# Ralf Riedel

Ralf Riedel (born 11 February 1956) is a German professor of Materials Science at the Technical University of Darmstadt (TU Darmstadt) in Germany. He is known for his contributions to ceramics, polymer-derived ceramics (PDCs), and high-performance materials, which has advanced the understanding and application of ceramic materials in fields such as aerospace, automotive, and energy technologies.

## Early life and education

Riedel studied chemistry at the University of Stuttgart with his Diploma Thesis concerning "Versuche zur Reduktion von Aldehyden mit weißem Phosphor". From 1984, he pursued a Ph.D. in the field of Inorganic Chemistry at the University of Stuttgart. In 1986, he graduated with his dissertation Weißer Phosphor als Edukt für die Synthese phosphororganischer Verbindungen.
After education, Riedel undertook postdoctoral research at Max Planck- Institute for Metals Research, Institute for Materials Research, PML, Stuttgart in materials processing and characterization techniques. Between 1986 and 1992, he worked on his habilitation concerning "Nicht-oxidische Keramiken aus anorganischen Vorstufen" under supervision of Prof. Dr. G. Becker and Prof. F. Aldinger.

## Career

Riedel was establishing and leading the Dispersive Solids Group at the Institute of Materials Science, Technical University of Darmstadt (TU Darmstadt) as professor from 1993 until his retirement in 2022. His research in the Dispersive Solids Group focused on the development of polymer-derived ceramics, high- temperature materials, and functional ceramics for structural and electronic applications.
Ralf Riedel's career spans several decades with contributions to materials science, particularly in the development and application of polymer-derived ceramics (PDCs) as well as high pressure materials synthesis. His work bridges theoretical research and practical applications. Below is a detailed exploration of his professional journey.

## Research contributions

Riedel´s early research focused on developing ceramic materials through synthesis routes, Highlights of Riedel´s research at the Dispersive Solids Group are as follows:

### Polymer-derived ceramics (PDCs)

Riedel is known for his work on PDCs. He has developed methods to design ceramics at the molecular level, enabling the production of materials with tailored properties. These advances have applications in high-performance coatings, lightweight structural materials, and energy storage technologies. His research into PDCs has been on extending their use to fields like aerospace engineering and microelectronics.

### High-Temperature Ceramics

Riedel's work on ceramics designed for high-temperature environments has advanced the understanding of the thermal stability, creep resistance, and oxidation behavior of ceramics under extreme conditions.

### Ceramic composites

In addition to PDCs, Riedel has contributed to the field of ceramic composites, where he has developed lightweight, high-strength materials by integrating ceramic matrices with other reinforcing materials. These composites are used in applications requiring exceptional mechanical properties, such as turbine blades and wear-resistant components.

### Sustainability and green technologies

In recent years, Riedel has focused on using sustainable materials and processes in ceramics manufacturing, contributing to the development of environmentally friendly materials for energy-efficient systems.

## Collaboration with industry

Throughout his career, Riedel has worked closely with industrial partners to ensure the translation of his research into practical applications. He has collaborated with companies in sectors such aerospace, automotive and energy

## Awards and honors

* 1999: Dionyz-Stur-Gold Medal for Merits in Natural Science, Slovak Academy of Science, Bratislava, Slovak Republic
* 2000: Fellow of "The American Ceramic Society" (USA)
* 2006: Honorary Doctor (Dr. h. c.) of the Slovak Academy of Sciences, Bratislava, Slovak Republic
* 2009: Honorary Professor (Prof. h. c.) of the Tianjin University, Tianjin, P.R. China
* 2012: Tammann-Gedenkmünze of the Deutschen Gesellschaft für Materialkunde
* 2013: Fellow of the European Ceramic Society
* 2014: Fellow of the School of Engineering at The University of Tokyo, Japan
* 2020: International Ceramics Prize 2020 for "Basic Science" of the World Academy of Ceramics
* 2021: Honorary Professor (Prof. h. c.) of the Xiamen University, Xiamen, P.R. China
* 2023: Elected Member of the International Institute for the Science of Sintering

