硅酸盐学报

高温氧化条件下高熵钙钛矿氧化物陶瓷的电磁屏蔽性能

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刘永平 ¹ , 丁奇 ² , 范宇驰 ² , 江莞 ²

硅酸盐学报 | 研究论文 2025,53(9): 2622-2631

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硅酸盐学报 |研究论文 2025 , 53 (9) : 2622 -2631

高温氧化条件下高熵钙钛矿氧化物陶瓷的电磁屏蔽性能

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刘永平¹, 丁奇², 范宇驰², 江莞²

作者信息

^1．东华大学材料科学与工程学院，上海 201620

^2．东华大学功能材料研究中心，上海 201620

通讯作者:

范宇驰（1984—），男，教授。

作者简介:

刘永平（1996—），男，博士研究生。

Electromagnetic Interference Shielding Performance of High-Entropy Oxide Perovskite Ceramics Under High-Temperature Oxidation Conditions

Yongping LIU¹, Qi DING², Yuchi FAN², Wan JIANG²

Affiliations

^1.School of Materials Science and Engineering, Donghua University, Shanghai 201620, China

^2.Functional Materials Research Center, Donghua University, Shanghai 201620, China

Corresponding Author:

FAN Yuchi (1984-), male, Ph.D., Professor. E-mail: yuchifan@dhu.cn

LIU Yongping (1996-), male, Doctoral Candidate. E-mail: 2180352@mail.dhu.edu.cn

出版时间: 2025-09-20 doi: 10.14062/j.issn.0454-5648.20250132

文章导航

摘要

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在航空航天领域的高速发展中，能够在高温氧化环境下提供可靠电磁屏蔽性能的材料显得尤为重要。然而，目前针对高温氧化条件下电磁屏蔽材料的研究仍较为匮乏。本研究采用高熵化设计策略，成功制备了A位多元掺杂的高熵钙钛矿氧化物陶瓷，并系统研究了其在X波段（8.2~12.4 GHz）的电磁屏蔽性能，以及高温退火处理对材料电磁屏蔽性能的影响机制。结果表明：基于SrTiO₃陶瓷的高熵化设计显著提升了材料的电导率和晶格畸变，使复介电常数和介电损耗显著增大，从而增强了材料对电磁波的反射与吸收能力，最终使总屏蔽效能提升至25 dB以上。然而，经高温退火处理后，由于氧空位的湮灭导致陶瓷电导率急剧下降，介电极化和介电损耗显著降低，致使电磁屏蔽性能明显劣化。本工作不仅阐明了高温退火处理对钙钛矿氧化物陶瓷电磁屏蔽性能的影响机制，还揭示了高熵效应在提升钙钛矿陶瓷电磁屏蔽性能方面的作用。

关键词

高熵钙钛矿 / 氧化物陶瓷 / 电磁屏蔽 / 电导率 / 高温氧化

Abstract

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Introduction

The rapid advancement of electronic technologies leads to a widespread electromagnetic interference (EMI), which disrupts device performance and poses health risks, including neurological disorders, due to the prolonged exposure. Some emerging fields such as 5G communications, IoT, aerospace, and defense demand high-performance EMI shielding materials capable of operating under extreme conditions (e.g., high temperatures, radiation, and humidity) to ensure device reliability and data security. Conventional shielding materials (i.e., metals, carbon-based materials, and MXenes) have some limitations. Metals suffer from high density and corrosion, while carbon-based materials and MXenes degrade in high-temperature or oxidation environments. In contrast, ceramic materials, particularly perovskite oxides, offer superior thermal stability, corrosion resistance, and mechanical strength, making them promising candidates for next-generation EMI shielding. Among perovskite oxides, SrTiO₃ ceramics exhibit a high dielectric constant and superior insulating properties, but their intrinsically low conductivity limits their EMI shielding performance. The high-entropy design strategy, which incorporates multiple elements to enhance synergistic effects, provides a novel approach to improve electrical conductivity and thermal stability. Applying this high-entropy design to perovskite oxide ceramics can optimize their electromagnetic shielding performance under high-temperature environment, providing new research perspectives and technical pathways for developing novel high-temperature EMI shielding materials. In addition, the effect of high-temperature annealing on perovskite oxide performance remains unclear. Annealing in air leads to oxygen vacancy annihilation, causing structural and electronic changes that degrade both conductivity and EMI shielding efficiency. It is thus crucial to optimizing material design and ensuring stable performance under harsh environmental conditions. This study was to use a high-entropy design approach to develop perovskite oxide ceramics, and the EMI shielding properties in the X-band and their stability under high-temperature annealing were investigated. This work was to advance the development of robust, high-temperature EMI shielding materials via elucidating the annealing-induced structural and performance evolution, thus providing both theoretical insights and practical solutions for next-generation electronic and aerospace applications.

Methods

The perovskite oxide ceramics were synthesized via solid-state reaction with high-purity raw materials (i.e., SrCO₃, BaCO₃, CaCO₃, La₂O₃, Na₂CO₃, K₂CO₃, and TiO₂, all >99% purity from Aladdin Co., China). The powders were initially calcined at 400 ℃ for 3 h to remove moisture, and then ground by stoichiometric ball-milling in ethanol (150 r/min, 6 h). After rotary evaporation drying, the mixture was sintered in air at 1500 ℃ for 5 h to obtain pre-sintered powders, which were further ground into fine particles. The dense disk-shaped samples (φ26 mm) were prepared via vacuum hot-pressing (i.e., 10 Pa, 1400 ℃, and a heating rate of 10 ℃/min) at 70 MPa for 30 min, and subsequently annealed in air at 1000 ℃ for 1 h.

