TY - CONF A1 - Krause, Martin A1 - Milmann, Boris A1 - Feldmann, Rüdiger A1 - Friese, Martin A1 - Wöstmann, Jens A1 - Zoëga, Andreas A1 - Sodeikat, C. T1 - Thickness measurement & quality assurance of floor slabs & diaphragm walls T2 - Structural faults & repair 2010 - International conference and exhibition CY - Edinburgh, Scotland, UK DA - 2010-06-15 KW - Ultrasonic echo KW - Radar KW - Impact-echo KW - Synthetic aperture focusing technique (SAFT) KW - Compaction faults PY - 2010 SN - 0-947644-67-9 SP - 1 EP - 9 PB - Engineering Technics Press CY - Edinburgh, Scotland AN - OPUS4-22897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas A1 - Goering, Harald A1 - Böhning, Martin A1 - Fritz, Andreas A1 - Rübner, J. T1 - Structure Analysis of Polymeric Nanomaterials by Relaxation Spectroscopy T2 - Polydays 2002 CY - Berlin, Germany DA - 2002-09-30 PY - 2002 SP - 1(?) AN - OPUS4-2044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böhning, Martin A1 - Goering, Harald A1 - Fritz, Andreas A1 - Brzezinka, Klaus-Werner A1 - Turky, Gamal A1 - Schönhals, Andreas A1 - Schartel, Bernhard T1 - Dielectric Study of Molecular Mobility in Poly(propylene-graft-maleic anhydride)/Clay Nanocomposites N2 - Polymer/clay nanocomposite materials based on poly(propylene-graft-maleic anhydride) (PPgMAH) and two different organophilic modified clays were investigated by dielectric relaxation spectroscopy (DRS). In contrast to ungrafted polypropylene (PP), PPgMAH shows a dielectrically active relaxation process which can be assigned to localized fluctuations of the polar maleic anhydride groups. Its relaxation rate exhibits an unusual temperature dependence, which could be attributed to a redistribution of water molecules in the polymeric matrix. This is confirmed by a combination of Raman spectroscopy and thermogravimetric experiments (TGA) with real-time dielectric measurements under controlled atmospheres. In the nanocomposites this relaxation process is shifted to higher frequencies up to 3 orders of magnitude compared to the unfilled polymer. This indicates a significantly enhanced molecular mobility in the interfacial regions. In the nanocomposite materials a separate high-temperature process due to Maxwell-Wagner-Sillars (MWS) polarization was observed. The time constant of this MWS process can be correlated with characteristic length scales in nanocomposites and therefore provides additional information on dispersion and delamination/exfoliation of clay platelets in these materials. These properties also influence the diffusivity of the water molecules as revealed by real-time dielectric investigations. KW - Polymer clay nanocomposites KW - Molecular mobility KW - Dielectric relaxation spectroscopy PY - 2005 DO - https://doi.org/10.1021/ma048315c SN - 0024-9297 SN - 1520-5835 VL - 38 IS - 7 SP - 2764 EP - 2774 PB - American Chemical Society CY - Washington, DC AN - OPUS4-7281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kautek, Wolfgang A1 - Hertwig, Andreas A1 - Martin, Sven A1 - Krüger, Jörg A1 - Lenzner, Matthias A1 - Spielmann, C. A1 - Lenner, M. A1 - Bunte, J. A1 - Puester, T. A1 - Burmester, T. A1 - Fiedler, A. A1 - Heberer, E. A1 - Brose, M. A1 - Stingl, A. A1 - Kiehl, P. A1 - Hönigsmann, H. A1 - Trautinger, F. A1 - Grabner, G. T1 - Safety in Femtosecond Laser Technology - Recent Results of a European Research Project (406) T2 - International Laser Safety Conference 2003 ; ILSC 2003 CY - Jacksonville, FL, USA DA - 2003-03-10 PY - 2003 SN - 0-912035-38-2 SP - 1(?) EP - 10(?) PB - Laser Institute of America CY - Orlando, Fla. AN - OPUS4-2259 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böhning, Martin A1 - Goering, Harald A1 - Hao, Ning A1 - Mach, Reinhard A1 - Oleszak, Franz A1 - Schönhals, Andreas T1 - Molecular Mobility and Gas Transport Properties of Polycarbonate-Based Nanocomposites PY - 2003 UR - http://www.ipme.ru/e-journals/RAMS/no_3503/bohning/bohning.html SN - 1606-5131 VL - 5 SP - 155 EP - 159 PB - Advanced Study Center CY - St. Petersburg AN - OPUS4-2884 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hasenstab, Andreas A1 - Krause, Martin A1 - Rieck, C. A1 - Hillemeier, B. T1 - Use of Low Frequency Ultrasound Echo Technique to Determine Cavities in Wooden Construction Composites T2 - 6th International Symposium Non-Destructive Testing in Civil Engineering (NDT-CE) CY - Berlin, Germany DA - 2003-09-16 PY - 2003 UR - http://www.ndt.net/article/ndtce03/papers/p051/p051.htm SN - 3-931381-49-8 SP - 1(?) EP - 9(?) PB - DGZfP CY - Berlin AN - OPUS4-3230 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hasenstab, Andreas A1 - Krause, Martin ED - Cziesielski, E. T1 - Ultraschallechoverfahren an Holz PY - 2004 SN - 3-433-01705-0 SP - 52 EP - 58 PB - Ernst CY - Berlin AN - OPUS4-3145 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Böhning, Martin A1 - Goering, Harald A1 - Hao, Ning A1 - Schönhals, Andreas T1 - Gas Transport in Polymer based Nanocomposite Systems T2 - Workshop "Glasübergang" CY - Rostock, Germany DA - 2002-12-16 PY - 2002 AN - OPUS4-2054 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Goering, Harald A1 - Böhning, Martin A1 - Turky, Gamal A1 - Hao, Ning A1 - Schönhals, Andreas T1 - Molecular Dynamics in Polymer Nanocomposites T2 - Workshop "Glasübergang" CY - Rostock, Germany DA - 2002-12-16 PY - 2002 AN - OPUS4-2061 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hasenstab, Andreas A1 - Rieck, C. A1 - Hillemeier, B. A1 - Krause, Martin T1 - Hohlstellenortung in Holzbalken mit dem Ultraschallverfahren N2 - Zusammenfassung Die Anwendung des Ultraschallecho-Verfahrens zur Hohlstellenortung in Holzbalken wird beschrieben. An Hand der Versuchsergebnisse wird der Einfluss der Anisotropie des Holzes auf die Messkopfanordnung und Schallgeschwindigkeit dargestellt. Mit der optimierten Messanordnung ist die erfolgreiche Detektierung von Nachbildungen von Minderdicken und Kernfäule möglich. Besonders klar sind Schäden in Faserrichtung (Kernfäulenachbildung) nachzuweisen. Die sehr guten Ergebnisse zeigen die Anwendbarkeit des Ultraschallecho-Verfahrens an Holz. T2 - Jahrestagung Zerstörungsfreie Materialprüfung 2002 CY - Weimar, Deutschland DA - 2002-05-06 KW - ZfP an Holzbauteilen KW - Fehlstellen KW - Minderdicken KW - Ultraschallecho-Experimente an Probekörpern PY - 2002 UR - http://www.ndt.net/article/dgzfp02/papers/p32/p32.htm SN - 3-931381-39-0 N1 - Serientitel: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. – Series title: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. IS - 80-CD PB - DGZfP CY - Berlin AN - OPUS4-1937 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hasenstab, Andreas A1 - Hillemeier, B. A1 - Krause, Martin ED - Bröker, F. T1 - Defect localisation in wood with low frequency ultrasonic echo technique T2 - 14th International Symposium on Nondestructive Testing of Wood CY - Eberswalde, Germany DA - 2005-05-02 PY - 2005 SN - 3-8322-3949-9 SP - 331 EP - 336 PB - Shaker CY - Aachen AN - OPUS4-11307 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hasenstab, Andreas A1 - Krause, Martin A1 - Lutz, J. A1 - Hillemeier, B. A1 - Rieck, C. T1 - Niederfrequente Ultraschall-Echo-Verfahren und Bohrwiderstandsmessung zur Untersuchung von Holzbauteilen T2 - DGZfP Jahrestagung CY - Rostock, Deutschland DA - 2005-05-02 KW - ZfP an Holzbauteilen KW - Fehlstellen KW - Minderdicken KW - Ultraschallecho-Experimente an Probekörpern KW - Ultraschall-Echo KW - Fäulnis KW - Bauwesen PY - 2005 SN - 3-931381-64-1 N1 - Serientitel: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. – Series title: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. IS - 94-CD SP - 1(?) EP - 11(?) PB - DGZfP CY - Berlin AN - OPUS4-11960 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hasenstab, Andreas A1 - Krause, Martin A1 - Hillger, w. A1 - Bühling, L. A1 - Ilse, D. A1 - Hillemeier, B. A1 - Rieck, C. T1 - Luftultraschall und Ultraschall-Echo-Technik an Holz T2 - DGZfP Jahrestagung CY - Rostock, Deutschland DA - 2005-05-02 KW - ZfP an Holzbauteilen KW - Fehlstellen KW - Minderdicken KW - Ultraschallecho-Experimente an Probekörpern KW - Ultraschall-Echo KW - Fäulnis KW - Bauwesen KW - Luftultraschall PY - 2005 SN - 3-931381-64-1 N1 - Serientitel: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. – Series title: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. IS - 94-CD SP - 1(?) EP - 15(?) PB - DGZfP CY - Berlin AN - OPUS4-11961 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hertwig, Andreas A1 - Martin, Sven A1 - Krüger, Jörg A1 - Spielmann, C. A1 - Lenner, M. A1 - Kautek, Wolfgang ED - Dausinger, F. ED - Lichtner, F. ED - Lubatschowski, H. T1 - Primary hazards and reliability of protective materials N2 - Femtosecond laser pulses are close to industrial use. The advantages of ultrashort laser pulses for micromachining applications especially in the case of dielectric and biological samples down to pulse durations of 5 fs have been established. The current international standards of laser safety are primarily concerned with CW and pulsed lasers down to the nanosecond range. Therefore, human tissue and laser-protection equipment was investigated with respect to its resistance and protection performance for femtosecond laser illumination down to 30 fs. This included filter glasses for laser protection eyewear, polymer and textile materials used in curtains and guards. Bulk absorber filters can provide enough protection against laser radiation, give a sufficiently broad absorption spectrum. Materials are damaged more easily by femtosecond laser radiation. The need for sufficient spectral broadness as well as the different damage thresholds have to be included in international laser safety standards. This work should trigger the development of novel eye-protection devices that are lighter and ergonomically more acceptable than present commercial models. KW - Lasersicherheit KW - Kurzpulslaser KW - Femtosekunden KW - Lasertechnik KW - Materialbearbeitung PY - 2004 SN - 3-540-20114-9 DO - https://doi.org/10.1007/b96440 SN - 0303-4216 N1 - Serientitel: Topics in applied physics – Series title: Topics in applied physics IS - 96 SP - 287 EP - 307 PB - Springer CY - Berlin AN - OPUS4-4661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hasenstab, Andreas A1 - Krause, Martin A1 - Scheer, C. T1 - Zerstörungsfreie Integritätsprüfung von Holz mit dem Ultraschallecho-Verfahren T2 - Forschungskolloquium "Holzbau Forschung + Praxis" CY - Stuttgart, Deutschland DA - 2006-02-23 PY - 2006 SP - 33 EP - 40 PB - Technische Universität Stuttgart CY - Stuttgart AN - OPUS4-12242 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böhning, Martin A1 - Hao, Ning A1 - Schönhals, Andreas T1 - Gas transport and molecular mobility in polymer/POSS nanocomposites PY - 2006 DO - https://doi.org/10.1016/j.desal.2006.03.127 SN - 0011-9164 VL - 200 IS - 1-3 SP - 142 EP - 143 PB - Elsevier CY - Amsterdam AN - OPUS4-13707 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Böhning, Martin A1 - Goering, Harald A1 - Hao, Ning A1 - Mach, Reinhard A1 - Schönhals, Andreas ED - Cassidy, P. T1 - Polycarbonate/SiC nanocomposites - Influence of nanoparticle dispersion on molecular mobility and gas transport T2 - 7th International Symposium on Polymers for Advanced Technologies CY - Fort Lauderdale, FL, USA DA - 2005-09-21 KW - Nanocomposites KW - Nanoparticles KW - Polycarbonates KW - Dielectric properties KW - Gas permeation PY - 2005 VL - 16 IS - 2-3 SP - 262 EP - 268 PB - Wiley CY - Chichester AN - OPUS4-7062 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Stelling, Karen A1 - Böllinghaus, Thomas A1 - Wolf, Martin A1 - Schöler, Annett A1 - Burkert, Andreas A1 - Isecke, Bernd ED - Böllinghaus, T. ED - Herold, H. T1 - Hot cracks as stress corrosion cracking initiation sites in laser welded corrosion resistant alloys N2 - Although hot cracks at weld surfaces of corrosion resistant alloys (CRAs) might provide access to respective aggressive media and thus, might provide the conditions for a local potential and pH drop, the interaction between hot cracking and corrosion phenomena has not been investigated up to the present. This particularly concerns the initiation of stress corrosion cracking inside such crevices. As a first approach to clarify the influence of hot cracks on corrosion resistance, considering particularly stress corrosion cracking, hot crack afflicted laser welds of three different CRAs have been subjected to a series of different corrosion tests. Besides the fact that the Drop Evaporation (DE) Test represents a more realistic procedure than standard immersion tests it turned out that hot cracks can obviously represent an initiation site of stress corrosion cracking in the austenitic stainless steel AISI 309 (German No. 1.4828). The susceptibility of such hot crack afflicted laser welds to stress corrosion cracking (SCC) significantly depends on temperature and chloride concentration of the test environment In comparison, the high nitrogen austenitic stainless steel AISI S 34565 (German No. 1.4565) did not exhibit any stress corrosion cracking associated with hot cracking. This material exhibited pitting corrosion and stress corrosion only in the base material. The Alloy 50 (German No. 2.4850), a Nickel based material, was susceptible to pitting corrosion, but showed no tendency towards stress corrosion cracking at all. T2 - International Workshop "Hot Cracking Phenomena in Welds" CY - Berlin, Germany DA - 2004-03-04 KW - Ni-Base Alloy KW - Stress corrosion Cracking KW - Hot Cracking KW - Laser Welding KW - Austenitic Stainless Steel KW - Drop Evaporation Test PY - 2005 SN - 3-540-22332-0 DO - https://doi.org/10.1007/3-540-27460-X_10 SP - 165 EP - 182 PB - Springer CY - Berlin AN - OPUS4-11852 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Osterloh, Kurt