THE PHASE EQUILIBRIA OF THE PbS-La(Pr)2S3-Y(Er)2S3 SYSTEMS
DOI:
https://doi.org/10.32782/pcsd-2021-2-7Keywords:
crystalline structure, a unit cell, isothermal section, quasi-binary sectionAbstract
Research of phase equals in quasi-ternary systems – creation of a stage of formation of basic knowledge about materials. Each crystal structure is a new motive for the organization of atoms, which allows us to explain some patterns of formation without creating more complex phases. During the research of the quasi-ternary systems PbS–La(Pr)2S3–Y(Er)2S3 by studying the complex interactions between binary and ternary phases, which are created on the corresponding quasi-binary transfers. Samples for analysis are obtained by direct synthesis from elementary components of high purity. The maximum synthesis temperature was 1323 K. For this temperature, the samples are maintained for 2 hours. Subsequently, annealing was performed at 770 K for better homogenization. After aging, the ampoules are hardened in water at the room temperature. Diffractograms of the samples were obtained on DRON-4-13. According to X-ray phase analysis, the creation of new quaternary phases is not observed in the systems. This motif of phase equilibria is explained by the organization of atoms in binary compounds. In the analysis of binary compounds that create quasi-binary transitions SnS2 - Y(Er)2S3, it was found that the motives of the organization of atoms are not reproduced for the formation of the ternary phase, in contrast to the case of SnS2 - La(Pr)2S3 motifs are combined with the formation of ternary phases La2SnS5 and Pr2SnS5. In fact, the motif State-content of the phase is part of the structure of the La-content and as a result, the parameters of the cells increase slightly. Collectively, during the transitions to the quasi-ternary system, as a result of the above-mentioned description, the motifs of the atoms are not combined and new quaternary compounds are not created. At work, the results of X-ray phase analysis constructed isothermal sections of the quasi-ternary systems PbS – La(Pr)2S3 – Y(Er)2S3 at the temperature 770 K. Between the compounds Y(Er)2S3 – La(Pr)2SnS5 there are quasi-binary equilibria.
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