Defect structure and morphology of alkali niobate (Na0.5K 0.5)NbO3 powder calcined under low oxygen partial pressure

Keisuke Kobayashi; Hiroyuki Shimizu; Yutaka Doshida; Youichi Mizuno; Clive A. Randall

doi:10.7567/APEX.6.101502

Defect structure and morphology of alkali niobate (Na_0.5K _0.5)NbO₃ powder calcined under low oxygen partial pressure

Keisuke Kobayashi, Hiroyuki Shimizu, Yutaka Doshida, Youichi Mizuno, Clive A. Randall

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4 Scopus citations

Abstract

The effects of oxygen partial pressure (pO₂) in the calcination process of perovskite (Na_0.5K_0.5)NbO₃ (NKN) are investigated in terms of morphology and defect structure. Ceramic powders calcined in low-pO₂ atmospheres exhibit cubic-shaped particles with smaller mean diameter. The tail of the absorption edge in UV-visible diffuse reflectance spectra becomes smaller at low-pO₂ atmospheres in the calcination process, implying the suppression of alkali vacancies. The smaller powder size and lower concentration of alkali vacancies in low-pO ₂-calcined powder improves the sinterability, thereby leading to higher resistivity. Therefore, the low-pO₂ calcination is an essential process for NKN-based piezoelectrics.

Original language	English (US)
Article number	101502
Journal	Applied Physics Express
Volume	6
Issue number	10
DOIs	https://doi.org/10.7567/APEX.6.101502
State	Published - Oct 2013

All Science Journal Classification (ASJC) codes

General Engineering
General Physics and Astronomy

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title = "Defect structure and morphology of alkali niobate (Na0.5K 0.5)NbO3 powder calcined under low oxygen partial pressure",

abstract = "The effects of oxygen partial pressure (pO2) in the calcination process of perovskite (Na0.5K0.5)NbO3 (NKN) are investigated in terms of morphology and defect structure. Ceramic powders calcined in low-pO2 atmospheres exhibit cubic-shaped particles with smaller mean diameter. The tail of the absorption edge in UV-visible diffuse reflectance spectra becomes smaller at low-pO2 atmospheres in the calcination process, implying the suppression of alkali vacancies. The smaller powder size and lower concentration of alkali vacancies in low-pO 2-calcined powder improves the sinterability, thereby leading to higher resistivity. Therefore, the low-pO2 calcination is an essential process for NKN-based piezoelectrics.",

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T1 - Defect structure and morphology of alkali niobate (Na0.5K 0.5)NbO3 powder calcined under low oxygen partial pressure

AU - Kobayashi, Keisuke

AU - Shimizu, Hiroyuki

AU - Doshida, Yutaka

AU - Mizuno, Youichi

AU - Randall, Clive A.

PY - 2013/10

Y1 - 2013/10

N2 - The effects of oxygen partial pressure (pO2) in the calcination process of perovskite (Na0.5K0.5)NbO3 (NKN) are investigated in terms of morphology and defect structure. Ceramic powders calcined in low-pO2 atmospheres exhibit cubic-shaped particles with smaller mean diameter. The tail of the absorption edge in UV-visible diffuse reflectance spectra becomes smaller at low-pO2 atmospheres in the calcination process, implying the suppression of alkali vacancies. The smaller powder size and lower concentration of alkali vacancies in low-pO 2-calcined powder improves the sinterability, thereby leading to higher resistivity. Therefore, the low-pO2 calcination is an essential process for NKN-based piezoelectrics.

AB - The effects of oxygen partial pressure (pO2) in the calcination process of perovskite (Na0.5K0.5)NbO3 (NKN) are investigated in terms of morphology and defect structure. Ceramic powders calcined in low-pO2 atmospheres exhibit cubic-shaped particles with smaller mean diameter. The tail of the absorption edge in UV-visible diffuse reflectance spectra becomes smaller at low-pO2 atmospheres in the calcination process, implying the suppression of alkali vacancies. The smaller powder size and lower concentration of alkali vacancies in low-pO 2-calcined powder improves the sinterability, thereby leading to higher resistivity. Therefore, the low-pO2 calcination is an essential process for NKN-based piezoelectrics.

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Defect structure and morphology of alkali niobate (Na_0.5K _0.5)NbO₃ powder calcined under low oxygen partial pressure

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