With the rapid advancement of advanced aerospace equipment, there is an urgent demand for high-performance-integrated structural and functional materials in extreme thermal protection components for new-generation aircraft. Oxide and nitride ceramic fibers, which combine thermal protection and load-bearing capabilities, serve as the key reinforcing phases in electromagnetic wave-transparent ceramic composites. The high-temperature resistance of continuous ceramic fibers is a critical factor for both composite preparation temperatures and service temperatures, making high-temperature-resistant ceramic fibers a key development focus for advanced ceramics. Currently, polycrystalline alumina fibers exhibit excessive grain coarsening above 1400°C, while amorphous silicon nitride fibers experience a sharp decline in strength at temperatures exceeding this threshold. This directly impacts the temperature resistance of oxide and nitride ceramic fibers, posing a challenge for the application of ceramic fiber-reinforced ceramic matrix composites in extremely high-temperature environments.
Silicon nitride oxide ceramics, as the only stable structure between SiO 2 and Si 3 N 4 , exhibit outstanding high-temperature resistance and hold significant application value in extreme thermal protection materials. There are few reports focus on continuous sinoite fibers with stable structures and outstanding high-temperature resistance. Therefore, developing continuous sinoite fibers holds significant importance for advancing the temperature resistance limits of both oxide and nitride fibers.
Leveraging the superior properties of silicon oxynitride ceramics, recently, a team of material scientists led by Changwei Shao from the Science and Technology on Advanced Ceramic Fibers and Composites Laboratory at National University of Defense Technology, China, reported the continuous sinoite ceramic fibers with a near-stoichiometric Si 2 N 2 O ratio and resistance to 1700°C using a precursor conversion method. This study reports for the first time the structural and performance characteristics of this novel ceramic fibers, consistent with theoretical calculations. Through systematic analysis of the fibers composition, microstructure, mechanical properties, and high-temperature evolution patterns, the outstanding high-temperature resistance of sinoite fibers was verified, revealing a mosaic-like Si 2 N 2 O shell layer formed by surface grain growth. This work provides highly promising reinforced fibers for thermal protection systems and electromagnetic functional devices in extreme environments, while offering new insights for the design and preparation of high-performance ceramic fibers.
The team published their work in Journal of Advanced Ceramics on February 16, 2026.
“In this work, we developed a near-stoichiometric continuous sinoite fibers resistant to 1700℃. We investigated its compositional structure and performance evolution along with the high-temperature mosaic-shell formation mechanism. The reported sinoite fibers exhibit the tensile strength of 1.53 GPa at room temperature and low-dielectric properties, which maintains amorphous state and structural stability below 1600℃, retaining 51% of strength at 1700℃. The extremely low internal porosity ensures strength retention ratio after high-temperature treatment. At 1700°C, Si 2 N 2 O grains with a radially distributed, mosaic-shell structure form on the surface of sinoite fibers. This process follows the mechanism of heterogeneous nucleation at the surface and dissolution-growth in an oxygen-rich SiO 2 liquid phase. Essentially, it involves the tetrahedral rearrangement of Si-N and Si-O bond networks and the elemental segregation between the crystalline grains and the amorphous regions along the grain-growth direction. First-principle-thinking calculations based on density functional theory indicate that near-stoichiometric sinoite fibers facilitate the formation of more bond networks, thereby promoting Si 2 N 2 O phase formation and exhibiting superior thermodynamic stability. Compared to regular dielectric ceramic fibers, the novel sinoite fibers maintain a high strength retention rate at temperatures ranging from 1500 to 1700°C, demonstrating significant high-temperature performance advantages. This lays the foundation for their application in high-temperature structural-functional integrated composites.”
Other contributors include Zhiqian Liu, Xin Long, Qiansi Zhang, Zhangbocheng Tang, Bing Wang from the Science and Technology on Advanced Ceramic Fibers and Composites Laboratory at National University of Defense Technology, China.
About Author
Changwei Shao is an Associate Researcher at Science and Technology on Advanced Ceramic Fibers and Composites Laboratory, College of Aerospace Science and Engineering, National University of Defense Technology, China. His primary research focuses on high-performance ceramic fibers and element-containing organic polymers, encompassing fundamental studies on synthesis methods and structure-property relationships, as well as key preparation techniques and applied research.
Funding
This work was financially supported by the “Advanced Materials-National Science and Technology Major Project (No. 2025ZD0613500)”, “National Natural Science Foundation of China (No. 52572038, No. 52572090)” and “The science and technology innovation Program of Hunan Province (No. 2025RC1046)”.
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
Journal of Advanced Ceramics
High-temperature structural evolution and mosaic-shell formation of sinoite fibers resistant to 1700℃
16-Feb-2026