Synthesis and Characterization of High-Entropy A2B2O7 Pyrochlore with Multiple Elements at A and B Sites

  • Branko Matović Center of Excellence “CEXTREME LAB”, Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade; State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences
  • Jelena Maletaškić Center of Excellence “CEXTREME LAB”, Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade
  • Vesna Maksimović Center of Excellence “CEXTREME LAB”, Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade
  • Silvana Dimitrijević Mining and Metallurgy Institute Bor
  • Bratislav Todorović Faculty of Technology Leskovac, University of Niš
  • Jelena Zagorac Center of Excellence “CEXTREME LAB”, Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade
  • Aleksa Luković Center of Excellence “CEXTREME LAB”, Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade
  • Yu-Ping Zeng State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences
  • Ivana Cvijović-Alagić Center of Excellence “CEXTREME LAB”, Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade

Abstract

Single nano high-entropy pyrochlore-type compound (A2B2O7) with 7 different rare-earth cations at site A and 3 different metal cations at site B with equiatomic amounts (7A1/7)2(3B1/3)2O7 is successfully obtained. The powder with nominal composition (La1/7Sm1/7Nd1/7Pr1/7Y1/7Gd1/7Yb1/7)2(Sn1/3Hf1/3Zr1/3)2O7 was fabricated by reacting metal nitrates (site A) and metal chlorides (site B) with glycine during the combustion reaction. The XRD analysis revealed that the powder attained during synthesis is in an amorphous state. To induce crystallization of the obtained pyrochlore structure, the post-calcination process at 600-1500 °C was conducted and studied. Results of this study showed that the monophase pyrochlore (A2B2O7) structure is obtained during the calcination at 900 °C. The high-density ceramic pellet with 97% of theoretical density and free of any additives was obtained through pressureless sintering at 1650 °C for 4 h in the air using the powder calcined at 900 °C.

Published
2022-10-28
Issue
Vol 56 No 1 (2024)
Section
Articles

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