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Contact (User Office)

 

Karlsruhe Nano Micro Facility
KIT-Campus North

Building 440

H.-von-Helmholtz-Platz 1

76344 Eggenstein-Leopoldshafen, Germany

 

phone: +49(721)608-23123

fax: +49(721)608-26273

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User Office

KNMF Profile

KNMF User Meeting 2018

KNMF User Meeting 2018
Place:

Karlsruhe, Germany

Date:

20-21 February 2018

The Karlsruhe Nano Micro Facility (KNMF) provides open and for public work free access to multimaterial state-of-the-art micro and nanotechnologies for national or international users from industry and academia. Our technology portfolio and expertise stimulate the users’ needs and expectations for structuring and characterising a multitude of functional materials, components, and systems at the micro- and nanoscale. We aim at close collaboration and vivid discussions between KNMF technology experts and users.

KNMF cordially invites you to participate in the next KNMF User Meeting. You can meet the KNMF experts, share experiences with KNMF users and improve your knowledge about cutting-edge technologies, and you can participate in training courses.

The participation in the user meeting and the training courses is free but we require a binding online registration. Optionally, a contribution can be submitted (oral or poster presentation). Unfortunately we are not able to offer travel grants except to invited speakers.

We look forward to welcoming you in Karlsruhe.

 

Registration

Deadline for registration and submission of contributions was February 11, 2018.

All participants have been notified by e-mail.

Note to poster authors: Your poster should not exceed a size of width 84,1 cm x height 118,9 cm (DIN A0).

 

Directions, Access & Accomodation

All events will take place at the Karlsruhe Institute of Technology (KIT), Campus North, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany - see directions. A KIT Shuttle is connecting Campus South (downtown Karlsruhe) and Campus North - see timetable. To enter the campus you need an identity document, on-site parking is available. Proceed to building 640 (Institute of Nanotechnology), Lecture Hall. Training courses may take place at other locations on the campus.

Hotels are available in the area. Please use your favourite booking portal and center your search at "Eggenstein-Leopoldshafen". Public transportation is available but a taxi transfer is suggested for quick and easy access.

 

Agenda

Notes:

  • All participants receive automatic confirmations of their registrations.
  • Notifications about the participation in training courses will be sent shortly after the registration deadline.
  • Times and session details may be subject to change.
  • Posters are on display throughout the User Meeting. Please bring your poster and attach it to the prepared poster walls.
  • Usual presentation times (exceptions may apply): invited 25 min + 5 min discussion, all others 15 min + 5 min discussion.

 

February 19, 2018 (Monday) - extra time for polymer microfabrication course, part 1

14:00-17:00 Training Course „Polymer Microfabrication 1“

 

February 20, 2018 (Tuesday)

09:00-12:00 Training Courses

12:00 Registration and Lunch Buffet, setting-up of the posters

13:00 Welcome, KNMF Status and KUC Announcements

13:40 TECHNOLOGY PRESENTATIONS

  • SURMOFs: A new material platform for the development of sensors, optical metamaterials and electric devices (Hartmut Gliemann)
    SURMOFs represent a new class of highly porous and highly crystalline materials that may be used as host structures for molecules or nanoparticles with high application potential in gas storage or filtering systems, optical sensors, and catalytically active materials, to name a few examples. They consist of two main components: metallic nodes and organic linker molecules which are assembled by a layer-by-layer (LBL) deposition procedure (e.g. automated spray or dip coating techniques). The thickness of the layers is determined by the number of synthesis cycles while the size and chemical properties of the SURMOF pores are defined by the used linker molecules.
  • Atom Probe Tomography and Field Ion Microscopy (Torben Boll)
    Atom probe tomography (APT) permits a three-dimensional analysis of species distribution with individually resolved atoms and allows to quantify even small amounts of trace elements. For this a needle shaped tip with a diameter around 100 nm is exposed to a high electric field. With an additional voltage or laser pulse single atoms are evaporated and accelerated to a 2D-Detector, where their time of flight is measured. Form the obtained data a 3D representation of the tip is reconstructed.
  • Recent advances in in situ TEM and 4D-STEM (Christian Kübel)
    With the recent advances in electron microscopy, it has become possible to provide an increasingly complete and quantitative characterization of materials and to perform this in situ with different stimuli to directly image structural changes including intermediate structures. With this presentation, some of these possibilities will be illustrated using in situ HRTEM to follow the formation of nanocrystalline graphene and quantitative in situ 4D STEM to study the mechanical deformation and thermal annealing of nanocrystalline metals as examples.
  • 3D-Printing: Principles, Materials and Limitations (Steffen Scholz, Tobias Müller, Thomas Hanemann)
    3D printing has been and still is in the focus of researchers and industry because of its ability to create complex shaped, customizable parts without the need for expensive and time-consuming tool-construction and high material consumption. Despite the wide interest in the technology its industrial application is still limited and research areas are still manifold. The talk will be focusing on the differences between existing 3D printing technologies, available materials as well as restrictions and possible applications.

