Densification and grain growth during early-stage sintering of Ce0.9Gd0.1O1.95a degree I in a reducing atmosphere

The present work investigates the processes of densification and grain growth of Ce0.9Gd0.1O1.95a degree I (CGO10) during sintering under reduced oxygen partial pressure. Sintering variables were experimentally characterized and analyzed using defect chemistry and sintering constitutive laws. Based...

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Bibliographic Details
Published in:Acta materialia 2010-06, Vol.58 (11), p.3860-3866
Main Authors: He, Zeming, Yuan, Hao, Glasscock, Julie Anne, Chatzichristodoulou, Christodoulos, Phair, John William, Kaiser, Andreas, Ramousse, Severine
Format: Article
Language:English
Subjects:
Activation energy
Densification
Density
Grain growth
Grain size
Lattice vacancies
Partial pressure
Reducing atmospheres
Sintering
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Summary:The present work investigates the processes of densification and grain growth of Ce0.9Gd0.1O1.95a degree I (CGO10) during sintering under reduced oxygen partial pressure. Sintering variables were experimentally characterized and analyzed using defect chemistry and sintering constitutive laws. Based on the results achieved, the grain size-relative density relationship, the densification rate and the grain-growth rate were determined. The activation energies for densification and grain growth were evaluated, and the dominant densification mechanism was indicated. For comparison, the densification behavior of CGO10 sintered in air was also studied. Accelerated densification was observed in early-stage sintering of CGO10 in a reducing atmosphere. This might be attributed to the oxygen vacancies generated by the reduction of Ce4+ to Ce3+ in the reducing atmosphere, which facilitate the diffusion of ions through the lattice. The densification activation energy of CGO10 in the reducing atmosphere was evaluated to be 290A plus or minus 20kJmola degree 1 in the relative density range of 0.64-0.82, which was much smaller than that of CGO10 sintered in air (770A plus or minus 40kJmola degree 1). The grain-growth activation energy of CGO10 sintered in the reducing atmosphere was evaluated to be 280A plus or minus 20kJmola degree 1 in the grain size range of 0.34-0.70I14m. The present work describes a systematic investigation of sintering behavior of CGO10 under reduced oxygen partial pressure, which contributes to the first known determination of the fundamental parameters associated with densification and grain growth during early-stage sintering of CGO10 in a reducing atmosphere.
ISSN:1359-6454
DOI:10.1016/j.actamat.2010.03.046