Experimental study and thermodynamic modelling of Co-Se-Sn ternary system


                          Dávid Mikšík^1,2*, Jana Pavlů^1, Ondřej Zobač^2


                1 Department of Chemistry, Masaryk University, Brno, Czech Republic

       2 Institute of Physics of Materials, Czech Academy of Sciences, Brno, Czech Republic

                                      * E-mail: miksik@ipm.cz


Keywords: Co-Se-Sn system, Phase equilibria, CALPHAD, Thermodynamic modelling, Scanning electron
microscopy, X-ray diffraction, Thermal analysis


The ternary Co-Se-Sn system has been investigated experimentally to determine the phase equilibria
and the microstructure of the alloys formed at different temperatures (400, 600 and 1000 °C).
Samples of various compositions were prepared by melting, annealing, and quenching techniques and
characterized using scanning electron microscopy, X-ray diffraction and thermal analysis. The
combined experimental results confirmed the presence of several binary phases in this system,
including Co[3]Sn[2]^1, CoSn[2]^1, CoSe^2, Co[9]Se[8]^2, CoSe[2]^2, SeSn^3 and one ternary phase
Co[2](SnSe)[3]^4.


Furthermore, a new thermodynamic description of this system was introduced using the CALPHAD
(CALculation of PHAse Diagrams) approach to predict and describe the phase equilibria, including
the development of new models for phases CoSe Co[9]Se[8 ]and CoSe[2]. The models and thermodynamic
description were verified by comparing the predicted phase diagrams with the experimental data
obtained in this study.


The experimental and modelling results obtained in this study provide new insights into the
behaviour of the Co-Se-Sn system and can be applied in the design and optimization of Co-based
alloys for various industrial applications, such as magnetic storage media, high-temperature
materials, and thermoelectric devices.



References


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3. Sharma, R.C., Chang, Y.A., The Se−Sn (selenium-tin) system. Bull. alloy phase diagr. 7, 68–72
(1986).

4. Laufek, F., Navrátil, J., Plášil, J., Plecháček, T., Drašar, Č., Synthesis, crystal structure
and transport properties of skutterudite-related CoSn[1.5]Se[1.5]. J. Alloys Compd. 479, Issues
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