TY - CONF A1 - Legall, Herbert A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Emission of X-rays during ultrashort pulse laser processing T2 - Proceedings Lasers in Manufacturing Conference 2021 N2 - Ultrashort pulse laser materials processing can be accompanied by the production of X-rays. Small doses per laser pulse can accumulate to significant dose rates at high laser pulse repetition rates which may exceed the permitted X-ray limits for human exposure. Consequently, a proper radiation shielding must be considered in laser machining. A brief overview of the current state of the art in the field of undesired generation of X-ray radiation during ultrashort pulse laser material processing in air is presented. T2 - Lasers in Manufacturing Conference 2021 CY - Online meeting DA - 21.06.2021 KW - Ultra-short pulse laser processing KW - Laser-induced X-ray emission KW - Radiation protection PY - 2021 SP - 1 EP - 5 AN - OPUS4-53866 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo A1 - Deziel, J.-L. A1 - Kirner, Sabrina V. A1 - Siegel, J. A1 - Bonse, Jörn T1 - Femtosecond laser-induced oxidation in the formation of periodic surface structures T2 - Proceedings of 2021 Conference on Lasers and Electro-Optics/Europe – European Quantum Electronics Conferences N2 - Micro- and nanostructuring with laser-induced periodic surface structures (LIPSS) has been demonstrated to be feasible in a wide variety of materials including metals, semiconductors and dielectrics. Suitable processing regimes for flat, curved and complex surfaces have been identified for many materials, allowing the generation of diverse applications in fields such as optics, tribology and medicine, to name a few. A common side effect when producing such structures in air environment is the formation of a thin surface oxide layer in the laser irradiated areas. Previous studies have shown that oxidation plays an important role in the tribological performance for which the structures where created, and very recently it has been shown that the laser-induced oxide graded layers may contribute to the formation of a new type of embedded low-spatial frequency LIPSS (LSFL) with annomalous orientation parallel to the laser polarization, in addition to the appearance of the well-known high-spatial frequency LIPSS (HSFL) at the surface. In this contribution, we explore this effect experimentally for chromium nitride (CrN) irradiated with femtosecond laser pulses and compare the findings to finite-difference time-domain (FDTD) simulations of the intensity distributions at different depth positions. T2 - 2021 Conference on Lasers and Electro-Optics/Europe – European Quantum Electronics Virtual Conferences CY - Munich, Germany DA - 21.06.2021 KW - Femtosecond laser ablation KW - Finite-difference time-domain calculations KW - Laser-induced periodic surface structures (LIPSS) KW - Surface oxidation PY - 2021 SN - 978-1-6654-1876-8 DO - https://doi.org/10.1109/CLEO/Europe-EQEC52157.2021.9542774 VL - 2021 SP - 1 PB - Institute of Electrical and Electronics Engineers (IEEE) CY - Piscataway, NJ, USA AN - OPUS4-53457 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Baier, Jennifa A1 - Fischer, Daniel A1 - Griepentrog, Michael A1 - Hertwig, Andreas A1 - Hielscher-Hofinger, Stefan A1 - Stockmann, Jörg Manfred A1 - Weise, Matthias T1 - Mapping und Imaging modifizierter Oberflächen: Generische Kenngrößen, Fehlstellen, Reinigungszustand und Haftfestigkeit T2 - Tagungsband zum 37. ak-adp 2020, Leipzig N2 - Der Vortrag widmet sich dem Mapping und Imaging modifizierter Oberflächen: generische Kenngrößen, Fehlstellen, Reinigungszustand und Haftfestigkeit. Es werden Untersuchungsmethoden zu ihrer Prüfung dargestellt. T2 - 37. ak-adp 2021 CY - Jena, Germany DA - 16.06.2021 KW - Qualitätssicherung KW - Mapping modifizierter Oberflächen KW - Imaging modifizierter Oberflächen KW - Generische Kenngrößen KW - Haftfestigkeit KW - Klebfestigkeit PY - 2021 SP - 1 EP - 10 AN - OPUS4-52893 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Uwe A1 - Mitzkus, Anja A1 - Sahre, Mario A1 - Weise, Matthias A1 - Köppe, Enrico A1 - Bartholmai, Matthias A1 - Basedau, Frank A1 - Hofmann, Detlef A1 - Schukar, Vivien T1 - Faser-basierter magneto-optischer Schicht-Sensor zum Monitoring von Bauteilen T2 - 13. ThGOT Thementage Grenz- und Oberflächentechnik und 11. Thüringer Biomaterial-Kolloquium N2 - In Glasfasern eingeschriebene Bragg-Gitter (FBG: fibre-based Bragg gratings) sind über die Verschiebung der Bragg-Wellenlänge in der Lage, Stauchungen und Dehnungen von Glasfasern hochgenau zu erfassen. In Kompositwerkstoffe eingebettete faseroptische Sensoren können Bauteile bezüglich ihrer mechanischen Integrität überwachen und früh-zeitig Informationen über Materialveränderungen gewinnen. Um die Zuverlässigkeit eines solchen Sensors zu gewährleisten, ist es wichtig, die korrekte Funktion des Sensors im Verbund mit der Werkstoff-Matrix on-line und in-situ sicherzu-stellen. Im Rahmen des DFG-Projekts FAMOS² (FAser-basierter Magneto-Optischer SchichtSensor) wurde ein selbstdiagnosefähiger Schichtsensor entwickelt, der mit Hilfe von magnetostriktiven Aktorschichten aus Nickel bzw. Eisen-Nickel validiert werden kann. Der FAMOS²-Schichtsensor wird durch ein PVD (physical vapour deposition)/ECD (electro-chemical deposition) Hybridschichtsystem realisiert, das auf dem Fasermantel im Bereich des FBG haftfest, homogen und langzeitfunktional abzuscheiden ist. Dabei wird in einem ersten Schritt ein etwa 100 Nanometer dünnes PVD-Schichtsystem aus Chrom und Kupfer als Haftvermittler auf der Glasfaser bzw. als leitfähige Startschicht für den nachfolgenden ECD-Prozess abgeschieden. Um eine rotationssymmetrische Schich-tabscheidung zu gewährleisten, erfolgt während der PVD-Beschichtung eine Rotation der Glasfasern. In einem zweiten Schritt wird dann unter Verwendung eines klassischen Watts-Elektrolyten in einer speziell entwickelten ebenfalls rotationssymmetrisch aufgebau-ten ECD-Durchströmungszelle dann die etwa 30 Mikrometer dicke, magnetostriktive Ak-torschicht auf dem PVD-Schichtsystem abgeschieden, im Vergleich sowohl reine Nickel-Schichten als auch Nickel-Eisen-Schichten. Ein äußeres Magnetfeld dehnt die magnetostriktive Aktorschicht und damit auch die Faser reversibel. Diese Dehnung führt zu einer Verschiebung der Bragg-Wellenlänge, welche direkt mit der Stärke eines zu messenden oder zu Validierungszwecken vorgegebenen Magnetfeldes korreliert. Die Anpassung