Enthalpies of formation for boron silicides

Analyzing the phase composition of Si-B and Si-B-Ti alloys based on silicon

“…On the other hand, our analysis shows that the shift of the boron solubility lines toward lower concentrations at temperatures above 1400 K leads to a considerable reduction in the eutectic transformation temperature. Our enthalpy value for the formation of silicon boride SiB 3 is closer to the data in [21].…”

“…The enthalpy values given for the formation of the considered phase in [21] (-90.8 kJ/mol) and in [22] (-26.99 kJ/mol) differ by more than a factor of 3. High temperature mass spectrometry was used in [21]; in [22], the Δ f H(SiB 3 ) value was calculated from the values for the density and melt temperature, and from the available structural data.…”

“…High temperature mass spectrometry was used in [21]; in [22], the Δ f H(SiB 3 ) value was calculated from the values for the density and melt temperature, and from the available structural data. Moreover, the struc tural type of the compound was identified as SiB 4 in both works.…”

Thermodynamic assessment of the B–C–Si system

“…Phase name ity of B 3 Si determined by Bolgar et al [29] and Gordienko [27], the enthalpy of formation of B 3 Si is f H 0 (298.15) = −86.6 kJ/mol, coincided with the value determined by Gordienko [27]. Considering those results, the value of formation enthalpy of B 3 Si estimated by Chubinidze et al [28] is considered to be not reasonable and therefore being excluded from this work.…”

“…The enthalpies of formation ( f H 0 (298.15 K)) and Gibbs energy of formation ( f G) for the boron silicides show good agreement with each other, except for the enthalpy of B 3 Si phase. The enthalpy of formation of B 3 Si determined by Gordienko [27] (to be −90.8 kJ/mol) and Chubinidze et al [28] (to be −26.99 kJ/mol) differs by more than a factor of three. The difference was contributed to the fact that the value of f H 0 (298.15 K) determined by Chubinidze et al [28] was estimated by the comparison using CaSi 2 as the reference point:…”