IV. Progress in experimental methods: Thermodynamic investigations in the Si‐Ge‐rich part of the ruthenium‐silicon‐germanium system

Abstract

This paper reports molar heat capacities of Ru50SixGe(50‐x) and Ru40SiyGe(60‐y) ternary solid solutions determined by differential scanning calorimetry. A second order transition has been characterised for alloys ranging from Ru40Ge60 to Ru40Si10Ge50 at temperatures ranging from 850 to 1040 K, respectively. Tie lines have been established at 1000‐900‐800‐700‐600°C by electron microprobe measurements on annealed alloys of the two phase domains: Ru50SixGe(50‐x)‐Ru40SiyGe(60‐y) and Ru40SiyGe(60‐y)‐Si zGe(100‐z).

Thermodynamic description of Ru–Ge–Si ternary system

“…Heat capacity of RuSi and Ru2Si3 was measured by Kuntz et al [8] and Perring et al [21] from 310 K to 1080 K. Meschel and Kleppa [22], and Topor and Kleppa [23] measured the enthalpy of formation of the compounds at 298 K with high temperature calorimetry and solute-solvent drop calorimetry, respectively, while Perring et al [19] measured the data at high temperature. Formation enthalpies of the ruthenium silicides are summarized in Table 1.…”

“…The isothermal section of the Ru-Ge-Si ternary system at 1173 K has been measured by Perring et al [21,28]. RuGe and RuSi, Ru2Ge3 and Ru2Si3 can form continuous solid solution, respectively.…”

“…By using presently optimized parameters of the Ru-Ge and Ru-Si systems along with the reported parameters of the Ge-Si system [27], and based on the ternary phase relations proposed by Perring et al [21,28], phase equilbria in the Ru-Ge-Si ternary system has been assessed. The calculated and experimental Ru-Ge-Si isothermal section at 1173 K is shown in Fig.…”