TY - CONF A1 - Beck, Uwe A1 - Weise, Matthias ED - Bräuer, G. T1 - Replica-Techniques for Indirect Inspection of Surface and Coating Defects and for Evaluation of Topography and Topometry of 3D-Shaped Surfaces T2 - Proceedings of the Eight International Conference on Plasma Surface Engineering (Surface & coatings technology 174/175.2003) T2 - 8th International Conference on Plasma Surface Engineering (PSE) CY - Garmisch-Partenkirchen, Germany DA - 2002-09-09 PY - 2002 SN - 0257-8972 VL - 174-175 IS - TuPSC24 SP - 264 PB - Elsevier CY - Amsterdam AN - OPUS4-1622 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Hertwig, Andreas A1 - Reiners, Georg A1 - Weise, Matthias A1 - Hartung, J. A1 - Reinhold, E. A1 - Strümpfel, J. T1 - Ion-assisted vs. Plasma-assisted PVD: Preparation of Optical Multi-layers in a Versatile Cluster System Implementing Electron Beam and Sputter Technology T2 - 47th Annual Technical Conference Proceedings KW - Thin Film Technology KW - Ion-assisted PVD KW - Plasma-assisted PVD KW - Optical Multi-layers KW - Cluster Deposition System PY - 2004 SN - 0737-5921 SP - 86 EP - 90 PB - Society of Vacuum Coaters AN - OPUS4-3536 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beck, Uwe A1 - Hertwig, Andreas A1 - Reiners, Georg A1 - Weise, Matthias A1 - Hartung, J. A1 - Reinhold, E. A1 - Strümpfel, J. T1 - Ion Assisted vs. Plasma Assisted PVD: Preparation of Optical Multilayers in a Versatile Cluster System Implementing Electron Beam and Sputter Technology JF - Society of vacuum coaters N2 - Functionality of optical systems requires optical coatings of high quality which have to be adapted to the application in terms of the performance of optical parameters such as reflectivity (AR, low, defined, high), the substrate material of interest (polymers, ceramics, and glass), the environmental conditions (such as temperature or humidity), and the service conditions (such spectral range and power density). Moreover, in many cases, additional non-optical requirements have to be met, including mechanical features such as scratch resistance, hardness and modulus. Consequently, thickness and overall uniformity requirements are steadily increasing. In general, these demands can usually not be achieved by a single film or coating. Instead, films with specific design features (such as gradients), layer stacks and multilayers are a prerequisite for high quality layers and their reliability. For the development of such layer systems, a versatile cluster deposition system consisting of three clusters and a cluster-to-cluster handler has been designed. Besides a PECVD cluster for DLC coatings, two PVD clusters implement ion assisted electron beam evaporation and plasmabased sputter technology. In addition to metallic films, preparation of oxide and nitride optical coatings (SiO2, TiO2, Ta2O5, ITO, Al2O3, TiN, AlN) in various process modifications (nonreactive, partially reactive, full-reactive; rf-, dc-, mf- mode; PEM control) has been carried out. Within this paper, the effect of several process parameters on layer quality (optical constants, density, and uniformity) is discussed for selected applications examples (AR- and HR coatings, applications at elevated temperatures and applications of enhanced mechanical performance). It has been shown that specific features of ion and plasma assisted PVD processes, including ion-beam and plasma preand post-treatment of substrates and layer systems, may widen the application range and improve functionality features of given coating/substrate systems. T2 - 47th Annual Technical Conference Proceedings CY - Dallas, TX, United States of America DA - 2004-04-24 KW - Ion assisted PVD KW - Optical multilayers KW - Plasma assisted PVD KW - Cluster deposition system PY - 2004 UR - http://www.knovel.com/knovel2/Toc.jsp?BookID=1082 SN - 0737-5921 SN - 1539-2236 SP - 86 EP - 90 CY - Albuquerque, NM AN - OPUS4-4148 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beck, Uwe A1 - Hönig, D. A1 - Schneider, S. A1 - Domnick, R. A1 - Belzner, M. A1 - Hertwig, Andreas A1 - Stephanowitz, Ralph A1 - Sahre, Mario A1 - Weise, Matthias T1 - Fabry-Perot-based layer stacks for ellipsometric encoding - Embedded public, hidden, and forensic information for product authentication JF - Vakuum in Forschung und Praxis N2 - Public, hidden, and forensic features either encoded or directly legible are used for authentication. Fabry-Perot layer stacks as information carriers in combination with imaging ellipsometry as optical read-out system provide all-in-one anti-counterfeiting capability that may establish the new security level 'encoded forensic'. Different layer designs are described with regard to all three security levels: public features (e.g. color and tilt effect) perceptible by the human eye, hidden features (e.g. spectroscopic response in the UV or IR), and forensic features (ellipsometric quantities Ψ and Δ as a function of wavelength λ and angle of incidence AOI). Physically uncloneable functions (PUF) could be realized as a result of a multi-material and a multi-parameter deposition approach as well as by means of specific design features of the Fabry-Perot layer stack. Hence, they are not subject to any reverse engineering strategies. Examples of stratified, micro-structured, and laser-modified Fabry-Perot layer systems are considered that may be used at all perception levels (e.g. human eye, bar code reader, and imaging ellipsometry) for authentication against product counterfeiting and related areas. -------------------------------------------------------------------------------------------------------------------- Zur Authentifizierung werden offene, versteckte und forensische Merkmale entweder codiert oder direkt auslesbar verwendet. Mit Fabry-Perot Schichtsystemen als Informationsträger in Kombination mit der abbildenden Ellipsometrie als optischem Auslesesystem steht ein 'all-in-one' Fälschungsschutz-System zur Verfügung, das ein neues Sicherheitsniveau 'kodiert-forensisch' darstellt. Es werden unterschiedliche Schichtdesigns beschrieben, mit denen alle drei Sicherheitsniveaus realisiert werden können: offene Merkmale (z.B. Farbe und Kippeffekt), die mit dem menschlichen Auge wahrnehmbar sind, versteckte Merkmale (z.B. die spektrale Antwort im Sichtbaren oder im IR) sowie forensische Merkmale (ellipsometrische Größen Ψ und Δ als Funktion der Wellenlänge λ und des Einfallswinkels AOI). Physikalisch nicht klonbare Funktionen (PUF) können im Ergebnis einer Multi-Material- und Multi-Parameter Beschichtungsstrategie sowie durch spezifische Design-Merkmale des Fabry-Perot Schichtsystems realisiert werden. Folglich sind solche Schichtsysteme dem 'reverse engineering' nicht zugänglich. Es werden Beispiele für lateral ausgedehnte, mikrostrukturierte und Laser modifizierte Schichtsysteme auf verschiedenen Ausleseniveaus (menschliches Auge, Barcode-Lesegerät, abbildendes Ellipsometer) vorgestellt, die zur Authentifizierung von Produkten und verwandte Gebiete geeignet sind. KW - Fabry-Perot Schichten KW - Ellipsometrie KW - Produkt- und Markenschutz PY - 2012 DO - https://doi.org/10.1002/vipr.201200494 SN - 0947-076X SN - 1522-2454 VL - 24 IS - 4 SP - 6 EP - 11 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-26180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Hertwig, Andreas A1 - Koter, Robert A1 - Weise, Matthias A1 - Beck, Uwe A1 - Reinstädt, Philipp A1 - Griepentrog, Michael A1 - Krüger, Jörg A1 - Picquart, M. A1 - Haro-Poniatowski, E. T1 - Femtosecond laser pulse irradiation effects on thin hydrogenated amorphous carbon layers JF - Applied physics A N2 - The irradiation of ~0.9-µm-thick hydrogenated amorphous carbon (a-C:H) layers deposited on silicon substrates with single femtosecond (fs) laser pulses (35 fs pulse duration, 790 nm centre wavelength) in air is studied experimentally. Irradiation spots