溶融金2元合金系におけるスズの活量
1977 年 41 巻 9 号 p. 950-955
詳細
1977 年 41 巻 9 号 p. 950-955
Activities of tin in liquid gold-tin alloys have been determined for NSn=0.17∼0.90, over the temperature range of 944∼1256 K, by the following E.M.F. method:
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The activities of both components for the Au-Sn system demonstrate a considerable negative deviation from Raoult’s law over the whole concentration range.
In the alloys with NSn=0.30∼0.80, there are remarkable variations in partial enthalpy and entropy of tin with temperature, as discussed with reference to previous investigations. The reason for this is considered to be due to the ordered structure of the alloy which persists above the liquidus temperature.
These strongly temperature dependent anomalies are explained by the existence of AuSn, AuSn2, AuSn4-compound clusters in the melt.
With increasing temperature the clusters dissociate and the anomalies disappear. The effects of compound cluster formation in liquid alloys on thermodynamic properties are discussed.
In addition, other thermodynamic functions are calculated on the basis of the results obtained.