der Beschichtungsverfahren an die Fasergeome-trie und die mechanischen Eigenschaften der Hybridschichten werden hinsichtlich der me-chanischen Integrität des faseroptischen Sensors diskutiert und der Nachweis der Selbst-diagnosefähigkeit erbracht. T2 - 13. ThGOT Thementage Grenz- und Oberflächentechnik und 11. Thüringer Biomaterial-Kolloquium CY - Zeulenroda, Germany DA - 13.03.2018 KW - Magneto-optischer Sensor KW - Faser-Bragg Gitter KW - Magnetostriktive Beschichtung KW - Selbstkalibrierung KW - Bauteilmonitoring PY - 2018 SN - 978-3-00-058187-8 SP - 1 EP - 5 CY - Jena AN - OPUS4-44599 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hielscher, Stefan A1 - Beck, Uwe A1 - Lange, Thorid A1 - Grunwald, Daniel A1 - Stockmann, Jörg M. A1 - Lerche, D. A1 - Rietz, U. T1 - Die Zentrifuge als universelles Prüfsystem für Beanspruchungen auf Zug und Druck T2 - 13. ThGOT Thementage Grenz- und Oberflächentechnik und 11. Thüringer Biomaterial-Kolloquium N2 - Mit der Zentrifugentechnologie ist seit einigen Jahren ein neuartiges Mehr-Proben-Prüf-verfahren auf dem Markt etabliert, welches die klassische Zugprüfung in den Trommelrotor einer Tischzentrifuge überträgt. In der Beanspruchung auf Zug ist die Prüfung der Verbundfestigkeit seit 2017 nach DIN EN ISO/IEC 17025 akkreditiert, wobei die Verbundfestigkeit von Klebungen direkt bestimmt wird und in Abhängigkeit von den Versagensformen Rückschlüsse auf die Klebfestigkeit von Klebstoffen/Klebebändern oder die Haftfestigkeit von Beschichtungen gezogen werden können. Bei der zerstörenden Beanspruchung auf Zug ist zu beachten, dass es sich bei der Verbundfestigkeit um eine Systemeigenschaft handelt, d.h. nicht nur die chemischen und topografischen Oberflächeneigenschaften, sondern auch die plasto-elastischen Volumeneigenschaften des Klebstoffes und der Fügeteile haben Einfluss auf die ermittelten Kennwerte. Dabei ist eine qualitative Bestimmung der Versagensformen und Bruchbilder nach DIN EN ISO 10365 zwingend erforderlich, um eine Aussage über die Art des Versagens treffen zu können. Mit der Erweiterung der Zentrifugentechnologie um Beanspruchungen auf Druck wurde dann der Nachweis erbracht, dass auch die klassische Härteprüfung in einer Zentrifuge als Mehr-Proben-Prüfung durchgeführt werden kann. Im Verbundvorhaben QUO VADIS PLUS werden derzeit invasive Beanspruchungen auf Druck zur Bestimmung der Härte von Materialien, der Kompressibilität von Metallschäumen sowie der Kompaktierbarkeit von Pulvern untersucht, was das Anwendungspotential der Zentrifugentechnologie nochmals erweitert. Dazu gehören auch kombinierte Beanspruchungen wie Zug-Scher- und Druck-Scher-Prüfungen. Die Verbundfestigkeit von CFK-Platten in Abhängigkeit der Beanspruchungsart (Zug vs. Zug-Scher) bzw. der Faserorientierung (0°, 45°, 90°), die Klebfestigkeit von Klebstoffen bzw. Klebebändern auf unterschiedlichen Fügeteilwerkstoffen in Abhängigkeit von der Vorbehandlung, die Haftfestigkeit optischer Schichten auf Kunststoffen, die Bestimmung der Vickers-, Brinell- bzw. Kugeldruck-Härte sowie die Kompressibilität von metallischen Schäumen und Federn werden als ausgewählte Beispiele diskutiert. T2 - 13. ThGOT Thementage Grenz- und Oberflächentechnik und 11. Thüringer Biomaterial-Kolloquium CY - Zeulenroda, Germany DA - 13.03.2018 KW - Zentrifugentechnologie KW - Haftfestigkeit KW - Härteprüfung KW - Mehr-Proben-Prüfung KW - Beanspruchung auf Zug und Druck PY - 2018 SN - 978-3-00-058187-8 SP - 1 EP - 5 CY - Jena AN - OPUS4-44572 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bakenecker, A. A1 - Topolniak, Ievgeniia A1 - Lüdtke-Buzug, K. A1 - Pauw, Brian Richard A1 - Buzug, T. T1 - Additive manufacturing of superparamagnetic micro-devices for magnetic actuation T2 - Additive Manufacturing Meets Medicine 2019 N2 - 3D microstructures with sub-micron resolution can be manufactured in additive manner applying multi-photon laser structuring technique. This paper is focused on the incorporation of superparamagnetic iron oxide nanoparticles into the photoresist in order to manufacture micrometer-sized devices featuring a magnetic moment. The aim of the project is to achieve untethered actuation of the presented objects through externally applied magnetic fields. Future medical application scenarios such as drug delivery and tissue engineering are targeted by this research. T2 - Additive Manufacturing Meets Medicine 2019 CY - Lübeck, Germany DA - 12.09.2019 KW - MPI KW - Two-Photon Polymerization KW - Magnetic swimmers KW - MPLS PY - 2019 UR - www.journals.infinite-science.de/ammm DO - https://doi.org/10.18416/AMMM.2019.1909S09T06 SP - 153 EP - 154 PB - Infinite Science Publishing AN - OPUS4-49114 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rhode, Michael A1 - Wetzel, Annica A1 - Oczan, Ozlem A1 - Nietzke, Jonathan A1 - Richter, Tim A1 - Schröpfer, Dirk T1 - Hydrogen diffusion and local Volta potential in high- and medium-entropy alloys T2 - IOP Conference Series: Materials Science and Engineering N2 - High-entropy alloys (HEAs) are characterized by a solid solution of minimum five and medium-entropy alloys (MEAs) of minimum three principal alloying elements in equiatomic proportions. They show exceptional application properties, such as high-strength and ductility or corrosion resistance. Future HEA/MEA-components could be exposed to hydrogen containing environments like vessels for cryogenic or high-pressure storage where the hydrogen absorption and diffusion in these materials is of interest. In our study, we investigated the HEA Co20Cr20Fe20Mn20Ni20 and the MEA Co33.3Cr33.3Ni33.3. For hydrogen ingress, cathodic charging was applied and diffusion kinetic was measured by high-resolution thermal desorption spectros-copy using different heating rates up to 0.250 K/s. Peak deconvolution resulted in high-temperature desorption peaks and hydrogen trapping above 280 °C. A total hydrogen concentration > 40 ppm was identified for the MEA and > 100 ppm for HEA. This indicates two important effects: (1) delayed hydrogen diffusion and (2) considerable amount of trapped hydrogen that must be anticipated for hydrogen assisted cracking phenomenon. Local electrochemical Volta potential maps had been measured for the hydrogen free condition by means of high-resolution Scanning Kelvin Probe Force Microscopy (SKPFM). T2 - Symposium on Materials and Joining Technology CY - Online meeting DA - 07.09.2020 KW - Hydrogen KW - High-entropy alloy KW - Diffusion KW - Scanning kelvin