A1 - Hasenstab, Andreas A1 - Ewert, Uwe A1 - Krause, Martin A1 - Goebbels, Jürgen T1 - Mobile radiographische Untersuchung von Holz und Bäumen T2 - DGZfP Jahrestagung CY - Rostock, Deutschland DA - 2005-05-02 KW - Digitale Radiographie KW - Mobiles Röntgen PY - 2005 SN - 3-931381-64-1 N1 - Serientitel: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. – Series title: Berichtsband / Deutsche Gesellschaft für zerstörungsfreie Prüfung e. V. IS - 94-CD SP - 1(?) EP - 8(?) PB - DGZfP CY - Berlin AN - OPUS4-11866 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bunte, J. A1 - Barcikowski, S. A1 - Burmester, T. A1 - Püster, T. A1 - Hertwig, Andreas A1 - Kautek, Wolfgang A1 - Krüger, Jörg A1 - Martin, Sven A1 - Spielmann, C. A1 - Lenner, M. A1 - Brose, M. T1 - Sicherer Umgang mit Ultrakurzpuls-Lasern, Teil 2: Sekundäre Gefährdungen PY - 2005 SN - 0945-8875 IS - 4 SP - 13 EP - 18 PB - Magazin-Verl. CY - Bad Nenndorf AN - OPUS4-11002 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hertwig, Andreas A1 - Martin, Sven A1 - Krüger, Jörg A1 - Kautek, Wolfgang T1 - Interaction area dependence of the ablation threshold of ion-doped glass N2 - The laser ablation behaviour of ion-doped glass filter materials under irradiation with femtosecond laser pulses was investigated with respect to spot size and repetition rate. The damage threshold fluence of Schott BG18 depends on the size of the irradiated area. The effect is discussed in terms of a defect-site model. KW - Femtosecond KW - Laser KW - Materials processing KW - Ablation KW - Threshold KW - Glass PY - 2004 DO - https://doi.org/10.1016/j.tsf.2003.11.131 SN - 0040-6090 VL - 453-454 SP - 527 EP - 530 PB - Elsevier CY - Amsterdam AN - OPUS4-11046 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hertwig, Andreas A1 - Martin, Sven A1 - Krüger, Jörg A1 - Kautek, Wolfgang T1 - Surface damage and color centers generated by femtosecond pulses in borosilicate glass and silica N2 - Color center generation by femtosecond laser pulses (30 fs) is observed in a fluence range below the damage threshold in an alkali-free barium borosilicate (BBS) glass, and in a thin layer of SiO2 on a fused silica substrate. The color centers are characterized spectroscopically. The optical density of the color centers in BBS glass is by two orders of magnitude higher than that in silica. A healing process with a time constant of about 30 h can be found. PY - 2004 UR - http://www.sciencedirect.com/science/journal/0926860X DO - https://doi.org/10.1007/s00339-004-2634-x SN - 0947-8396 VL - 79 SP - 1075 EP - 1077 PB - Springer CY - Berlin AN - OPUS4-11047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bunte, J. A1 - Barcikowski, S. A1 - Burmester, T. A1 - Püster, T. A1 - Hertwig, Andreas A1 - Kautek, Wolfgang A1 - Krüger, Jörg A1 - Martin, Sven A1 - Spielmann, C. A1 - Lenner, M. A1 - Brose, M. T1 - Sicherer Umgang mit Ultrakurzpuls-Lasern, Teil 1: Primäre Gefährdungen PY - 2005 SN - 0945-8875 IS - 2 SP - 6 EP - 11 PB - Magazin-Verl. CY - Bad Nenndorf AN - OPUS4-11001 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Reimund, Verena A1 - Pelkner, Matthias A1 - Neubauer, Andreas A1 - Thomas, Hans-Martin A1 - Kreutzbruck, Marc T1 - Automatische Detektion von Rissen in Stahlbauteilen unter Verwendung von GMR-Sensoren bei der magnetischen Streuflussprüfung N2 - GMR-Sensor Arrays ermöglichen eine örtlich hoch aufgelöste Messung magnetischer Streufeldamplituden an Stahlbauteilen, bei der abhängig von der Größe der zu prüfenden Oberfläche erhebliche Datenmengen erzeugt werden. Eine automatische Detektion von Rissen kann anschließend mittels digitaler Bildverarbeitung erreicht werden, welche hauptsächlich auf einer Kantenerkennung basiert. Diese wurde anhand einer Magnetometer-Messung getestet, die an einem zylindersymmetrischem Bauteil mit funkenerosiv eingebrachten Rissen geringer Tiefe durchgeführt wurde. Die erzielte Selektion der Defekte wird für eine angestrebte Rekonstruktion der Defektgeometrie benötigt. T2 - DGZfP-Jahrestagung 2011 CY - Bremen, Deutschland DA - 30.05.2011 KW - GMR-Sensor KW - Streuflussprüfung PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-253451 SN - 978-3-940283-33-7 IS - DGZfP-BB 127 (Mo.3.C.4) SP - 1 EP - 7 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-25345 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Pelkner, Matthias A1 - Neubauer, Andreas A1 - Blome, Mark A1 - Reimund, Verena A1 - Thomas, Hans-Martin A1 - Kreutzbruck, Marc ED - Chady, T. ED - Gratkowski, S. ED - Takagi, T. ED - Udpa, S.S. T1 - Flux leakage measurements for defect characterization using NDT adapted GMR sensors N2 - High-precision magnetic field sensors are of increasing interest in non destructive testing (NDT). In particular GMR-sensors (giant magneto resistance) are qualified because of their high sensitivity, high signal-to-noise ratio and high spatial resolution. We performed magnetic flux leakage measurements of artificial cracks with a GMR-gradiometer and a 3-axes GMR-magnetometer. Cracks of a depth of 44 μm still could be detected with a sufficient high signal-to-noise ratio. A semi-analytic magnetic dipole model was used for swiftly predicting magnetic stray fields. The reliable reconstruction based on measurements of artificial rectangular-shaped defects is demonstrated. KW - GMR KW - NDT KW - Magnetic flux leakage KW - Reconstruction PY - 2011 SN - 978-1-60750-749-9 SN - 1383-7281 N1 - Serientitel: Studies in applied electromagnetics and mechanics – Series title: Studies in applied electromagnetics and mechanics VL - 35 SP - 217 EP - 224 PB - IOS Press CY - Amsterdam, The Netherlands AN - OPUS4-25374 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hasenstab, Andreas A1 - Krause, Martin A1 - Rieck, C. A1 - Hillemeier, B. T1 - Materialuntersuchung an Holz mit niederfrequenter Ultraschall-Echotechnik N2 - Kurzfassung Die Anwendung niederfrequenter Ultraschall-Echotechnik mit Longitudinal- und Transversalwellen für die Materialuntersuchung von Holzbauteilen wird beschrieben. Weiterhin wird der Einfluss der Holzfasern auf die Schallgeschwindigkeiten und Oberflächenwellen an Hand von Messergebnissen aufgezeigt. Die Leistungsfähigkeit des Ultraschall-Echoverfahrens an ungeschädigten Holzkörpern und Körpern mit eingebrachten Bohrungen in Faserrichtung (Kernfäulnissimulation) wird dargestellt. Es ist zudem möglich, bei koppelmittelfreier Ankopplung mit Transversalwellen indirekt Fäulnis von der ungeschädigten Bauteilseite aus zu orten. Als Referenzverfahren werden die Bohrwiderstandsmethode oder die Röntgendurchstrahlung eingesetzt. T2 - Jahrestagung Zerstörungsfreie Materialprüfung 2004 CY - Salzburg, Österreich DA - 2004-05-17 PY - 2004 UR - http://www.ndt.net/article/dgzfp04/papers/v87/v87.htm SN - 3-931381-55-2 SP - 1(?) EP - 9(?) PB - DGZfP CY - Berlin AN - OPUS4-5216 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hasenstab, Andreas