## Editorial activities

* Since 2016: Editor-in-Chief of the Journal “Ceramics International”
* Since 2016: Member of the Editorial Board of the Journal of Ceramic Science and Technology
* April 2018 – December 2027: Editor in Chief, Journal of the American Ceramic Society
* 2023-2025: Associate Editor Nature Portfolio Journal Advanced Manufacturing

## Selected Publications

1. Li Lu, Tonghui Wen, Wei Li, Qingbo Wen, Zhaoju Yu, Shasha Tao, Jincan Yang, Yalei Wang, Xingang Luan, Xiang Xiong, Ralf Riedel, Single-source-precursor synthesis of dense monolithic SiC/(Ti$_0$.$_{25}$Zr$_{0.25}$Hf$_{0.25}$Ta$_{0.25}$)C ceramic nanocomposite with excellent high-temperature oxidation resistance, J. Eur. Ceram. Soc. 44 (2024) 556-609.
2. Honghong Tian, Magdalena Graczyk-Zajac, Alois Kessler, Anke Weidenkaff, Ralf Riedel, Recycling and Reusing of Graphite from Retired Lithium-ion Batteries: A Review, Adv. Mater. 2023, 2308494
3. Liu, Jiongjie; Dong, Changyu; Lu, Xuefeng; Qiao, Zhuhui; Zhou, Feng; Liu, Weimin; Riedel, Ralf, Sn-containing Si$_3$N$_4$-based composites for adaptive excellent friction and wear in a wide temperature range, Journal of the European Ceramic Society, 42 (2022), 913-920.
4. Shrikant Bhat, Leonore Wiehl, Shariq Haseen, Peter Kroll, Konstantin Glazyrin, Philipp Gollé Leidreiter, Ute Kolb, Robert Farla, Jo-Chi Tseng, Emanuel Ionescu, Tomoo Katsura, and Ralf Riedel, A Novel High-Pressure Tin Oxynitride Sn$_2$N$_2$O, Chem. Eur. J. 0.1002/chem. 201904529.
5. Takashi Taniguchi, Dmytro Dzivenko, Ralf Riedel, Thierry Chauyeau, Andreas Zerr, Synthesis of cubic zirconium (IV) nitride, c-Zr$_3$N$_4$, in the 6-8 GPa pressure region, Ceramics international 45 (2019) 20028-20032.
6. Reinold, L.M.; Yamada, Y.; Graczyk-Zajac, M.; Munakata, H.; Kanamura, K.; Riedel, R.; "The influence of the pyrolysis temperature on the electrochemical behavior of carbon-rich SiCN polymer-derived ceramics as anode materials in lithium-ion batteries", J. Power Sources 282 (2015) 409-415.
7. Maged F. Bekheet, Marcus Schwarz, Stefan Lauterbach, Hans-Joachim Kleebe, Peter Kroll, Ralf Riedel, Aleksander Gurlo, "Orthorhombic In2O3: A metastable polymorph of indium sesquioxide", Angew. Chem. Int. Ed. 52 (2013) 6531-6535.
8. S. Sen, S. J. Widgeon, A. Navrotsky, G. Mera, A. Tavakoli, E. Ionescu, R. Riedel, "Can carbon substitute for oxygen in silicates in planetary interiors?", Proceedings of the National Academy of Sciences (PNAS) 110 (2013) 15904 – 15907.
9. E. Horvath-Bordon, R. Riedel, P. F. McMillan, P. Kroll, G. Miehe, P.A. van Aken, A. Zerr, P. Hoppe, O. Shebanova, I. McLaren, S. Lauterbach, E. Kroke, R. Boehler, High-pressure synthesis of crystalline carbon nitride imide, C2N2(NH). Angew. Chem. Int. Ed. 46 (2007) 1476.
10. A. Zerr, G. Miehe, G. Serghiou, M. Schwarz, E. Kroke, R. Riedel, H. Fueß, P. Kroll, R. Boehler, Synthesis of cubic silicon nitride. Nature 400 (1999) 340.