15:00 Coffee Break

15:30 LIGHTHOUSE PRESENTATIONS: CATALYSIS (4 x 30 minutes including discussions)

  • Complementarity of electrons and X-rays for characterization in catalysis
    (Jan-Dierk Grunwaldt, KIT, Germany)
  • Impact of the mesopore size distribution on hindered diffusion in KIT-6 and SBA-15 silicas: Insights from pore-scale simulations in physical reconstructions
    (Ulrich Tallarek, Philipps-Universität Marburg, Germany) - INVITED
  • Tuning the selectivity of furfural hydrogenation over Pd and Ru catalysts
    (Alberto Villa, Università degli Studi di Milano, Italy) - INVITED
  • Nanoparticles as Model Catalysts in the Direct Synthesis of Dimethyl Ether
    (Silke Behrens, KIT, Germany)

17:30 Happy Hour & Poster SessionFlying Barman

18:30 Dinner Buffet

20:00 End of Meeting Day 1

 

February 21, 2018 (Wednesday)

09:00 Welcome

09:05 KNMF USER PRESENTATIONS

  • Coverage analysis of alumina coated cathode active material particles for lithium-ion batteries (Nadine Dannehl, Robert Bosch GmbH)
    Lithium nickel cobalt manganese oxides are widely used cathode materials in commercial lithium-ion batteries. Inorganic coatings can improve their capacity retention. To reveal the most relevant working mechanism of the stabilization it is crucial to determine the degree of coverage and morphology of the particle coatings with thicknesses in the nanometer regime. Silicon wafers as a reference system were coated with various thicknesses of alumina coatings by atomic layer deposition (ALD). Cathode active material powders were coated either by ALD or by chemical solution deposition. We used a multiple technique analysis approach for the wafers and powders including Time-of-Flight Secondary Ion Mass Spectrometry, Scanning Electron Microscopy/Energy Dispersive X-Ray Spectroscopy, elemental analysis and Transition Electron Microscopy. We show first results of our investigations and estimate the information depth of surface analysis for the coated cathode material.
  • Thin ultrananocrystalline diamond films as implant coatings (Daniel Merker, Kassel University)
    The biocompatibility of diamond combined with excellent physical and chemical properties motivated various medical and biological applications of diamond films. We investigate the possible application of ultrananocrystalline diamond (UNCD) for bone implant coating. The layers are grown by MWCVD, modified with plasma or photochemical treatment and characterized with various techniques (SEM, AFM, contact angle, zeta-potential, friction behavior). The biological compatibility is investigated by the study of the cell morphology and protein content of several cell lines grown on the different UNCD samples. Furthermore, we aim to incorporate silver nanoparticles into the layer to achieve antibacterial properties for the implant.
  • First in-vivo x-ray dark-field chest radiography: A feasibility study in a living pig (Konstantin Willer, TU Munich)
    X-ray chest radiography is the tool predominantly used for the initial assessment of the human lung in daily clinical routine. However, it lacks diagnostic sensitivity for detection of pulmonary disorders related to structural changes in the lung parenchyma, in particular at an early stage. Recent studies on x-ray dark-field imaging with mice have shown high potential to overcome this issue as the generated signal is highly correlated with microstructural parameters of the lungs. The goal of this study was to demonstrate the translation of this technique to an application suitable for human chest x-ray imaging.
  • Ordering in Al-containing Refractory High Entropy Alloys Analyzed by Complemental Microstructure Characterization Techniques (Hans Chen, KIT)
    Al-containing refractory high entropy alloys (HEAs) combine metals with high melting points, low density and passivating oxide scales and are prospective for applications as high temperature materials. We present investigations on several derivatives of the Nb-Mo-Cr-Ti-Al systems that form single-phase microstructures after arc-melting and subsequent homogenization at 1200 °C up to 1500 °C. TEM bright field (BF) images exhibit thermal anti-phase domain boundaries (APB) which prove a disorder-order phase transformation during cooling. By means of APT, the local composition of the APB was quantified. Thus, elements contributing to the ordering could be identified.
  • Multifunctional Bioinspired Polymeric Nanofur for Environmental Applications (Hendrik Hölscher, KIT)

