Article ID Journal Published Year Pages File Type
9804004 Journal of Alloys and Compounds 2005 6 Pages PDF
Abstract
EMF measurements on silicon concentration cell were carried out using lithium silicate electrolyte in the temperature range 1300-1500 K. Using the EMF-temperature relations obtained, the standard free energies of formation for W5Si3 and WSi2 have been calculated as functions of temperature: ΔG0(W5Si3) (kJ mol−1) = −128.6 − 0.0132 (T (K)) ± 0.42 and ΔG0(WSi2) (kJ mol−1) = −98.5 + 0.0095 (T (K)) ± 0.15, respectively. Combining the results with thermodynamic data, the standard enthalpies of formation for silicides at 298 K have been obtained as ΔH0(W5Si3, 298) (kJ mol−1) = −133 ± 25 and ΔH0(WSi2, 298) (kJ mol−1) = −82 ± 6, respectively. A new eutectoid reaction W5Si3 ⇒ W + WSi2 occurring around 700 K is suggested in W-Si binary system.
Related Topics
Physical Sciences and Engineering Materials Science Metals and Alloys
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