Journal of Mining and Metallurgy. Section B: Metallurgy (Jan 2020)

Experimental determination of activity interaction coefficients of components in Si-B-Fe and Si-B-Al ternary systems at 1723 K

  • Yang F.,
  • Zhou Y.-Q.,
  • Wu J.-J.,
  • Ma W.-H.,
  • Lei Y.

DOI
https://doi.org/10.2298/JMMB190731006Y
Journal volume & issue
Vol. 56, no. 2
pp. 153 – 160

Abstract

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The interactions among impurity components in Si-based solution are the important thermodynamic parameters for the purification of silicon materials. A “same concentration” method was used to determine the activity interaction coefficients of Fe to B and Al to B in the silicon solution. Fe and Al were respectively dissolved into the binary Si-B solution at 1723 K with the holding time of 5 h, 7 h, 9 h, and 11 h. The equilibrium concentrations of Fe, B in the Si-B-Fe system and Al, B in the Si-B-Al system were determined. The interaction coefficients of Fe to B and Al to B were obtained by fitting the solubility data of B, Fe, and Al. The solubility relationships between B and [%Fe], and between B and [%Al] were obtained, respectively. It was found by the SEM and EPMA pictures of the samples that the third component Fe or Al added to the binary Si-B solution was alloyed, which verifies the accuracy of the experimental determination results. The significance of the activity interaction coefficient of B on boron removal from industrial silicon was analyzed.

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