10:45 KNMF User Committee (KUC) Session

11:00 Coffee Break

11:20 TECHNOLOGY PRESENTATIONS

  • Scanning Probe Lithography and Related Techniques (Michael Hirtz)
    Scanning Probe Lithography methods as dip-pen nanolithography (DPN) and polymer pen lithography (PPL) offer a broad range of tools for the functionalization of surfaces with arbitrary surface patterns of high resolution and accuracy. In this talk, the basic concepts of DPN, PPL and related techniques will be explained and some applications in surface and device functionalization will be shown. Special emphasis will be laid upon applications in bioactive surfaces and sensor functionalization.
  • Secondary Ion Mass Spectrometry – SIMS (Alexander Welle)
    SIMS offered since several years from KNMF is a versatile surface analysis tool for many kinds of applications: Polymers, organic and inorganic semiconductors, alloys with respect of their composition, layer structure, corrosion and catalysis; protein adsorption, environmental studies, etc. SIMS provides not only mass spectra but also chemical imaging with lateral resolution down to 200nm, and depth profiling to reach layers in up to 1 µm depth. The principles of this technology will be presented along with several application examples.
  • X-Ray Photoelectron Spectroscopy (XPS): Basics and Rapid Chemical Imaging (Vanessa Trouillet)
    XPS, one of the available surface analysis techniques at the KNMF, provides quantitative information about the elements present in the first 6-10 nm of sample surfaces and in addition about their chemical state. In particular, surface modifications in general, polymer grafting, catalysts etc. can be characterized regarding chemical composition. Moreover, XPS can provide the necessary proof of successful single reaction steps of complete synthesis routes e.g. to polymer-modify surfaces. Furthermore, the newly available snap map option for our K-Alpha+ spectrometer enables rapid chemical imaging of structured surfaces. First results on quantitative chemical state mapping within an area up to 3 mm x 3 mm will be presented.

12:20 LATE SUBMISSIONS

  • Alignment of single-crystalline cobalt-doped zinc oxide platelets by Langmuir-Blodgett technique (Rudolf Hoffmann, TU Darmstadt)
    The oriented deposition of zinc oxide single crystals is a potentially attractive route to novel piezotronic devices. A synthetic procedure for hexagonal discs of Co-doped ZnO was found, which allows the subsequent coating of substrates by means of the Langmuir-Blodgett technique. In contrast to plethora of reports on nanowires and –rods, the formation of single-crystalline discs or platelets of ZnO is complicated. This involves a chemical bath process with adjustment of solvent and additives. In a second step the LB process was optimized to deposit tesselations of monolayers of such hexagons.
  • ...

