Problems of YBa2Cu3Ox formation and decomposition kinetics and mechanism

Šesták, Jaroslav; Koga, Nobuyoshi

doi:10.1016/0040-6031(92)85207-c

Cited by 23 publications

(1 citation statement)

References 52 publications

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“…Also their residual carbonate content varies strongly with synthesis temperatures [6,[9][10][11]. Sintering at different temperatures leads to the formation, at the critical invariant points, of various melt phases [12,13], some of which can wet grain boundaries [14]. The resulting samples have bimodal grain size distributions, inconsistent grain boundary quality and differing carbon contents [15,16].…”

Section: Introductionmentioning

confidence: 99%

The preparation of uniform grain size ceramics from sedimented single-crystalline powder fractions

Sargánková

Diko

Tweed

et al. 1996

Supercond. Sci. Technol.

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A sedimentation method has been used to separate YBa 2 Cu 3 O 7−x powder with a large particle size distribution into size fractions, each of different mean particle size and narrow size distribution. These powder fractions were then pressed and sintered into ceramic specimens having uniform grain shapes and narrow grain size distributions. This method of separating powder fractions raises the question of the surface degradation of the material during sedimentation. The possibility of regenerating the degraded surface by re-annealing is then significant. In this work we have studied this behaviour by XPS and a.c. susceptibility measurements. Characteristic XPS peaks for monitoring changes due to degradation and regeneration were found in the Y 3d (∼160 eV), O 1s (∼528 eV) and C 1s (∼285 eV) regions. Our results suggest that annealing below the sintering temperature can regenerate the particle surfaces.

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Section: Introductionmentioning

confidence: 99%

The preparation of uniform grain size ceramics from sedimented single-crystalline powder fractions

Sargánková

Diko

Tweed

et al. 1996

Supercond. Sci. Technol.

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Oxide Superconductors as Model Systems for Studying Phase Relations, Stoichiometry, Reaction Kinetics, and Unconventional Glass Formability

Komatsu

Šesták

2012

Hot Topics in Thermal Analysis and Calorimetry

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Thermoanalytical investigations on the sol-gel synthesis of YBa2Cu3O72212;δ

Varadaraju

Venkadesan

et al. 1997

Journal of Thermal Analysis

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The high temperature superconducting compound YBa2Cu3OT~ (Y-123) is synthesised by sol-gel process using various precursors viz., acetate, acetate-citrate, nitrate-citrate and acrylamide. The phase purity of the final product depends on the homogeneity of the gels which intern depends on the bonding of the metal ions in the gels. The samples prepared by acrylamide and nitrate-citrate gel routes yielded phase pure Y-123 compound with better superconducting properties. The mechanism of formation of Y-123 in all these four gel routes is established by characterising the gels and intermediate phases using TG, DTA and XRD techniques. Kinetic analysis is carried out on the mass loss data using the method proposed by Phadni's and Deshpande. Avrami-Erofeev nuclei growth in case of acrylamide, diffusion controlled process in nitrate-citrate and phase boundary reaction mechanisms in case of acetate-citrate gels are found to be responsible for the formation of Y-123 phase.

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Problems of YBa2Cu3Ox formation and decomposition kinetics and mechanism

Cited by 23 publications

References 52 publications

The preparation of uniform grain size ceramics from sedimented single-crystalline powder fractions

The preparation of uniform grain size ceramics from sedimented single-crystalline powder fractions

Oxide Superconductors as Model Systems for Studying Phase Relations, Stoichiometry, Reaction Kinetics, and Unconventional Glass Formability

Thermoanalytical investigations on the sol-gel synthesis of YBa2Cu3O72212;δ

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