have been generated with different peak fluences and subsequently investigated by optical topometry, micro Raman spectroscopy and microscale mechanical indentation in order to evaluate their microscopic, topographical, structural and mechanical properties (e.g. elastic modulus). By this multi-method approach, a clear separation of different effects (delamination and graphitisation) becomes possible. The joint application of mechanical and spectroscopic techniques provides unique insights into the effects of the fs-laser radiation on the carbon layer. PY - 2013 DO - https://doi.org/10.1007/s00339-012-7170-5 SN - 0947-8396 VL - 112 IS - 1 SP - 9 EP - 14 PB - Springer CY - Berlin AN - OPUS4-28629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lucassen, F. A1 - Franz, G. A1 - Wirth, R. A1 - Weise, Matthias A1 - Hertwig, Andreas T1 - The morphology of the reaction front of the dissolution-precipitation reaction rutile + wollastonite = titanite in time series experiments at 600 °C/400 MPa JF - The American mineralogist N2 - Fluid-assisted mass transport reactions by dissolution-precipitation, where a precursor mineral reacts with a fluid, play an important role in metamorphism and metasomatism. We investigated titanite growth on rutile in time series experiments between one and 107 days at constant P-T conditions of 600 °C and 400 MPa in the system TiO2-CaO-SiO2-Na2O-HCl-H2O. A two-capsule assemblage allows for transport of Ca and Si from dissolving wollastonite to dissolving rutile, the Ti-source, in a NaCl-bearing aqueous fluid, according to the general reaction CaSiO3 + TiO2 = CaTiSiO5. Complete overgrowth of rutile by titanite occurred after just one day of experiment. Fine-grained lozenge-shaped titanite crystals of short-time runs (up to 14 days) reorganize to larger predominantly prismatic crystals after >14 days. After investigation by scanning electron microscopy, the titanite overgrowth was removed from the rutile by hydrofluoric acid, to provide a three-dimensional view of the dissolution-reaction front on the rutile surface. The morphology of the rutile surface is dominated by humps or ridges beneath the central region of a titanite crystal and valleys at the grain boundaries between adjacent titanite crystals. The dissolution pattern on the rutile surface mimics the titanite overgrowth and changes with changing grain size and shape of the titanite with longer run times. The preferred dissolution of rutile in the valleys is clearly linked to the position of the titanite grain boundaries, which served as pathways for fluid-assisted element transport. Rutile-titanite and titanite-titanite boundaries show a significant porosity in transmission electron microscopy images of foils prepared by focused ion beam milling. The large-scale dissolution pattern on the rutile surface is independent of the crystallographic orientation of the rutile and entirely dominated by the arrangement of titanite crystals in the overgrowth. Dissolution features on a scale smaller than ~1 µm are dominated by stepwise dissolution and etch-pits following the crystallographic orientation of the rutile. Similar observations were made in experiments with an additional Al-source, although these experiments result in a different overgrowth pattern; i.e., an exposed rutile surface is always present and solitary titanite crystals are accompanied by partial overgrowths. Quantitative characterization of the surface morphology by white-light interference microscopy demonstrates that, with increasing grain size of titanite, dissolution of rutile is strongly enhanced at the titanite grain boundaries. Natural examples of titanite overgrowths on rutile show the same relations between element pathways, arrangement of titanite crystals and 3D dissolution pattern on rutile as in the experimental systems. We conclude that the transport of Ti away from the rutile and of Ca + Si into the reaction rim occurred in a grain boundary fluid, the composition of which must have been strongly different from the composition of the bulk fluid in the experiment, as well as in the natural system. The reaction progress depends on the availability of a fluid, and relicts of rutile in titanite indicate restricted availability of fluid in the natural system (e.g., a fluid pulse that was consumed by the reactions). The reaction examined here can serve as a proxy for other reactions of the conversion of oxide minerals (e.g., spinel or corundum) into silicates. KW - Experimental mineralogy KW - Rutile KW - Titanite KW - Dissolution-precipitation KW - Reaction morphology KW - Geochemistry & Geophysics PY - 2012 DO - https://doi.org/10.2138/am.2012.3742 SN - 0003-004X SN - 1945-3027 VL - 97 IS - 5-6 SP - 828 EP - 839 PB - Mineralogical Society of America CY - Washington, DC AN - OPUS4-27680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Daschewski, Maxim A1 - Harrer, Andrea A1 - Prager, Jens A1 - Kreutzbruck, Marc A1 - Beck, Uwe A1 - Lange, Thorid A1 - Weise, Matthias T1 - A resonance-free nano-film airborne ultrasound emitter T2 - 39th Annual review of progress in quantitative nondestructive evaluation (Proceedings) N2 - In this contribution we present a novel thermo-acoustic approach for the generation of broad band airborne ultrasound and investigate the applicability of resonance-free thermo-acoustic emitters for very short high pressure airborne ultrasound pulses. We report on measurements of thermo-acoustic emitter consisting of a 30 nm thin metallic film on a usual soda-lime glass substrate, generating sound pressure values of more than 140 dB at 60 mm distance from the transducer and compare the results with conventional piezoelectric airborne ultrasound transducers. Our experimental investigations show that such thermo-acoustic devices can be used as broad band emitters using pulse excitation. T2 - 39th Annual review of progress in quantitative nondestructive evaluation CY - Denver, Colorado, USA DA - 2012-07-15 KW - Thermo-acoustic KW - Broad band airborne ultrasound KW - High pressure airborne ultrasound KW - Resonance free ultrasound transducer KW - Broad band ultrasonic emitter KW - Measurement sound particle velocity PY - 2013 SN - 978-0-7354-1129-6 DO - https://doi.org/10.1063/1.4789225 SN - 0094-243X SN - 1551-7616 N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings VL - 1511 SP - 1541 EP - 1546 AN - OPUS4-27790 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Binder, Christian A1 - Kasch, Thomas A1 - Brock, Thomas A1 - Beck, Uwe A1 - Weise, Matthias A1 - Sahre, Mario T1 - Promoted combustion testing of pure and ceramic-coated metals in high pressure oxygen by the federal institute of materials research and testing (BAM) JF - Journal of ASTM International N2 - The new promoted ignition combustion test apparatus at BAM matches the requirements of ASTM test method G 124 [ASTM G 124, Standard Test Method for Determining the Combustion Behavior of Metallic Materials in Oxygen-Enriched Atmospheres, 2003] and of EIGA publication, IGC Doc 13/02/E [EIGA Gas Association Document IGC Doc 13/02/E, Oxygen Pipeline Systems, 2003]. The test apparatus is most likely the only one in Europe. The test chamber allows investigations with pure oxygen or oxygen mixtures at pressures up to 500 bar and at temperatures up to 400°C at static or flowing gas conditions. The ignition device consists of an electrical ignition wire and a promoter. IR-sensors, distributed over the whole length of the rod, measure and record the burning temperature and allow measurement of the burn rate. A video system records the experiment for visual characterization of the burning behavior. BAM test results are compared with published data. Results on investigations with coated rods are presented. Ceramic coatings seem to be a solution for the use of certain less compatible metallic materials at higher oxygen