Corrugated structure SiCf/Si3N4 composite with high-temperature broadband microwave absorption through the regulation of high-temperature dielectric properties

With the development of aerospace technology, the demand for stealth in high-temperature components of aircraft such as engines has become increasingly urgent. Furthermore, the trend of radar detection toward lower frequencies has resulted in a growing requirement for low-frequency electromagnetic (EM) wave absorption of stealth aircraft. To further enhance the stealth performance of aircraft, it is necessary to develop high-temperature broadband microwave absorber.

Because of the temperature resistance and tunable dielectric properties, the SiC fiber reinforced ceramic matrix composites (SiC_f-CMC) have become one of the candidates for high-temperature electromagnetic wave microwave absorber. Combining SiC_f-CMC with macroscopic absorbing structures can further broaden the absorption bandwidth. However, the semiconductor characteristics of SiC fiber cause significant changes of dielectric properties at high temperatures, disrupting the balance between the material and structure, which resulting in severe attenuation of high-temperature absorption performance.

Recently, a team of material scientists led by Xiaomeng Fan from Northwestern Polytechnical University, China reported a method to enhance the high-temperature broadband absorption performance of corrugated structure SiC_f/Si₃N₄ through high-temperature dielectric property regulation.

This work not only systematically investigates the influence of microstructure evolution on the high-temperature dielectric properties of SiC_f/Si₃N₄ and their absorption mechanism at high temperatures, but also provides a new method for improving the absorption performance at high temperatures.

The team published their work in Journal of Advanced Ceramics on March 24, 2026.

“In this work, we prepared the corrugated structure SiC_f/Si₃N₄ by chemical vapor infiltration (CVI) process. The fibers pretreatment and SiC-Si₃N₄ multi-phase matrix are used to regulate the high-temperature dielectric properties of SiC_f/Si₃N₄. The microstructure and the variation of dielectric properties with temperature of composites are studied. The absorption mechanism of corrugated structure SiC_f/Si₃N₄ are also revealed. This study provides a novel method to improve the high-temperature microwave absorption performance through material-structure multi-scale design.” said Xiaomeng Fan, associate professor at School of Materials Science and Engineering at Northwestern Polytechnical University (China), an expert whose research interests focus on the field of electromagnetic wave absorbing ceramics matrix composites.

“An amorphous area with a thickness of 5-7 nm exists between the SiC fiber and the BN interphase. This verifies the presence of sizing agent on the surface of SiC fibers, and the sizing agent is converted into an amorphous phase during the CVI process. After oxidation of SiC fiber, the amorphous area between the SiC fiber and the BN interphase disappears. The content and distribution of free carbon in SiC_f/Si₃N₄ would affect the variation range of dielectric properties with temperature.” said Fan.

“By choosing SiC_f/Si₃N₄ with appropriate high-temperature dielectric properties, the effective absorption bandwidth (EAB) of corrugated structure SiC_f/Si₃N₄ at 1000 °C increases to 7.6 GHz. In low-frequency region (4-8 GHz), the EAB covers 4-6 GHz and the average reflection loss is less than -13 dB, exhibiting excellent broadband and low-frequency absorption performance at high temperature. The improvement of absorption performance can be attributed to the improved impedance matching caused by the matching of dielectric properties and corrugated structure, as well as the multiple loss mechanism brought by them. Therefore, the multi-scale design of materials and structures provides a new idea for the development of high-temperature microwave absorber.” said Fan.

Other contributors include Xinlei Wang, Haohui Hao, Jimei Xue, Fang Ye from the School of Materials Science and Engineering at Northwestern Polytechnical University, China.

About Author

Xiaomeng Fan is an associate professor at the School of Materials Science and Engineering, Northwestern Polytechnical University, China. He received his PhD degree from Northwestern Polytechnical University in 2015. His current interests and fields of research are mechanics and functionalization of ceramics matrix composites for high temperature applications.

Funding

This work was supported by the National Natural Science Foundation of China (Nos. 52231007).

About Journal of Advanced Ceramics

Journal of Advanced Ceramics (JAC) is an international academic journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press, and exclusively available via SciOpen. JAC’s 2024 IF is 16.6, ranking in Top 1 (1/34, Q1) among all journals in “Materials Science, Ceramics” category, and its 2024 CiteScore is 25.9 (5/130) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508