Dielectric properties of novel high-entropy (La0.2Li0.2Ba0.2Sr0.2Ca0.2)Nb2O6-δ tungsten bronze ceramics

Novel high-entropy (La 0.2 Li 0.2 Ba 0.2 Sr 0.2 Ca 0.2 )Nb 2 O 6-δ tungsten bronze ceramics, fabricated by conventional solid-state reaction, were first studied to reveal the effects of sintering temperatures on the crystal structure, microstructure and dielectric properties of these ceramics. The r...

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Bibliographic Details
Published in:Journal of materials science 2022-09, Vol.57 (33), p.15901-15912
Main Authors: Zhang, Xiaoyan, Li, Jinsheng, Ni, Bo, Yang, Rutong, Xie, Huihui, Yang, Shuzhen, Qi, Xiwei
Format: Article
Language:English
Subjects:
Ceramics
Characterization and Evaluation of Materials
Chemistry and Materials Science
Classical Mechanics
Crystal structure
Crystallography and Scattering Methods
Dielectric properties
Energy Materials
Entropy
Materials Science
Permittivity
Polymer Sciences
Sintering
Solid Mechanics
Temperature
Tungsten bronze
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Summary:Novel high-entropy (La 0.2 Li 0.2 Ba 0.2 Sr 0.2 Ca 0.2 )Nb 2 O 6-δ tungsten bronze ceramics, fabricated by conventional solid-state reaction, were first studied to reveal the effects of sintering temperatures on the crystal structure, microstructure and dielectric properties of these ceramics. The results show that all the prepared ceramics have tetragonal tungsten bronze structures after sintering at 1250–1350 °C. With increasing sintering temperature, high density up to 93% theoretical and uniform grain distribution are obtained. The dielectric properties are apparently affected by both frequency and temperature, and all ceramics exhibit quintessential relaxation peaks and obvious frequency dispersion phenomena. The optimal value of dielectric constant ε r reaches as high as 1.1 × 10 6 at 100 Hz and 625 °C for the ceramic sintered at 1250 °C, which is almost 1290 times that of the (Ba 1/3 Sr 1/3 Ca 1/3 )Nb 2 O 6 ceramics under the same conditions. Furthermore, the temperature stability of dielectric constant can also be improved through high-entropy effect. The obtained results demonstrate that it is feasible to design high-entropy ceramics to improve the dielectric properties of ANb 2 O 6 ceramics. We have reason to believe that entropy engineering is a credible strategy for tailoring properties of ceramic systems.
ISSN:0022-2461
1573-4803
DOI:10.1007/s10853-022-07617-7