A1 - Osterloh, Kurt A1 - Robbel, Joachim A1 - Krause, Martin A1 - Ewert, Uwe A1 - Hillemeier, B. T1 - Mobile Röntgenblitzröhren zum Auffinden von Holzschäden N2 - In diesem Beitrag wird die Anwendung von Radiographiesystemen zum Auffinden von Holzschäden beschrieben. Die Anlage besteht aus einer mobilen Röntgenblitzröhre und einem digitalen Radiographiesystem mit Speicherfolie oder einem Flachdetektor. An Hand der durchgeführten Versuche an Laub- und Nadelbäumen sowie an Eichenbalken der Marienkirche der Lutherstadt- Wittenberg wird die Detektion innerer Schäden gezeigt. T2 - Jahrestagung Zerstörungsfreie Materialprüfung 2004 CY - Salzburg, Österreich DA - 2004-05-17 PY - 2004 UR - http://www.ndt.net/article/dgzfp04/papers/p15/p15.htm SN - 3-931381-55-2 SP - 1(?) EP - 8(?) PB - DGZfP CY - Berlin AN - OPUS4-5217 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martin, Sven A1 - Hertwig, Andreas A1 - Lenzner, Matthias A1 - Krüger, Jörg A1 - Kautek, Wolfgang T1 - Spot-size dependence of the ablation threshold in dielectrics for femtosecond laser pulses N2 - The multi-pulse ablation threshold of barium borosilicate glass was measured using 30-fs pulses of a high repetition rate (1 kHz) laser system. The threshold fluence was found to decrease with increasing beam radius ranging from 20 to 400 m. Two existing models are applied by considering thermal accumulation and point defects, respectively . PY - 2003 DO - https://doi.org/10.1007/s00339-003-2213-6 SN - 0947-8396 VL - 77 IS - 7 SP - 883 EP - 884 PB - Springer CY - Berlin AN - OPUS4-6317 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Böhning, Martin A1 - Goering, Harald A1 - Hao, Ning A1 - Schönhals, Andreas T1 - Polymer-based Nanocomposites - Particle Dispersion and Physical Properties T2 - Nanofair 2005 CY - Dresden, Germany DA - 2005-11-29 KW - Polymerbasierte Nanokomposite PY - 2005 SN - 3-18-091920-5 N1 - Serientitel: VDI-Berichte – Series title: VDI-Berichte IS - 1920 SP - 263 EP - 267 PB - VDI-Verl. CY - Düsseldorf AN - OPUS4-11589 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hertwig, Andreas A1 - Martin, S. A1 - Kautek, Wolfgang A1 - Krüger, Jörg ED - Maruray, L. T1 - Ultra-short Pulse Laser Safety - a Challenge to Materials Science N2 - In this paper, safety-related experiments with ultra-short laser pulses (down to 30 fs) on various components (goggles, curtains) for laser protection are presented. The damage and failure behaviour of protective devices has been investigated dependent on practical conditions such as pulse duration, laser .uence, pulse number, and repetition rate. The e.ects of laser-irradiation on materials can be roughly divided into transient ones like laserinduced transmission (LIT) or short-lived colour centres and permanent damages like the stable colour centres and ablation. The former e.ects are particularly important for transparent devices like laser goggles. To obtain a complete overview on laser safety issues and the prevention of failure there are two important .elds of investigation: 1. the e.ects of laser radiation on human eyes and skin, and 2. on the possible protection materials. Both .elds have been addressed during the recently .nished German project SAFEST (safety aspects in femtosecond technology). The amount of safety data available in the ultrashort pulse region has been increased remarkably. This allows for a re-evaluation of known laser protection materials for this region of pulse durations and for the evaluation of new designs that promise high protection levels while being light-weight and convenient to use. T2 - Optical design and engineering II CY - Jena, Germany DA - 2005-09-13 PY - 2005 N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE IS - 5962 SP - 59622J-1 - 59622J-10 PB - SPIE CY - Bellingham AN - OPUS4-11593 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martin, Sven A1 - Krüger, Jörg A1 - Hertwig, Andreas A1 - Fiedler, A. A1 - Kautek, Wolfgang T1 - Femtosecond laser interaction with protection materials N2 - Textile, aluminium and polyethylene used as components in laser protection curtains were investigated with respect to their ablation behaviour. Employing 33-fs pulses (800 nm wavelength, 1 kHz repetition rate), ex situ geometrical measurements of the ablation cavities and in situ acoustic investigations with a microphone were performed to determine the ablation thresholds in the single- and multi-pulse cases. The acoustical method proved advantageous for complex surface morphologies and/or single laser pulse interactions. Incubation phenomena can be observed for all the materials studied. Technically relevant multi-pulse ablation thresholds are presented and are compared with the single-pulse (1-on-1) irradiation. KW - Damage KW - Femtosecond laser ablation KW - Laser safety KW - Threshold KW - Aluminium KW - Textile PY - 2003 DO - https://doi.org/10.1016/S0169-4332(02)01392-2 SN - 0169-4332 SN - 1873-5584 VL - 208-209 SP - 333 EP - 339 PB - North-Holland CY - Amsterdam AN - OPUS4-11546 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hao, Ning A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Gas Transport Properties of Polymeric Nanocomposites Based on Polyhedral Oligomeric Silsesquioxanes PY - 2007 SN - 0743-0515 VL - 97 SP - 444 EP - 445 PB - Division of Polymeric Materials Science and Engineering, American Chemical Society CY - Washington, DC AN - OPUS4-15846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hao, Ning A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Structure Property Relationships of Polymeric Nanocomposites based on Polyhedral Oligomeric Silsesquioxanes PY - 2007 SN - 0743-0515 VL - 97 SP - 789 EP - 790 PB - Division of Polymeric Materials Science and Engineering, American Chemical Society CY - Washington, DC AN - OPUS4-15848 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hao, Ning A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Dielectric Properties of Nanocomposites Based on Polystyrene and Polyhedral Oligomeric Phenethyl-Silsesquioxanes N2 - Nanocomposites were prepared by solution blending of polyhedral oligomeric silsesquioxane with phenethyl substituents (PhenethylPOSS) into polystyrene (PS). The prepared materials were investigated by dielectric spectroscopy, differential scanning calorimetry (DSC), and density measurements. Additional FTIR investigations were carried out. Pure polystyrene shows two relaxation processes, an intermediate β*-process at lower and the α-relaxation at higher temperatures, the latter corresponding to segmental dynamics (dynamic glass transition). The molecular assignment of the β*-process needs further investigation. PhenethylPOSS can be incorporated into PS up to about 40 wt % without any indication of phase separation. With increasing PhenethylPOSS content, the α-relaxation of the composites shifts to lower temperatures and the loss