Abstract

Chemical interaction in the Bi₂Se₃-Tb₂Se₃ system was studied using physicochemical analysis methods (differential thermal analysis, X-ray phase analysis, microstructural analysis, microhardness measurement and density determination).

Based on the analysis results, a phase diagram of the Bi₂Se₃-Tb₂Se₃ system was constructed. It was found that the Bi₂Se₃-Tb₂Se₃ section is a quasi-binary section of the Tb-Bi-Se ternary system and belongs to the eutectic type.

In the Bi₂Se₃-based system, a region of solid solution of 8mol. % Tb₂Se₃ is formed at room temperature. The area of the solid solution was determined by microstructural analysis and is 13mol. % at a eutectic temperature of 813K and 8 mol. % Tb₂Se₃ at room temperature. It is evident from the phase diagrams that in the Bi₂Se₃-Tb₂Se₃ section a new ternary incongruently melting compound of the TbBiSe₃ composition is formed by a peritectic reaction at a temperature of 1150K with a component ratio of 1:1.

According to the results of X-ray phase analysis, it was established that the TbBiSe₃ compound crystallizes in the orthorhombic syngony with the lattice parameters: a=12.25, b=12.66, c=4.76Å. The solubility of Tb₂Se₃ in Bi2Se3 is 5.0mol.% at 300K, respectively.

Keywords:System; Analysis; Crystallization; Phase; Diagram; Temperature