Effect of alumina addition on the electrical and mechanical properties of Ce0.8Gd0.2O2−δ ceramics

Zhang, Tianshu; Zeng, Zhiqiang; Huang, Haitao; Hing, Peter; Kilner, John A.

doi:10.1016/s0167-577x(02)00717-6

Cited by 91 publications

(68 citation statements)

References 10 publications

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“…The fact that it has low mechanical strength at high temperatures limits the use of 8YSZ as a solid electrolyte. Due to excessive grain growth at high temperatures and long-term working conditions, the mechanical strength of the electrolyte material decreases, making the fuel cell unworkable [8].…”

Section: Introductionmentioning

confidence: 99%

Influence of Borosilicate Addition on Mechanical Properties and Sinterability of 8YSZ

Aktaş

2016

Acta Phys. Pol. A

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The influence of borosilicate (BS) addition on the mechanical properties and sinterability of yttria-stabilized zirconia (8YSZ) was investigated using scanning electron microscopy (SEM) and Vickers-hardness test. Undoped and 0.5-10 wt.% BS-doped 8YSZ powders were prepared using a colloidal process. The powders were then pelletized under a pressure of 200 MPa. The BS-doped 8YSZ specimens were sintered at 1200-1400• C for 1 h. SEM results showed that intergranular glass phases were formed at the grain boundaries of 8YSZ, particularly in the 5 and 10 wt.% BS-doped 8YSZ specimens. These intergranular glass phases caused a decrease in grain size of 8YSZ. The grain sizes of the undoped and 0.5 wt% BS-doped 8YSZ specimens were 2.68 µm and 1.83 µm, respectively. The addition of BS to 8YSZ caused a decrease in the relative density. In addition, the relative density was found to be increased with higher sintering temperature. The hardness of 8YSZ decreased with the increase in BS dopant amount, due to presence at the grain boundaries of a BS glassy phase that has a lower hardness than 8YSZ.

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Section: Introductionmentioning

confidence: 99%

Influence of Borosilicate Addition on Mechanical Properties and Sinterability of 8YSZ

Aktaş

2016

Acta Phys. Pol. A

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“…In these applications, not only high conductivity, but also better mechanical, chemical and electrical stability, is required [7]. ue to the need for a high operating temperature (1000 • C) in the SOFCs, a lower operating e ciency occurs at high operating temperatures [8]. In addition, the mechanical strength of 8YSZ also decreases with holding at high temperatures for a long time.…”

Section: Introductionmentioning

confidence: 99%

Influence on Static Grain Growth and Sinterability of BaO Addition into 8YSZ

2014

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In this study, 8 mol.% yttria stabilized cubic zirconia (8YSZ) powders as a matrix material and 0 15 wt% BaO powders as an additive were used in order to determine the e ect of BaO addition and amount on the microstructure, sintering and static grain growth properties of the 8YSZ. For these purposes, undoped and BaO-doped 8YSZ specimens were annealed for grain growth at 1400, 1500, and 1600 • C for 10, 50, and 100 h, respectively. An increase of annealing temperature and holding time resulted in grain growth in all specimens. The grain size of the 8YSZ decreased with the higher level of BaO added. A limited amount of BaO dissolved in 8YSZ, and insoluble BaO reacted with ZrO2 at high sintering temperature and generated the BaZrO3 second sphase compound. Energy dispersive X-ray spectroscopy results showed that the BaZrO3 second phase segregated at the surrounding grains and grain boundaries of the 8YSZ. These BaZrO3 second phases had a pinning e ect at the grain boundaries and prevented the migration of the grain boundaries of the 8YSZ. In conclusion, the grain growth results showed that the grain growth in the BaO-doped 8YSZ specimens was controlled by a solid solution drag mechanism.

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“…Impurities in the grain boundary region partly explain this effect. In the low/intermediate temperature range, resistive grain boundaries are responsible for high ohmic losses preventing better electrolyte performance [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Al 2 O 3 is recognized to be the most effective additive to promote the silica scavenging effect in YSZ. Segregation of SiO 2 impurities along the grain boundaries causes a deleterious effect on the total conductivity of CGO ceramics [7][8]. However, alumina additions to CGO ceramics showed a deleterious effect due to formation of another non-conductive phase, GdAlO 3 [7].…”

Section: Introductionmentioning

confidence: 99%

Efecto de eliminación de sílice en electrolitos sólidos basados en óxido de cerio

Ivanova¹,

Kovalevsky²,

Хартон³

et al. 2008

Bol. Soc. Esp. Ceram. Vidr.

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Composite materials based on gadolinium doped ceria (CGO) with additions of silica, with both silica and lanthanum oxide, and with lanthanum silicate, were prepared by the conventional ceramic route, to assess the silica scavenging role of lanthanum oxide additions. Structural, microstructural and electrical characterization of these samples confirmed the formation of one apatite type lanthanum silicate-based phase from reaction of silica with lanthanum oxide. The formation of this phase occurred in parallel with a significant enhancement of the grain boundary conductivity of these composite materials. Further interaction between constituents, involving diffusion of La to CGO, and Ce and Gd to the apatite phase, had no significant consequences on the electrical performance of these materials. Overall, lanthanum oxide was shown to remove the siliceous phases from the grain boundaries of CGO. Keywords: ceria, scavenging effect, silica, grain boundary Efecto de eliminación de sílice en electrolitos sólidos basados en óxido de cerio.Se prepararon materiales compuestos basados en óxido de cerio dopado con gadolinio (TGO) con adicciones de sílice, con sílice y óxido de lantano y silicato del lantano, mediante procesamiento cerámico convencional con objeto de confirmar el papel secuestrante de sílice de las adicciones. La caracterización estructural, microestructural y eléctrica de las muestras confirmó la formación de una fase tipo apatito basada en silicato de lantano a partir de la reacción de la sílice con el óxido de lantano. La formación de esta fase ocurre en paralelo con un incremento significativo de la conductividad a través del borde de grano de estos materiales. La interacción entre los constituyentes, incluyendo la difusión del La al CGO, y el Ce y el Gd a la fase apatito, no tiene consecuencias significativas sobre el comportamiento eléctrico de estos materiales. Resumiendo, el óxido de lantano es capaz de eliminar las fases silicias del borde de grano del CGO.

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Effect of alumina addition on the electrical and mechanical properties of Ce0.8Gd0.2O2−δ ceramics

Cited by 91 publications

References 10 publications

Influence of Borosilicate Addition on Mechanical Properties and Sinterability of 8YSZ

Influence of Borosilicate Addition on Mechanical Properties and Sinterability of 8YSZ

Influence on Static Grain Growth and Sinterability of BaO Addition into 8YSZ

Efecto de eliminación de sílice en electrolitos sólidos basados en óxido de cerio

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