peak broadens. Thus, the main effect of the nanofiller in the polystyrene matrix is to enhance the segmental dynamics, i.e., plasticization. The incorporation of approximately 40 wt % (approximately 5 mol %) PhenethylPOSS shifts the glass transition temperature Tg by 50 K to lower temperatures. The obtained results for polystyrene are discussed together with those reported recently for polycarbonate where a phase-separated morphology is observed for higher concentrations of PhenethylPOSS. The different behavior of PhenethylPOSS in polystyrene and polycarbonate is interpreted in terms of the different interaction of the phenyl rings within the POSS substituents with the phenyl rings of the polymers. For polystyrene, the interaction is stronger than for polycarbonate which probably leads to the enhanced miscibility of PhenethylPOSS into polystyrene. A detailed analysis of the temperature dependence of the dielectric relaxation strengths points also to additional interactions in the nanocomposites when compared to pure polystyrene. The broadening of the loss peak with increasing concentration is discussed in the framework of composition fluctuations. KW - Polyhedral oligomeric silsesquioxane (POSS) KW - Polymer-based nanocomposites KW - Broadband dielectric spectroscopy KW - Polystyrene PY - 2007 DO - https://doi.org/10.1021/ma071777g SN - 0024-9297 SN - 1520-5835 VL - 40 IS - 26 SP - 9672 EP - 9679 PB - American Chemical Society CY - Washington, DC AN - OPUS4-16492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hao, Ning A1 - Böhning, Martin A1 - Wohlrab, Sebastian A1 - Schönhals, Andreas T1 - Polymer Based Nanocomposites with PhenethylPOSS as Nanofilter Investigated by Dielectric Spectroscopy and Gas Transport Measurements N2 - Polyhedral oligomeric silsesquioxane with phenethyl substituents (PhenethylPOSS) as nanofiller was incorporated within Poly(bisphenol A carbonate) (PBAC) as matrix. Dielectric spectroscopy proved an almost complete miscibility of PhenethylPOSS up to 7 wt. %. At higher concentrations phase separation yields composites with a PBAC-rich matrix and POSS-rich domains which posses well shaped interfaces. The nanocomposites were also investigated with respect to their gas transport behaviour. An increase of the gas permeability was found at higher PhenethylPOSS concentrations, which is due to the phase separated structure. KW - Dielectric measurements KW - Nanocomposites KW - Permeation KW - Polycarbonates KW - Polyhedral oligomeric silsesquioxanes PY - 2008 DO - https://doi.org/10.1002/masy.200850712 SN - 1022-1360 SN - 0258-0322 SN - 1521-3900 VL - 267 IS - 1 SP - 69 EP - 73 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-17751 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reinsch, Martin A1 - Töpfer, Antje A1 - Lehmann, Andreas A1 - Nehls, Irene T1 - Determination of ochratoxin A in wine by liquid chromatography tandem mass spectrometry after combined anion-exchange/reversed-phase clean-up N2 - Ochratoxin A (OTA) is a mycotoxin produced by Aspergillus ochraceus and Penicillium verrucosum. It has been found and analysed in several foods and feeds. Owing to its toxicity and occurrence in food and feed, the European Community has issued directives and some countries have their own regulations for OTA contents in food, feed and beverages. This work describes a method for the determination of OTA in mulled and red wine. It is based on combined anion exchange/reversed-phase clean-up and was analysed by liquid chromatography coupled with tandem mass spectrometry (multiple reaction monitoring). The method was validated with natural contaminated and spiked wine samples with OTA contents from 1.34 to 3.48 g kg–1. Owing to its accuracy, good reproducibility and repeatability, this easy method is a good alternative to liquid chromatography–fluorescence detection methods. KW - Ochratoxin A KW - Wine KW - Tandem mass spectrometry KW - Solid-phase extraction KW - Anion exchange KW - Liquid chromatography PY - 2005 DO - https://doi.org/10.1007/s00216-005-3097-4 SN - 1618-2642 SN - 1618-2650 VL - 381 IS - 8 SP - 1592 EP - 1595 PB - Springer CY - Berlin AN - OPUS4-10306 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Frunza, L. A1 - Schönhals, Andreas A1 - Frunza, S. A1 - Parvulescu, V.I. A1 - Cojocaru, B. A1 - Carriazo, D. A1 - Martín, C. A1 - Rives, V. T1 - Rotational Fluctuations of Water Confined to Layered Oxide Materials - Nonmonotonous Temperature Dependence of Relaxation Times N2 - The rotational molecular dynamics of water confined to layered oxide materials with brucite structure was studied by dielectric spectroscopy in the frequency range from 10-2 to 107 Hz and in a broad temperature interval. The layered double hydroxide samples show one relaxation process, which was assigned to fluctuations of water molecules forming a layer, strongly adsorbed to the oxide surface. The temperature dependence of the relaxation rates has an unusual saddlelike shape characterized by a maximum. The model of Ryabov et al. (J. Phys. Chem. B 2001, 105, 1845) recently applied to describe the dynamics of water molecules in porous glasses is employed also for the layered materials. This model assumes two competing effects: rotational fluctuations of water molecules that take place simultaneously with defect formation, allowing the creation of free volume necessary for reorientation. The activation energy of rotational fluctuations, the energy of defect formation, a pre-exponential factor, and the defect concentration are obtained as main parameters from a fit of this model to the data. The values of these parameters were compared with those found for water confined to nanoporous molecular sieves, porous glasses, or bulk ice. Several correlations were discussed in detail, such as the lower the value of the energy of defect formation, the higher the number of defects. The pre-exponential factor increases with increasing activation energy, as an expression of the compensation law, and indicates the cooperative nature of the motional process. The involvement of the surface OH groups and of the oxygen atoms of the interlayer anions in the formation of hydrogen bonds was further discussed. For the birnessite sample, the relaxation processes are probably overlaid by a dominating conductivity contribution, which is analyzed in its frequency and temperature dependence. It is found that the conductivity of birnessite obeys the characteristics of semiconducting disordered materials. Especially the Barton/Nakajima/Namikawa relationship is fulfilled. Analyzing the temperature dependence of the direct current (dc) conductivity σ0 in detail gives some hint that σ0(T) has also an unusual saddlelike form. PY - 2007 DO - https://doi.org/10.1021/jp0717140 SN - 1089-5639 SN - 1520-5215 VL - 111 IS - 24 SP - 5166 EP - 5175 PB - Soc. CY - Washington, DC AN - OPUS4-15718 