Materials Science, Biomaterials, Surfaces, Coatings and Films, Polymers and Plastics
158
Scopus Publications
Scopus Publications
Thermophysical properties and solidification behavior of liquid Vit106a in microgravity Damien Terebenec, Markus Mohr, Rainer Wunderlich, Hans-Jörg Fecht, Stephan Schneider, et al. Npj Microgravity, 2026 Understanding thermophysical properties such as surface tension ( σ ), total hemispherical emissivity ( ε ), specific heat capacity ( c p ) and viscosity ( η ) as a function of temperature is essential for optimizing the vitrification of bulk metallic glasses (BMGs). In this study, the thermophysical properties of liquid Vit106a were measured aboard the International Space Station (ISS) using the electromagnetic levitator (EML). The surface tension σ exhibited a similar value with other Zr-based BMG, with a weak temperature dependence described by σ(T) = 1.557–4.36 ×10 −5 × (T - 1106) N.m −1 . The viscosity temperature-dependence η(T) was analyzed using the Vogel–Fulcher–Tammann (VFT) equation, yielding a kinetic fragility parameter of D* = 9.8 at high temperature, compared to D* = 21.6 at low temperature, that indicates a fragile-to-strong transition characteristic of Zr-based metallic glass formers. XRD analysis confirms full crystallization of the sample, despite being cooled at a rate of 16 K.s⁻¹, over nine times faster than the critical cooling rate of 1.75 K.s⁻¹ reported in the literature. The crystallized sample reveals a heterogeneous distribution of binary intermetallic phases, including ZrAl 3 , Zr 2 Cu, Zr 2 Ni, ZrAl and Nb 2 Ni. These findings provide insights into the thermophysical behavior of liquid Vit106a for large-scale manufacturing but also raise important questions regarding its good glass-forming ability for larger casting thickness.
Advancing Understanding of High-Temperature Micro-Electro-Mechanical System Failures with New Simulation-Assisted Approach Weronika Lidia Sadurska, Matthias Imboden, Jürgen Burger, Alex Jean Dommann Sensors, 2025 High-temperature micro-electro-mechanical systems (MEMSs) are critical for applications in extreme environments and applications where the operating temperature can exceed 1000 °C, but their long-term performance is limited by complex failure mechanisms, including material degradation caused by atomic migration. This study introduces a simulation-assisted approach to analyze and predict the dominant failure modes, focusing on vacancy fluxes and their driving forces, within high-temperature MEMS structures. The focus is on tungsten-based structures operating at a temperature of 1580 °C. This approach couples electric-, stress- and temperature-dependent simulations to evaluate atomic migration pathways, which are key contributors to failure. This study demonstrates that void accumulation, driven by vacancy migration, results in localized current density increase, hotspot formation, and accelerated structural degradation. The mean time to failure (MTTF) is shown to have exponential dependence on temperature and inverse-square dependence on current density, highlighting the critical role of these parameters in device reliability. These findings provide a deeper understanding of the failure mechanisms in high-temperature MEMSs and underscore the need for design strategies that mitigate electromigration and stress-induced void growth to enhance device performance and longevity.
Electromagnetic levitation containerless processing of metallic materials in microgravity: thermophysical properties M. Mohr, Y. Dong, G. P. Bracker, R. W. Hyers, D. M. Matson, et al. Npj Microgravity, 2023 Transitions from the liquid to the solid state of matter are omnipresent. They form a crucial step in the industrial solidification of metallic alloy melts and are greatly influenced by the thermophysical properties of the melt. Knowledge of the thermophysical properties of liquid metallic alloys is necessary in order to gain a tight control over the solidification pathway, and over the obtained material structure of the solid. Measurements of thermophysical properties on ground are often difficult, or even impossible, since liquids are strongly influenced by earth’s gravity. Another problem is the reactivity of melts with container materials, especially at high temperature. Finally, deep undercooling, necessary to understand nucleus formation and equilibrium as well as non-equilibrium solidification, can only be achieved in a containerless environment. Containerless experiments in microgravity allow precise benchmark measurements of thermophysical properties. The electromagnetic levitator ISS-EML on the International Space Station (ISS) offers perfect conditions for such experiments. This way, data for process simulations is obtained, and a deeper understanding of nucleation, crystal growth, microstructural evolution, and other details of the transformation from liquid to solid can be gained. Here, we address the scientific questions in detail, show highlights of recent achievements, and give an outlook on future work.
Lattice Strain and Defects Analysis in Nanostructured Semiconductor Materials and Devices by High-Resolution X-Ray Diffraction: Theoretical and Practical Aspects Simone Dolabella, Aurelio Borzì, Alex Dommann, Antonia Neels Small Methods, 2022 The reliability of semiconductor materials with electrical and optical properties are connected to their structures. The elastic strain field and tilt analysis of the crystal lattice, detectable by the variation in position and shape of the diffraction peaks, is used to quantify defects and investigate their mobility. The exploitation of high‐resolution X‐ray diffraction‐based methods for the evaluation of structural defects in semiconductor materials and devices is reviewed. An efficient and non‐destructive characterization is possible for structural parameters such as, lattice strain and tilt, layer composition and thickness, lattice mismatch, and dislocation density. The description of specific experimental diffraction geometries and scanning methods is provided. Today's X‐ray diffraction based methods are evaluated and compared, also with respect to their applicability limits. The goal is to understand the close relationship between lattice strain and structural defects. For different material systems, the appropriate analytical methods are highlighted.
Analysis of stress in silicon-based microsystems by X-ray diffraction techniques Empc 2013 European Microelectronics Packaging Conference the Winding Roads of Electronics Packaging, 2013
Advanced in- and out-off plane high resolution X-ray strain analysis on MEMS Nanotechnology 2010 Electronics Devices Fabrication MEMS Fluidics and Computational Technical Proceedings of the 2010 Nsti Nanotechnology Conference and Expo Nsti Nanotech 2010, 2010
In-situ MEMS testing Nanotechnology 2010 Electronics Devices Fabrication MEMS Fluidics and Computational Technical Proceedings of the 2010 Nsti Nanotechnology Conference and Expo Nsti Nanotech 2010, 2010
Solid on liquid deposition J. Charmet, O. Banakh, E. Laux, B. Graf, F. Dias, et al. Thin Solid Films, 2010
Silicon flexure-based micro-balance for batch weighing processes Proceedings of the 9th International Conference of the European Society for Precision Engineering and Nanotechnology Euspen 2009, 2009
Dual-axis single-mirror mechanism for beam steering and stabilisation in optical inter satellite links European Space Agency Special Publication ESA SP, 2003
Reciprocating silicon microtribometer Philippe Dubois, Stephane von Gunten, August Enzler, Urs Lippuner, Alex Dommann, et al. Proceedings of SPIE the International Society for Optical Engineering, 2003
Low energy plasma enhanced chemical vapour deposition - Plasma enhanced deposition of epitaxial Si and SiGe Materials Research Society Symposium Proceedings, 2002
Structural and electrical characterization of Si-modfet structures grown at high rates by LEPECVD Materials Research Society Symposium Proceedings, 2000
Structural and electrical characterization of Si-MODFET structures grown at high rates by LEPECVD Materials Research Society Symposium Proceedings, 2000
