Conductivity Measurements of CaF<SUB>2</SUB> Crystal under Controlled Fluorine Chemical Potentials

• Ono Katsutoshi

  Department of Metallurgy, Faculty of Engineering, Kyoto University

• Fujimura Toshio

  Graduate School, Kyoto University

• Moriyama Joichiro

  Department of Metallurgy, Faculty of Engineering, Kyoto University

抄録

The limit on the use of CaF₂ in galvanic cells for thermodynamic measurements under reducing conditions has been studied by determining the a.c. conductivity from 880 to 1120 K with fluorine chemical potentials ranging from Co–CoF₂ to Ca–CaF₂ coexistence. The conductivity of CaF₂ single crystal was determined by an a.c. bridge measurement-complex impedance plot combination method. Fluorine activities were established by using a metal-metal fluoride electrode.<BR>The data showed that the conductivity values for the Mg–MgF₂, Al–AlF₃, Mn–MnF₂ and Co–CoF₂ electrodes were scattered more or less randomly and the conductivity values for the Ca–CaF₂ electrode which is the stability limit of CaF₂ were evidently higher than the values obtained for the other electrodes. It has been shown that the isothermal logσ vs logp_F<SUB>2</SUB> plot remains flat all the way down to the Mg–MgF₂ electrode. This is indicative of an ionic conductivity which is independent of p_F<SUB>2</SUB>, and the rise in conductivity for the Ca–CaF₂ electrode would be due to partial electronic conduction.

収録刊行物

• Transactions of the Japan Institute of Metals

  Transactions of the Japan Institute of Metals 20 (9), 543-549, 1979

  社団法人 日本金属学会

キーワード

• General Engineering

詳細情報

• CRID: 1390001205117609216
• NII論文ID: 130003485779
• DOI: 10.2320/matertrans1960.20.543
• COI: 1:CAS:528:DyaL3cXhtVaks7k%3D
• ISSN: 24324701
• ISSN: 00214434
• Web Site: https://www.jstage.jst.go.jp/article/matertrans1960/20/9/20_9_543/_pdf
• 本文言語コード: en
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