Results and discussion

Two A-site high-entropy perovskite ceramics, i.e., (SrBaCaLaNa)_0.2TiO₃ and (SrBaCaLaK)_0.2TiO₃, are prepared through high-entropy design strategy. The XRD patterns indicate that the both ceramics maintain a single-phase cubic perovskite structure before and after 1000 ℃ annealing, and a peak shifts corresponding to average A-site ionic radii. The SEM images/EDS mapping and TEM images/EDS mapping demonstrate excellent elemental homogeneity without segregation, showing an effective solid solution formation. The Grain e analysis reveals a good structure stability after annealing due to the lower treatment temperature, compared to sintering temperature. The electron paramagnetic resonance (EPR) measurements show an enhanced oxygen vacancy concentration in high-entropy ceramics, compared to SrTiO₃. The electrical characterization indicates a room-temperature conductivity of 21 S/cm for (SrBaCaLaNa)_0.2TiO₃ and 16 S/cm for (SrBaCaLaK)_0.2TiO₃ due to La³⁺ aliovalent doping and oxygen vacancies. However, annealing causes 4-order conductivity reduction due to oxygen vacancy annihilation via oxygen re-filling. The dielectric analysis demonstrates superior properties in high-entropy ceramics (ε′=50-70, ε″=40-60), which are 20% higher than those of STO, where the conduction loss dominates the dielectric loss mechanism. The enhanced dielectric properties originated from increased dipole polarization and conduction loss associate with a higher oxygen vacancy concentration.

EMI shielding evaluation shows the superior performance with SE_Total >25 dB (99.6% efficiency) in X-band for both high-entropy ceramics, where reflection dominates the shielding mechanism (i.e., SE_R>10 dB, >90% reflectivity) due to large impedance mismatch. (SrBaCaLaNa)_0.2TiO₃ ceramic exhibits a slightly better shielding performance due to its higher oxygen vacancy concentration and conductivity. After annealing, high-entropy ceramics still outperform STO, while shielding performance degraded (i.e., SE_Total<20 dB), maintaining SE_R and SE_A at 10 dB. This result demonstrates that high-entropy design effectively enhances EMI shielding properties through lattice distortion effects, i.e., 1) modified local dipole moments from atomic displacement, and 2) enhanced dipole polarization through electron cloud redistribution. However, the performance degradation after annealing indicates that high-entropy design cannot completely prevent property deterioration in high-temperature oxidation environment, primarily due to oxygen vacancy and conductivity elimination.

Conclusions

A-site high-entropy perovskite ceramics, i.e., (SrBaCaLaNa)_0.2TiO₃ and (SrBaCaLaK)_0.2TiO₃, prepared via a high-entropy design, exhibited a single-phase cubic perovskite structure with a homogeneous elemental distribution. Compared to single-component STO ceramics, these high-entropy ceramics demonstrated higher oxygen vacancy concentration and electrical conductivity, leading to enhanced electromagnetic wave reflection and absorption. In the X-band, their total EMI shielding effectiveness exceeded 25 dB, with shielding efficiency surpassing of 99.6%. However, after annealing in air at 1000 ℃, the elimination of oxygen vacancies caused a notable decrease in conductivity, severely weakening polarization and loss capabilities. The reduction in complex permittivity diminished electromagnetic wave reflection and impaired dissipation ability, ultimately deteriorating EMI shielding performance. These results indicated that high-entropy design could improve the EMI shielding properties of perovskite ceramics, but it could not fully prevent performance degradation under high-temperature oxidative conditions.

Key words

high-entropy perovskite / oxide ceramic / electromagnetic interference shielding / electrical conductivity / high-temperature oxidation

引用本文

刘永平, 丁奇, 范宇驰, 江莞. 高温氧化条件下高熵钙钛矿氧化物陶瓷的电磁屏蔽性能. 硅酸盐学报, 2025 , 53 (9) : 2622 -2631 . DOI: 10.14062/j.issn.0454-5648.20250132

Yongping LIU, Qi DING, Yuchi FAN, Wan JIANG. Electromagnetic Interference Shielding Performance of High-Entropy Oxide Perovskite Ceramics Under High-Temperature Oxidation Conditions[J]. Journal of the Chinese Ceramic Society, 2025 , 53 (9) : 2622 -2631 . DOI: 10.14062/j.issn.0454-5648.20250132

基金

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国家自然科学基金(52472066; 52302061)
上海市教委科研创新计划重大项目(2023ZKZD43)
曙光计划(24SG32)

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2025年第53卷第9期

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文章信息

doi: 10.14062/j.issn.0454-5648.20250132

接收时间：2025-03-01
首发时间：2026-10-21
出版时间：2025-09-20

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收稿日期：2025-03-01
修回日期：2025-03-23

基金

国家自然科学基金(52472066; 52302061)

上海市教委科研创新计划重大项目(2023ZKZD43)

曙光计划(24SG32)

作者信息

^1．东华大学材料科学与工程学院，上海 201620

^2．东华大学功能材料研究中心，上海 201620

通讯作者:

范宇驰（1984—），男，教授。

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https://castjournals.cast.org.cn/joweb/gsyxb/CN/10.14062/j.issn.0454-5648.20250132

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2种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

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