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hasenstab, Andreas A1 - Krause, Martin T1 - Ultraschall-Echo-Technik zur Ortung von Minderdicken und Schäden in Holzbauteilen T2 - DGZfP-Fachtagung Bauwerksdiagnose "Praktische Anwendungen Zerstörungsfreier Prüfungen" CY - Berlin, Deutschland DA - 2006-02-22 KW - Zerstörungsfreie Prüfung KW - Holz KW - Ultraschallecho KW - ZfP an Holzbauteilen KW - Fehlstellen KW - Minderdicken KW - Ultraschall-Echo KW - Fäulnis KW - Bauwesen PY - 2006 SN - 3-931381-71-4 SP - 1(?) EP - 11(?) PB - DGZfP CY - Berlin AN - OPUS4-14233 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hasenstab, Andreas A1 - Krause, Martin A1 - Osterloh, Kurt T1 - Testing Of Wooden Construction Elements with Ultrasonic Echo Technique and X-Ray T2 - 9th European Conference on NDT CY - Berlin, Germany DA - 2006-09-25 KW - NDT of Wood PY - 2006 SN - 3-931381-86-2 SP - 1(?) EP - 8(?) PB - European Federation for Non-Destructive Testing CY - Berlin AN - OPUS4-14422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hao, Ning A1 - Böhning, Martin A1 - Goering, Harald A1 - Schönhals, Andreas T1 - Nanocomposites of Polyhedral Oligomeric Phenethylsilsesquioxanes and Poly(bisphenol A carbonate) as Investigated by Dielectric Spectroscopy N2 - Nanocomposites were prepared by solution blending of polyhedral oligomeric silsesquioxane with phenethyl substituents (PhenethylPOSS) into poly(bisphenol A carbonate) (PBAC). The nanocomposites were investigated by dielectric spectroscopy, differential scanning calorimetry (DSC) and density measurements. PhenethylPOSS shows one relaxation process, the α-relaxation, confirmed by DSC investigations. PBAC shows a β-relaxation at lower and an α-relaxation at higher temperatures. With increasing PhenethylPOSS content the α-relaxation of the composites shifts to lower temperatures. Thus, incorporation of PhenethylPOSS leads to a plasticization of PBAC due to a decrease of the packing density which is rationalized by density measurements. For higher concentrations of PhenethylPOSS (>10 wt %) the α-relaxation of the polycarbonate matrix splits into two peaks. Moreover, close to the α-relaxation of PhenethylPOSS a third process is observed. These results indicate a phase separation into a PBAC matrix with a few percents of molecularly solved POSS and POSS-rich domains. These POSS-rich domains are surrounded by an interfacial layer of PBAC having a higher concentration of POSS than the matrix. A phase diagram is deduced providing a miscibility criterion. For the phase separated nanocomposites an interfacial polarization phenomena is observed. Using a simplified model the time constant of this process is correlated with the size of the PhenethylPOSS-rich domains and theire increasing size with the increase of the concentration of POSS. KW - Polyhedral oligomeric silsesquioxane (POSS) KW - Polymer-based nanocomposites KW - Broadband dielectric spectroscopy KW - Interfacial polarisation PY - 2007 SN - 0024-9297 SN - 1520-5835 VL - 40 IS - 8 SP - 2955 EP - 2964 PB - American Chemical Society CY - Washington, DC AN - OPUS4-14768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Starke, K. A1 - Ristau, D. A1 - Martin, Sven A1 - Hertwig, Andreas A1 - Krüger, Jörg A1 - Allenspacher, P. A1 - Riede, W. A1 - Meister, S. A1 - Theiss, C. A1 - Sabbah, A. A1 - Rudolph, W. A1 - Raab, V. A1 - Grigonis, R. A1 - Rakickas, T. A1 - Sirutkaitis, V. ED - Exarhos, G. J. T1 - Results of a round-robin experiment in multiple-pulse LIDT measurement with ultrashort pulses T2 - 35th Annual Boulder Damage Symposium ; 35th Annual Symposium on Optical Materials for High-Power Lasers CY - Boulder, CO, USA DA - 2003-09-22 KW - Multiple-pulse damage KW - ISO 11254-2 KW - S on 1-LIDT KW - Round-robin experiment KW - CHOCLAB PY - 2004 SN - 0-8194-5163-0 DO - https://doi.org/10.1117/12.525135 SN - 0038-7355 N1 - Serientitel: Proceedings of SPIE – Series title: Proceedings of SPIE IS - 5273 SP - 388 EP - 395 PB - SPIE, the International Society for Optical Engineering CY - Bellingham, Wash. AN - OPUS4-4948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rosemann, P. A1 - Müller, Thoralf A1 - Babutzka, Martin A1 - Heyn, Andreas ED - J. Grosch, ED - E.J. Mittemeijer, T1 - Qualitätsbewertung von Schneidwaren durch Kurzzeit-Korrosionsprüfung N2 - Bei der Qualitätsbewertung von Schneidwaren aus nichtrostenden martensitischen Chrom-Stählen stellt die Überprüfung der Korrosionsbeständigkeit ein wichtiges Kriterium dar. Allgemein üblich sind Wechseltauchversuche mit relativ hohem zeitlichem und auswertungsbedingtem Aufwand, die noch dazu zerstörend sind und teilweise fragwürdige Ergebnisse liefern. In den letzten Jahren wurden neue Ansatze der Prüfung geschaffen, die eine nahezu zerstörungsfreie Kurzzeit-Korrosionsprüfung erlauben. Es wird gezeigt, dass mit dem elektrochemischen Rauschen sehr empfindlich Einflüsse des Härtens und der Oberflächenbehandlung auf die Korrosionsbeständigkeit nachgewiesen werden können, wodurch eine schnelle und objektive Qualitätsbewertung innerhalb des Fertigungsprozesses und der Endkontrolle von Produkten möglich ist. Das für die Prüfmethodik ausgenutzte Phänomen des elektrochemischen Rauschens zielt darauf ab, den Beginn der Korrosion empfindlich und schnell zu detektieren, ohne die Prüfbedingungen maßlos zu verschärfen und Produkte damit zu zerstören. Neben der Funktionalität der Prüfung stehen aber auch die Anwenderfreundlichkeit und somit die Akzeptanz bei den Herstellern im Vordergrund. Aus diesem Grund wurde zusätzlich ein Indikatortest (KorroPad) als praxistaugliche Alternative zum elektrochemischen Rauschen angewendet. Die Ergebnisse zeigen eine gute Übereinstimmung beider Methoden und ermöglichen eine effektive betriebliche Qualitätsüberwachung von Schneidwaren. KW - Schneidwaren KW - Nichtrostender Stahl KW - Korrosion KW - Prüfmethoden KW - Qualitätskontrolle KW - Cutlery KW - Stainless steel KW - Corrosion KW - Testing methods KW - Quality control PY - 2013 DO - https://doi.org/10.3139/105.110195 SN - 1867-2493 VL - 68 IS - 5 SP - 224 EP - 235 PB - Hanser CY - München AN - OPUS4-29341 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böhning, Martin A1 - Hao, Ning A1 - Schönhals, Andreas T1 - Correlation of activation energies of gas diffusivity and local matrix mobility in polycarbonate/POSS nanocomposites N2 - According to basic phenomenological models describing the solution-diffusion based mechanism of penetrant diffusion in dense polymers, a connection between the diffusive transport of gas molecules in a polymeric matrix and the molecular mobility of that matrix on a certain length scale is, in principle, established for a long time. However, experimental data directly showing this correlation are rare. The investigation of a series of nanocomposites based on a polyhedral oligomeric silsesquioxane (POSS) and a polycarbonate matrix allows a systematic change of the molecular mobility on a local length scale (β-relaxation) and of the corresponding activation energy EA, both determined by broadband dielectric spectroscopy. Independently, activation energies of penetrant diffusion (ED) of these nanocomposites were determined for N2, O2, CO2, and CH4 and a clear linear correlation between the two activation energies was established for the first time. KW - Broadband dielectric spectroscopy KW - Diffusion KW - Dielectric properties KW - Gas permeation KW - Molecular mobility KW - Nanocomposites KW - Polyhedral oligomeric silsesquioxane (POSS) KW - Relaxation KW - Beta-relaxation PY - 2013 UR - http://onlinelibrary.wiley.com/doi/10.1002/polb.23381/full DO - https://doi.org/10.1002/polb.23381 SN - 0887-6266 SN - 1099-0488 VL - 51 IS - 22 SP - 1593 EP - 1597 PB - Wiley CY - Hoboken, NJ AN - OPUS4-29284 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hao, N. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - CO2 gas transport properties of nanocomposites based on polyhedral oligomeric phenethyl-silsesquioxanes and poly(bisphenol A carbonate) N2 - Polymer-based nanocomposites were prepared by solution blending of polyhedral oligomeric silsesquioxane with phenethyl substituents (PhenethylPOSS) into poly(bisphenol A carbonate) (PBAC). First investigations focused on structure, morphology and dynamics, addressed mainly by dielectric relaxation spectroscopy are substantially extended in this study by the investigation of the CO2 gas transport behavior of these materials, i.e., permeation experiments using the time-lag technique as well as gravimetric gas sorption measurements. The nanocomposite materials were prepared with nanofiller contents ranging from 0 to about 40 wt % by solution blending and films of about 50-100 µm thickness were cast from this solution and used for the investigation of gas transport properties after drying and annealing. From the time-lag measurements the permeability and an effective diffusion coefficient for CO2 is obtained in dependence of POSS concentration and temperature. As main results, both, the permeability and the diffusivity, increase whereas the solubility decreases with increasing POSS concentration. These findings are discussed in the framework of a microphase separated morphology of the nanocomposite systems for POSS concentrations greater than a value cPOSScrit of ca. 7 wt % consisting of a polycarbonate-rich matrix and POSS-rich domains which are surrounded by an interfacial layer. The experimental solubility data suggest that the POSS-rich domains are more or less impermeable for CO2. On the basis of this assumption a quantitative model is provided to correct the solubility data for the phase separated morphology. Moreover the importance of the interfacial layer between the POSS particles or its domains for the properties of nanocomposites especially for the gas transport behavior is addressed by analyzing the sorption isotherms. Also, for the first time results from gas transport measurements and dielectric spectroscopy were quantitatively related to each other by taking the activation energies of CO2 diffusion and of the dielectric β-relaxation into consideration. The obtained clear correlation indicates that the CO2 gas transport is due to localized molecular fluctuations. As a further result, the diffusion coefficient obtained from time-lag and gas sorption measurements is in good agreement with respect to both their absolute values and in their concentration dependence. PY - 2010 DO - https://doi.org/10.1021/ma101463m SN - 0024-9297 SN - 1520-5835 VL - 43 IS - 22 SP - 9417 EP - 9425 PB - American Chemical Society CY - Washington, DC AN - OPUS4-22378 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Friese, Martin A1 - Taffe, Alexander A1 - Wöstmann, Jens A1 - Zoëga, Andreas T1 - Zerstörungsfreie Untersuchungen am Brückenbauwerk A1 Hagen/Schwerte KW - Ultraschallecho KW - Impakt-Echo KW - Radar KW - Zerstörungsfreie Prüfung KW - Brücke KW - Hagen KW - Scannende Systeme KW - Spannglied KW - Bildgebende Darstellung PY - 2009 SN - 0943-9307 IS - B 65 SP - 1 EP - 52 PB - Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH CY - Bremerhaven AN - OPUS4-20958 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Babutzka, Martin A1 - Valet, Svenja A1 - Kotula, Stefan A1 - Burkert, Andreas A1 - Gümmer, K. A1 - Bender, S. A1 - Huckshold, M. T1 - Normentwurf für ein Prüfverfahren zur Bestimmung von Deckschichtwiderständen an Zinküberzügen mittels gelartiger Elektrolyte N2 - Das Grundproblem der heute verfügbaren und normativ geregelten Prüfverfahren für Zinküberzüge besteht neben den realitätsfernen Prüfbedingungen vor allem in der subjektiv geprägten Auswertung der Prüfergebnisse. Die systematische Betrachtung der Entwicklungen der letzten Jahre zeigt, dass die üblichen Verfahren den aktuellen Anforderungen damit schon vom Ansatz her nicht gerecht werden können und auch die bisher betriebene, fortlaufende Variation und Anpassung von Prüfbedingungen keinen grundlegend neuen Lösungsansatz bieten können. Ein solcher ergibt sich nur, wenn die Zinküberzüge hinsichtlich der kinetischen Eigenschaften der Deckschichtbildung und -auflösung umfassend beschrieben werden können, was nur durch den Einsatz elektrochemischer Untersuchungsmethoden mittels Gelelektrolyten möglich ist. Aus diesem Grund wurde im Verbundforschungsvorhaben GELELEK auf der Basis elektrochemischer Methoden unter Verwendung eines Gelelektrolyten ein Normenvorschlag für eine Prüfnorm erarbeitet und zur Normungsreife geführt, welcher den Anforderungen an ein Messsystem für Feldanwendungen entspricht. Im Verbundforschungsvorhaben GELELEK wurde eine gezielte Kombination von Laboruntersuchungen mit Untersuchungen im Feld und Bauteilen unter realen Einsatzbedingungen angestrebt. Randbedingungen für eine gesicherte Messung von atmosphärisch bewitterten Zinküberzügen unter Einsatz von Gelelektrolyten wurden erarbeitet und im Normenvorschlag festgeschrieben. Darüber hinaus wurde ein mobiles Messgerät für Messungen mit Gelelektrolyten an realen Bauteilen entwickelt. Nach Abschluss des Forschungsvorhabens steht Industrievertretern und Prüfinstituten ein wissenschaftlich gesichertes Messverfahren basierend auf Kennwerten zur Verfügung, um Zinküberzüge und deren momentane Schutzwirkung unter praxisrelevanten Bedingungen einschätzen und normativ geregelt prüfen zu können. Der vorliegende Forschungsbericht gibt einen Überblick über die Motivation zur Durchführung des Forschungsvorhabens, wichtige Arbeitsschritte, Details zur entwickelten Prüfmethode sowie Einsatzmöglichkeiten für Prüfinstitute und Unternehmen. KW - Normung KW - Zink KW - Korrosion KW - Deckschichtbildung KW - Atmosphärische Korrosion KW - Korrosionsprüfung PY - 2022 UR - https://www.gav-verzinken.de/forschung/wissenspool SP - 1 EP - 24 AN - OPUS4-54947 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Babutzka, Martin