Improvement of microwave dielectric properties of (Ca, Sr)TiO3‐based ceramics by high‐entropy design.
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| Title: | Improvement of microwave dielectric properties of (Ca, Sr)TiO |
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| Authors: | Hou, Xiong1 (AUTHOR), Li, Chengle1 (AUTHOR), Gou, Tianchenxi1 (AUTHOR), Xu, Jialing1 (AUTHOR), Yu, Hongtao1 (AUTHOR) htyu_76@163.com |
| Source: | Journal of the American Ceramic Society. Sep2025, Vol. 108 Issue 9, p1-13. 13p. |
| Subjects: | Ceramic engineering, Permittivity, Specific gravity, Quality factor, Space groups, Dielectric properties |
| Abstract: | In this study, a series of high‐entropy (Ca, Sr, Ba)[Ti, (Mg1/3Nb2/3)]O3 ceramics were fabricated through solid‐state reaction. Systematic investigations were conducted to examine the effects of varying configurational entropy (Sconf) values on crystal structure, microstructural evolution, and microwave dielectric performance. All samples sintered at temperatures ranging from 1390°C to 1490°C exhibited single‐phase perovskite structures within the Pbnm space group. By employing the P‒V‒L complex chemical bonding theory, we calculated bond ionicity, lattice energy, and bonding energy to elucidate the influence of high‐entropy configurations on dielectric properties. The results indicated that the dielectric constant (εr) exhibited a strong correlation with bond ionicity, relative density, and ionic polarizability as Sconf increased. Notably, high‐entropy ceramics demonstrated superior quality factor (Q × f) values compared to their low‐entropy counterparts, primarily due to the synergistic effects of lattice energy, microstructural refinement, and grain size control. Furthermore, the high‐entropy design induced pronounced [TiO6] octahedral distortion, leading to a significantly reduced temperature coefficient of resonant frequency (τf) compared to conventional (Ca, Sr)TiO3‐based ceramics. The optimal composition (Sconf = 1.71 R), sintered at 1450°C for 2 h, achieved exceptional dielectric properties: εr = 54.23 ± 0.61, Q × f = 16 286 ± 252 GHz, and τf = 17.49 ± 1.12 ppm/°C. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | In this study, a series of high‐entropy (Ca, Sr, Ba)[Ti, (Mg1/3Nb2/3)]O3 ceramics were fabricated through solid‐state reaction. Systematic investigations were conducted to examine the effects of varying configurational entropy (Sconf) values on crystal structure, microstructural evolution, and microwave dielectric performance. All samples sintered at temperatures ranging from 1390°C to 1490°C exhibited single‐phase perovskite structures within the Pbnm space group. By employing the P‒V‒L complex chemical bonding theory, we calculated bond ionicity, lattice energy, and bonding energy to elucidate the influence of high‐entropy configurations on dielectric properties. The results indicated that the dielectric constant (εr) exhibited a strong correlation with bond ionicity, relative density, and ionic polarizability as Sconf increased. Notably, high‐entropy ceramics demonstrated superior quality factor (Q × f) values compared to their low‐entropy counterparts, primarily due to the synergistic effects of lattice energy, microstructural refinement, and grain size control. Furthermore, the high‐entropy design induced pronounced [TiO6] octahedral distortion, leading to a significantly reduced temperature coefficient of resonant frequency (τf) compared to conventional (Ca, Sr)TiO3‐based ceramics. The optimal composition (Sconf = 1.71 R), sintered at 1450°C for 2 h, achieved exceptional dielectric properties: εr = 54.23 ± 0.61, Q × f = 16 286 ± 252 GHz, and τf = 17.49 ± 1.12 ppm/°C. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 00027820 |
| DOI: | 10.1111/jace.20630 |