12:55 Closing Remarks

13:00 End of Meeting Day 2

 

Training Courses

  1. CANCELLED: Atomic Force Microscopy (AFM) - Dr. Stefan Walheim
    Tuesday 9am - 12am, building 640
    Hands-on training course for AFM beginners. A presentation of the basic principles will be given and the participants will get a short introduction into the operation of an AFM in the KNMF AFM-Lab at INT.
  2. Introduction to Direct Laser Writing (DLW) and practical use of the DLW instrument - Stefan Hengsbach, Dr. Klaus Bade
    Tuesday 9am - 12am (limited to 5 participants). Join the group at 9am in the foyer of building 301.
    The training starts with an introduction into lithography and machine with respect to Direct Laser Writing. A following practical course in the clean room will show the way from layout via spin-coating to writing. After development the fabricated pattern will be inspected. This training for potential users of DLW will show some practical insight into a typical process line and its constraints.
  3. CANCELLED: Scanning Probe Lithography and Related Techniques - Dr. Dr. Michael Hirtz, Dr. Ravi Kumar
    Tuesday Tuesday 9am - 12am (limited to 4 participants). Join the group at 9am in the foyer of building 640.
    In this course you will get some in-lab, hands-on experience in scanning probe lithography methods as dip-pen nanolithography (DPN) and polymer pen lithography (PPL). You will be able to discuss in depth with technology experts and take part into the functionalization of a substrate. If desired, you can discuss your own test pattern with the technology expert and try to implement it right away. Target audience: beginners.
  4. Introduction to Electron Microscopy (SEM, FIB, TEM) - Dr. Christian Kuebel, Dr. Sabine Schlabach
    Tuesday 9am - 12am, building 640, room 0-440
  5. Polymer Microfabrication 1: Manufacturing of Nickel Molds (Shims) - Dr. Markus Guttmann
    Monday 2pm - 5pm, (limited to 5 participants). Join the group at 2pm in the foyer of building 301.
    Introduction to structured substrates (master) and electroforming of nickel shims with practical demonstrations.
  6. Polymer Microfabrication 2: Micro Replication - Dr. Matthias Worgull
    Tuesday 9am - 12am, join the group at 9am in building 307, room 322 (limited to 5 participants)
    Note: this course requires the participation in Polymer Microfabrication 1: Manufacturing of Shim Molds.
    Introduction to the replication of plastic micro and nano structures with practical demonstrations.
  7. Spectroscopy and spectromicroscopy with soft x-rays – a primer
    Dr. Stefan Schuppler, Dr. Michael Merz, Dr. Peter Nagel
    Tuesday 9am - 12am, meeting point: KIT Synchrotron, building 348
    The soft x-ray analytics facility WERA at the Karlsruhe Synchrotron combines experimental chambers (“endstations”) for x-ray absorption, x-ray magnetic circular dichroism, and photoemission with a photoemission electron microscope (PEEM), which adds high lateral resolution and “spectroscopic mapping” to the mix. Excitation with soft x-rays from the synchrotron turns all this into a highly versatile “toolbox” for studying in detail the electronic and magnetic structure of many novel materials. Typically, the results are specific to each element in the compounds, often also to its valence state and spin state. The training course gives an introduction into the cluster of experimental possibilities at WERA.

 

List of Posters

(as of February 9, 2018)

