NOMATEN HYBRID-SEMINAR May 26: Utilisation of the High-Entropy Concept for Designing Complex Structures for Extreme Environments
NOMATEN HYBRID-SEMINAR
online: https://meet.goto.com/NCBJmeetings/nomaten-seminar
In-person: NOMATEN seminar room (102)
Tuesday, May 26th 2026 1 PM (CET)
Utilisation of the High-Entropy Concept for Designing Complex Structures for Extreme Environments
Dr. Peter Tatarko
Institute of Inorganic Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia
Abstract:
High-entropy ultra-high temperature ceramics (UHTCs) have emerged as highly promising materials for extreme environment applications due to their exceptional thermal stability, high melting temperatures, oxidation resistance, and superior mechanical performance at elevated temperatures. These characteristics make them attractive candidates for aerospace, energy, and hypersonic applications, where complex multi-material architectures are often required. However, the practical implementation of these advanced ceramics critically depends on the development of reliable joining technologies capable of producing mechanically robust and thermally stable interfaces without degrading the parent materials.
This work presents the development of high-purity single-phase high-entropy carbides (HECs), including (HfZrTaNbTi)C and (MoNbTaVW)C, fabricated by Spark Plasma Sintering (SPS), together with innovative approaches for joining these novel UHTCs. The presentation is divided into two parts. The first part focuses on the wetting and joining behaviour of (MoNbTaVW)C using a NiTa eutectic alloy interlayer. The addition of 17.2 at.% Ta to Ni effectively reduced interfacial reactions and dissolution of the HEC while maintaining excellent wetting characteristics.
The second part presents a pioneering approach employing a compositionally compatible high-entropy alloy (HfZrTaNbTi) for joining (HfZrTaNbTi)C HEC. The central concept was to utilise the same transition metals in both the ceramics and the interlayer alloy to promote chemical compatibility, controlled diffusion, and enhanced interfacial stability. Joining was performed through solid-state diffusion via SPS. Detailed microstructural characterization using EBSD, HR-SEM, and HR-TEM revealed homogeneous, crack-free, and well-bonded interfaces. Mechanical testing demonstrated excellent joint strengths, with no significant deterioration up to 1000°C. These findings demonstrate the significant potential of high-entropy design concepts for the fabrication of complex, mechanically reliable ceramic structures intended for operation in extreme environments.
Bio:
Dr. Peter Tatarko is a Director of the Institute of Inorganic Chemistry of Slovak Academy of Sciences in Bratislava, Slovakia. After receiving a PhD degree in Materials Science at the Institute of Materials Research of Slovak Academy of Sciences in 2011, for 2 years he worked at the Institute of Physics of Materials of the Czech Academy of Sciences, and 3 years at Queen Mary University of London. Since 2017, he has worked as a senior researcher at the Institute of Inorganic Chemistry. His research activities are focused on the development of new ceramic materials for extreme environments, such as Ultra-High Temperature Ceramics, or High Entropy Ceramics, and the development of new joining materials and technologies for integration of advanced ceramics for aerospace and nuclear applications. He is an Associate Editor of the International Journal of Applied Ceramic Technology of the American Ceramic Society. Dr. Peter Tatarko has supervised 5 PhD students. He has recently received a funding from European Union with the total budget of 3 mil. € to build a new lab on high-entropy perovskite oxides for thermoelectric applications
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