Thermodynamic approach to studying of processes of contact interaction between W – C filler and iron-based binder of composite materials during infiltration

DOI: 10.62564/M4-YS1427

Yuliya Syrovatko^1,2, Eduard Shtapenko<sup>1

1</sup>Ukrainian State University of Science and Technologies, Ukraine
²Dnipropetrovsk Branch of the State Institution “Soil Protection Institute of Ukraine”


Higher performance characteristics of the composite materials with iron-based binders can be achieved by reducing the fragility of contact interaction zones through changing of the structure of granules of the W – C filler alloy. Previous experimental work showed the lower rate of dissolution of phases of the microcrystalline W – C filler alloy in the binder, compared to the crystalline W – C filler alloy [1]. The entropy of microcrystalline and crystalline structures of W – C alloys was determined by scanning of their digital photo-images with the use of TLC_Manager software. Further, statistical distribution of the probability density for the optical absorption coefficients was formed. Based on the fact, that logarithmic representation of the normal distribution functions is of the form of quadratic functions, we calculated the statistical distribution parameters [2]. It allowed calculating the entropy of structures at 300 K. Obtained values were 82 and 76 J/(mol∙К) for the crystalline and microcrystalline structures, accordingly. On the other hand, using the Debye model representations, we expressed the Helmholtz free energy and entropy as the functions of temperature and Debye temperature. From these expressions, knowing the values of entropy of the structures at 300 K, we found the Debye temperatures of structures, as well as the values of entropy, free energy and Gibbs energy of these W – C alloys at the temperature of infiltration of composite materials (1523 К). W – C filler and iron binder of the composite materials during infiltration were considered as two systems being in diffusion and thermal contact. The larger the difference in the chemical potentials of these systems, the more intense are the processes of diffusion and dissolution occurring at the interface of the systems [3]. It is found that the difference in chemical potentials of the microcrystalline filler alloy and the binder is less than that of the crystalline filler alloy.

Keywords
Composites, infiltration, contact interaction zones, entropy

Acknowledgments
This work was performed within the research “Development of plasma technologies for strengthening coatings used in extreme conditions”, No. of the State registration 0123U104531

References
[1] O. V. Sukhova, Yu. V. Syrovatko, Adhesion of Melts and Brazing of Materials, 2012. V.45. P. 86 - 93. [2] E. V. Sukhovaya, Yu. V. Syrovatko, Metallofiz. Noveishie Tekhnol., 2019. V. 41, No. 9. P. 1171 - 1185. [3] Ch. Kittel, Thermal Physics (New York: John Wiley and Sons Inc., 1969).