Thermodynamic properties of Ba-Pb alloys determined by EMF measurements using binary CaF2-BaF2 electrolyte

Jarrod Gesualdi, Thomas P. Nigl, Timothy Lichtenstein, Nathan D. Smith, Hojong Kim

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Abstract

The thermodynamic properties of Ba-Pb alloys (activities, phase transitions, and partial molar quantities of Gibbs energy, entropy and enthalpy) were determined based on electromotive force (emf) measurements for thirteen mole fractions (xBa = 0.05–0.76) from 700–1060 K using an electrochemical cell: Ba(s) | CaF2-BaF2 | Ba(in Pb). The activity of Ba in liquid Pb was found to be as low as 2.0 × 10–10 at xBa = 0.05 and 973 K, reflecting a large excess partial molar Gibbs energy of –156 kJ mol–1 due to strong chemical interactions between Ba and Pb. Emf measurements were most reliable in the presence of a liquid phase, but were less reliable for high-melting compositions due to the formation of metastable phases during thermal cycling, confirmed by thermal and structural analyses using differential scanning calorimetry and X-ray diffraction. The experimentally-determined activity values of Ba-Pb alloys provide a new, reliable data set for further refinement in the assessment of thermodynamic properties for the Ba-Pb system.

Original languageEnglish (US)
Pages (from-to)D268-D275
JournalJournal of the Electrochemical Society
Volume166
Issue number8
DOIs
StatePublished - Jan 1 2019

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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