title: Liquid gallium-lead mixture phase diagram, surface tension near the critical mixing point, and prewetting transition.
abstract: 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.
authors.affiliation: Physics Department, College of Science, Sultan Qaboos University, P.O. Box 36, Postal Code 123, Al-Khod, Muscat, Oman. osm@squ.edu.om
authors.forename: S M
authors.initials: SM
authors.lastname: Osman
authors.forename: B
authors.initials: B
authors.lastname: Grosdidier
authors.forename: I
authors.initials: I
authors.lastname: Ali
authors.forename: A Ben
authors.initials: AB
authors.lastname: Abdellah
mesh_terms: D045424:Complex Mixtures / Q000737:chemistry; D003198:Computer Simulation; D005708:Gallium / Q000737:chemistry*; D007854:Lead / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D044367:Phase Transition; D012996:Solutions / Q000737:chemistry; D013500:Surface Tension; D017155:Wettability
chemical_list: D045424:Complex Mixtures; D012996:Solutions; D007854:Lead; D005708:Gallium