Current-ramp assisted sintering of 3YSZ: Electrochemical and microstructural comparison to flash and thermal sintering

Kent Harrison Christian, Harry Charalambous, Shikhar Krishn Jha, Thomas Tsakalakos

Research output: Contribution to journalArticle

Abstract

Flash sintering features an unoptimized and uncontrolled rise in current density and sample conductivity. By using a controlled current-ramp technique with a predetermined ramp function, microstructure and electrochemical properties can be improved. This current-ramp method is investigated through use of test functions that follow square-root, linear, and parabolic time dependence with comparison to conventional flash sintering and thermal sintering. Steeper ramp functions during the sintering result in higher activation energy, suggesting a change in the vacancy concentration for both the bulk and grain boundary regions. Estimation of the grain boundary domain width suggests a grain size dependence of the unique space charge contribution to conduction independent of sintering method. Contrary to conventional wisdom, flash sintering can actually result in enhanced grain growth compared to controlled current-ramps and conventional sintering, implying that uncontrolled rise in current to a set cutoff may not be the optimal method for densification.

Original languageEnglish (US)
Pages (from-to)436-443
Number of pages8
JournalJournal of the European Ceramic Society
Volume40
Issue number2
DOIs
StatePublished - Feb 2020

Fingerprint

Yttrium oxide
Yttria stabilized zirconia
Grain growth
Zirconia
Grain boundaries
Sintering
Activation energy
Hot Temperature
zirconium oxide
yttria
Electrochemical properties
Densification
Electric space charge
Vacancies
Current density
Microstructure

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

Keywords

  • Current assisted sintering
  • Flash sintering
  • Impedance spectroscopy
  • Space charge layer
  • Yttria-stabilized zirconia

Cite this

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title = "Current-ramp assisted sintering of 3YSZ: Electrochemical and microstructural comparison to flash and thermal sintering",
abstract = "Flash sintering features an unoptimized and uncontrolled rise in current density and sample conductivity. By using a controlled current-ramp technique with a predetermined ramp function, microstructure and electrochemical properties can be improved. This current-ramp method is investigated through use of test functions that follow square-root, linear, and parabolic time dependence with comparison to conventional flash sintering and thermal sintering. Steeper ramp functions during the sintering result in higher activation energy, suggesting a change in the vacancy concentration for both the bulk and grain boundary regions. Estimation of the grain boundary domain width suggests a grain size dependence of the unique space charge contribution to conduction independent of sintering method. Contrary to conventional wisdom, flash sintering can actually result in enhanced grain growth compared to controlled current-ramps and conventional sintering, implying that uncontrolled rise in current to a set cutoff may not be the optimal method for densification.",
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Current-ramp assisted sintering of 3YSZ : Electrochemical and microstructural comparison to flash and thermal sintering. / Christian, Kent Harrison; Charalambous, Harry; Jha, Shikhar Krishn; Tsakalakos, Thomas.

In: Journal of the European Ceramic Society, Vol. 40, No. 2, 02.2020, p. 436-443.

Research output: Contribution to journalArticle

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