A mass spectrometer has been used to study activities of the constituents in liquid Cu-Mg and Cu-Ca alloys. Activities and heats of mixing have been determined from a series of measurements of the ratios of the ion current intensity of the solution components according to the Belton-Fruehan treatment. The activities in both systems exhibit negative deviation from ideality and tend to approach an ideal behavior at higher temperatures. The terms of RT ln γCu and RT ln γMg show very small temperature dependence within the present experimental range and agree well with the values reported by Garg et al. for the Cu-Mg system. The terms of RT ln γCa and RT ln γCu are independent of temperature and in excellent agreement with the values assessed by Risold et al. for the Cu-Ca system. Relative partial molar enthalpy and integral heat of mixing in the liquid Cu-Mg and Cu-Ca systems were also estimated.
|Number of pages||9|
|Journal||Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science|
|Publication status||Published - 2000|