  1. ZnO-based thin films characterization by XPS and ToF-SIMS (Filipe Correia, University of Minho)
    In this works we develop ZnO-based thin films to produce a totally transparent thermoelectric module, to be applied on specific application, solar cells or touchscreen. For this purpose, the films besides having good electric and thermoelectric properties have to be optically transparent and be able to be doped as n- type and p- type. The strategy is to tune the ZnO thin films properties by cationic and anionic doping: with Ga/Al to improve the type n conductivity, with N to have an p type conductivity and Bi to decrease the thermal conductivity. The first results of XPS and ToF-SIMS allows to optimize the production parameters.
  2. Hydrogen Distribution on Atomic Scale: Atom Probe Tomography (Ryota Gemma, Tokai University)
    Atom probe tomography (APT) is an emerging analysis technique to visualize hydrogen or deuterium (D) distribution on near atomic scale. We have been investigating local deuterium distribution in metallic thin films by APT. In our previous report [1], use of heavier isotope, namely D was suggested to achieve correct analysis results because of a lower diffusivity than that of hydrogen (H). Moreover, the importance of the analysis temperature has been clearly indicated also for V single layered films. In these results, local enrichment of hydrogen at defect sites was suggested. In contrast, a local D-depletion, called dead layer (DL) [2] with 0.4-0.5 nm thickness, has been found directly for the first time, in the vicinities of interface of Fe/V layer-structured films.
  3. Development of multi-focus compound refractive X-ray lenses (Alexander Opolka, KIT)
    High energy full-field X-ray microscopy is a powerful technique. It is used both with synchrotron sources and with X-ray tubes. Compared to synchrotrons, X-ray tubes are relatively cheap. A drawback using X-ray tube sources is the relatively long exposure time (currently on the order of hours). One way to decrease the exposure time would be to arrange multiple compound refractive lenses in a lens-array in which every lens is directed at the same point in the sample plane at the optical axis. With such a multi-focus objective lens the exposure time could be reduced dramatically (in the case of a 5 x 5 lens-array, to minutes). To fabricate such a device KNMF’s deep X-ray lithography technology is used.
  4. Investigation of Local Deformation Behavior of Ultrafine-Grained Steel via Compression of Facetted Micro Pillars Produced by Focused Ion Beam (Laura Ahmels, TU Darmstadt)
    During the SPD-related forming process linear flow splitting a strongly elongated pancake UFG microstructure is produced. Since this microstructure exhibits an unusual saturation behavior during the process, the local deformation behavior of the HSLA steel pancake microstructure under compression is of high interest. In the present work, micropillars with a polished facet were FIB milled and compressed inside an SEM using an in-situ nanoindenter with a diamond flat punch. The facet was used to observe of the microstructure of the pillar during the compression as well as to perform EBSD before and after the compression and thereby obtaining information about the local deformation behavior.
  5. A phantom (quality control test structure) for the quantitative determination of the spatial resolution in slice-selective 2D-FT Magnetic Resonance Microscopy based on deep X-ray Lithography (XRL): first results (Andreas Berg, Medical University of Vienna)
    The most important quality control criterions for improvements in high resolution imaging apparatus are represented by the features: contrasting capabilities and spatial resolution. There exist no test structures (phantoms) for Magnetic Resonance Microscopy for standardized quantitative measurements on spatial resolution in the range of 100-1 µm. Within a research proposal (2015-013-006488) at KNMF a prototype phantom consisting of several sets of fine grids with different spatial periods is developed and evaluated, which can be used not only for a quick visual qualitative check on spatial resolution, but also offers the possibility for the quantitative determination of the modulation transfer function (MTF) and derive a quantitative number on the achieved spatial resolution. The proposed design is especially suited for the slice selective 2DFT MR-imaging protocols with different spatial encoding principle in the two orthogonal in-plane directions, usually applied in MRM. This design poses high demands on the manufacturing technology especially with regard to the ratio of height to width of the µ-structures (aspect ratio). We report about our first results on a) achieved maximum spatial frequencies for MTF-evaluation, b) grid-plate-slit ratios, c) height of the plates with reference to the width (aspect ratio) and d) mechanical stability limitations and manufacturing artefacts using the low divergence of synchrotron irradiation within X-ray lithography (XRL). First MR-microscopic evaluations are shown. Though the envisaged minimum structural size of 1 µm in design proposal could not be achieved, the developed prototype offers already unique possibilities for quantitative resolution quality control in slice selective 2DFT imaging for all commercially available MR-microscopy systems, very important for the documentation of visualization improvements.