pressures. KW - Promoted combustion KW - High pressure oxygen KW - Metallic materials KW - Flammability KW - Safety engineering KW - Coatings PY - 2006 DO - https://doi.org/10.1520/JAI13533 SN - 1546-962X VL - 3 IS - 4 SP - JAI13533, 1 EP - 6 PB - American Society for Testing and Materials CY - West Conshohocken, Pa. AN - OPUS4-12676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Binder, Christian A1 - Kasch, Thomas A1 - Lehné, Siegfried A1 - Beck, Uwe A1 - Weise, Matthias A1 - Sahre, Mario T1 - Combustion tests under high pressure oxygen: Promoted ignition combustion test versus metallic disk ignition test JF - Journal of ASTM International N2 - Two different test apparatuses are used at BAM to evaluate the safety of oxygen components: First, the “promoted ignition combustion test” according to ASTM G 124 [1] and to EIGA IGC Doc 13/02/E [2], and second, the new “metallic disk ignition test” that has not been standardized yet. The standard test method ASTM G 124 allows a ranking of metallic materials for use at high pressure oxygen. However, the transfer of those test results to valves and fittings in real-life situations is rather complex. The “metallic disk ignition test,” developed at BAM, is more practice oriented and uses metallic disks of different thicknesses of the investigated material. A commonly used nonmetallic sealing ring is placed in front of this disk and serves as an igniter. This test array is then exposed to high pressure gaseous oxygen impacts in a standardized pneumatic impact tester according to DIN EN 1797 [3]. KW - Adiabatic compression KW - Pneumatic impact KW - Flammability KW - High pressure oxygen KW - Metallic materials KW - Promoted ignition KW - Coatings PY - 2006 DO - https://doi.org/10.1520/JAI13532 SN - 1546-962X VL - 3 IS - 5 SP - JAI13532, 1 EP - 5 PB - American Society for Testing and Materials CY - West Conshohocken, Pa. AN - OPUS4-12677 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hertwig, Andreas A1 - Krüger, Jörg A1 - Weise, Matthias A1 - Beck, Uwe T1 - Hydrogen-Containing Amorphous Carbon Layers as Optical Materials in the Near-IR Spectral Range JF - Plasma processes and polymers N2 - Hydrogenated amorphous carbon layers were deposited on various substrates by means of a plasma CVD process with a RF substrate bias as well as an ECR plasma source. The optical properties of the a-C:H layers were obtained via spectroscopic ellipsometry and correlated with their mechanical and chemical properties. The layers from pure RF plasma exhibit a higher absorption constant in the visible spectral range and a higher refractive index. All layers are nearly transparent in the NIR spectral range making them candidates for optical thin layer systems. The laser damage behaviour of the a-C:H layers was investigated with ultrashort pulses. The damage thresholds were consistent with the absorption constants of the layers. Interesting damage morphologies were observed indicating a sensitivity of this experiment to sub-structures in the layer. KW - Kohlenstoffschichten KW - Optische Konstanten KW - Ellipsometrie KW - Laser-Material-Bearbeitung KW - Amorphous KW - Diamond-like carbon KW - Hydrocarbons KW - Laser ablation KW - Optical proper PY - 2007 SN - 1612-8850 SN - 1612-8869 VL - 4 IS - S1 SP - S76 EP - S82 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-14862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hönig, D. A1 - Schneider, S. A1 - Domnick, R. A1 - Belzner, M. A1 - Beck, Uwe A1 - Hertwig, Andreas A1 - Stephanowitz, Ralph A1 - Weise, Matthias T1 - Optical layer systems for product authentication: interference, scattering, light diffusion and ellipsometric encoding as public, hidden and forensic security features T2 - PSE 2012 - 13th International conference on plasma surface engineering N2 - Embedding of information on surfaces is state of the art for identification testing in which public, hidden and forensic features are used. In many instances, the legal authentication of a product, a material or a document is required. Among the surface-based encoded labels, bar codes and data matrices are most frequently applied. They are publicly visible. The material itself is irrelevant, only a sufficient optical contrast is required. However, a strong material dependence of the label can be achieved by means of Fabry-Perot layer stacks. Stack designs are described with regard to all three security levels: public features (e.g. color and tilt effect) perceptible by the human eye, hidden features (e.g. optical response in a given spectral range) detectable by commonly available instruments and forensic features (ellipsometric quantities Ψ and Δ as a function of wavelength λ and angle of incidence AOI) only detectable by sophisticated instruments. Regarding material-correlated authentication, ellipsometric quantities Ψ and Δ are used as encoded forensic features for the first time. Hence, Fabry-Perot layer stacks as information carriers in combination with imaging ellipsometry as optical read-out system provide all-in-one anti-counterfeiting capabilities. T2 - PSE 2012 - 13th International conference on plasma surface engineering CY - Garmisch-Partenkirchen, Germany DA - 10.09.2012 KW - Fabry-Perot layers KW - Ellipsometry KW - Anti-counterfeiting PY - 2012 UR - http://www.pse-conferences.net/tl_files/pse2012/abstractupload/PSE2012-PO1001-ext.pdf SP - 1 EP - 4 AN - OPUS4-27304 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Hielscher, Stefan A1 - Weise, Matthias A1 - Mix, Renate A1 - Lerche, D. A1 - Rietz, U. T1 - Progress in quantitative adhesion testing of films and coatings by means of centrifuge technology - present state of the art T2 - PSE 2012 - 13th International conference on plasma surface engineering N2 - Standardised conventional adhesion tests are time-consuming single-sample tests. Moreover, except for the pull-off test, all these tests provide only qualitative or semi-quantitative (ranking, respectively measurement of an adhesion-correlated quantity) information on adhesion. Sometimes, adhesion is evaluated even under compressive stress conditions (e.g. cross-cut and scratch test), which itself is a contradiction to adhesive strength as defined in terms of tensile force per area. For optical coatings it has been shown that the pull-off test in a centrifuge is definitely a promising alternative with respect to the reliable, fast and quantitative determination of adhesive strength in N/mm2. The force-controlled centrifuge test is the only multiple-sample test which provides reliable quantitative information on the adhesive strength in agreement with DIN EN 15870 and DIN EN ISO 4624 on a statistical basis for up to eight samples simultaneously tested under identical testing conditions. T2 - PSE 2012 - 13th International conference on plasma surface engineering CY - Garmisch-Partenkirchen, Germany DA - 10.09.2012 KW - Adhesion KW - Centrifuge test KW - Plasma modification KW - Tensile strength PY - 2012 UR - http://www.pse-conferences.net/tl_files/pse2012/abstractupload/PSE2012-OR2601-ext.pdf SP - 1 EP - 4 AN - OPUS4-27305 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Döring, Joachim A1 - Bartusch, Jürgen A1 - Beck, Uwe A1 - Weise, Matthias A1 - Bovtun, Viktor Petrovic A1 - Brekow, Gerhard A1 - Kreutzbruck, Marc T1 - Parameter reproducibility of polypropylene ferroelectret transducers for air-coupled ultrasonic testing T2 - IUS 2011 - IEEE International ultrasonics symposium N2 - The extremely low acoustic impedance of polypropylene ferroelectret combined with its piezoelectric properties makes this material suitable for construction of aircoupled ultrasonic transducers for non-destructive testing. For the fabrication of transducers with a stable quality, the reproducibility of their key parameters is of interest. The reproducibility was evaluated by means of (i) impedance spectroscopy