Abstract
In the present study, four novel quinary nanostructured thermoelectric materials belong to copper-chalcogenide (Cu2ZnSnS4/Se4 (QTEM1), Cu2MnSiS4/Se4 (QTEM2), Cu2MnSnS4/Se4 (QTEM3), and Cu2ZnSiS4/Se4 (QTEM4)) were designed and synthesized via mechanical alloying (300 rpm, 25 h, and BPR 10:1). Various phase formations in the synthesized materials was identified using XRD such as the hexagonal phases (Se, ZnS, and MnS), orthorhombic phases (S8, and Cu5Se4), and cubic phases (SnSe, ZnSe, Si, and MnSe). The 3D crystal system of each phase and the arrangement of atoms were presented and explained. HRSEM microstructural results revealed the formation of a solid solution with nanoscale polycrystals. These polycrystals revealed an average particle size of 523, 594, 725, and 518 nm for QTEM1, QTEM2, QTEM3, and QTEM4, respectively. The phase formations were explained based on HRTEM and HRSEM examinations. The solid solution formation, elemental distribution, and chemical composition were examined using HRSEM equipped with an EDAX system. The compressibility results revealed that the QTEM4 (Cu2ZnSiS4/Se4) exhibited the highest densification rate and attained the maximum percentage relative density of 97.07% at 1100 MPa. The examined compaction behavior using several equations revealed that the linear Balshin's equation and the non-linear Cooper and Eaton's equation exhibited well-fitted curves with regression coefficients (R2) greater than 0.999. These equations can be used to predict the densification behavior of these thermoelectric materials.
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•Synthesized four quinary chalcogenide nanostructured thermoelectric materials.•Examined the phase evolutions and structural properties.•Investigated powder particle size and microstructural characterizations.•Analyzed the compressibility and compaction behaviour using several models.