Patterns of the Effect of the Temperature of Spark Plasma Sintering on the Microstructure of Thermoelectric Composites Based on the Matrix of Bi2Te2.1Se0.9Bi2 with Cobalt Inclusions

• Published in: Bulletin of the Russian Academy of Sciences. Physics 2023-06, Vol.87 (6), p.687-691
• Main Authors: Zhezhu, M., Vasil’ev, A. E., Ivanov, O. N.
• Format: Article
• Language: English
• Subjects: Activation energy; Diffusion coefficient; Fillers; Hadrons; Heavy Ions; High temperature; Inclusions; Nuclear Physics; Physics; Physics and Astronomy; Plasma sintering; Spark plasma sintering
• ISSN: 1062-8738; 1934-9432
• DOI: 10.3103/S1062873823701915

A study is performed of the effect the temperature of spark plasma sintering has on the formation of Co filler particles in the matrix of Bi 2 Te 2.1 Se 0.9 . Core–shell filler particles (Co@CoTe 2 ) form in Bi 2 Te 2.1 Se 0.9 + 0.33Co (wt %) due to the high-temperature diffusion redistribution of atoms in the matrix and filler materials, and the chemical interaction between these materials. The fraction of CoTe 2 shells in the particles grows along with the temperature of sintering, while the fraction of the Co cores shrinks. This behavior is due to an increase in the diffusion coefficient of Co in the Bi 2 Te 2.1 Se 0.9 matrix as the temperature of sintering rises. The concentration profiles of the Co distribution of in the Bi 2 Te 2.1 Se 0.9 matrix, governed by diffusion, are described well by Fick’s second law of diffusion from a limited source of a diffusing substance. The coefficient of Co diffusion grows along with the temperature of sintering in accordance with the Arrhenius law, and with an energy of activation of ~0.61 eV.