Projection of the liquidus surface of the $ \mathrm{Ag_2}S $-$ \mathrm{In_{2}S_{3}} $-FeS quasi-ternary system

The complex methods of physicochemical analysis, including differential thermal analysis (DTA), X-ray diffraction analysis (XRD), microstructure analysis (MSA), as well as measurements of microhardness and density, have been applied to investigate the \mathrm{Ag_2}S - \mathrm{In_{2}S_{3}} -FeS quasi-ternary system along the polythermal section for the first time. The nature of the chemical interactions within the system has been identified, and the phase diagram of the polythermal section, as well as the projection of the liquidus surface of the quasi-ternary system, has been constructed. In the investigated system, the coordinates of nonvariant points, monovariant curves, the boundaries of primary crystallization fields, and isotherms have been determined. It has been established that the system comprises six primary crystallization fields, which are bounded by seven monovariant curves. Among the ten nonvariant equilibria identified in the system, seven are attributed to three-phase binary eutectic, one to a three-phase binary peritectic, one to a four-phase ternary peritectic, and one to a four-phase ternary eutectic reaction.