Energetics of mixing and transport phenomena in Cd-X (X=Pb, Sn) melts

Abstract

We report a quasi-chemical study of the thermodynamic and transport properties of mixing of liquid Cd-Pb and Cd-Sn alloys at 773K. The interaction energy in the alloys is found to be positive which suggests homo-coordination of atoms in the alloys. The viscosities of the alloys at 773K computed from two different approaches exhibit non-linear concentration dependence with the results for Cd-Sn alloy being in very good agreement and satisfactory agreement for Cd-Pb alloy. In lower concentrations of Cd-component, Cd-Pb alloy has larger viscosity and on the other side of concentration, Cd-Sn alloy has larger value. The calculations of inter-diffusion coefficients result in concave diffusion isotherms for the alloys. The higher values of inter-diffusion coefficients for Cd-Sn suggest that Cd and Sn metals tend to mix more readily than Cd and Pb metals do in Cd-Pb alloy. The correlation between viscosity and diffusion implies that the inter-diffusion coefficient is large for low viscous liquid alloy and vice-versa.

Theoretical assessment on hetero-coordination of Alloys Silver-Antimony at Molten State

“…In the present work, one of the Silver alloys Ag-Sb is studied theoretically to determine certain properties at 1250 K assuming Ag x Sb y (x=3, y=1) complex in melt by using Quasi lattice model. Thermodynamic properties such as free energy of mixing, heat of mixing and entropy of mixing , chemical activity provide the knowledge on the interaction, stability and bonding strength among the constituent atoms whereas information on the structural ordering of atoms in binary alloys in the liquid state is provided by the quantitative analysis of microscopic functions, the concentration fluctuations in the long wavelength limit (Scc(0)), short-range order parameter (α1)and diffusivity(D M /D id ) Jha et al, 2015;Koirala et al, 2018). Scc(0) represents the nature of ordering of the atoms ,α1 quantifies the degree of ordering and diffusion coefficient ratio (D M /D id ) gives the structural behaviour of the alloy .…”