Shinya Yao

Activity coefficient of oxygen in copper-tellurium melts

Activity coefficient of oxygen, γo, in copper-tellurium melts was determined at 1423 K utilizing a modified coulometric titration technique with the following electrochemical cell: O in Cu-Te melts/ZrO2(+CaO)/air, Pt. The γo values in the vicinity ofNTe = 0.30 are much smaller than those in the tellurium-dilute copper-tellurium melts, and increase rapidly with the tellurium composition. The shape of the In γovs solvent composition curve is quite similar to that in Cu-S and Tl-Te melts. This type of compositional dependence can be successfully described by a proposed solution model.

The activity coefficients of oxygen in liquid (germanium + bismuth), (germanium + lead), and (germanium + indium) alloys

The activity coefficients γo of oxygen in {(1−x)Ge xPb}(1), and (0.50Ge + 0.50In)(1) have been measured at 1233 K utilizing a modified coulometric-titration method with the electrochemical cell: Re or W/O in {(1−x)Ge+x(Bi or Pb or In)}(1)|ZrO2+CaO|air|Pt . The measured values of ln γo in {(1−x)Ge+xBi}(1) and {(1−x)Ge+xPb}(1) exhibit a large negative deviation from additivity, while the experimental value of ln γo in (0.50Ge + 0.50In)(1) is close to the additive line.

Thermodynamic study of oxygen in liquid InPb and InTl alloys

Abstract The activity coefficients γ o of oxygen in liquid InPb and InTl alloys at 1073 and 1273 K have been measured over the entire composition range utilizing a modified coulometric titration method with the electrochemical cell Re, O in liquid InPb or InTl alloys ¦ZrO 2 (+CaO)¦air, Pt. The molar enthalpy change ΔH o ° and the molar entropy change ΔS o ° of oxygen dissolution for 1 2 O 2 (101 325 Pa) → O(1 mol.%) were evaluated from the results. The In γ o , ΔH o ° and ΔS o ° values exhibit a large negative deviation from the line corresponding to the additive equation.

The activity coefficients of oxygen in Ni-S and Co-S melts

Activity coefficients of oxygen,γo, in nickel-sulfur melts and cobalt-sulfur melts were determined at 1423 K utilizing a modified coulometric titration technique with the following electrochemical cell: O in Ni-S or Co-S melt/ZrO2(+CaO)/air, Pt. Theγo values around NNI=0.26 and NCO=0.35 are much smaller than those in the hypothetically undercooled liquid nickel and cobalt, respectively, at 1423 K, which were evaluated by extrapolating the literature values at higher temperatures. Theγo values in the nickel-sulfur and cobalt-sulfur melts are rapidly increased with increasing the sulfur compositions. The shapes of the Inγo vs solvent composition curves are quite similar to those in Cu-S, Cu-Te, and Tl-Te melts. The present results are discussed in terms of several solution models.