probe force microscopy KW - Corrosion PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511684 DO - https://doi.org/10.1088/1757-899X/882/1/012015 VL - 882 SP - 1 EP - 15 PB - IOP Publishing CY - Bristol AN - OPUS4-51168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rietz, U. A1 - Küchler, S. A1 - Lerche, D. A1 - Lange, Thorid A1 - Hielscher, Stefan A1 - Beck, Uwe T1 - Zentrifugalkraftbasierte Mehrprobenprüfung in einer analytischen Zentrifuge zur Bestimmung von Kleb- und Haftfestigkeiten: Metallische Referenzverbunde, Plasmaaktivierung von Polymeren, Schichthaftung auf GFK, Wirkung von Primern T2 - Atmosphärische Plasmen, Anwendungen - Entwicklungen - Anlagen N2 - Das Fügeverfahren Kleben bietet viele Vorteile wie z.B. das Verbinden schwieriger Materialklassen, geringe thermische Belastung (Strukturveränderung/-schwächung) der Fügepartner und eine Lastverteilung über den gesamten Fügebereich. Die Auswahl an verfügbaren Klebstoffen und Vorbehandlungsoptionen ist dabei ebenfalls vielfältig. Einige Polymere weisen darüber hinaus Eigenschaften auf, die eine Herstellung von festen und dauerhaft beanspruchbaren Klebverbindungen erschweren. Mittels Oberflächenbehandlung, z.B. durch Plasmafeinreinigung bzw. –aktivierung, können die Grenzflächern solcher Polymere - bezogen auf die Eignung als Fügeteilpartner – optimiert werden. Schnelle Prüfverfahren zur Ermittlung von Verbundeigenschaften sind somit erforderlich. Das Messprinzip Centrifugal Adhesion Testing Technologie verwendet die radial gerichtete Zentrifugalkraft als Belastungsgröße des zu testenden Verbunds, die durch Variation der Drehzahl gesteuert wird. Bei Erreichen der kritischen Beanspruchung trennt sich ein aufgeklebter Prüfstempel vom Substrat. Zeitgleich wird ein positionsbezogenes IR-Signal aus dem drehenden Rotor an das Basisgerät gesendet und zusammen mit der Drehzahl an die PC-Software übertragen. Für jede Probe wird die Bruchkraft berechnet und in Echtzeit angezeigt. Der Adhesion Analyser LUMiFrac® untersucht bis zu acht Prüfkörper unter identischen Bedingungen. Das neue Messprinzip erfüllt die Anforderungen von DIN EN 15870, DIN EN 14869-2, ISO 4624 sowie DIN EN 13144. Die Multiprobentestung ermöglicht schnelle Charakterisierungen von Klebverbindungen. So kann der Effekt einer Plasmabehandlung von Bauteilen auf die Verbundfestigkeit zeitsparend bestimmt werden. Die gezielte Veränderung unterschiedlicher Plasma-Parameter, wie beispielsweise, die Plasmazusammensetzung, der Abstand vom Plasmabrenner zur Oberfläche oder die Verweildauer unter dem Brenner, beeinflußt die Festigkeit des Klebsystems und ist dem LUMiFrac direkt quantifizierbar. Neben der Festigkeitsbestimmung von Klebverbindungen ist die Haftung von Schichtsystemen ein wichtiger Anwendungsbereich. Ergebnisse für Zug- und Scherbeanspruchung, realisiert mit unterschiedlichen Prüfkörper-Geometrien, werden vorgestellt. Ferner werden verschiedene festigkeitsbeeinflussende Faktoren, wie Prüfgeschwindigkeit oder Substratverformung bei Beanspruchung untersucht T2 - 35. Workshop des ak-adp CY - Nuremberg, Germany DA - 20.11.2019 KW - Adhäsion KW - Mehrprobenprüfung KW - Analytische Zentrifuge KW - Kleb- und Haftfestigkeit PY - 2019 SN - 978-3-00-063646-2 SP - 100 EP - 109 AN - OPUS4-50149 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Surface functionalization by laser-induced periodic surface structures T2 - 2019 ICALEO Conference Proceedings N2 - In recent years, the improved understanding of the formation of laser-induced periodic surface structures (LIPSS) has led to an emerging variety of applications that modify the optical, mechanical and chemical properties of many materials. Such structures strongly depend on the laser beam polarization and are formed usually after irradiation with ultrashort linearly polarized laser pulses. The most accepted explanation for the origin of the structures is based on the interference of the incident laser radiation with electromagnetic surface waves that propagate or scatter at the surface of the irradiated materials. This leads to an intensity modulation that is finally responsible for the selective ablation in the form of parallel structures with periods ranging from hundreds of nanometers up to some micrometers. The versatility when forming such structures is based on the high reproducibility with different wavelength, pulse duration and repetition rate laser sources, customized micro- and nanometric spatial resolutions, and the compatibility with industrially relevant processing speeds when combined with fast scanning devices. In this contribution, we review the latest applications in the rapidly emerging field of surface functionalization through LIPSS, including biomimetic functionalities on fluid transport, control of the wetting properties, specific optical responses in technical materials, improvement of tribological performance on metallic surfaces and bacterial and cell growth for medical devices, among many others. T2 - 38th International Congress on Applications of Lasers & Electro-Optics CY - Orlando, FL, USA DA - 07.10.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Laser processing KW - Surface functionalization KW - Applications PY - 2019 SN - 978-1-940168-1-42 SP - Paper Nano 404 AN - OPUS4-50070 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stuff, Maria A1 - Rübner, Katrin A1 - Prinz, Carsten A1 - Rische, N. A1 - Chronz, M. A1 - Kühne, Hans-Carsten ED - Siegesmund, S. ED - Middendorf, B. T1 - Towards a better understanding of tuff stone deterioration T2 - Monument Future: Decay and conservation of stone. - Proceedings of the 14th international congress on the deterioration and conservation of stone N2 - Stone deterioration is the result of a complex interaction of external physical, chemical and biological forces with the mineralogical-petrophysical properties of the stone. With a better understanding of how these properties are linked to material behavior and durability, more effective measures for stone conservation can be developed. Studying these interactions in tuff is particularly complex due to the naturally high heterogeneity of tuff rocks. The first aim of a current research project is to combine the results of recent and older studies on tuff deterioration. Furthermore, the literature overview is complemented by our own investigation of Weibern and Ettringen tuff, with a focus on pore structure characteristics. T2 - STONE - 14th international congress on