Enthalpy of mixing of liquid Co–Sn alloys

Abstract

HighlightsThe enthalpies of mixing of liquid Co–Sn alloys between T = (673 and 1773) K.The temperature dependence of the enthalpies of mixing was described.Full report of measured values including polynomial coefficients.

Structural studies of liquid Co–Sn alloys

“…Such structure anomalies bring to deviations of the structure sensitive properties from the ideal behavior: the concentration dependence of the activation energy of viscous flow of liquid Co–Sn alloys is similar to the liquidus curve of the phase diagram and shows an unexpected increase near the eutectic concentration [17]; the surface tension data versus concentration have a negative deviation from the Raul’s law at 1823 K [18]. Besides, the enthalpy of mixing shows the temperature dependence with more negative values at lower temperatures [19]. On the other hand, there is some disagreement in the analysis of the experimental data.…”

Enthalpies of mixing of liquid ternary Co–Li–Sn alloys

“…% are liquid at the investigated temperature [ 43 ]; taking this into account, Co 0.02 Sn 0.98 , Co 0.10 Sn 0.90 , and Co 0.15 Sn 0.85 were taken as the starting alloys for the present investigations. The starting values of for the binary Li–Sn and Co–Sn subsystems required for the evaluation of the integral molar enthalpy of mixing for ternary liquid Co–Li–Sn alloys were directly taken from recent investigations [ 32 , 36 ].…”

“…For a mathematical description of the composition dependence of the integral molar enthalpy of mixing of liquid Co–Li–Sn alloys, the experimental data were subjected to a least-squares fit based on a Redlich–Kister–Muggianu polynomial [ 16 , 17 ]: where i , j , k are equal to 1, 2, 3 for the elements Co, Li, and Sn, respectively; are the interaction parameters of the three binary systems; are three ternary interaction parameters; x i , x j , x k are the mole fractions of ternary alloys. For this evaluation, it is necessary to know the interaction parameters of the binary subsystems which are available in literature for the systems Li–Sn and Co–Sn [ 32 , 36 ].…”

“…However, the reported values of the molar enthalpy of mixing as well as their temperature dependence are highly contradictory. The most recent experimental determination of the mixing enthalpies of liquid Co–Sn alloys between 673 and 1,773 K was performed by Yakymovych et al [ 32 ]. These authors found a significant temperature dependence of the integral molar mixing enthalpy.…”

Enthalpy Effect of Adding Cobalt to Liquid Sn-3.8Ag-0.7Cu Lead-Free Solder Alloy: Difference between Bulk and Nanosized Cobalt

“…Although both molar volume and surface energy are T -dependent quantities, the total value of Δ H i,nano ex (as it is at the dropping temperature) is lost due to the elimination of the surface of the nanoparticles upon their dissolution in the liquid alloy, and therefore, the measured nanoheat-effect is not T -dependent. The temperature dependence of the enthalpy term of the surface energy is written as 28 where σ sg, H ,0 K (J·m –2 ) is the surface energy at T = 0 K, α is the ratio of broken bonds on the surface of the solid metal, C p (J·mol –1 K –1 ) is the heat capacity of the bulk solid metal, f is the geometric coefficient being a function of bulk and surface packing fractions, 28 N Av = 6.02 · 10 23 mol –1 is the Avogadro number. For solid cobalt, the following approximated value follows from eq 8 at T D = 298 K using the data of Mezey and Giber 29 for the surface structure and for σ sg,0 K , the thermodynamic data of the JANAF table 30 and the volumetric data of Touloukian et al: 31 σ sg, H , T D ≅ (2.80 ± 0.15) J·m –2 .…”