  6. Decomposition of methane over carbon microfibers modified by Ni, Co, Cu catalysts to produce hydrogen (Katarina Sisakova, Pavol Jozef Šafárik University in KO)
    H2-O2 fuel cells are environmentally friendly and high efficient devices that produce electricity and heat by electrochemical oxidation of hydrogen. However, current hydrogen production processes produce a huge amount of carbon dioxide. The synthesis of hydrogen by thermal decomposition of methane does not produce any CO, so it can be supplied directly to the fuel cell. In the pyrolysis process alone without the use of a catalyst, the maximum yield is a couple of decimal places. Catalyst application significantly increases the yield of hydrogen. As catalysts for conversion of methane were used carbon microfibers doped by metals, due to their interesting properties such as high temperature resistance, none formation of metal carbides, tolerance against aggressive impurities from methane, production of pure carbon. Graphite is basically inactive, so it is necessary to use active carbon which will increase reaction speed of pyrolysis decomposition of methane. We assume that studying structure and surface of carbon microfibers doped with metals will help us to better understand mechanism of catalysis.
  7. Lanthanide-Based Single Ion Magnets with pressed antiprismatic geometry (D4d Symmetry) (Zhao-Sha Meng, Southern University of Science and Technology)
    Last year, we prepared a series of isostructural complexes {Ln3Cd}(Ln = Gd 1, Tb 2, Dy 3, Ho 4). There is a triangle within three Ln3+ in different geometries linked by two deprotonated phenol hydroxyl from two ligands, one carboxylate and one rare peroxide group. In the magnetic studies, 2, 3 and 4 exhibits strong magnetic anisotropy. Dy3Cd (3) shows frequency dependent single-molecule magnet behavior, but with quantum tunneling problems. Based on the quantum tunneling problems above, we try to solve the problem in two steps: First, investigating Dy3+ single-ion anisotropy itself in the absence or weak coupling; reintroducing the role of different coupling strength, anisotropic coupling problem gradually increased when coupling. So we start from the studying of a Dy-Based Single Ion Magnets with pressed antiprismatic geometry, which shows a higher energy barrier and blocking temperature.
  8. The air retaining surface of the backswimmer Notonecta – A new sensory system for pressure and flow measurement (Matthias Mail, Nees-Institute for Biodiversity of Plants)
    Biological surfaces provide a fascinating variety of structures and functions. By analyzing the hairs on superhydrophobic surfaces of the backswimmers Notonecta we found a new type of sensory system. Investigating the fine structure at the base of the hairs we found clear evidence for mechanosensitive cells which, in combination with the compressible air layer, allow the backswimmer to detect its prey as well as possible predators. This new sensory system is not only interesting from a scientific point of view; transferred into technical devices it will allow the development of novel pressure and acoustic sensors.
  9. Air layers under water – Imaging the air-water interface of submerged superhydrophobic surfaces by AFM (Matthias Mail, Nees-Institute for Biodiversity of Plants)
    Some superhydrophobic surfaces are capable of keeping a stable air layer when submerged in water. Such air layers bear a great potential and are of high scientific interest. They could be utilized in several technical applications, amongst others, as drag reducing ship coatings or as anti-fouling coatings. One of the most important parameters in terms of the stability of the air layer, its diffusion behavior and its drag reducing properties is the shape of the air-water interface. Measuring its topography is difficult especially on surfaces with very small structures. Despite the interface being very sensitive to mechanical impact we succeeded in imaging the topography by contact mode Atomic Force Microscopy.
  10. Nd-Fe-B Grain Boundaries (Tim Helbig, TU Darmstadt)
    Grain boundary engineering is an important task for the production of high Nd-Fe-B coercivity permanent magnets. The grain boundary in Nd-Fe B consists of different Nd-rich phases. The interface between the Nd2Fe14B main phase and the grain boundary phases largely determines the coercivity of the magnet.
  11. RDF-imaging for heterogeneous amorphous materials (Xiaoke Mu, KIT)
    To overcome some of the challenges in characterizing heterogeneous nanostructured glasses, we developed a new method, RDF imaging, combining scanning transmission electron microscopy diffraction mapping with radial distribution function (RDF) analysis followed by hyperspectral analysis, to enable phase analysis and mapping of heterogeneous amorphous materials purely based on their short- and medium range atomic ordering. We applied this newly developed method to an amorphous zirconium oxide and zirconium iron multilayer system, demonstrating an extreme sensitivity of the method to small atomic packing variations. This approach has great potential to understand local structure variations in glassy composite materials and to provide new insights to correlate structure and properties of glasses.