and (ii) pulse-echo measurements. (i) Impedance spectroscopy was applied to identify the resonance frequency, the coupling factor and the acoustic impedance of several nominally identical transducers. (ii) Pulse-echo measurements yielded the signal form of these transducers. The variation of the signal amplitude measured with pulseecho technique was about 10 dB. A part of this variation Comes from the deposition of transducer electrodes and another part from local variations of ferroelectret properties. The variation of the signal amplitude was caused by the observed variation of the coupling factor, which was also about 10 dB. The variation of the acoustic impedance was only about 1 dB, thus having no effect on the variation of the signal amplitude. These results indicate that the variability can be reduced by improving the control of electrode deposition and by optimizing the production technology affecting the reproducibility of material properties. T2 - 2011 IEEE International ultrasonics symposium (IUS) CY - Orlando, FL, USA DA - 18.10.2011 KW - Air-coupled ultrasonic transducers KW - Polypropylene ferroelectret KW - Reproducibility PY - 2011 IS - Abstract-ID 258 SP - 1 EP - 3 AN - OPUS4-26405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Daschewski, Maxim A1 - Harrer, Andrea A1 - Prager, Jens A1 - Kreutzbruck, Marc A1 - Beck, Uwe A1 - Lange, Thorid A1 - Weise, Matthias T1 - Metallic nanofilm as resonance-free airborne ultrasound emitter T2 - IUS 2012 - IEEE International Ultrasonics Symposium (Proceedings) N2 - A novel approach for the generation of broadband airborne ultrasound by using the thermo-acoustic effect is presented in this contribution. We investigate the applicability of resonance-free thermo-acoustic emitters for generation of very short high pressure airborne ultrasound pulses. A thermoacoustic emitter consisting of a 30 nm thin metallic film on a usual soda-lime glass substrate generates sound pressure values of more than 140 dB at 60 mm distance. The results are compared with conventional piezoelectric airborne ultrasound transducers. Our investigations show the applicability of the thermo-acoustic devices for broadband and high pressure ultrasound emitters using pulse excitation. T2 - 2012 IEEE International Ultrasonics Symposium (IUS) CY - Dresden, Germany DA - 2012-10-07 KW - Thermo-acoustic KW - Broadband airborne ultrasound KW - Resonance-free ultrasound transducer KW - High pressure airborne ultrasound KW - Sound particle velocity measurement PY - 2012 SN - 978-1-4673-4562-0 DO - https://doi.org/10.1109/ULTSYM.2012.0241 SN - 1948-5719 SP - 965 EP - 967 AN - OPUS4-29152 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weise, Frank A1 - von Werder, Julia A1 - Manninger, Tanja A1 - Maier, Bärbel A1 - Fladt, Matthias A1 - Simon, Sebastian A1 - Gardei, Andre A1 - Höhnel, Desirée A1 - Pirskawetz, Stephan A1 - Meng, Birgit T1 - A multiscale and multimethod approach to assess and mitigate concrete damage due to alkali-silica reaction JF - Advanced engineering materials N2 - Alkali-silica reaction (ASR) is a chemical reaction within concrete which can lead over time to cracking and spalling. Due to the complexity of the problem, it still causes damage to concrete constructions worldwide. The publication aims to illustrate the interdisciplinary research of the German Federal Institute for Materials Research and Testing (BAM) within the last 20 years, considering all aspects of ASR topics from the macro to the micro level. First, methods for characterization and assessment of ASR risks and reaction products used at BAM are explained and classified in the international context. Subsequently the added value of the research approach by combining different, preferably nondestructive, methods across all scales is explained using specific examples from a variety of research projects. Aspects covered range from the development of new test-setups to assess aggregate reactivity, to analysis of microstructure and reaction products using microscopical, spectroscopical and X-ray methods, to the development of a testing methodology for existing concrete pavements including in-depth analysis of the visual damage indicator and the de-icing salt input using innovative testing techniques. Finally, research regarding a novel avoidance strategy that makes use of internal hydrophobization of the concrete mix is presented. KW - Mitigation strategies KW - Concrete KW - Damage analysis KW - Alkali silica reaction KW - Road pavement KW - Accelerated testing KW - Non-destructive testing KW - Microstructure PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:101:1-2022052515100075090235 DO - https://doi.org/10.1002/adem.202101346 SN - 1527-2648 VL - 24 IS - 6 SP - 1 EP - 36 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54951 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ermilova, Elena A1 - Weise, Matthias A1 - Hertwig, Andreas T1 - Hybrid optical measurement technique for detection of defects in epitaxially grown 4H-SiC layers T2 - EOS Annual Meeting (EOSAM 2022) N2 - Recent developments in power electronics require the use of new wide bandgap compound semiconductor. We demonstrate the use of the ellipsometry and white light interference microscopy to detect defects in epitaxially grown SiC layers on SiC substrates. Such hybrid optical metrology methods can be used to better understand the mechanism of the development of the defects as well as their effects on the material´s optoelectronic properties. T2 - EOS Annual Meeting (EOSAM 2022) CY - Porto, Portugal DA - 12.09.2022 KW - Imaging ellipsometry KW - White light interference microscopy KW - Wide bandgap compound semiconductor KW - Epitaxially grown 4H-SiC layers PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561113 DO - https://doi.org/10.1051/epjconf/202226610001 VL - 266 SP - 1 EP - 2 AN - OPUS4-56111 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Frank A1 - Fladt, Matthias A1 - Wieland, M. T1 - Internal water-repellent treatment - a novel strategy for mitigating alkali-aggregate reaction in concrete pavements T2 - Proceedings of the 16th International Conference on Alkali-Aggregate Reaction in Concrete N2 - To prevent future alkali-aggregate reaction (AAR) damage, which has occurred frequently in the Germanhighway network in recent years, a new regulation has been drafted. This regulation severely limits the use of alkali-sensitive aggregates by requiring that their suitability be verified by certified inspectors using newly developed AAR concrete tests that involve the external supply of alkali. This has led to a significant limitation in the number of aggregates usable for concrete pavements. A novel AAR avoidance strategy is now being pursued, which aims to enable the use of borderline alkali-sensitive aggregates through the application of an internal water-repellent treatment. The addition of water repellents during concrete production should significantly reduce the ingress of water and external de-icing salts into the concrete pavement, thus reducing the potential for AAR damage. This paper presents the results of laboratory tests to assess the suitability of this new AAR prevention strategy. Representative, highly AAR-susceptible road paving concrete made with an alkali- sensitive greywacke and various water repellents were used as the basis for these experiments. The tests for concrete suitability included determining the conventional fresh and hardened concrete properties as well as concrete prism tests with external alkaline supply. Building on these results, laser-induced breakdown spectroscopy (LIBS) analyses of de-icing-salt intrusion as well as microscopic examinations for verification of the AAR characteristics were carried out. The results of the AAR concrete tests with external alkaline supply support the conclusion that, when