155/2018/1205708
Popis: The thermodynamic stability of the double perovskite YBaCo2O6−δ was studied using the coulometric titration technique and verified by measurements of the overall conductivity depending on oxygen partial pressure at a given temperature. As a result, the stability diagram of YBaCo2O6−δ was plotted. YBaCo2O6−δ was found to be thermodynamically stable in air at 850°C and higher temperatures, whereas its thermodynamic stability at 900°C is limited by the range of oxygen partial pressures −3.56 ≤ log(pO2/atm) ≤ −0.14. Oxygen content in YBaCo2O6−δ slightly decreases at 900°C from 5.035 at log(pO2/atm) = −0.14 to 4.989 in the atmosphere with log(pO2/atm) = −3.565 indicating a crucial role which variation of Co+3/Co+2 ratio plays in its stability. YBaCo2O6−δ decomposes into the mixture of YCoO3 and BaCoO3−z at the high pO2 stability limit, whereas YBaCo4O7, BaCo1−xYxO3−γ, and Y2O3 were identified as the products of its decomposition at the low pO2 one.
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