Abstract

The structural, vibrational, densification, and microwave properties of Ba(Co1/3Nb2/3)O3 ceramics with small compositional variations along several tie lines in the ternary BaO–CoO–Nb2O5 diagram were studied. The results showed that very small deviation from stoichiometric Ba(Co1/3Nb2/3)O3 composition has profound effect on Q × f, degree of ordering, densification, and phase assemblage. The 0.94 Ba(Co1/3Nb2/3)O3–0.06 Ba5Nb4O15 ceramic has the highest Q × f value (71 THz) – a value two times larger than that of stoichiometric Ba(Co1/3Nb2/3)O3 (36 THz). Transformation from the (partial) disordered distribution of Co and Nb cations to 1:2 ordered arrangement in the octahedral sites was found to increase the Q factor of the high density and single phase ceramics. It was also observed that formation of very small amount of Ba9CoNb14O45 second phase degraded Q × f value severely for the dense and highly ordered Nb-rich and Ba-deficient ceramics.

Original languageEnglish (US)
Pages (from-to)3335-3346
Number of pages12
JournalJournal of the European Ceramic Society
Volume37
Issue number10
DOIs
StatePublished - Aug 1 2017

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Dielectric losses
Densification
Crystal structure
Microstructure
Cations
Positive ions
Microwaves
Chemical analysis

Keywords

  • Cation ordering
  • Dielectric loss
  • Microstructure
  • Point defects
  • Sintering

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

Cite this

Effect of non-stoichiometry on the densification, phase purity, microstructure, crystal structure, and dielectric loss of Ba(Co1/3Nb2/3)O3 ceramics. / Sayyadi-Shahraki, Ahmad; Taheri-Nassaj, Ehsan; Gonzales, Justin; Newman, Nathan; Kolodiazhnyi, Taras.

In: Journal of the European Ceramic Society, Vol. 37, No. 10, 01.08.2017, p. 3335-3346.

Research output: Contribution to journalArticle

Sayyadi-Shahraki, Ahmad ; Taheri-Nassaj, Ehsan ; Gonzales, Justin ; Newman, Nathan ; Kolodiazhnyi, Taras. / Effect of non-stoichiometry on the densification, phase purity, microstructure, crystal structure, and dielectric loss of Ba(Co1/3Nb2/3)O3 ceramics. In: Journal of the European Ceramic Society. 2017 ; Vol. 37, No. 10. pp. 3335-3346.
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abstract = "The structural, vibrational, densification, and microwave properties of Ba(Co1/3Nb2/3)O3 ceramics with small compositional variations along several tie lines in the ternary BaO–CoO–Nb2O5 diagram were studied. The results showed that very small deviation from stoichiometric Ba(Co1/3Nb2/3)O3 composition has profound effect on Q × f, degree of ordering, densification, and phase assemblage. The 0.94 Ba(Co1/3Nb2/3)O3–0.06 Ba5Nb4O15 ceramic has the highest Q × f value (71 THz) – a value two times larger than that of stoichiometric Ba(Co1/3Nb2/3)O3 (36 THz). Transformation from the (partial) disordered distribution of Co and Nb cations to 1:2 ordered arrangement in the octahedral sites was found to increase the Q factor of the high density and single phase ceramics. It was also observed that formation of very small amount of Ba9CoNb14O45 second phase degraded Q × f value severely for the dense and highly ordered Nb-rich and Ba-deficient ceramics.",
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AU - Taheri-Nassaj, Ehsan

AU - Gonzales, Justin

AU - Newman, Nathan

AU - Kolodiazhnyi, Taras

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AB - The structural, vibrational, densification, and microwave properties of Ba(Co1/3Nb2/3)O3 ceramics with small compositional variations along several tie lines in the ternary BaO–CoO–Nb2O5 diagram were studied. The results showed that very small deviation from stoichiometric Ba(Co1/3Nb2/3)O3 composition has profound effect on Q × f, degree of ordering, densification, and phase assemblage. The 0.94 Ba(Co1/3Nb2/3)O3–0.06 Ba5Nb4O15 ceramic has the highest Q × f value (71 THz) – a value two times larger than that of stoichiometric Ba(Co1/3Nb2/3)O3 (36 THz). Transformation from the (partial) disordered distribution of Co and Nb cations to 1:2 ordered arrangement in the octahedral sites was found to increase the Q factor of the high density and single phase ceramics. It was also observed that formation of very small amount of Ba9CoNb14O45 second phase degraded Q × f value severely for the dense and highly ordered Nb-rich and Ba-deficient ceramics.

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