Processing and Application of Ceramics 2023 Volume 17, Issue 2, Pages: 113-117
https://doi.org/10.2298/PAC2302113M
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Heavily doped high-entropy A2B2O7 pyrochlore
Matović Branko 
(Center of Excellence “CEXTREME LAB”, Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia + State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China), mato@vinca.rs
Maletaškić Jelena (Center of Excellence “CEXTREME LAB”, Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia)
Maksimović Vesna (Center of Excellence “CEXTREME LAB”, Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia)
Zagorac Jelena (Center of Excellence “CEXTREME LAB”, Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia)
Luković Aleksa (Center of Excellence “CEXTREME LAB”, Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia)
Zeng Yu-Ping (State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai, China)
Cvijović-Alagić Ivana (Center of Excellence “CEXTREME LAB”, Vinča Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia)
A novel class of high-entropy pyrochlore compounds with multiple elements at
the A and B site positions (A2B2O7) was successfully obtained. Powders with
(La1/7Sm1/7Nd1/7Pr1/7Y1/7Gd1/7Yb1/7)2(Sn1/3Hf1/3Zr1/3)2O7 nominal
composition were fabricated from pure metal oxides obtained through a
reaction of metal nitrates (for site A) and metal chlorides (for site B)
with sodium hydroxide during the solid-state displacement reaction (SSDR).
The phase evolution was analyzed using XRD method. During the thermal
treatment of ten individual metal oxides, the single pyrochlore phase was
created. The present study showed that the highdensity (98%TD) ceramics with
a hardness of 8.1GPa was successfully obtained after pressureless sintering
at 1650 °C for 4 h. Results of the Raman study and the Rietveld structural
refinement showed that sintered highentropy ceramics is characterized by a
single-phase pyrochlore structure, which was investigated in detail.
Keywords: high-entropy oxide, pyrochlore, phase evolution, XRD, microstructure, hardness
Project of the Ministry of Science, Technological Development and Innovation, Republic of Serbia, Grant no. 451-03-47/2023-01/200017
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