The effect of the sintering atmosphere on the electrical and chemical characteristics of grain boundaries in SrTiO3 ceramics prepared from semiconducting powders

Park, M.-B.; Cho, N.-H.

doi:10.1016/s0167-2738(02)00425-3

Cited by 6 publications

(3 citation statements)

References 9 publications

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“…The presence and importance of vacancy-type defects in SrTiO 3 has been inferred from electrical conductivity measurements as a function of thermal treatments, and the Sr/Ti ratio, analyzed using defect chemistry models. [10][11][12][13][14] Evidence has also been presented that vacancy defects can also control the grain boundary structure, and hence grain growth. 15 The SrTiO 3 structure is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Vacancy defect positron lifetimes in strontium titanate

et al. 2009

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The results of positron annihilation lifetime spectroscopy measurements on undoped, electron irradiated, and Nb doped SrTiO3 single crystals are reported. Perfect lattice and vacancy defect positron lifetimes were calculated using two different first-principles schemes. The Sr vacancy defect related positron lifetime was obtained from measurements on Nb doped, electron irradiated, and vacuum annealed samples. Undoped crystals showed a defect lifetime component dominated by trapping to Ti vacancy related defects.Comment: 31 pages 5 figures 2 Table

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Section: Introductionmentioning

confidence: 99%

Vacancy defect positron lifetimes in strontium titanate

et al. 2009

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“…29 Although this behaviour seems mainly driven by non-stoichiometry, several authors observed segregation during sintering and cooling of cationstoichiometric compounds as well. [30][31][32] This may be ascribed to formation of space-charge potentials in individual grains as function of differences in individual defect formation energies. 33 Whereas extrinsic acceptor dopants tend to segregate at grain boundaries already under oxidising conditions, donor dopants have recently also been found to show this behaviour when sintered under reducing atmospheres.…”

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confidence: 99%

Modified strontium titanates: from defect chemistry to SOFC anodes

et al. 2015

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Modified strontium titanates have received much attention recently for their potential as anode material in solid oxide fuel cells (SOFC). Their inherent redox stability and superior tolerance to sulphur poisoning and coking as compared to Ni based cermet anodes could improve durability of SOFC systems dramatically.Various substitution strategies can be deployed to optimise materials properties in these strontium titanates, such as electronic conductivity, electrocatalytic activity, chemical stability and sinterability, and thus mechanical strength. Substitution strategies not only cover choice and amount of substituent, but also perovskite defect chemistry, distinguishing between A-site deficiency (A 1Àx BO 3 ) and cationstoichiometry (ABO 3+d ). Literature suggests distinct differences in the materials properties between the latter two compositional approaches. After discussing the defect chemistry of modified strontium titanates, this paper reviews three different A-site deficient donor (La, Y, Nb) substituted strontium titanates for their electrical behaviour and fuel cell performance. Promising performances in both electrolyte as well as anode supported cell designs have been obtained, when using hydrogen as fuel.Performances are retained after numerous redox cycles. Long term stability in sulphur and carbon containing fuels still needs to be explored in greater detail.

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“…As for the mechanism of improved densification during sintering at 950°C under the reducing atmosphere, sintering under low oxygen partial pressure is believed to form an oxygen vacancy and subsequently forms Ti 3+ ions in the lattice, following the reactions, 13,14 …”

Section: Resultsmentioning

confidence: 99%

Effect of Oxygen Partial Pressure During Liquid‐Phase Sintering on the Dielectric Properties of 0.9MgTiO₃–0.1CaTiO₃

Shin

Bae

et al. 2007

Journal of the American Ceramic Society

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Microstructural evolution and microwave dielectric properties of liquid‐phase‐sintered 0.9MgTiO3–0.1CaTiO3 dielectric ceramic material have been investigated as a function of oxygen partial pressure () during sintering. Sintering in a weakly reducing atmosphere (=10−14 atm) generally increased the density, permittivity, quality factor (Q×f), and the temperature coefficient of resonance frequency (τf), but further reducing atmosphere down toof 10−14 atm generally decreased Q×f and τf. When the 5 wt% lithium borosilicate glass‐added specimen was sintered at 950°C and=10−14 atm, it demonstrated a permittivity of 18.8, Q×f of 19 000 GHz, and τf of 10 × 10−6 K−1.

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The effect of the sintering atmosphere on the electrical and chemical characteristics of grain boundaries in SrTiO3 ceramics prepared from semiconducting powders

Cited by 6 publications

References 9 publications

Vacancy defect positron lifetimes in strontium titanate

Vacancy defect positron lifetimes in strontium titanate

Modified strontium titanates: from defect chemistry to SOFC anodes

Effect of Oxygen Partial Pressure During Liquid‐Phase Sintering on the Dielectric Properties of 0.9MgTiO₃–0.1CaTiO₃

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The effect of the sintering atmosphere on the electrical and chemical characteristics of grain boundaries in SrTiO3 ceramics prepared from semiconducting powders

Cited by 6 publications

References 9 publications

Vacancy defect positron lifetimes in strontium titanate

Vacancy defect positron lifetimes in strontium titanate

Modified strontium titanates: from defect chemistry to SOFC anodes

Effect of Oxygen Partial Pressure During Liquid‐Phase Sintering on the Dielectric Properties of 0.9MgTiO3–0.1CaTiO3

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Product

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Effect of Oxygen Partial Pressure During Liquid‐Phase Sintering on the Dielectric Properties of 0.9MgTiO₃–0.1CaTiO₃