This title appears in the Scientific Report :
2015
Please use the identifier:
http://dx.doi.org/10.1016/j.ssi.2015.11.001 in citations.
Expansion behaviour of (Gd, Pr)-substituted CeO$_{2}$ in dependence on temperature and oxygen partial pressure
Expansion behaviour of (Gd, Pr)-substituted CeO$_{2}$ in dependence on temperature and oxygen partial pressure
Substituted ceria is a material which has attracted great interest in solid oxide fuel cell technology [45]. Due to its chemical stability, it may also be a promising candidate as a mixed conductive membrane for oxygen separation with flue gas contact. As part of this paper, dilatometry measurements...
Saved in:
Personal Name(s): | Heidenreich, M. (Corresponding author) |
---|---|
Kaps, Ch. / Simon, A. / Schulze-Küppers, F. / Baumann, S. | |
Contributing Institute: |
Werkstoffsynthese und Herstellungsverfahren; IEK-1 |
Published in: | Solid state ionics, 283 (2015) S. 56-67 |
Imprint: |
Amsterdam [u.a.]
Elsevier Science
2015
|
DOI: |
10.1016/j.ssi.2015.11.001 |
Document Type: |
Journal Article |
Research Program: |
Methods and Concepts for Material Development |
Publikationsportal JuSER |
Substituted ceria is a material which has attracted great interest in solid oxide fuel cell technology [45]. Due to its chemical stability, it may also be a promising candidate as a mixed conductive membrane for oxygen separation with flue gas contact. As part of this paper, dilatometry measurements and X-ray powder diffraction experiments were carried out on ceramic materials in air and in argon with two separate series involving the substitution of ceria; cerium was substituted with different amounts of Gd and Pr. The first substitution of Gd caused an increase of the unit cell with a small rise in linear thermal expansion in relation to pure ceria. CeO2 − δ and Ce0.8Gd0.2O2 − δ showed no chemical expansion in both atmospheres. The second substitution of Gd with Pr decreased the unit cell in relation to pure ceria. It is therefore understandable that Pr is preferentially introduced and shown in this work as Pr4 + in ceria. These samples showed a remarkable chemical expansion in air and in argon. The chemical expansion displayed a clear positive correlation with increasing Pr content. The thermal expansion coefficients are comparable to the first substitution without any trend in relation to the amount of Pr. The dilatometry behaviour above 400 °C can be explained due to the release of oxygen and simultaneous reduction of Pr4 +, forming Pr3 + and oxygen vacancies. The results are in accordance with the two competing processes of forming vacancies (lattice contraction) and ionic radius change (lattice expansion) [16] and [27]. After cooling in air, the samples showed no residual expansion. In contrast, these samples displayed a remarkable residual expansion in argon of about 0.87% of the total relative expansion of 1.85% for Ce0.8Pr0.2O2 − δ |