the deterioration and conservation of stone CY - Meeting was canceled DA - 07.09.2020 KW - Pore structure KW - Weathering KW - Weibern tuff KW - Ettringen tuff PY - 2020 SN - 978-3-96311-172-3 SP - 805 EP - 810 PB - Mitteldeutscher Verlag CY - Halle (Saale) AN - OPUS4-51549 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan A1 - Yamamoto, K. A1 - Grulke, E. A. A1 - Maurino, V. ED - Bosse, H. ED - Buhr, E. ED - Dziomba, T. ED - Hodoroaba, Vasile-Dan ED - Klein, T. ED - Krumrey, M. T1 - Shape controlled TiO2 nanoparticles as candidates for nano-CRM’s – an ISO case study T2 - PTB-Bericht F-61 - NanoWorkshop 2018: Workshop on Reference Nanomaterials N2 - Extraction of true, 3D shape (and size) of non-spherical nanoparticles (NPs) is associated with Errors by conventional 2D electron microscopy using projection images. Significant efforts within the ISO technical committee TC 229 ‘Nanotechnologies’ are aimed at establishing accurate TEM and SEM measurement of NP size and shape as robust, standard procedures. Study groups have been organizing inter-laboratory comparisons on well-selected NP systems according to the market needs, such as aggregated titania nano-powder for which size and shape distribution of primary crystallites of irregular shape must be measured accurately. To be noticed is e. g. the fact that the measurement procedure allows only manual selection of the particles clearly distinguishable for analysis as well as manual definition of the contour of the imaged NPs. An inter-laboratory exercise on titania NPs (pure anatase, grown by hydrothermal synthesis) of well-defined non-spherical shape, i.e. bipyramidal, has been recently started within ISO/TC 229 under similar conditions as for the irregular shaped titania. In the TEM micrograph the particles tracked manually according to the measurement protocol. Overlapped particles were allowed to be considered, as long as they are clearly distinguishable. One decisive NP selection criterion was to analyze only those NPs with a roundness value below 0.7, i.e. the NPs laying on the support foil and, hence, with projection areas clearly deviating from perfect circles (R=1). The overall evaluation (for 15 labs) of the size descriptors (area, Feret, minFeret, perimeter) and shape descriptors (aspect ratio, roundness, compactness, extent) by analysis of variance is just to be finished and included in ISO/WD 21363 Nanotechnologies -- Protocol for particle size distribution by transmission electron microscopy. T2 - NanoWorkshop 2018: Workshop on Reference Nanomaterials CY - Berlin, Germany DA - 14.05.2018 KW - Titanium dioxide KW - Nanoparticles KW - Shape-controlled KW - Electron microscopy PY - 2019 SN - 978-3-95606-440-1 DO - https://doi.org/https://doi.org/10.7795/110.20190412 SN - 0179-0609 VL - F-61 SP - 245 EP - 255 PB - Physikalisch-Technische Bundesanstalt CY - Braunschweig und Berlin AN - OPUS4-49990 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mech, A. A1 - Gaillard, C. A1 - Marvin, H. A1 - Wohlleben, W. A1 - Hodoroaba, Vasile-Dan A1 - Babick, F. A1 - Friedrich, C. M. A1 - Brüngel, R. A1 - Rückert, J. A1 - Ghanem, A. A1 - Weigel, S. T1 - The NanoDefine Decision Framework and NanoDefiner e-Tool: a practical guide to the identification of nanomaterials T2 - PTB-Bericht F-61 - NanoWorkshop 2018: Workshop on Reference Nanomaterials N2 - The European Commission's recommendation on the definition of nanomaterial [2011/696/EU] is broadly applicable across different regulatory sectors and requires the quantitative size Determination of constituent particles in samples down to 1 nm. A material is a nanomaterial if 50 % or more of the particles are in the size range 1-100 nm. The implementation of the definition in a regulatory context challenges measurement methods to reliably identify nanomaterials and ideally also nonnanomaterials as substance or product ingredient as well as in various matrices. The EU FP7 NanoDefine project [www.nanodefine.eu] addressed these challenges by developing a robust, readily implementable and cost-effective measurement strategy to decide for the widest possible range of materials whether it is a nanomaterial or not. It is based on existing and emerging particle measurement techniques evaluated against harmonized, material-dependent performance criteria and by intra- and inter-lab comparisons. Procedures were established to reliably measure the size of particles within 1-100 nm, and beyond, taking into account different shapes, coatings and chemical compositions in industrial materials and consumer products. Case studies prove their applicability for various sectors, including food, pigments and cosmetics. A main outcome is the establishment of an integrated tiered approach including rapid screening (Tier 1) and confirmatory methods (tier 2), a decision support flow scheme and a user manual to guide end-users, such as manufacturers, in selecting appropriate methods. Another main product is the “NanoDefiner” e-Tool which implements the flow scheme in a user-friendly software and guides the user in a semi-automated way through the entire decision procedure. It allows a cost-effective selection of appropriate methods for material classification according to the EC's nanomaterial definition and provides a comprehensive report with extensive explanation of all decision steps to arrive at a transparent identification of nanomaterials as well as non-nanomaterials for regulatory purposes. T2 - NanoWorkshop 2018: Workshop on Reference Nanomaterials CY - Berlin, Germany DA - 14.05.2018 KW - Definition of nanomaterial KW - Regulation PY - 2019 SN - 978-3-95606-440-1 SN - 0179-0609 VL - F-61 SP - 114 EP - 124 PB - Physikalisch-Technische Bundesanstalt CY - Braunschweig und Berlin AN - OPUS4-49992 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maurino, V. A1 - Pellutiè, L. A1 - Pellegrino, F. A1 - Ortel, Erik A1 - Hodoroaba, Vasile-Dan A1 - Isopescu, R. T1 - Synthesis of size and shape controlled TiO2 nanoparticles: possible CRM’s candidates for size, shape and functional properties T2 - PTB-Bericht F-61 - NanoWorkshop 2018: Workshop on Reference Nanomaterials N2 - Titanium dioxide is one of the most studied metal oxides due to its chemical, surface, electronic and (photo)catalytic properties, providing this material of multisectorial applications ranging from healthcare, photocatalysis, smart materials with self cleaning and self sterilizing properties and solar energy harvesting. However