Zensaku Kozuka

Activities of Oxygen in Liquid Lead and Antimony from Electrochemical Measurements

AbstractThe activities of oxygen in liquid lead and liquid antimony were measured for the temperature range of 1073 to 1323 and 973 to 1123 K, respectively, using the following electrochemical cell:

Activities of oxygen in liquid copper and silver from electrochemical measurements

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Activities of oxygen in liquid Bi, Sn, and Ge from electrochemical measurements

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Activities of oxygen in liquid thallium and indium from electrochemical measurements

}}{O} in liquid Pb or Sb/ZrO_2 ( + CaO)/Air,Pt.

Activity of oxygen in liquid In-Sb alloys

in liquid Pb or Sb/ZrO2(+CaO)/Air, Pt. After measuring the equilibrium emf, the liquid metal was deoxidized by imposing a preselected voltage on the electrodes. The fairly low oxygen concentration in liquid metal could be easily determined by a modified analysis of the quantity of electrical charge passing through the cell. The standard free energies of solution of oxygen in liquid lead and liquid antominy for the reaction of l/2 O2 → O (1 at. pct) were determined respectively to be: ΔG° (in Pb) = −28,300 + 3.38T (± 300) cal/g-atom = −118,600 + 14.1T (± 1300) J/g-atom, ΔG° (in Sb) = −32,880 + 5.20T (± 350) cal/g-atom = −137,600 + 21.8T (± 1500) j/g-atom, where the reference state for dissolved oxygen was an infinitely dilute solution.

Activities of oxygen in liquid Cu-Sb and Cu-Ge alloys

Abstract E.m.f. measurements of the following galvanic cells with the solid oxide electrolyte (ZrO 2 + CaO) were carried out to determine the standard molar Gibbs energies of formation of NiO, Cu 2 O, and CoO from solid and liquid metals and oxygen gas: (I) Pt|LaCrO 3 |Ni(s,1),NiO(s)|ZrO 2 +CaO|air|Pt, (II) Pt|LaCrO 3 |Cu(s,1),Cu 2 |ZrO 2 +CaO|air|Pt, (III) Pt|LaCrO 3 |Co(s,1),CoO(s)|ZrO 2 +CaO|air|Pt. The differences between the e.m.f.s of cells (I) and (II), and of cells (I) and (III) were compared with the e.m.f.s of the cells: (IV) Pt|Ni(s),NiO(s)|ZrO 2 +CaO|Cu(s,1),Cu 2 O(s,1)|LaCrO 3 Pt, (V) Pt|LaCrO 3 |Ni(s,1),NiO(s)|ZrO 2 +CaO|Co(s,1),CoO(s)|LaCrO 3 |Pt. The results were compared with previously reported values.

Solubility limit and thermodynamic properties of oxygen in liquid nickel

Modified coulometric titrations on the galvanic cell:O in liquid Cu or Ag / ZrO2( + CaO) / Air, Pt, were performed to determine precisely the oxygen activities in liquid copper and silver in the range of relatively low oxygen concentration. The present experimental results were remarkably reproducible in comparison with the published data. The standard Gibbs energies of solution of oxygen in liquid copper and liquid silver for 1/2 O2(l atm) → O(l at. pct) were determined respectively to be ΔG° (in Cu) = −18040 −0.03 T(K) (± 120) cal · g-atom−1 = −75500 −0.12 T(K)(± 500) J · g-atom−1, ΔG°(inAg)= -3860+ 1.56 T(K) (±90) cal · g-atom−1 = −16140 + 6.52 T(K)(±380) J · g-atom−1 where the reference state for dissolved oxygen was an infinitely dilute solution. The present value of the partial entropy of oxygen dissolved in liquid copper differs significantly from that suggested by many investigators. Further, the present equation for liquid copper has been found to be consistent with a correlation proposed previously by the present authors. The equation for liquid silver is in good agreement with the published ones.

The diffusivity of oxygen in liquid lead by electrochemical measurements

Modified coulometric titrations on the galvanic cell: O in liquid Bi, Sn or Ge/ZrO2( + CaO)/Air, Pt, were performed to determine the oxygen activities in liquid bismuth and tin at 973, 1073 and 1173 and in liquid germanium at 1233 and 1373 K. The standard Gibbs energy of solution of oxygen in liquid bismuth, tin and germanium for 1/2 O2 (1 atm) →O (1 at. pct) were determined respectively to be ΔG° (in Bi) = −24450 + 3.42T (±200), cal· g-atom−1 = − 102310 + 14.29T (±900), J·g-atom−1, ΔG° (in Sn) = −42140 + 4.90T (±350), cal· g-aton−1 = −176300 + 20.52T (± 1500), J-g-atom−1, ΔG° (inGe) = −42310 + 5.31 7 (±300), cal·g-atom−1 = −177020 + 22.21T(± 1300), J· g-atom−1, where the reference state for dissolved oxygen was an infinitely dilute solution. It was reconfirmed that the modified coulometric titration method proposed previously by two of the present authors produced far more reliable results than those reported by other investigators.