hydrophobic agents containing a suitable active ingredient are used, the AAR damage process in road paving concrete can be sufficiently prevented. T2 - 16th International Conference on Alkali-Aggregate Reaction in Concrete CY - Lisboa, Portugal DA - 31.05.2022 KW - Concrete pavements KW - Internal water-repellent treatment KW - Preventive measures KW - Testing for potential AAR PY - 2021 SN - 978-972-49-2315-4 VL - 1 SP - 511 EP - 524 AN - OPUS4-54551 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritzsche, Sven A1 - Topolniak, Ievgenia A1 - Weise, Matthias A1 - Sturm, Heinz T1 - Shape deviations of DLW microstructures in dependency of fabrication parameters JF - Journal of Micromechanics and Microengineering N2 - Deep understanding of the effects associated with fabrication parameters and their influence on the resulting structures shape is essential for the further development of direct laser writing (DLW). In particular, it is critical for development of reference materials, where structure parameters are precisely fabricated and should be reproduced with use of DLW technology. In this study we investigated the effect of various fabrication and preparation parameters on the structural precision of interest for reference materials. A well-studied photo-curable system, SZ2080 negative photo-resist with 1 wt.% Michler's ketone (Bis) photo-initiator, was investigated in this work. The correlation between applied laser power, laser velocity, fabrication direction on the deviations in the structure shape were observed by means of white light interferometry microscopy. Moreover, influence of slicing and hatching distances as well as prebake time were studied as function of sample shape. Deviations in the structure form between the theoretically expected and the one detected after DLW fabrication were observed in the range up to 15%. The observed shape discrepancies show the essential importance of fine-tuning the fabrication parameter for reference structure production. KW - Direct laser writing KW - Fabrication parameters KW - Structural precision KW - SZ2080 negative photo-resist KW - White light interferometry microscopy PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535906 DO - https://doi.org/10.1088/1361-6439/ac2a14 VL - 31 IS - 12 SP - 1 EP - 8 PB - IOP Science AN - OPUS4-53590 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Daschewski, Maxim A1 - Bartusch, Jürgen A1 - Schadow, Florian A1 - Dohse, Elmar A1 - Kreutzbruck, Marc A1 - Weise, Matthias A1 - Beck, Uwe T1 - Novel air-coupled ultrasonic transducer combining the thermoacoustic with the piezoelectric effect T2 - Proceedings of WCNDT 2016 N2 - In recent years, there has been an increasing industrial demand for one-sided inspection of various structures by means of air-coupled ultrasonic technique. Lightweight structures based on carbon-fibre-reinforced polymers may have very complex shapes, making air-coupled transmission difficult or even impossible. The inspection of concrete structures is another example where one-sided inspection is required. To address these challenges a new type of transducer for air-coupled pulse-echo inspection was developed, which unites two principles: thermoacoustic emission and piezoelectric reception. The thermoacoustic emitter is a titanium electrode with a thickness of several tens of nanometer. This electrode was deposited onto charged cellular polypropylene, which serves as a piezoelectric receiver. The thermoacoustic transmission is based on a transformation of the thermal energy of an electrically heated electrode into the acoustic energy of an ultrasonic wave. Thermoacoustic emitters provide resonance-free behaviour and thus extremely broadband pulses. Charged cellular polypropylene is piezoelectric due to the polarization of its cells and it is well matched to air, with a Young modulus in the order of magnitude of MPa. In this contribution we present some pulse-echo measurements with the first prototypes of the combined thermoacoustic-piezoelectric transducer. T2 - World Conference of Non-Destructive Testing CY - Munich, Germany DA - 13.6.2016 KW - Thermoacoustic KW - Piezoelectric KW - Ultrasonic transducer KW - Ferroelectret PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367151 VL - 158 SP - Mo.1.F.4, 1 EP - 6 AN - OPUS4-36715 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dietrich, Paul A1 - Nietzold, Carolin A1 - Weise, Matthias A1 - Unger, Wolfgang A1 - Alnabulsi, Saad A1 - Moulder, John T1 - XPS depth profiling of an ultrathin bioorganic film with an argon gas cluster ion beam JF - Biointerphases N2 - The growing interest in artificial bioorganic Interfaces as a platform for applications in emerging Areas as personalized medicine, clinical diagnostics, biosensing, biofilms, prevention of biofouling, and other fields of bioengineering is the origin of a need for in Detail multitechnique characterizations of such layers and interfaces. The in-depth analysis of biointerfaces is of special interest as the properties of functional bioorganic coatings can be dramatically affected by in-depth variations of composition. In worst cases, the functionality of a device produced using such coatings can be substantially reduced or even fully lost. KW - XPS KW - Ar gas cluster gun KW - Depth profiling KW - Bioorganic film PY - 2016 UR - http://scitation.aip.org/content/avs/journal/bip/11/2/10.1116/1.4948341 DO - https://doi.org/10.1116/1.4948341 SN - 1934-8630 VL - 11 IS - 2 SP - 029603-1 EP - 029603-5 PB - American Vacuum Society CY - New York AN - OPUS4-36218 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beck, Uwe A1 - Baier, Jennifa A1 - Hidde, Gundula A1 - Hielscher, Stefan A1 - Kittler-Packmor, Kai A1 - Lange, Thorid A1 - Mix, Renate A1 - Weise, Matthias T1 - Multiple-sample approach: reliable ranking and validated statistics of bonding and adhesive strength JF - Dispersion Letters N2 - Bonding strength of adhesive-bonded joints and adhesive strength of coatings have been exclusively determined in single-sample tests using a tensile testing machine. Necessarily, the single-sample approach was also applied to the corresponding bonding procedure. As a consequence, reliability and reproducibility of results were restricted. By applying the newly introduced centrifuge technology, the multiple-sample approach was realized for simultaneous tensile testing of up to eight samples under identical conditions without any disturbing shear-force effects. In order to introduce the multiple-sample approach into the bonding procedure, a hydraulic bonding set-up was developed which enables identical bonding pressure also for slightly different heights of sample assemblies. Both sample approaches were compared for various application examples: ranking of different classes of adhesives, validated statistics of adhesive-bonded joints using one particular adhesive and effects of cleaning and plasma-treatment on the adhesive strength of coatings. The investigated systems included glass, metals and polymer substrates, different adhesives, metallic and dielectric coatings on polymers. KW - Bonding strength KW - Adhesive strength KW - Multi-sample approach KW - Centrifuge technology PY - 2014 SN - 978-3-944261-28-7 SN - 978-3-944261-36-2 SN - 978-3-944261-52-2 VL - 5 SP - 1 EP - 5 AN - OPUS4-31310 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Baier, Jennifa A1 - Hidde, Gundula A1 - Hielscher, Stefan A1 - Kittler-Packmor, Kai A1 - Lange, Thorid A1 - Mix, Renate A1 - Weise, Matthias T1 - Multiple-sample approach: reliable ranking and validated statistics of bonding and adhesive strength T2 - EURADH 2014 - 10th European Adhesion Conference (Proceedings) N2 - Bonding strength of adhesive-bonded joints and adhesive strength of coatings have been exclusively determined in single-sample tests using a tensile testing machine. Necessarily, the