it is difficult to correlate the functional properties of TiO2 nanomaterials to the properties at single nanoparticle level due to the high polydispersity in shape, size and surface features of the currently available TiO2 nanoparticles (NPs). Although intensive experimental and theoretical studies have been conducted on the reactivity of different surfaces of metal oxides such as TiO2 much less attention is paid on the dependence of functional properties, like photocatalytic activity, dye adsorption, open circuit potential and fill factor in dye sensitized solar cells, on crystal facets in different orientations. One of the goal of SETNanoMetro project was the development of design rules to tune crystal facets of TiO2 NPs in order to optimize and control functional properties. In the present work we have developed a series of design rules in order to obtain sets of anatase TiO2 NPs with low polydispersity and to tune their shape and size by hydrothermal processing of Ti(IV)- Triethanolamine complex in presence of different shape controllers. Through a careful experimental design, a predictive soft model was developed. The model is able to predict the synthesis outcome allowing to tune the shape factor from 5 (prisms) to 1.5 (bipyramids) to 0.2 (platelets). This allows to control the main crystal facets exposed ranging from (100) to (001). Due to the dependence of functional properties of nanomaterials on shape distribution and not only size, the availability of NPs sets with uniform and well defined and tunable shapes can be of paramount relevance in order to produce reference nanomaterials for shape measurement. T2 - NanoWorkshop 2018: Workshop on Reference Nanomaterials CY - Berlin, Germany DA - 14.05.2018 KW - Anatase KW - shape control KW - Hydrothermal synthesis PY - 2019 SN - 978-3-95606-440-1 SN - 0179-0609 VL - F-61 SP - 146 EP - 162 PB - Physikalisch-Technische Bundesanstalt CY - Braunschweig und Berlin AN - OPUS4-49993 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn T1 - Quo vadis LIPSS? – Applications of laser-induced periodic surface structures T2 - Tagungsband zur 11. Mittweidaer Lasertagung N2 - Laser-induced periodic surface structures (LIPSS, ripples) are a universal phenomenon that can be observed on almost any material after the irradiation by linearly polarized laser beams, particularly when using ultrashort laser pulses with durations in the femtosecond to picosecond range. During the past years significantly increasing industrial and research activities have been reported in the field of LIPSS, since their generation in a single-step process provides a simple way of nanostructuring and surface functionalization towards the control of optical, mechanical or chemical surface properties. In this contribution the mechanisms of formation and current trends and applications of LIPSS are reviewed, including the colorization of technical surfaces, the control of surface wetting properties, the mimicry of the natural texture of animals, the tailoring of surface colonization by bacterial biofilms, the advancement of leadless medical pacemakers, and the improvement of the tribological performance of nanostructured metal surfaces. T2 - 11. Mittweidaer Lasertagung CY - Mittweida, Germany DA - 13.11.2019 KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Surface functionalization KW - Applications PY - 2019 VL - 3/1 SP - 41 EP - 43 PB - Hochschule Mittweida CY - Mittweida AN - OPUS4-49673 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Fischer, Daniel A1 - Beck, Uwe T1 - Visualisierung von mikro- und nanoskalierten Oberflächenstrukturen mittels abbildender Ellipsometrie T2 - Tagungsband, 14. ThGOT Thementage Grenz- und Oberflächentechnik und 6. Kolloquium Dünne Schichten in der Optik N2 - In den letzten Jahren hat die Einbindung der abbildenden Ellipsometrie in die Gruppe der optischen Verfahren zur Oberflächencharakterisierung ein enormes Potential bei der Analyse von topologischen Strukturänderungen gezeigt. Der dabei abgebildete Kon-trast wurde typischerweise auf Änderungen im Brechungsindex, Absorptionseffekte oder Schichtdickenänderungen zurückgeführt. In späteren Studien wurde festgestellt, dass auch andere Faktoren, wie etwa die Krümmung der Oberfläche oder Kanten von Struktu-ren einen signifikanten Einfluss auf die Messung der ellipsometrischen Paramater haben. Um diese Effekte aus der ellipsometrischen Messung extrahieren zu können, wird auf die Analyse der Müller-Matrix zurückgegriffen. In dem hier vorliegenden Beitrag wird gezeigt, wie die Müller-Matrix-Imaging Ellipsomet-rie (MM-IE) zur Charakterisierung von Oberflächenstrukturen verwendet werden kann. Dazu werden mikro- und nanoskaliert gekrümmte Oberflächen zunächst mit verschiede-nen Referenzmethoden, wie Rasterelektronenmikroskopie (SEM), Lichtmikroskopie (OM), Weißlichtinterferenzmikroskopie (WLIM) und Rasterkraftmikroskopie (AFM) vali-diert erfasst. Der anschließende Vergleich mit den Ergebnissen der Müller-Matrix-Ima-ging-Ellipsometrie ermöglicht eine Korrelation der zugrunde liegenden Strukturphäno-mene mit den ellipsometrischen Daten. In diesem Artikel wird das Prinzip an drei industriell relevanten Strukturgruppen demonstriert: Sub-Mikropartikel, Mikropartikel und sub-mikroskalierte Vertiefungen. T2 - 14. ThGOT Thementage Grenz- und Oberflächentechnik und 6. Kolloquium Dünne Schichten in der Optik CY - Zeulenroda, Germany DA - 12.03.2019 KW - Ellipsometrie KW - Nanoskaliert KW - Mikroskaliert KW - Oberflächengeometrie KW - Brechungsindex KW - Müller-Matrix-Ellipsometrie PY - 2019 SN - 978-3-00-062102-4 SP - 1 EP - 5 AN - OPUS4-47646 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lange, Thorid A1 - Hidde, Gundula A1 - Beck, Uwe A1 - Naumann, F. A1 - Kärkkänen, I. A1 - Gargouri, H. T1 - Nanoskalige Haftvermittler zur Erhöhung der Haft- bzw. Klebfestigkeit unter Verwendung von ALD-Hybridprozessen T2 - 14. ThGOT ThementageTagungsband Grenz- und Oberflächentechnik und 6. Kolloquium Dünne Schichten in der Optik N2 - Ziel des Projektes HARFE (Haftfestigkeit Reproduzierbarkeit Festigkeit) war es, eine Er-höhung der Haft- bzw. Klebfestigkeit auf Niedrigenergie-Polymeren (PE, PP, PTFE) zu erreichen. SENTECH realisierte dazu plasmachemische Oberflächenaktivierungen mit O2 und die Abscheidung von Aluminiumoxidschichten (Al2O3) mittels Atomic Layer Deposition (ALD), wobei die Ellipsometrie zum in-situ Monitoring der ALD-Prozesse diente. Die BAM charakterisierte die modifizierten