Abstract:

Polymer-derived ceramics (PDCs) have been intensively studied for nearly 50 years due to their unique advantages to producing ceramic fibers, coatings, foams, nanocomposites and for additive manufacturing. SiC-based ceramic nanocomposites modified with transition metals such as Hf and Ta, are effectively synthesized via the PDC approach. The resultant SiC-UHTC nanocomposites possess advanced properties including oxidation resistance and electromagnetic (EM) properties, which have to be considered as potential candidate materials applied for the harsh environment.  Depending on the transition metal, in-situ formed carbon nanophases as well as (multinary) ceramic phases are generated. The introduction of Hf and/or Ta results in the in-situ formation of Hf_yTa_1-yC_xN_1-x-carbon core-shell microstructure together with graphene-like carbon dispersed within the SiC-based matrix. Due to the enhanced dielectric properties, Hf and/or Ta containing SiC-based ceramic nanocomposites exhibit excellent EM performance and versatile designability ranging from EM absorbing to shielding behavior, which shows substantial progress beyond the state of the art. The introduction of boron offers the final ceramic nanocomposites outstanding high-temperature oxidation resistance. The relationship between the obtained nano/microstructure of the synthesized SiC-based ceramics and their property features will be highlighted. All in all, our research contributes to broaden the UHTC family and to deliver candidate materials towards the UHTC-based nanocomposites with integrated functional and structural properties and exceptional levels of performance for applications in the harsh environment.

 Bio:

Zhaoju Yu is a full professor in the College of Materials at the Xiamen University, China. She is the deputy director of the Key Laboratory of High Performance Ceramic Fibers (Xiamen University), Ministry of Education, China. She got a PhD degree in polymer chemistry and physics in 2004 at the Wuhan University. She is the recipient of a Humboldt Research Fellowship awarded in 2016 and is guest professor in the frame of an international scientist exchange program with the research group “Disperse Feststoffe” at the Materials and Geosciences Department of the Technische Universität Darmstadt. She received the prestigious ECD Jubilee Global Diversity Award and ACerS Global Ambassador (2022). She serves as Associate Editor for the journals Journal of the American Ceramic Society, Ceramics International and International Journal of Applied Ceramic Technology. She was Guest Editor-in-chief for the Journal of the European Ceramic Society. Besides, she is on the editorial boards for several journals such as Journal of Advanced Ceramics, Materials, and Advanced Powder Materials. She has authored more than 100 peer-reviewed papers. In addition, she presented more than 40 Invited Talks at international academic conferences. These highlight her interests covering a variety of different hot topics in materials chemistry as well as in materials science and nanotechnology ranging from synthesis of preceramic polymers to polymer-derived nanoscaled ceramics and characterization of their structural and functional properties.