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 language | English (US) |
---|---|
Pages (from-to) | D268-D275 |
Journal | Journal of the Electrochemical Society |
Volume | 166 |
Issue number | 8 |
DOIs | |
State | Published - 2019 |
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Electrochemistry
- Materials Chemistry