Thermodynamic properties of Barium-Bismuth alloys determined by emf measurements

Timothy Lichtenstein, Nathan D. Smith, Jarrod Gesualdi, Kuldeep Kumar, Hojong Kim

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Thermodynamic properties of Ba-Bi alloys, including the activity, partial molar entropy and enthalpy, were determined using the electromotive force (emf) technique for fourteen compositions, xBa = 0.05–0.80. Emf measurements were performed at ambient pressure using a Ba(s)|CaF2-BaF2|Ba(in Bi) or Ba-Bi(xBa = 0.05)|CaF2-BaF2|Ba(in Bi) electrochemical cells at 723–1073 K. At 773 K, activity values of Ba were as low as 6.6 × 10−16 at mole fraction xBa = 0.05 and approached unity for mole fractions xBa ≥ 0.80. Stable emf values were observed at mole fractions xBa = 0.05–0.25, exhibiting less than a 5 mV difference between the heating and cooling cycles. Mole fractions xBa ≥ 0.30 exhibited increased hysteresis or had an unexpected emf profile due to the formation of metastable phases such as Bi and Ba5Bi3, confirmed by X-ray diffraction. The Ba-Bi alloys were further characterized using differential scanning calorimetry over the entire composition range. Based on these data, a revised Ba-Bi binary phase diagram is proposed.

Original languageEnglish (US)
Pages (from-to)628-635
Number of pages8
JournalElectrochimica Acta
Volume228
DOIs
StatePublished - Feb 20 2017

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Electrochemistry

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