起電力法による溶融銅および銅-スズ合金中の酸素の定量

抄録

The concentration and activity of oxygen in molten copper and copper-tin alloy have been measured by the galvanic cells,
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over the temperature range of 1100°∼1250°C for the oxygen concentration range of 2∼1000 ppm and for the tin mole fraction of 0∼5.5×10⁻².
The activity of tin in molten copper-tin alloy has also been measured.
These measurements have shown that:
(1) The activity of oxygen in copper follows Henry’s law in the measured concentration range of oxygen and its activity coefficient is expressed by the equation,
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(2) The activity of oxygen in the copper alloy with a tin mole fraction of 7.0×10⁻⁴ follows Henry’s law in the measured concentration range of oxygen.
(3) The activities of oxygen in copper alloys with tin mole factions of 2.6×10⁻³, 5.3×10⁻³, 2.7×10⁻² and 5.5×10⁻² follow Henry’s law in the higher concentration range of oxygen but do not in the lower concentration ranges. And their activity coefficients decrease with decreasing oxygen concentration.
(4) The activity coefficient of oxygen in copper-tin alloys decreases with increasing tin concentration.
(5) The activity of tin in copper-tin alloys follows Henry’s law in the measured concentration range of tin and exhibits a large negative deviation from Raoult’s law.
Its activity coefficient can be written as logγ_Sn=−2.805×10³⁄T+0.6557
The solubility of oxygen in molten copper-tin alloys has also been discussed.