single-sample approach was also applied to the corresponding bonding procedure. As a consequence, reliability and reproducibility of results were restricted. By applying the newly introduced centrifuge technology, the multiple-sample approach was realized for simultaneous tensile testing of up to eight samples under identical conditions without any disturbing shear-force effects. In order to introduce the multiple-sample approach into the bonding procedure, a hydraulic bonding set-up was developed which enables identical bonding pressure also for slightly different heights of sample assemblies. Both sample approaches were compared for various application examples: ranking of different classes of adhesives, validated statistics of adhesive-bonded joints using one particular adhesive and effects of cleaning and plasma-treatment on the adhesive strength of coatings. The investigated systems included glass, metals and polymer substrates, different adhesives, metallic and dielectric coatings on polymers. T2 - EURADH 2014 - 10th European Adhesion Conference CY - Alicante, Spain DA - 22.04.2014 KW - Bonding strength KW - Adhesive strength KW - Multi-sample approach KW - Centrifuge technology PY - 2014 SN - 978-84-616-9067-1 SN - 84-616-9067-2 SP - Paper 49, 211 EP - 214 AN - OPUS4-31309 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koter, Robert A1 - Weise, Matthias A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Krüger, Jörg T1 - Influence of film thickness and optical constants on femtosecond laser-induced ablation of hydrogenated amorphous carbon films JF - Journal of optoelectronics and advanced materials N2 - Hydrogenated amorphous carbon layers were deposited on BK7 glass in a plasma-assisted chemical vapor deposition process. Low and high refracting films with thicknesses d ranging from 11 nm to 5.8 µm were produced having refractive indices n between 1.68 and 2.41 and linear absorption coefficients of α~100 cm-1 and α~20000 cm-1 at 800 nm wavelength as a result of different plasma modes. Laser ablation thresholds Fth in dependence on d were determined using 30-fs laser pulses. Low absorbing layers show a constant Fth while Fth increases with rising d up to the optical penetration depth of light α-1 for high absorbing films. KW - Physical radiation damage (61.80.-x) KW - Laser-beam impact phenomena (79.20.Ds) KW - Radiation treatment (81.40.Wx) KW - Carbon (81.05.Uw) KW - Optical constants (78.20.Ci) PY - 2010 SN - 1454-4164 VL - 12 IS - 3 SP - 663 EP - 667 PB - INOE & INFM CY - Bucharest AN - OPUS4-21084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rybachuk, Maksym A1 - Hertwig, Andreas A1 - Weise, Matthias A1 - Sahre, Mario A1 - Männ, Marion A1 - Beck, Uwe A1 - Bell, J. M. T1 - Near infrared optical materials from polymeric amorphous carbon synthesized by collisional plasma process JF - Applied physics letters N2 - The synthesis of polymerlike amorphous carbon (a-C:H) thin-films by microwave excited collisional hydrocarbon plasma process is reported. Stable and highly aromatic a-C:H were obtained containing significant inclusions of poly(p-phenylene vinylene) (PPV). PPV confers universal optoelectronic properties to the synthesized material. That is a-C:H with tailor-made refractive index are capable of becoming absorption-free in visible (red)-near infrared wavelength range. Production of large aromatic hydrocarbon including phenyl clusters and/or particles is attributed to enhanced coagulation of elemental plasma species under collisional plasma conditions. Detailed structural and morphological changes that occur in a-C:H during the plasma synthesis are also described. KW - Kohlenstoffschichten KW - Plasmachemie KW - PA-CVD KW - Amorphous state KW - Carbon KW - Coagulation KW - Hydrogen KW - Optical materials KW - Plasma collision processes KW - Plasma deposition KW - Refractive index KW - Thin films PY - 2010 DO - https://doi.org/10.1063/1.3431292 SN - 0003-6951 SN - 1077-3118 VL - 96 IS - 21 SP - 211909-1 - 211909-3 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-21365 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Matthias A1 - Hertwig, Andreas A1 - Beck, Uwe T1 - Characterization of Surface Topometry and Determination of Layer Thickness by Scanning White Light Interference Microscopy N2 - 3D coherence scanning interferometry (CSI) is an optical, non-contact and rapide measurement technique using a defined bandwidth of white light at normal incidence. Based on this operational principle, white light interference microscopy (WLIM) provides three-dimensional surface topometry data up to a resolution of 0.4 μm lateral and 0.1 nm vertical. Three operating modi, i.e. surface, films and advanced films, enable measurements of step heights, roughness, wear volume, cone angle, surface pattern and layer thickness of transparent coatings. The determination of layer thickness by WLIM requires the knowledge of optical constants, i.e.the refractive index n and the extinction coefficient k. For technical surfaces, data base values - if available at all - have to be determined or validated by spectroscopic ellipsometry (SE). From this oblique incidence technique both optical constants and layer thickness can be derived based on a model for at least semi-transparent coatings. For different layer thicknesses, a comparison is made between WLIM and SE. Measurement uncertainty is discussed for both topometric features and layer thickness for different use cases. Traceability to SI system is ensured by certified standards (PTB/NIST) within a DAkkS DIN EN ISO/IEC 17025:2018 accredited lab. T2 - 17th International Conference on Plasma Surface Engineering (PSE) CY - Erfurt, Germany DA - 07.09.2020 KW - Rroughness and step heights KW - Lateral surface pattern KW - Layer thickness of transparent coatings KW - Scanning white light interferometry KW - Spectroscopic ellipsometry PY - 2020 AN - OPUS4-51301 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schiebel, J. A1 - Noack, J. A1 - Rödiger, S. A1 - Kammel, A. A1 - Menzel, Friederike A1 - Schwibbert, Karin A1 - Weise, Matthias A1 - Weiss, R. A1 - Böhm, A. A1 - Nitschke, J. A1 - Elimport, A. A1 - Roggenbuck, D. A1 - Schierack, P. T1 - Analysis of three-dimensional biofilms on different material surfaces JF - Biomaterials Science N2 - Biofilms cause complications and high costs in both industry and medicine. Of particular interest are bacterial infections of prosthetic materials, which usually cannot be eliminated due to the high antibiotic resistance known for bacteria forming biofilms. The search for new materials and coatings with lower colonization potential and antibacterial activity is of great importance to reduce biofilm formation. However, there is no standardized procedure to examine the colonization characteristics of bacteria in the Biofilm state in situ. Here, we describe an automated epifluorescence microscopy system for the semi-quantitative analysis of three-dimensional (3D) biofilms on various surfaces. To analyze adherent bacteria, three materials (glass, steel and titanium) were incubated with bacteria in a flow chamber system. After fluorescence staining of the bacteria, automated image capturing, quantification of the bacteria, measurement of the colonized area and determination of the 3D biofilm height were carried out by using novel software. Furthermore, the materials were examined for their surface topography using white light scanning interferometry. Titanium compared to glass showed a significantly higher number of adherent bacteria. We argue that this was due to the higher microroughness of titanium. The colonized area was in accordance with the number of adherent bacteria and was also significantly larger on titanium coupons compared to glass. Maximum 3D biofilm height on glass coupons was significantly lower compared to the ones on steel and