  12. TEM study of phase distribution in partially charged LiFePO4 (Xiaoke Mu, KIT)
    TEM based automated crystal orientation mapping (ACOM) and energy filtered TEM (EFTEM) was used to map the de/lithiated phases of half discharged LFP nanoparticles ex situ. The map indicates that large number of particles are either LFP or FePO4 (FP) under thermodynamically stable condition. However, interestingly, quite a number of particles are observed with a typically well-defined planar phase boundary between LFP and FP. We analysed the crystallographic properties of the LFP/FP interface. This experimentally confirms the theoretical predictions based on the interfacial strain energy. The results offer a deeper understanding of the intercalation reaction. It indicates the existence of an energetically preferred two-phase reaction boundary.
  13. Austenitic Nanoclustered ODS Steels for High Temperature Applications (Sascha Seils, KIT)
    Oxide dispersion strengthened (ODS) steels are promising materials for applications at temperatures up to 700 °C in harsh environments. The key to achieve these extraordinary properties are homogenously distributed, nanometer scaled oxide dispersoids (below 4 nm in size). In our work, we focus on new kinds of austenitic ODS steels expected to exhibit advantageous high temperature properties compared to well-studied ferritic ODS steels. Austenitic ODS steels composed as simple as possible were produced by mechanical alloying and subsequent sintering. Microstructural properties were analyzed in the as-milled powders as well as in the consolidated and annealed material. On the nanoscopic length scale atom probe tomography (APT) revealed nanoclusters rich in yttrium, titanium, chromium and oxygen, occurring after every processing step. Nanoclusters and austenite grain size of these alloys revealed to be stable even after annealing for 1000 h at 1000 °C.
  14. Accurate effective atomic number determination with polychromatic grating-based phase-contrast computed tomography (Lorenz Birnbacher, TU Munich)
    Grating-based phase-contrast computed tomography (GBPC-CT) is a recently developed experimental imaging X-ray technique, which also allows to measure the electron density and effective atomic number. However, the determination of both quantities is challenging when dealing with polychromatic GBPC-CT setups. We present an approach to calculate the effective atomic numbers with a polychromatic, laboratory GBPC-CT setup operating between 35 and 50 kVp. We investigated the accuracy of the attenuation coefficient and the electron density. With the reliable experimental quantitative values we were able to evaluate the effective atomic numbers of the investigated materials. As a result, we could calculate two physical absolute quantities that are in general independent of the specific experimental conditions like the spectrum or the setup design.
  15. Scanning X-ray Vector Radiography (Yash Sharma, TU Munich)
    X-ray Vector Radiography (XVR) is an imaging modality that reveals the orientations of sub-pixel sized structures. It uses the anisotropic property of the dark-field signal obtained in an X-ray grating interferometry setup. In this work, we present a novel way to perform XVR of continuously moving samples without any grating translation during the measurement. Avoiding grating motion provides significant advantages in terms of stability and repeatability, thus making this time of system more robust for industrial applications.
  16. Optimization of the first in-vivo X-Ray Dark-field and Phase-Contrast CT-Scanner (Stephan Umkehrer, TU Munich)
    During the past decade grating based interferometers enabled phase-contrast imaging with low-brilliance, lab based X-ray sources and became more and more important. By means of the first in-vivo dark-field and phase-contrast small-animal CT scanner several medical imaging applications have been shown in the past few years. Especially for early detection of lung disorders, the dark-field is a useful contrast modality as it provides useful information by reflecting the amount of scattering of the lung. Using 2D radiography, structural damages in the lung tissue, caused by diseases like COPD or pulmonary carcinoma, could already be observed by changes in the dark-field signal. Compared to conventional absorption contrast, the dark-field contrast shows an increased sensitivity. Though, for dark-field and phase-contrast imaging a time consuming phase stepping routine has to be performed, at least for this setup. As in-vivo tomographies have to deal with limited total imaging time due to anesthesia and the aim not to harm the animals, the data acquisition has to be as time-efficient as possible. Therefore we investigated the impact of several imaging parameters to the data acquisition protocol. In a first step it could be shown that it is sufficient to separate the reference scan from the sample scan. Beyond that, we studied the influence of reducing the exposure time, the amount of phase steps and several delay parameters, and therefore adapting and increasing the number of angular projections.
