ZrO2-Y2O3系固体電解質を用いた起電力法によるPb-Sn, Pb-Sb二元合金中の活量測定
1982 年 98 巻 1131 号 p. 429-435
詳細
1982 年 98 巻 1131 号 p. 429-435
The e. m. f., s of galvanicells with the solid-oxide electrolyte (ZrO2+Y2O3) were measured to determine the activities of components in the Pb-Sn, Pb-Sb alloys and PbO-Sb2O3 slags in equilibrium with Pb-Sb alloys at the low temperature range of 673-1073 K and the various thermodynamic values were also calculated.
The cell used were as follows:
(+) Pt, Ir/Pb.PbO/ZrO2+Y2O3/Sn. SnO2/Mo or Re, Fe-Cr (-)
(+) Pt, Ir/Pb. PbO/ZrO2+Y2O3/Sn-Pb. SnO2/Re, Fe-Cr (-)
(+) Pt, Ir/Pb. PbO/ZrO2+Y2O3/Pb-Sb. PbO-Sb2O3/Re, Fe-Cr (-)
From the present experiments, the following conclusions were obtained.
1) The standard free energy of formation of SnO2 was shown by ΔG°SnO2 (kJ/mol) =-569.6+0.2018T (k)±0.54 in the temperature range of 773-1165 K.
2) The activities of Sn in liquid Pb-Sn alloys at 823 and 1073 K showed a slight positive deviation from Raoult's law at low Sn concentrations and obeyed Raoult's law at high Sn concentrations. These results agreed very closely with the data by Das et al.
3) Several integral thermodynamic quantities of Pb-Sn alloys were calculated and compared with the selected values by Hultgren et al.
4) The activities of Pb and Sb in the Pb-Sb alloys at 893 K showed a slight negative deviations from Raoult's law. These results were in good agreement with other reliable data.
5) The activities of PbO and Sb2O3 in the PbO-Sb2O3 and PbO-SbO1.5 slags at 1023 K showed a considerable large negative deviations from Raoult's law.
6) The liquidus curves of Pb-Sb and PbO-Sb2O3 were determined and compared with those of other authors.
