Abstract
The experimental phase equilibria of the Ge-Ru system was first determined by Raub and Fritzsche [1] who reported the existence of two intermediate phases: GeRu which formed congruently at 1470°C and Ge3Ru2 which formed by a peritectic reaction at 1452°C. Later, Perring et al. [2] reinvestigated the phase relationship of this system by means of differential thermal analysis (DTA), X-ray diffraction (XRD) and electron probe microanalyses (EPMA). They found that GeRu and Ge3Ru2 melted congruently at 1510°C and 1551°C respectively. The first optimization of the Ge-Ru system was performed by Charles et al. [3] on the basis of the experimental results of Perring et al. [2]. They noted a problem concerning the calculated temperature of the eutectic L ↔ GeRu + βGe3Ru2 equilibrium which differs from experiment by about 20°C equal to the melting point of GeRu (1508°C). Most recently, Long et al. [4] performed an assessment of the Ge-Ru system using the mixing enthalpies of the liquid calculated from the Miedema’s empirical model [5] in spite of the fact that a factor of 4 could be noted between the experimental enthalpy of formation and the Miedema’s model predicted one for the Ge3Ru2 phase. These authors adopted the peritectic reaction L + βGe3Ru2 ↔ GeRu instead of the eutectic equilibrium reported more recently by [2] and mentioned that further studies on this reaction are necessary. In light of these results, we have reassessed the thermodynamic parameters of the Ge-Ru system to take into account the recent experimental data determined by [2-6]. Particular attention was accorded to the controversial equilibrium involving the liquid, βGe3Ru2 and GeRu phases. This work first provides a critical review of the experimental phase equilibrium and thermodynamic data available in the literature, then presents the thermodynamic models used, and discusses the results obtained.
Highlights
The experimental phase equilibria of the Ge-Ru system was first determined by Raub and Fritzsche [1] who reported the existence of two intermediate phases: GeRu which formed congruently at 1470°C and Ge3Ru2 which formed by a peritectic reaction at 1452°C
The first optimization of the Ge-Ru system was performed by Charles et al [3] on the basis of the experimental results of Perring et al [2]. They noted a problem concerning the calculated temperature of the eutectic L ↔ GeRu + βGe3Ru2 equilibrium which differs from experiment by about 20°C equal to the melting point of GeRu (1508°C)
Long et al [4] performed an assessment of the Ge-Ru system using the mixing enthalpies of the liquid calculated from the Miedema’s empirical model [5] in spite of the fact that a factor of 4 could be noted between the experimental enthalpy of formation and the Miedema’s model predicted one for the Ge3Ru2 phase
Summary
The experimental phase equilibria of the Ge-Ru system was first determined by Raub and Fritzsche [1] who reported the existence of two intermediate phases: GeRu which formed congruently at 1470°C and Ge3Ru2 which formed by a peritectic reaction at 1452°C. Later, Perring et al [2] reinvestigated the phase relationship of this system by means of differential thermal analysis (DTA), X-ray diffraction (XRD) and electron probe microanalyses (EPMA).
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.