Study of (In₂S₃)_х·(AgIn₅S₈)_1–х solid solutions

Herein, single crystals of compounds In₂S₃, AgIn₅S₈ and solid solutions (In₂S₃)_х·(AgIn₅S₈)_1–х were grown by directional crystallization. The composition of the obtained single crystals was determined by microprobe X-ray spectral analysis. It is found that the content of the components in the grown single crystals is in satisfactory agreement with the specified composition in the initial charge. The structure of the obtained materials was determined by the X-ray method. It is shown that both the initial compounds and the solid solutions based on them were crystallized in the cubic structure of the spinel. The unit cell parameters of the In₂S₃, AgIn₅S₈ compounds and the solid solutions based on them, which vary linearly with the composition x, were calculated by the least squares method. The density was determined by the pycnometric method, and the microhardness of the In₂S₃ and AgIn₅S₈ compounds and the (In₂S₃)_х·(AgIn₅S₈)_1–х solid solutions was determined by the Knoop method. It is shown that the density, like the unit cell parameter, changes linearly with the composition x, but the dependence of microhardness on the x parameter has a maximum for x = 0.4. Using differential thermal analysis (DTA), the temperatures of phase transformations were determined and the phase diagram of the In₂S₃–AgIn₅S₈ system was constructed, which is characterized by a small crystallization interval and belongs to type III according to the Rosebom classification. The curves of liquidus and solidus are concave to the abscissa axis and have a common point.

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