Combined Use of Oxide and Fluoride Solid Electrolytes for the Measurement of Gibbs Energy of Formation of Ternary Oxides: System Bi–Ca–O

• Jacob K. T.

  Department of Metallurgy and Materials Research Centre, Indian Institute of Science

• Jayadevan K. P.

  Department of Metallurgy and Materials Research Centre, Indian Institute of Science

書誌事項

タイトル別名

• Combined Use of Oxide and Fluoride Solid Electrolytes for the Measurement of Gibbs Energy of Formation of Ternary Oxides: System Bi–Ca–O
• Combined Use of Oxide and Fluoride Soli

抄録

Phase equilibrium studies of the ternary system Bi–Ca–O at 1000 K and ambient pressure indicate that all the ternary oxides lie along the pseudo-binary line Bi₂O₃–CaO. Four ternary oxides, Bi₂Ca₂O₅, Bi₆Ca₄O₁₃, Bi₂CaO₄ and Bi₁₄Ca₅O₂₆ and two phases of variable composition (δ and β) are identified. The chemical potential of CaO in two-phase fields of the pseudo-binary Bi₂O₃–CaO is determined as a function of temperature using solid state cells based on single crystal CaF₂ as the electrolyte. The chemical potential of Bi₂O₃ in the two-phase fields is measured using cells incorporating (Y₂O₃)ZrO₂ as the solid electrolyte. The standard Gibbs free energy of formation of each ternary oxide from the binary oxides is calculated independently from the chemical potentials of CaO and Bi₂O₃ in two-phase fields on either side of the compound composition. The independent assessments agree closely; the maximum difference in the value of ΔG_f⁰(Bi_2mCa_nO_3m+n)/(m+n) is 170 J/mol of the component binary oxides. The results are discussed in the light of the phase diagram and compared with calorimetric and free energy measurements reported in the literature. The combined use of emf data from cells incorporating fluoride and oxide electrolytes enhances the reliability of derived data. Free energies of formation of ternary oxides from component binary oxides are given by the following equations:<BR>Bi₂Ca₂O₅: ΔG⁰_f,ox(J/mol)=−43800+5.79T(±900)<BR>Bi₆Ca₄O₁₃: ΔG⁰_f,ox(J/mol)=−109800+7.04T(±2300)<BR>Bi₂CaO₄: ΔG⁰_f,ox(J/mol)=−31910+2.31T(±650)<BR>Bi₁₄Ca₅O₂₆: ΔG⁰_f,ox(J/mol)=−184560+12.76T(±4320)<BR>Bi_1.4Ca_0.3O_2.4 (β): ΔG⁰_f,ox(J/mol)=−12290(±300) at 900 K<BR>Bi_1.56Ca_0.22O_2.56 (β): ΔG⁰_f,ox(J/mol)=−9890(±180) at 900 K

収録刊行物

• Materials Transactions, JIM

  Materials Transactions, JIM 38 (5), 427-436, 1997

  社団法人 日本金属学会

キーワード

• phase diagram
• thermodynamics
• entropy
• enthalpy
• gibbs free energy
• interoxide compounds

詳細情報

• CRID: 1390001204245501184
• NII論文ID: 10002452568
• NII書誌ID: AA10699969
• DOI: 10.2320/matertrans1989.38.427
• COI: 1:CAS:528:DyaK2sXkt1aqsLc%3D
• ISSN: 2432471X
• ISSN: 09161821
• NDL書誌ID: 4231131
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4231131
• Web Site: https://www.jstage.jst.go.jp/article/matertrans1989/38/5/38_5_427/_pdf
• 本文言語コード: en
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可