Enhanced mass diffusion phenomena in highly defective doped ceria

Esposito, Vincenzo; Ni, De Wei; He, Zeming; Zhang, Wei; Prasad, Arun; Glasscock, Julie; Chatzichristodoulou, Christodoulos; Ramousse, Séverine; Kaiser, Andreas

doi:10.1016/j.actamat.2013.07.012

Cited by 73 publications

(97 citation statements)

References 65 publications

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“…For other extrinsic cases such as YSZ and ceria solid solutions the experimental evidences are less clear [61,73,84]. As discussed above, the thickness of the SCL can be reduced by the large concentration of charge carriers, dopants, aliovalent impurities and even the material preparation methods all of which have shown to affect further the profile of the charge carriers' concentration [61,73,85,[93][94][95]. Different profiles of charge concentration are therefore possible to implement and some alternative models have been further considered [73,90].…”

Section: "Disordered Interfaces"mentioning

confidence: 99%

When two become one: An insight into 2D conductive oxide interfaces

Pryds

Esposito

2016

J Electroceram

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Section: "Disordered Interfaces"mentioning

confidence: 99%

When two become one: An insight into 2D conductive oxide interfaces

Pryds

Esposito

2016

J Electroceram

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“…4 O]=2.7 % still showed minor crack lines with insufficient densification. However, to obtain nearly fully dense GDC pellet with few cracks, the cooling cycle and annealing process must be controlled [35]. With slow heating/cooling or Po 2 change, the sample would not crack since cracking is expected to occur due to the gradient in oxygen-vacancy concentration within the material i.e.…”

Section: Resultsmentioning

confidence: 99%

“…No decomposition of GDC20 into individual oxides was also shown at high temperature under reduced Po 2 region (10 −11 ≤Po 2 ≤10 -13 atm) [34]. Meanwhile, the densification and grain growth of GDC10 both in air and in reducing atmosphere from room temperature to 1500°C was also presented [35]. A nearly fully-densified GDC20 sample was obtained after firing in Po 2 <10 −12 atm and annealed at 1050°C without any sintering aids.…”

Section: Introductionmentioning

confidence: 94%

“…Although we need to understand the behaviors of GDC in a wide range of sintering condition in reducing atmosphere for diverse applications, particularly for co-firing of MS-SOFCs, limited studies were so far reported [35][36][37]. GDC20 pellet samples were fired in various reducing atmosphere and temperature and their phase and the weight change after firing was determined at room temperature.…”

Section: Introductionmentioning

confidence: 99%

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Phase stability and oxygen non-stoichiometry of Gd-doped ceria during sintering in reducing atmosphere

Kim

2015

J Electroceram

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Firing of Gd-doped ceria (GDC) powder compact in reducing atmosphere leads to reduction and subsequent decomposition of GDC, and cracking of the pellet upon cooling, depending upon the firing temperature T and oxygen partial pressure Po 2 . In this study, GDC powder compacts were fired in various reducing atmosphere by controlling the ratio of H 2 and H 2 O mixing (H 2 O content: 0.28, 1.3, 2.7, 3 %) at temperatures T=703, 835, 975, 1088, 1180, 1262 and 1354°C. The phase and oxygen non-stoichiometry of GDC, respectively, were examined by using X-ray diffraction (XRD) and measuring the weight change of GDC pellet after cooling with fixed cooling rate to room temperature. Po 2 below which GDC decomposes was determined as a function of temperature for a fixed cooling rate (5°C/min). GDC pellets were stable at T≤1088°C regardless of Po 2 , and decomposed at T=1354°C in all tested Po 2 . A single-phase GDC without decomposition may be obtained at T=1180 or 1262°C with appropriate Po 2 . Both the degree of nonstoichiometry and the temperature are important factors to determine the stability of GDC pellet. To avoid cracking of GDC pellets due to chemical expansion during sintering in reducing atmosphere, GDC may be sintered at low T or high Po 2 or both, or it may be sintered to result in low porosity with small grain size for increased fracture strength.

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“…1500 °C for 10 h). As the driving force for the sintering process comes from the surface energy, this can be attributed to high surface area of nanocrystalline powders [40]. The shorter diffusion distance in the ultrafine powders also aids the sintering process.…”

Section: Microstructurementioning

confidence: 99%