Oberflächen bezüglich der Oberflächenenergie (OFE) und bestimmte die Verbund- bzw. Klebfestigkeit mittels der Zentrifugentechnologie T2 - 14. ThGOT Thementage Grenz- und Oberflächentechnik und 6. Kolloquium Dünne Schichten in der Optik CY - Zeulenroda, Germany DA - 12.03.2019 KW - Haftvermittler KW - ALD-Hybridprozesse KW - Klebfestigkeit KW - Atomic Layer Deposition KW - Al2O3-Schichten KW - Oberflächenenergie PY - 2019 SN - 978-3-00-062102-4 SP - 1 EP - 2 CY - Zeulenroda, Germany AN - OPUS4-47656 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Legall, Herbert A1 - Schwanke, Christoph A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - X-ray emission during ultrashort pulse laser processing T2 - Proceedings of SPIE - FRONTIERS IN ULTRAFAST OPTICS: BIOMEDICAL, SCIENTIFIC, AND INDUSTRIAL APPLICATIONS XIX N2 - The industrial use of ultrashort laser pulses has made considerable progress in recent years. The reasons for this lie in the availability of high average powers at pulse repetition rates in the several 100 kHz range. The advantages of using ultrashort laser pulses in terms of processing precision can thus be fully exploited. However, high laser intensities on the workpiece can also lead to the generation of unwanted X-rays. Even if the emitted X-ray dose per pulse is low, the accumulated X-ray dose can become significant for high-repetition-rate laser systems so that X-ray exposure safety limits must be considered. The X-ray emission during ultrashort pulse laser processing was investigated for a pulse duration of 925 fs at 1030 nm wavelength and 400 kHz repetition rate. Industrially relevant materials such as steel,aluminum and glass were treated. Tungsten served as reference. X-ray spectra were recorded, and X-ray dose measurements were performed for laser treatment in air. For laser intensities > 2 × 10^13 W/cm2, X-ray doses exceeding the regulatory exposure limits for members of the public were found. Suitable X-ray protection strategies are proposed. T2 - SPIE Photonics West CY - San Francisco, USA DA - 02.02.2019 KW - Laser-induced X-ray emission KW - Ultrashort laser material interaction KW - Radiation protection PY - 2019 SN - 978-1-5106-2459-7 DO - https://doi.org/10.1117/12.2516165 SN - 0277-786X SN - 1996-756X VL - 10908 SP - 1090802-1 EP - 1090802-7 PB - SPIE - The international society for optics and photonics CY - Bellingham, WA, USA AN - OPUS4-47510 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dittmann, Daniel A1 - Saal, L. A1 - Zietzschmann, F. A1 - Mai, M. A1 - Altmann, Korinna A1 - Al-Sabbagh, Dominik A1 - Ruhl, A. S. A1 - Jekel, M. A1 - Braun, U. T1 - Aktivkohlecharakterisierung als weiterer Schlüssel für Adsorptionsprognosen organischer Spurenstoffe in der vierten Reinigungsstufe T2 - Kurzreferate zur Wasser 2021 N2 - In diesem Beitrag wird der Einfluss des Aktivkohleprodukts auf die Adsorption von Spurenstoffen aus Kläranlagenablauf gezeigt und diskutiert. Im zweiten Teil wird das Material Aktivkohle analytisch charakterisiert und die Eigenschaften systematisiert. Die gewonnenen Erkenntnisse werden mit Bezug zu Praxislösungen zusammengefasst. T2 - Wasser 2021 CY - Online meeting DA - 10.05.2021 KW - Aktivkohle KW - Thermogravimetrie KW - Zersetzungsgasanalyse KW - Proximatanalyse PY - 2021 SP - 373 EP - 378 AN - OPUS4-52740 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zubia Aranburu, Judith A1 - Cappella, Brunero A1 - Zabala Eguren, A. A1 - Buruaga Lamarain, L. A1 - Aginagalde Lopez, A. A1 - Bonse, Jörn A1 - Schwibbert, Karin T1 - Quantification of the adhesion force of E. coli on Ti via single-cell force spectroscopy T2 - Libro de Actas del XL Congreso Anual de la Sociedad Española de Ingeniería Biomédica N2 - Antibiotic resistance is a growing global problem which poses a massive threat to human health. Although human activity contributes to the acceleration of the process, bacteria have a self-driven stabilisation mechanism to protect themselves from such and other external threats: biofilm formation. Nonetheless, it is the adhesion of a single bacterial cell to a surface that triggers the formation of such network of biomolecules and microorganisms, as well as its hazardous consequences. The main objective of this work was to quantify the adhesion force of a single E. coli cell on a Ti substrate via the AFM-related single-cell force spectroscopy, with both the cell and the substrate material being of high clinical relevance. A set of 25 x 25 force displacement curves was acquired with a maximum force of 3.2 nN without dwell time, yielding a topography map and an adhesion force map that showed to be correlated. A mean adhesion force of 0.85 ± 0.175 nN was measured and the presence of cell appendages on the bacterial cell wall was verified through individual force-displacement curves. Bacterial viability was assessed after the measurements via live/dead staining. T2 - XL Congreso Anual de la Sociedad Española de Ingeniería Biomédica CASEIB 2022 CY - Valladolid, Spain DA - 23.11.2022 KW - Bacteria KW - Atomic force microscopy KW - Force distance curve PY - 2022 SN - 978-84-09-45972-8 SP - 217 EP - 220 AN - OPUS4-57039 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kraft, S. A1 - Böttcher, Katrin A1 - Bonse, Jörn A1 - Schille, J. A1 - Löschner, U. A1 - Krüger, Jörg T1 - Unwanted X-ray emission in ultrashort pulse laser processing: From metallic to biological materials T2 - Proceedings of the Lasers in Manufacturing Conference 2023 N2 - X-rays can be generated as an unwanted side effect during ultrashort pulse laser material processing of technical work pieces and even biological samples with laser intensities above 10^13 W/cm^2. First studies demonstrate the need to address this effect in industrial as well as in medical applications. This secondary hazard should be considered in work safety and risk assessment. T2 - Lasers in Manufacturing 2023 (LiM 2023) CY - Munich, Germany DA - 26.06.2023 KW - Ultrashort pulse laser processing KW - Laser-induced X-ray emission KW - Secondary hazard PY - 2023 SP - LiM 2023 - 1 EP - LiM 2023 - 6 PB - Wissenschaftliche Gesellschaft Lasertechnik und Photonik e.V. (WLT) AN - OPUS4-58358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cornelsen Sampaio Kling, I. A1 - Pauw, Brian Richard A1 - Jacome, Leonardo A. A1 - Archanjo, B. S. A1 - Simão, R. A. T1 - Development and characterization of starch film and the incorporation of silver nanoparticles T2 - Semana MetalMat & Painal PEMM 2020 N2 - Starch is one of the biopolymers being used for bioplastic synthesis. For production, starch can be combined with different plasticizers, starches from different plant sources and even with nanomaterials to improve or to add film properties. The challenge of adding these, e.g. in the form of silver nanoparticles (AgNp) is to determine the concentration so as to avoid impairing the properties of the film, agglomeration or altering the visual characteristics of the film. In this study, a starch film synthesis route and the incorporation of silver nanoparticles has been proposed in order not to alter the properties of the film while maintaining the transparency and a clear colour of the starch film. The results showed that the proposed synthesis route is promising, efficient, reproducible, fast and the film has good mechanical properties. T2 - Semana MetalMat & Painal PEMM 2020 CY - Online meeting DA - 23.11.2020 KW - Biofilm KW - Silver nanoparticle KW - Starch KW - Starch nanoparticle PY - 2020 SP - 1 EP - 2 AN - OPUS4-51940 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bauer, J. A1 - Miclea, P.-T. A1 - Braun, U. A1 - Altmann, Korinna A1 - Turek, M. A1 - Hagendorf, C. T1 - Microplastic detection and analysis in water samples T2 - Sustainable Energy-Water-Environment Nexus in Deserts N2 - Microplastic detection in water samples becomes important for tracing microplastic sources. Microplastic may harm desalination facilities by blocking filters and disturbing the marine food chain. Thermo analytical methods such as pyrolysis gas chromatography mass spectroscopy, and spectroscopic methods like (micro) Raman spectroscopy or (micro) Fouriertransform infrared spectroscopy in combination with appropriate filters and sample preparation are suitable for analyzing microplastics on a scale from 1 µm to 1000 µm fast and unambiguous. While the thermo analytical methods are suitable for larger sample volumes, Raman spectroscopy and Fouriertransform infrared spectroscopy are able to detect and analyze single microplastic particles for instance in bottled water. Machine learning algorithms ensure a reliable classification of different plastic materials. T2 - International Conference on Sustainable Energy-Water-Environment Nexus in Desert Climate 2019 CY - Ar-Rayyan, Qatar DA - 02.12.2019 KW - Microplastics KW - Water samples PY - 2022 SP - 111 EP - 113 PB - Springer AN - OPUS4-56240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Röhsler, Andreas A1 - Sobol, Oded A1 - Nolze, Gert A1 - Unger, Wolfgang A1 - Böllinghaus, Thomas T1 - Use of time-of-flight secondary ion mass spectrometry for the investigation of hydrogen-induced effects in austenitic steel AISI 304L T2 - Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena N2 - During the energy transformation from fossil fuels to renewable energy sources, the use of hydrogen as fuel and energy storage can play a key role. This presents new challenges to industry and the scientific community alike. The storage and transport of hydrogen, which is nowadays mainly realized by austenitic stainless steels, remains problematic, which is due to the degradation of mechanical properties and the possibility of phase transformation by hydrogen diffusion and accumulation. The development of materials and technologies requires a fundamental understanding of these degradation processes. Therefore, studying the behavior of hydrogen in austenitic steel contributes to an understanding of the damage processes, which is crucial for both life assessment and safe use of components in industry and transportation. As one of the few tools that is capable of depicting the distribution of hydrogen in steels, time-of-flight secondary ion mass spectrometry was conducted after electrochemical charging. To obtain further information about the structural composition and cracking behavior, electron-backscattered diffraction and scanning electron microscopy were performed. Gathered data of chemical composition and topography were treated employing data fusion, thus creating a comprehensive portrait of hydrogen-induced effects in the austenite grade AISI 304L. Specimens were electrochemically charged with deuterium instead of hydrogen. This arises from the difficulties to distinguish between artificially charged hydrogen and traces existing in the material or the rest gas in the analysis chamber. Similar diffusion and permeation behavior, as well as solubility, allow nonetheless to draw conclusions from the experiments. T2 - 21st International Conference on Secondary Ion Mass Spectrometry CY - Kraków, Poland DA - 10.09.2017 KW - AISI 304L KW - Hydrogen KW - ToF-SIMS KW - Austenitic stainless steel PY - 2018 DO - https://doi.org/10.1116/1.5013931 SN - 1071-1023 VL - 36 IS - 3 SP - Article 03F103, 1 EP - 6 PB - American Vacuum Society (AVS) AN - OPUS4-44840 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Leinitz, Sarah A1 - Schmidt, Wolfram A1 - Mota, Berta A1 - Crasselt, Claudia ED - Ludwig, H.-M. T1 - Einfluss der wässrigen Phase von Zementleim und Polycarboxylatethern auf die Rheologie und die frühe Hydratation von Zement T2 - Tagungsband der 20. Internationalen Baustofftagung ibausil N2 - Die Rheologie von fließfähigen zementären Systemen mit Fließmitteln wird durch eine Vielzahl parallel stattfindender Effekte beeinflusst. Zu diesen Effekten zählen Wechselwirkungen zwischen den Polymeren und Ionen in der Porenlösung, frühe Phasenbildung, zeitabhängige und kompetitive Adsorption zwischen anionischen Polymeren und Sulfationen, Bildung von Phasen in der Porenlösung sowie Morphologieänderungen an Partikeloberflächen. Die frühe Hydratation von Zement, die durch Lösungs- und Fällungsprozesse angetrieben wird, beeinflusst diese Effekte erheblich. Das permanente Ungleichgewicht der Porenlösung führt zu Veränderungen der Partikeloberflächen, welches widerum zur Folge hat, dass rheometrische Messungen dieser Zementleime anfällig für Streuungen sind. Um die Einflüsse aus der Zementhydratation zu minimieren, wurden die rheometrischen Untersuchungen mit Zement in Porenlösung durchgeführt. Die Experimente wurden mit verschiedenen Feststoffvolumenfraktionen durchgeführt und mit den Ergebnissen identischer Systeme mit Wasser anstelle von Porenlösung verglichen. Zusätzlich wurden die gleichen Systeme mit Zugabe von Polycarboxylatethern untersucht. Die Ergebnisse zeigen, dass die Leime mit Wasser niedrigere Werte für Fließgrenze und plastische