Study of phase equilibria in the stable triangle NaCl–Na<sub>2</sub>CrO<sub>4</sub>–RbI of the four-component reciprocal system Na<sup>+</sup>,Rb<sup>+&

The paper studies the four-component mutual system Na+,Rb+||Cl–,I–,CrO4 2–, low-melting compositions based on which are promising for the development of electrolytes for chemical current sources and heat-accumulating materials. The system is divided into stable simplices using graph theory and a phase tree of the system is constructed, which includes three stable tetrahedra connected to each other by two stable triangles. Using differential thermal analysis (DTA) and thermogravimetric analysis (TGA), phase equilibria in the stable triangle NaCl–Na2CrO4–RbI were studied. As a result, the melting point and the content of components in the three-component eutectic were determined: E 430°C, NaCl – 20%, Na2CrO4 – 48%, RbI – 32% (equiv.). The composition of the crystallizing phases in the eutectic was confirmed by X-ray diffraction (XRD).