Osman S M, Grosdidier B, Ali I, Abdellah A Ben
Physics Department, College of Science, Sultan Qaboos University, P.O. Box 36, Postal Code 123, Al-Khod, Muscat, Oman.
Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Jun;87(6):062103. doi: 10.1103/PhysRevE.87.062103. Epub 2013 Jun 3.
Quite recently, we reported a semianalytical equation of state (EOS) for the Ga-Pb alloy [Phys. Rev. B 78, 024205 (2008)], which was based on the first-order perturbation theory of fluid mixtures, within the simplified random phase approximation, in conjunction with the Grosdidier et al. model pair potentials for Ga-Ga and Pb-Pb with a suitable nonadditive pair potential between Ga-Pb unlike pairs. In the present work, we employ the present EOS to calculate the Ga-Pb phase diagram along the immiscibility gap region. The accuracy of the EOS is tested by consulting the empirical binodal curve. A statistical-mechanical-based theory for the surface tension is employed to obtain an analytical expression for the alloy surface tension. We calculated the surface tension along the bimodal curve and at extreme conditions of temperatures and pressures. The surface tension exhibits reasonably well the prewetting transition of Pb atoms at the surface of the Ga-rich liquid alloy and could qualitatively explain the prewetting phenomena occurring in the Ga-rich side of the phase diagram. The predicted prewetting line and wetting temperature qualitatively agree with the empirical measurements.
最近，我们报道了一种用于Ga-Pb合金的半解析状态方程（EOS）[《物理评论B》78, 024205 (2008)]，它基于流体混合物的一阶微扰理论，在简化随机相位近似下，结合Grosdidier等人的Ga-Ga和Pb-Pb模型对势以及Ga-Pb异类对之间合适的非加和对势。在本工作中，我们使用当前的EOS来计算沿不混溶间隙区域的Ga-Pb相图。通过参考经验双节线曲线来检验EOS的准确性。采用基于统计力学的表面张力理论来获得合金表面张力的解析表达式。我们计算了沿双节线曲线以及在温度和压力极端条件下的表面张力。表面张力合理地展现了富Ga液态合金表面Pb原子的预润湿转变，并且能够定性地解释在相图富Ga一侧发生的预润湿现象。预测的预润湿线和润湿温度与经验测量结果定性相符。