Viskosität aufweisen, als die Systeme mit Porenlösung. Während die Polymere eine Verminderung der Fließgrenze zur Folge hatte, war die Wirkung von Polymeren auf die plastische Viskosität vernachlässigbar. Zusätzlich wurde die frühe Hydratation unter Verwendung von Wärmeflusskalorimetrie, Rasterelektronenmikroskopie und Nadeleindringtiefe beobachtet. T2 - 20. Internationale Baustofftagung CY - Weimar, Germany DA - 12.09.2018 KW - Rheologie KW - Polycarboxylatether KW - Zementleim KW - Fließmittel PY - 2018 SN - 978-3-00-059950-7 VL - 20 SP - 744 EP - 751 PB - F.A. Finger-Institut für Baustoffkunde CY - Weimar AN - OPUS4-45973 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Crasselt, Claudia A1 - Schmidt, Wolfram A1 - Sturm, Heinz T1 - Influence of rheology modifying admixtures on early hydration of cementitious suspensions T2 - PAPERS AND POSTERS PROCEEDINGS 15th International Congress on the Chemistry of Cement N2 - The presence of polycarboxylate ether (PCE) based superplasticizers (SPs) has enormous influence on the early hydration of cement. C3A as the most reactive phase of Portland cement plays a significant role in early hydration reactions and affects the rheological performance. Therefore, this paper presents experimental results about the influence of delayed addition of PCEs on the Hydration of cement and C3A-gypsum pastes investigated by isothermal heat flow calorimetry. Complementary in-situ XRD was carried out on C3A pastes to analyze hydration and phase changes related to the addition of PCE. Cement pastes with a delayed addition of PCE showed less Retardation compared to simultaneous addition. The alteration caused by PCE is much more pronounced for C3A-gypsum mixes. With a delayed addition of SP, the hydration of C3A is less retarded or even accelerated. It is obvious that there is less retardation the later the addition of SP. Furthermore, the PCE alter the hydration of C3A when added delayed and exhibit changes in kinetics and hydration rates. XRD results showed that more C3A is dissolved in the presence of PCE. Also, the gypsum depletion occurs earlier in the presence of PCE and even faster with delayed addition. Without PCE AFm starts to form just after the gypsum depletion. However, in the presence of PCE AFm already starts to form at the beginning of the hydration. Due to the faster gypsum depletion in the presence of PCE, also the transformation from ettringite into AFm begins earlier, but takes longer as without SP. T2 - 15th International Congress on the Chemistry of Cement CY - Prague, Czech Republic DA - 16.09.2019 KW - Cement KW - C3A KW - Early hydration KW - Polycarboxylate ether (PCE) KW - Delayed addition PY - 2019 SP - 1 EP - 8 AN - OPUS4-49104 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Crasselt, Claudia A1 - Schmidt, Wolfram A1 - Sturm, Heinz T1 - Influence of Rheology Modifying Admixtures on Hydration of Cementitious Suspensions T2 - Sixth International Symposium on Nanotechnology in Construction, Technology Transfer in Action N2 - The presence of polycarboxylate ether (PCE) based superplasticizers (SPs) has an enormous influence on the early hydration of cement. The hydration is retarded and the timing of formation and the morphology of hydrates is affected. This short paper presents experimental results about the influence of delayed addition time of PCE SPs on hydration of cement and alite pastes, investigated by isothermal heat flow calorimetry. For cement as well as for alite pastes the hydration is retarded with SP, whereby the high charge PCE has a stronger retarding effect than the low charge PCE. The retardation caused by PCE is much more pronounced for alite than for cement mixes. If PCE is added later to the mix, the induction period is shortened and the hydration is accelerated compared to simultaneous addition. This applies for cement and alite pastes. With delayed PCE addition the alite shows a clearly less retarded setting and main hydration than after simultaneous addition. It is obvious that for alite pastes there is less retardation the later the addition of SP. T2 - 6th International Symposium on Nanotechnology in Construction CY - Hong Kong, China DA - 02.12.2018 KW - Polycarboxylate ether (PCE) KW - Early hydration KW - Cement PY - 2018 SP - 1 EP - 8 AN - OPUS4-47204 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Crasselt, Claudia A1 - Schmidt, Wolfram A1 - Sturm, Heinz ED - M. Tyrer, ED - E. Ganjian, ED - West, A. T1 - Influence of rheology modifying admixtures on hydration of cementitious suspensions T2 - Proceedings of the 38th Cement and Concrete Science Conference N2 - The presence of polycarboxylate ether (PCE) based superplasticizers (SPs) has an enormous influence on the early hydration of cement. The hydration is retarded and the timing of formation and the morphology of hydrates is affected. This short paper presents experimental results about the influence of delayed Addition time of PCE SPs on hydration of cement and tricalcium aluminate (C3A) pastes, investigated by isothermal heat flow calorimetry. For cement pastes the hydration is retarded with SP, whereby the high charge PCE has a stronger retarding effect than the low charge PCE. With delayed PCE addition the cement shows a less retarded setting than with simultaneous addition. The alteration caused by PCE is much more pronounced for C3A and gypsum mixes than for cement. If the SP is added simultaneous, the exothermic peak of C3A is retarded. However, with delayed addition of SP the hydration is shortened, the gypsum depletion is fastened and the exothermic peak occurs less retarded or even accelerated compared to simultaneous addition. It is obvious that for C3A pastes there is less retardation the later the Addition of SP. Furthermore, the PCE alter the hydration of C3A when added delayed and exhibit changes in kinetics and hydration rates. The rate of reaction in the second stage is lower, discernible in decreased slopes and broader peaks. Besides this, a distinct ramp in the C3A heat flow curves within the first stage of C3A hydration occurs for all pastes with delayed addition of SP, which suggests an accelerated ettringite formation. T2 - 38th Cement and Concrete Science Conference CY - Coventry, UK DA - 10.09.2018 KW - Cement hydration KW - Polycarboxylate ether KW - C3A hydration PY - 2018 SN - 978-1-84600-088-1 SP - 64 EP - 67 CY - Coventry, UK AN - OPUS4-45995 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -