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Title: | Chemically induced expansion of La2NiO4+ δ-based materials |
Authors: | Kharton, VV Kovalevsky, AV Avdeev, M Tsipis, EV Patrakeev, MV Yaremchenko, AA Naumovich, EN Frade, JR |
Keywords: | Oxides Membranes Oxygen Ceramics Stoichiometry Electrochemistry Thermal gravimetric analysis Thermal expansion |
Issue Date: | 21-Mar-2007 |
Publisher: | American Chemical Society |
Citation: | Kharton, V. V., Kovalevsky, A. V., Avdeev, M., Tsipis, E. V., Patrakeev, M. V., Yaremchenko, A. A., Naumovich, E. N., & Frade, J. R. (2007). Chemically induced expansion of La2NiO4+ δ-based materials. Chemistry of Materials 19, 8, 2027–2033. doi:10.1021/cm070096x |
Abstract: | The equilibrium chemical strains induced by the oxygen hyperstoichiometry variations in mixed-conducting La2Ni1-xMxO4+δ (M = Fe, Co, Cu; x = 0−0.2) with K2NiF4-type structure, were studied by controlled-atmosphere dilatometry at 923−1223 K in the oxygen partial pressure range 5 × 10-4 to 0.7 atm. In combination with the oxygen content measured by coulometric titration and thermogravimetry, the results reveal a very low chemical expansivity, favorable for high-temperature electrochemical applications. Under oxidizing conditions, the isothermal expansion relative to atmospheric oxygen pressure (εC) is less than 0.02%. The ratio between these values and the corresponding nonstoichiometry increment varies from −3 × 10-3 to 6 × 10-3, which is much lower compared to most permeable mixed conductors derived from perovskite-like cobaltites and ferrites. Consequently, the chemical contribution to apparent thermal expansion coefficients at a fixed oxygen pressure, (13.7−15.1) × 10-6 K-1, does not exceed 5%. The high-temperature X-ray diffraction studies showed that this behavior results from strongly anisotropic expansion of the K2NiF4-type lattice, namely the opposing variations of the unit-cell parameters on changing oxygen stoichiometry. © 2007, American Chemical Society |
URI: | https://doi.org/10.1021/cm070096x https://apo.ansto.gov.au/dspace/handle/10238/9954 |
ISSN: | 1520-5002 |
Appears in Collections: | Journal Articles |
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