Thermodynamic properties of Cr 1 − xTe for x = 0.546 and 0.526

Abstract

The vapour pressures of tellurium over the alloy Cr 0.474Te 0.526 have been measured in the temperature range 1130 to 1217 K, and for chromium-rich alloys (Cr + Cr 1 − x Te, x = 0.546 and 0.526) in the temperature ranges 1055 to 1113 K and 1100 to 1260 K, respectively, using a Knudsen-effusion mass-loss technique. Using vapour pressures of tellurium over liquid tellurium, the change in chemical potential of Te in the alloy with respect to its standard state (Te, l) was calculated to be Δμ( Te in Cr 0.474Te 0.526, s , T)/( J · mol −1 ) ± 0.217 = −62412.5 + 7.52( T K ) . The molar Gibbs free energies of formation of Cr 0.454Te 0.546 (low-temperature phase: Cr 3Te 4) and Cr 0.474Te 0.526 (high-temperature phase: Cr 1 − x Te) were determined from the vapour pressure of tellurium over the chromium-rich alloys and can be represented by Δ f G m o(Cr 0.454Te 0.546, s , T)/( J · mol −1 ) ± 338 = −74978 + 41.04( T K ) and Δ f G m o(Cr 0.474Te 0.526, s , T)/( J · mol −1 ) ± 211 = −39755.4 + 6.79( T K ) , respectively. The change in chemical potential of Cr in the alloy (Cr 0.474Te 0.526) with respect to pure Cr(s) was calculated from the molar Gibbs free energy of formation of the alloy and the change in chemical potential of Te in the alloy with respect to pure Te(l).