Thermogravimetric and desorbed-gas analyses of perovskite-type Ba(Zn<i>_x</i>Nb₁₋<i>_x</i>)O<i>_y</i>(OH)<i>_z</i>

• SAITO Miwa

  Department of Materials and Life Chemistry, Faculty of Engineering, Kanagawa University

• ARAI Kenji

  Department of Materials and Life Chemistry, Faculty of Engineering, Kanagawa University

• UEKUSA Nami

  Department of Materials and Life Chemistry, Faculty of Engineering, Kanagawa University

• TOMINAGA Nozomi

  Department of Materials and Life Chemistry, Faculty of Engineering, Kanagawa University

• MOTOHASHI Teruki

  Department of Materials and Life Chemistry, Faculty of Engineering, Kanagawa University

抄録

Polycrystalline samples of perovskite-type Ba(Zn_xNb_1−x)O_3−δ with 0 ≤ δ ≤ 0.5 [δ = (3x − 1)/2; 1/3 ≤ x ≤ 2/3] were characterized by means of thermogravimetry (TG) combined with gas chromatography (GC). The TG-GC experiments on the Ba(Zn_xNb_1−x)O_3−δ samples revealed that these oxides are subject to water incorporation under humid atmospheres, and exhibit multiple steps of water desorption upon heating up to 873 K. The largely different desorption temperatures among these steps indicate a variety of water species being incorporated in different forms, such as physically/chemically adsorbed water molecules and hydroxide ions. For each sample, the number of hydroxide ions and thereby a nominal composition in an oxy-hydroxide form were quantitatively estimated. The total amount of the incorporated water species tends to increase as the oxygen deficiencies (δ) increase. The highly oxygen-deficient samples with δ = 0.4 and 0.5 were found to show significantly enhanced electrical conductivity at temperatures between 623 and 773 K in a humid atmosphere. The enhancement may be attributed to the additional contribution of proton conduction associated with the incorporated hydroxide ions.

収録刊行物

• Journal of the Ceramic Society of Japan

  Journal of the Ceramic Society of Japan 127 (11), 777-784, 2019-11-01

  公益社団法人 日本セラミックス協会

キーワード

• Oxygen-deficient perovskites
• Oxy-hydroxides
• Proton conduction

詳細情報

• CRID: 1390845702311077888
• NII論文ID: 130007740811
• DOI: 10.2109/jcersj2.19130
• ISSN: 13486535
• ISSN: 18820743
• Web Site: https://www.jstage.jst.go.jp/article/jcersj2/127/11/127_19130/_pdf
• 本文言語コード: en
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