titanium. This novel method enables the standardized, automated investigation of the colonization with bacteria on different materials. This approach can considerably support the characterization of new material surfaces and their innovative coatings by analyzing the amount of attached Bacteria and thickness of biofilms in situ and eliminates the need of conventional cultivation. KW - Biofilm KW - Bacterial adhesion KW - Biofilm quantification KW - Automated analysis PY - 2020 DO - https://doi.org/10.1039/D0BM00455C SP - 1 EP - 11 PB - Royal Society of Chemistry AN - OPUS4-50815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weise, Matthias A1 - Hertwig, Andreas A1 - Beck, Uwe T1 - Scanning White Light Interference Microscopy - Measurement of Topometry and Layer Thickness N2 - 3D coherence scanning interferometry (CSI) is anoptical, non-contact and rapide measurement technique using a defined bandwidth of white light at normal incidence. White light interference microscopy (WLIM) providest here-dimensional surface topometry data up to a resolution of 0.4 µm lateral and 0.1 nm vertical. Three operating modi, surface, films and advanced films, enable measurements of step heights, roughness, wear volume, cone angle, surface pattern and layer thickness. Traceability to SI system is ensured by certified standards (PTB/NIST) within a DAkkS DIN EN ISO/IEC 17025:2018 accredited lab. T2 - EFDS, V2019, Vakuum und Plasma, WS 4, Beschichtungen für Werkzeuge & Bauteile CY - Dresden, Germany DA - 08.10.2019 KW - DIN EN ISO/IEC 17025:2018 KW - Certified standards KW - White light interference microscopy(WLIM) KW - 3D coherence scanning interferometry (CSI) KW - Topometry PY - 2019 AN - OPUS4-49323 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Kai A1 - Mirabella, Francesca A1 - Knigge, Xenia A1 - Mezera, Marek A1 - Weise, Matthias A1 - Sahre, Mario A1 - Wasmuth, Karsten A1 - Voss, Heike A1 - Hertwig, Andreas A1 - Krüger, Jörg A1 - Radnik, Jörg A1 - Hodoroaba, Vasile-Dan A1 - Bonse, Jörn T1 - Chemical and topographical changes upon sub-100-nm laser-induced periodic surface structure formation on titanium alloy: the influence of laser pulse repetition rate and number of over-scans JF - Physica Status Solidi A N2 - Titanium and its alloys are known to allow the straightforward laser-based manufacturing of ordered surface nanostructures, so-called high spatial frequency laser-induced periodic surface structures (HSFL). These structures exhibit sub-100 nm spatial periods – far below the optical diffraction limit. The resulting surface functionalities are usually enabled by both, topographic and chemical alterations of the nanostructured surfaces. For exploring these effects, multi-method characterizations were performed here for HSFL processed on Ti–6Al–4V alloy upon irradiation with near-infrared ps-laser pulses (1030 nm, ≈1 ps pulse duration, 1–400 kHz) under different laser scan processing conditions, i.e., by systematically varying the pulse repetition frequency and the number of laser irradiation passes. The sample characterization involved morphological and topographical investigations by scanning electron microscopy (SEM), atomic force microscopy (AFM), tactile stylus profilometry, as well as near-surface chemical analyses hard X-ray photoelectron spectroscopy (HAXPES) and depth-profiling time-of-flight secondary ion mass spectrometry (ToF-SIMS). This provides a quantification of the laser ablation depth, the geometrical HSFL characteristics and enables new insights into the depth extent and the nature of the non-ablative laser-induced near-surface oxidation accompanying these nanostructures. This allows to answer the questions how the processing of HSFL can be industrially scaled up, and whether the latter is limited by heat-accumulation effects. T2 - 2023 E-MRS Spring Meeting, Symposium L "Making light matter: lasers in material sciences and photonics" CY - Strasbourg, France DA - 29.05.2023 KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses KW - Laser processing KW - Hard X-ray photoelectron spectroscopy (HAXPES) KW - Time-of-flight secondary ion mass spectrometry (ToF-SIMS) PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589902 UR - https://onlinelibrary.wiley.com/doi/full/10.1002/pssa.202300719 DO - https://doi.org/10.1002/pssa.202300719 SN - 1862-6319 VL - 220 SP - 1 EP - 12 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-58990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Minenkov, Alexey A1 - Hollweger, Sophia A1 - Duchoslav, Jiri A1 - Erdene-Ochir, Otgonbayar A1 - Weise, Matthias A1 - Ermilova, Elena A1 - Hertwig, Andreas A1 - Schiek, Manuela T1 - Monitoring the Electrochemical Failure of Indium Tin Oxide Electrodes via Operando Ellipsometry Complemented by Electron Microscopy and Spectroscopy JF - ACS Applied Materials & Interfaces N2 - Transparent conductive oxides such as indium tin oxide (ITO) are standards for thin film electrodes, providing a synergy of high optical transparency and electrical conductivity. In an electrolytic environment, the determination of an inert electrochemical potential window is crucial to maintain a stable material performance during device operation. We introduce operando ellipsometry, combining cyclic voltammetry (CV) with spectroscopic ellipsometry, as a versatile tool to monitor the evolution of both complete optical (i.e., complex refractive index) and electrical properties under wet electrochemical operational conditions. In particular, we trace the degradation of ITO electrodes caused by electrochemical reduction in a pH-neutral, water-based electrolyte environment during electrochemical cycling. With the onset of hydrogen evolution at negative bias voltages, indium and tin are irreversibly reduced to the metallic state, causing an advancing darkening, i.e., a gradual loss of transparency, with every CV cycle, while the conductivity is mostly conserved over multiple CV cycles. Post-operando analysis reveals the reductive (loss of oxygen) formation of metallic nanodroplets on the surface. The reductive disruption of the ITO electrode happens at the solid–liquid interface and proceeds gradually from the surface to the bottom of the layer, which is evidenced by cross-sectional transmission electron microscopy imaging and complemented by energy-dispersive X-ray spectroscopy mapping. As long as a continuous part of the ITO layer remains at the bottom, the conductivity is largely retained, allowing repeated CV cycling. We consider operando ellipsometry a sensitive and nondestructive tool to monitor early stage material and property changes, either by tracing failure points, controlling intentional processes, or for sensing purposes, making it suitable for various research fields involving solid–liquid interfaces and electrochemical activity. KW - General Materials Science PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597625 DO - https://doi.org/10.1021/acsami.3c17923 SN - 1944-8252 VL - 16 IS - 7 SP - 9517 EP - 9531 PB - American Chemical Society (ACS) AN - OPUS4-59762 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Schiek, Manuela A1 - Minenkov, Alexey A1 - Hollweger, Sophia A1 - Duchoslav, Jiri A1 - Erdene-Ochir, Otgonbayar A1 - Weise, Matthias A1 - Ermilova, Elena A1 - Hertwig, Andreas T1 - Optical constants of In2O3-SnO2 (Indium tin oxide, ITO) N2 - Optical constants of In2O3-SnO2 (Indium tin oxide, ITO) Minenkov et al. 2024: on glass; n,k 0.191–1.69 µm Optical constants of In2O3-SnO2 (Indium tin oxide, ITO) Minenkov et al. 2024: on Si wafer, top; n,k 0.191–1.69 µm Optical constants of In2O3-SnO2 (Indium tin oxide, ITO) Minenkov et al. 2024: on Si wafer, bottom; n,k 0.191–1.69 µm KW - Indium Tin Oxide KW - Optical constants KW - Magnetron Sputtering KW - Electrochemical Degradation KW - Spectroscopic Ellipsometry PY - 2024 UR - https://refractiveindex.info/?shelf=other&book=In2O3-SnO2&page=Minenkov-glass UR - https://refractiveindex.info/?shelf=other&book=In2O3-SnO2&page=Minenkov-wafer-top UR - https://refractiveindex.info/?shelf=other&book=In2O3-SnO2&page=Minenkov-wafer-bottom PB - Refractiveindex.info AN - OPUS4-59766 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ermilova, Elena A1 - Weise, Matthias A1 - Hertwig, Andreas T1 - Application of imaging ellipsometry and white light interference microscopy for detection of defects in epitaxially grown 4H-SiC layers JF - Journal of the European Optical Society-Rapid Publications N2 - Critical defects, also known as device killers, in wide bandgap semiconductors significantly affect the performance of power electronic devices. We used the methods imaging ellipsometry (IE) and white light interference microscopy (WLIM) in a hybrid optical metrology study for fast and non-destructive detection, classification, and characterisation of defects in 4H–SiC homoepitaxial layers on 4H–SiC substrates. Ellipsometry measurement results are confirmed by WLIM. They can be successfully applied for wafer characterisation already during production of SiC epilayers and for subsequent industrial quality control. T2 - EOS Annual Meeting (EOSAM 2022) CY - Porto DA - 12.09.2022 KW - Imaging ellipsometry KW - White light interference microscopy KW - 4H–SiC KW - Defects PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574209 DO - https://doi.org/10.1051/jeos/2023018 SN - 1990-2573 VL - 19 IS - 1 SP - 1 EP - 8 PB - EDP Sciences AN - OPUS4-57420 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grundmann, Jana A1 - Bodermann, Bernd A1 - Ermilova, Elena A1 - Weise, Matthias A1 - Hertwig, Andreas A1 - Klapetek, Petr A1 - Rafighdoost, Jila A1 - Pereira, Silvania F. T1 - Optical and tactile measurements on SiC sample defects JF - Journal of Sensors and Sensor Systems N2 - Abstract. In power electronics, compound semiconductors with large bandgaps, like silicon carbide (SiC), are increasingly being used as material instead of silicon. They have a lot of advantages over silicon but are also intolerant of nanoscale material defects, so that a defect inspection with high accuracy is needed. The different defect types on SiC samples are measured with various measurement methods, including optical and tactile methods. The defect types investigated include carrots, particles, polytype inclusions and threading dislocations, and they are analysed with imaging ellipsometry, coherent Fourier scatterometry (CFS), white light interference microscopy (WLIM) and atomic force microscopy (AFM). These different measurement methods are used to investigate which method is most sensitive for which type of defect to be able to use the measurement methods more effectively. It is important to be able to identify the defects to classify them as critical or non-critical for the functionality of the end product. Once these investigations have been completed, the measurement systems can be optimally distributed to the relevant defects in further work to realize a hybrid analysis of the defects. In addition to the identification and classification of defects, such a future hybrid analysis could also include characterizations, e.g. further evaluation of ellipsometric data by using numerical simulations. KW - Compound semiconductors KW - Hybrid metrology KW - Material defects KW - Spectroscopic Ellipsometry KW - Scanning Probe Microscopy KW - White-light Interference Microscopy PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601220 DO - https://doi.org/10.5194/jsss-13-109-2024 SN - 2194-878X VL - 13 IS - 1 SP - 109 EP - 121 PB - Copernicus GmbH AN - OPUS4-60122 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Voss, Heike A1 - Knigge, Xenia A1 - Knapic, D. A1 - Weise, Matthias A1 - Sahre, Mario A1 - Hertwig, Andreas A1 - Sacco, A. A1 - Rossi, A. M. A1 - Radnik, Jörg A1 - Müller, Kai A1 - Wasmuth, Karsten A1 - Krüger, Jörg A1 - Hassel, A. W. A1 - Hodoroaba, Vasile-Dan A1 - Bonse, Jörn T1 - Picosecond laser processing of hierarchical micro–nanostructures on titanium alloy upon pre- and postanodization: morphological, structural, and chemical effects JF - Physica Status Solidi A N2 - Recent publications indicate that the order of electrochemical anodization (before or after the laser processing step) plays an important role for the response of bone-forming osteoblasts—an effect that can be utilized for improving permanent dental or removable bone implants. For exploring these different surface functionalities, multimethod morphological, structural, and chemical characterizations are performed in combination with electrochemical pre- and postanodization for two different characteristic microspikes covered by nanometric laser-induced periodic surface structures on Ti–6Al–4V upon irradiation with near-infrared ps-laser pulses (1030 nm wavelength, ≈1 ps pulse duration, 67 and 80 kHz pulse repetition frequency) at two distinct sets of laser fluence and beam scanning parameters. This work involves morphological and topographical investigations by scanning electron microscopy and white light interference microscopy, structural material examinations via X-ray diffraction, and micro-Raman spectroscopy, as well as near-surface chemical analyses by X-ray photoelectron spectroscopy and hard X-ray photoelectron spectroscopy. The results allow to qualify the mean laser ablation depth, assess the spike geometry and surface roughness parameters, and provide new detailed insights into the near-surface oxidation that may affect the different cell growth behavior for pre- or postanodized medical implants. T2 - 2023 E-MRS Spring Meeting, Symposium L "Making light matter: lasers in material sciences and photonics" CY - Strasbourg, France DA - 29.05.2023 KW - Hierarchical micro-nanostructures KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses KW - Ti-6Al-4V alloy KW - X-ray photoelectron spectroscopy PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601962 DO - https://doi.org/10.1002/pssa.202300920 SN - 1862-6319 SP - 1 EP - 11 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-60196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schartel, Bernhard A1 - Beck, Uwe A1 - Bahr, Horst A1 - Hertwig, Andreas A1 - Knoll, Uta A1 - Weise, Matthias T1 - Sub-micrometre coatings as an infrared mirror: a new route to flame retardancy JF - Fire and materials N2 - Most of the polymeric materials used are easy to ignite and show extensive flame spread along their surfaces. Apart from extensive heat release rates, their short time to ignition (tig), in particular, is a key fire hazard. Preventing ignition eliminates fire hazards completely. Protection layers that shift tig by more than an order of magnitude are powerful flame retardancy approaches presenting an alternative to the usual flame retardancy concepts. Coatings are proposed that consist of a three-layer system to ensure adhesion to the substrate, acting as an infrared (IR) mirror and protecting against oxidation. The IR-mirror layer stack is realised by physical vapour deposition in the sub-micrometre (<1 µm) range, reducing heat absorption by up to an order of magnitude. Not only is the ease of ignition diminished (tig is increased by several minutes), the flame spread and fire growth indices are also remarkably reduced to as little as 1/10 of the values of the uncoated polymers open for further optimization. Sub-micrometre thin IR-mirror coatings yielding surface absorptivity <0.1 are proposed as a novel and innovative flame retardancy approach. KW - Coating KW - Fire protection KW - Physical vapour deposition (PVD) KW - IR mirror KW - Ignition PY - 2012 DO - https://doi.org/10.1002/fam.1122 SN - 0308-0501 SN - 1099-1018 VL - 36 IS - 8 SP - 671 EP - 677 PB - Heyden CY - London AN - OPUS4-27210 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -