Thermal Stability and Thermodynamics of the Ag2ZnGeS4 Compound

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Publication Details

List of Authors: Mykola Moroz, Fiseha Tesfaye, Pavlo Demchenko, Myroslava Prokhorenko, Daniel Lindberg, Oleksandr Reshetnyak, Leena Hupa
Editors: Guillaume Lambotte, Jonghyun Lee, Antoine Allanore, Samuel Wagstaff
Publication year: 2019
Publisher: Springer, Cham
Book title: Materials Processing Fundamentals 2019
Title of series: The Minerals, Metals & Materials Series
ISBN: 978-3-030-05727-5
eISBN: 978-3-030-05728-2
ISSN: 2367-1181


Abstract

Phase equilibria in the ZnS–Ag2GeS3–Ge–GeS2 part of the Ag–Zn–Ge–S system were investigated using differential thermal analysis, X-ray diffraction, and EMF methods. The data was used to model Ag2GeS3–ZnS polythermal section. Further, the mechanism of formation and thermal stability of the Ag2ZnGeS4 compound were established. The results suggest the presence of another quaternary phase Ag4ZnGe2S7 in the temperature range of 695–853 K. The determined phase relations were used to express the chemical reactions. Based on the electromotive force versus temperature measurements, experimental thermodynamic data of the Ag2ZnGeS4 quaternary phase were derived for the first time. The calculated Gibbs energy , enthalpy and entropy values of the Ag2ZnGeS4 compound in both phase regions are consistent, which indicates that Ag2ZnGeS4 has stoichiometric composition.


Keywords

Chalcogenide semiconductors, EMF method, Gibbs' free energy, Phase equilibria, Thermodynamic properties

Last updated on 2019-19-07 at 05:38