Thermodynamic activities in silicon binary melts

Abstract

The thermodynamic activities in the silicon binary melts with Al, Ca, Mg, Fe, Ti, Zn, Cu, Ag, Au, Sn, Pb, Bi, Sb, Ga, In, Pt, Ni, Mn and Rh are studied. The silicon activities along the liquidus are calculated through a quasi-regular solution model using the recently determined liquidus constants for the silicon binary systems. The silicon activities at its melting point are calculated considering regular solution approximation. The activities of the other melt component at the silicon melting point are also calculated through the graphical integration of the GibbsDuhem equation for the activity coefficient, which are further utilized to determine the corresponding activities along the liquidus. The calculated activities are presented graphically, and it is indicated that the results are consistent with the reported activity data in the literature. The activities in the dilute solutions are also calculated graphically. Moreover, the activities of particular dilute solute elements in silicon are calculated through a simple formula, which is a function of the liquidus constants.

Thermochemical Aspects of Boron and Phosphorus Distribution Between Silicon and BaO-SiO2 and CaO-BaO-SiO2 lags

“…Therefore, we may conclude that the reason for the mass transport of Ba and Ca through chemical reactions (3) and (4) is the large negative standard deviation of silicon rich Si-Ba and Si-Ca melts from the ideal solution, or in other word a driving force existence for the reactions. The previously determined activity coefficient for the dilute solutions of Ca in silicon as 0.0032 [21] at the silicon melting point at 1687 K (1414 • C) supports this explanation. In order to calculate the thermodynamic activity of Ba in liquid silicon the results of experiments 1 to 8 can be used.…”

“…13 for typical conditions. The calculations here yield the following expressions for the activity coefficient of B 2 O 3 in specific BaO-SiO 2 slags at different temperatures: 20) lnγ B2O3 (at 1873 K) = 2×10 −9 +1.39X B2O3 +0.62X 2 B2O3 (21) For the above expressions L B =1 was considered, which is a fair approximation ( Fig. 6) and the calculations for the experimental points are well correlated in Fig.…”

Application of molecular interaction volume model on removing impurity aluminum from metallurgical grade silicon by vacuum volatilization

“…The activity coefficients of Al in molten silicon at infinite dilution relative to the pure liquid state at 1723e1848 K were determined by Miki et al [4] using a chemical equilibration technique. The activity coefficient of the SieAl dilute solution at 1687 K was calculated by Safarian et al [5] based on the quasi-regular solution model. Desal [19] acquired the infinite dilution activity coefficient of Al in the molten silicon at 1700 K. Our calculated infinite dilution activity coefficients of Al in molten silicon by MIVM are compared with the above experimental results [4,5,19] as shown in Fig.…”

“…The evaluation of thermodynamic properties of aluminum in silicon had been performed by Miki et al [4] using a chemical equilibration technique. Safarian et al [5] acquired the activity coefficients of the SieMe dilute solutions at 1687 K through a quasi-regular solution model and applied the results to develop the behavior of the impurities in silicon in vacuum refining process. Matsumiya [6] predicted the activity coefficients of the impurity components in the infinite dilute silicon solution by the use of first-principle calculation based on the density functional theory.…”

Thermodynamic properties of iron, aluminum, boron and phosphorus in dilute silicon solutions by molecular interaction volume model

“…Therefore, a unique economic and effective method to estimate the thermodynamic parameters of silicon solutions depending on less experimental data by a computational module is required. Safarian et al [8] . .…”