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Thermodynamic properties of melts of the Ce—Ti system

V. G. Kudin 1,
 
M. S. Kobylinska 1,
 
Л.О.Романова 2,
 
M. O. Shevchenko 3,
 
В.С.Судавцова 2*
 

1 Київський національний університет ім. Т. Шевченка, Київ
2 Інститут проблем матеріалознавства ім. І. М. Францевича НАН України , Київ
3 The University of Queensland, Brisbane, Australia
sud.materials@ukr.net

Usp. materialozn. 2025, 10/11:73-83
https://doi.org/10.15407/materials2025.10-11.073

Анотація

The partial enthalpies of solution of Ti were determined for the first time by the isoperibolic calorimetry method, from which similar parameters for mixing were calculated. These data were extrapolated to the entire composition range, from which all thermochemical properties of melts of the Ce—Ti system were calculated at a temperature of 1800 ± 2 K in the composition range 0 < xTi < 0,5. It was established that the minimum value of the enthalpy of mixing of these melts is 9,2 ± 1 kJ/mol and falls on the melt with xTi = 0,5, and = 30 ± 2 kJ/mol. This agrees within the experimental error with the calculated CALPHAD method and the coordinates of the liquidus line of the phase diagram of the Ce— Ti system, which indicates stratification in this system in the middle composition range. To confirm the reliability of the obtained data and search for general patterns of thermodynamic characteristics of alloy formation of the Ce—Ti system, it was considered as a member of a series of Ce—3d-metal systems. For this purpose, the dependences of the melts, as well as the differences in molar volumes and electronegativities of the components of the Ce—3d-metal systems on the ordinal number of the 3d-metal, were constructed. It was shown that the dependence of ΔHmin on the ordinal number of the 3d-metal is non-monotonic with two extrema. Thus, melts of the systems from Ce—Ti to Ce—Mn are formed with heat absorption, and from Ce— Fe to Ce—Cu — with release. This can be explained by the difference in electronegativities of the components of the considered systems, which is the largest for the systems from Ce—Fe to Ce—Cu. Moreover, melts of the Ce—Ni system are formed with the largest release of heat. This may be due to the electrochemical factor and the occupancy of the 3d-orbitals of Ni. These factors are most favorable for melts of the Ce—Ni system. It has been established that the components of this system are characterized by the largest difference in electronegativities and almost filled 3d orbitals of Ni, to which the valence electrons of Ce pass, making it stable. Small exothermic enthalpies of mixing are predicted for melts of the Ce—Sc system, because its components have a small difference in molar volumes and electronegativities. This correlates with the phase diagram of the Ce—Sc system, the components of which form continuous series of solid solutions (HPTR) and have a eutectoid at 680 °C and xTi = 0,45.

Keywords: calorimetry method, melts, thermodynamic properties, Ce, Ti, 3d-metals.


Посилання

1. Hu, B., Wang, J., Wang, C., Du, Y., Zhu, J. B. (2016). CALPHAD-Type thermodynamic assessment of the Ti—Mo—Cr—V quaternary system. CALPHAD, Vol. 55, pp. 103—112.

2. Xiong, W., Du, Y., Lu, X. G., Schuster, J. C. and Chen, H. L. (2007). Reassessment of the Ce—Ni binary system supported by key experiments and ab initio calculations. Intermetallics, Vol. 15 (11), pp. 1401—1408.

3. Yang, Y. F., Luo, S. D., Schaffer, G. B. and Qian, M. (2013). Impurity scavenging, vicrostructural refinement and mechanical properties of powder metallurgy titanium and titanium alloys by a small addition of cerium silicide. Mater. Sci. Eng. A, Vol. 573 (20), pp. 166—174.

4. Goll, D. and Kronmu¨ller, H. (2000). High-performance permanent magnets. Naturwiss, Vol. 87 (10), pp. 423—438.

5. Sudavtsova, V. S., Shevchenko, M. O., Kudin, V. G. (2016). Thermodynamic properties of melts of titanium-lanthanide systems. Sovremennye problemy fizicheskogo materialovedeniya, Iss. 25, pp. 144—156 [in Ukrainian].

6. Hu, B., Wang, J., Du, Y., Zhu, J. B. (2017). Thermodynamic assessment of the Ti—RE (RE = Ce, Er, Tm, Y) binary systems. J. of Phase Equilibria and Diffusion. https://doi.org/10.1007/s11669-017-0605-0

7. Masalsky, T. B. (ed). (1990). Binary Alloy Phase Diagrams. 2nd edn. Metals Park, OH: ASM International.

8. Sudavtsova, V. S., Shevchenko, M. O., Ivanov, M. I., Kudin, V. G., Podoprygora, N. V. (2019). Thermodynamic properties and phase equilibria in alloys of the Nd— Ni system. Poroshkovaya metallurgiya, No. 9/10, pp. 107—118 [in Ukrainian].

9. Dinsdale, A. T. (1991). SGTE data for pure elements. CALPHAD, Vol. 15, No. 4, pp. 319—427. https://doi.org/10.1016/0364-5916(91)90030-N

10. Ivanov, M. I., Usenko, N. I., Berezutsky, V. V., Kotova, N. V. (2012). Thermodynamics of binary melts of lanthanides with transition metals (monograph), VPC KU, 87 р. [in Ukrainian].

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