New Materials, Compounds and Applications

To study the nature of the interaction in the PbSe-MnSe system, alloys were synthesized in a wide range of concentrations and studied using differential-thermal analysis (DTA), X-ray diffraction (XRD) and microstructural analysis (MSA), as well as density and microhardness measurements. A T-x phase diagram was constructed. It was established that the phase diagram of the PbSe-MnSe system is a quasi-binary section of the ternary Pb-Mn-Se system. A study of the phase equilibrium revealed that a compound containing PbMnSe₂ in a 1:1 component ratio is formed in the PbSe-MnSe system. The PbMnSe₂ compound melts congruently at 1150°C. X-ray diffraction analysis showed that the PbMnSe₂ compound crystallizes in the tetragonal crystal system with the unit cell: a = 13.97; c = 8.20 Å, density ρ_{_pycn} = 5.62 g/cm³, ρ_{X-ray =} 5.66 g/cm³. It was found that in the system at room temperature, the solid solution content of PbSe-based solid solutions contain up to 5 mol. % MnSe, while that of MnSe-based solid solutions reaches 2.5 mol. % PbSe. Co-crystallization of PbSe and PbMnSe₂ compounds ends at the eutectic point containing 25 mol. % MnSe, at 850°C. Another eutectic is formed between PbMnSe₂ and γ-MnSe with a content of 60 mol. % MnSe, temperature 960°C.