  17. Characterization of titanium dioxide nanoparticles extracted from commercialized sunscreens (Allan Philippe, University Koblenz-Landau)
    The fate and toxicity of TiO2 nanoparticles released from sunscreens have not been fully addressed due to the gap between model nanoparticles usually used in studies and the more complex particles found in commercial products. Therefore, we extracted TiO2 nanoparticles from various sunscreens and characterized their shape and their surface coating. TEM and dynamic light scattering revealed a high diversity of particle shape, although size parameters were comparable. Isoelectric points were below 4.6 for all extracts. TOF-SIMS revealed that most particles were coated with PDMS. Images inside the sunscreens using cryogenic TEM showed that particles were agglomerated. These findings are currently used for evaluating ecotoxicological data.
  18. How to improve injection moulded micro parts by simulation (Volker Piotter, KIT)
    Although established in macroscopic fabrication simulation of micro replication shows distinctive specialities. For example, the high shear stresses and the large surface to volume ratios of micro parts have to be considered. Nevertheless, if performed correctly micro simulation reduces the risk of expensive and long running reworking efforts.
  19. Grating-based X-ray phase-contrast scanner (Veronika Ludwig, Erlangen University)
    Bringing a Talbot-Lau grating interferometer into an X-ray imaging setup allows access to three different kinds of image information: the attenuation, the differential phase, and the dark-field image. To operate a grating-based system in clinical routine several challenges have to be overcome. The demand of very large, bent X-ray gratings can be avoided by using an X-ray scanning device. It is only necessary to extend the grating area in just one dimension. In this contribution, we present a grating based X-ray scanning device comprising gratings of 50cm x 1cm size. The system is operable in a range of 60kV to 125kV tube voltage.
  20. Hierarchical Tomographic Techniques of Nanoporous Gold Catalyst (Yakub Fam, KIT)
    Imaging techniques in a two-dimensional (2D) perspective are common, but three-dimensional (3D) ones have been increasingly utilized since they generate more information, which 2D methods alone are not able to. Moreover, the 3D-image results can also be further used as a model for computational or simulation studies. Here, three tomographic techniques, i.e. ptychographic x-ray computed tomography, focused-ion-beam slice-and-view and electron tomography, were utilized and compared to investigate the physical properties of ceria-incorporated nanoporous gold. Each technique has its own advantages and drawbacks, hence they are eventually complementary to each other.
  21. Stabilization methods for high-aspect ratio X-ray gratings (Philipp Riederer, TU Munich / KIT)
    We started to investigate two stabilization methods to fabricate high-aspect ratio X-ray gratings for differential phase-contrast imaging. One approach is the controlled electroplating of metal bridges on top of the laser-structured polymer-grating. The other approach focusses on a partial remove of the polymer resist between the metal-lamellas to ensure a bottom stabilization. Both methods are presented and first results are demonstrated.
  22. Laserstructuring of nickel enriched NMC thick film cathodes for Lithium-ion Batteries (Jan-Hendric Rakebrandt, KIT)
    Nickel-enriched lithium nickel manganese cobalt oxide (NMC) as cathode material and silicon-doped graphite anodes for lithium-ion batteries increase the specific energy density by more than 30%. In combination with ultrafast laser ablation the energy and power density is further improved to form the next generation of 3D batteries. Here we report recent results due to the impact of ultrafast laser structuring.
  23. HRTEM studies of tailored nanostructures in epitaxially grown FeRh thin films (Saleh Gorji, KIT)
    Magnetic properties of FeRh thin films can be modified by epitaxially growing it on a crystalline substrate with different lattice parameters, where the strain (compressive or tensile) between the FeRh and the substrate lattices alters the nanostructure of the thin film. Understanding these nanostructures is the key to reproduce and tune the functional magnetic properties of FeRh thin films. The thin films investigated here were epitaxially grown on MgO substrate, without and with W and, W-V buffer layers. The cross sectional TEM lamella of epitaxial FeRh thin films were prepared by focused ion beam and studied by aberration corrected transmission electron microscopy (TEM). Results show that it is possible to fine tune the magnitude of the ferromagnetic component, which is attributed to bct FeRh, in the thin films by selecting different buffer layers.