QUASIBINARY SECTIONS OF THE In2S3-FeS–PbS SYSTEM

Abstract

Phase equilibria in the In₂S₃–FeS–PbS ternary system were investigated based on experimental studies of quasi-binary sections. The samples were synthesized by the ampoule method and examined using differential thermal analysis (DTA), X-ray diffraction (XRD), and microstructural Analysis (MSA). Seven quasi-binary sections (FeIn₂S₄–PbIn₂S₄, FeS–PbIn₂S₄, FeS–Pb₆In₁₀S₂₁, FePbIn₄S₈–In₂S₃, FeS–FePbIn₄S₈, Fe_1,5Pb_5,5In₁₀S₂₂–PbIn₂S₄, Fe_1,5Pb_5,5In₁₀S₂₂–PbS) were experimentally studied, and their quasi-binary character was established. In addition, limited solid-solution regions were observed in several of these sections. It was established that two quaternary compounds, FePbIn₄S₈ and Fe_1,5Pb_5,5In₁₀S₂₂, are formed in the In₂S₃–FeS–PbS system. These compounds were identified as congruently melting phases with melting temperatures of 1140 K and 1150 K, respectively. The Fe_1,5Pb_5,5In₁₀S₂₂ compound crystallizes in the monoclinic crystal system with lattice parameters a = 14.558 Å, b = 3.856 Å, c = 15.558 Å, β = 96.87°, V = 867 ų, Z = 1. The obtained experimental results allowed the phase equilibria to be established and provide a consistent description of phase relations in the In₂S₃–FeS–PbS system.