A1 - Lehmann, Jens A1 - Burkert, Andreas T1 - Field exposure study under sheltered and open exposure conditions at different test sites in Germany: First‐year corrosion rate and atmospheric corrosivity N2 - The corrosivity of atmospheres in Europe has changed significantly in recent decades. For the Federal Republic of Germany, no current values for the corrosion rate based on 1‐year atmospheric exposure of standard specimens can be found in the scientific literature after 2000. This paper presents results from a field exposure study in the Berlin metropolitan area and Helgoland in 2016. Based on standard specimens, values for the corrosion rate and the corresponding atmospheric corrosivity category are determined for open exposure and indirect weathering in a ventilated enclosure as sheltering after 1 year of exposure. The results prove that determined corrosivity categories are material‐specific. Sheltered exposure is a typical atmospheric situation for many building components. It allows statements on the effect of the concentration of airborne substances on the corrosivity beyond the normative requirements. KW - Atmospheric corrosion KW - Corrosivity category KW - ISO 9223 KW - Mass loss KW - Atmosphärische Korrosion PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565099 DO - https://doi.org/10.1002/maco.202213582 SN - 0947-5117 (print) SN - 1521-4176 (online) SP - 1 EP - 15 PB - Wiley-VCH GmbH CY - Weinheim AN - OPUS4-56509 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Schönhals, Andreas A1 - Böhning, Martin A1 - Szymoniak, Paulina ED - Schönhals, Andreas ED - Szymoniak, Paulina T1 - (Nano)Composite Materials—An Introduction N2 - The chapter gives a brief introduction to (nano)compositecomposite materials having the focus on polymer-based nanocomposites. The different dimensionalities of nanoparticles are introduced, along with their distribution in the matrix. Different application fields of polymer-based nanocomposites, like flame retardancy, filled rubbers, nanofilled thermosets and thermoplastics, separation membranes and nanodielectrics, are considered in greater detail. KW - Polymer-based nanocomposites KW - Nanoparticle KW - Distribution of nanoparticles KW - Filled rubbers KW - Filled thermosets and plastics KW - Separation membranes KW - Nanodielectrics PY - 2022 DO - https://doi.org/10.1007/978-3-030-89723-9_1 SP - 1 EP - 31 PB - Springer CY - Cham, Switzerland AN - OPUS4-54565 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zorn, R. A1 - Szymoniak, Paulina A1 - Kolmangadi, Mohamed Aejaz A1 - Malpass-Evans, R. A1 - McKeown, N. A1 - Tyagi, M. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Low frequency vibrations and diffusion in disordered polymers bearing an intrinsic microporosity as revealed by neutron scattering N2 - The microscopic diffusion and the low frequency density of states (VDOS) of PIM-EATB(CH3) are investigated by inelastic and quasi-elastic neutron scattering where also the demethylated counterpart of PIM-EA-TB(H2) is considered. These intrinsic microporous polymers are characterized by large BET surface area values of several hundred m2/g and pore sizes between 0.5 and 2 nm. Detailed comparison is made to the archetype of polymers of intrinsic microporosity, PIM-1, and polynorbornenes also bearing a microporosity. Due to the wavelength of neutrons, the diffusion and vibrations can be addressed on microscopic length and time scales. From the inelastic neutron scattering experiments the low frequency density of states (VDOS) is estimated which shows excess contributions to the Debye-type VDOS known as Boson peak. It was found that the maximum frequency of the Boson peak decreases with increasing microporosity characterized by the BET surface area. However, besides the BET surface area, additional factors such as the backbone stiffness govern the maximum frequency of the Boson peak. Further the mean squared displacement related to microscopic motions was estimated from elastic fixed window scans. At temperatures above 175 K, the mean squared displacement PIM-EA-TB(CH3) is higher than that for the demethylated counterpart PIM-EA-TB(H2). The additional contribution found for PIM-EATB(CH3) is ascribed to the rotation of the methyl group in this polymer because the only difference between the two structures is that PIM-EA-TB(CH3) has methyl groups where PIM-EA-TB(H2) has none. A detailed comparison of the molecular dynamics is also made to that of PIM-1 and the microporous polynorbornene PTCNSi1. The manuscript focuses on the importance of vibrations and the localized molecular mobility characterized by the microscopic diffusion on the gas Transport in polymeric separation membranes. In the frame of the random gate model localized fluctuations can open or close bottlenecks between pores to enable the diffusion of gas molecules. KW - Polymer of intrisic microporosity KW - Neutron scattering KW - Boson peak KW - Methyl group rotation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538490 DO - https://doi.org/10.3390/cryst11121482 VL - 11 IS - 12 SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-53849 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolmangadi, Mohamed Aejaz A1 - Szymoniak, Paulina A1 - Zorn, R. A1 - Böhning, Martin A1 - Wolff, M. A1 - Zamponi, M. A1 - Schönhals, Andreas T1 - Molecular mobility in high-performance polynorbornenes:A combined broadband dielectric, advanced calorimetry,and neutron scattering investigation N2 - The molecular dynamics of two addition type polynorbornenes, exo-PNBSiand PTCNSi1, bearing microporosity has been investigated by broadbanddielectric spectroscopy, fast scanning calorimetry, and neutron scattering. Bothpolymers have the same side groups but different backbones. Due to theirfavorable transport properties, these polymers have potential applications inseparation membranes for gases. It is established in literature that molecularfluctuations are important for the diffusion of small molecules through poly-mers. For exo-PNBSi, two dielectric processes are observed, which are assignedto Maxwell/Wagner/Sillars (MWS) process due to blocking of charge carriersat internal voids or pore walls. For PTCNSi1, one MWS-polarization process isfound. This points to a bimodal pore-size distribution for exo-PNBSi. A glasstransition for exo-PNBSi and for PTCNSi1 could be evidenced for the first timeusing fast scanning calorimetry. For Tgand the corresponding apparent activa-tion energy, higher values were found for PTCNSi1 compared to exo-PNBSi.For both polymers, the neutron scattering data reveal one relaxation process.This process is mainly assigned to methyl group rotation probably overlayedby carbon–carbon torsional fluctuations. KW - Advanced calorimetry KW - Dielectric spectroscopy KW - Neutron scattering KW - Polynorbornenes PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547086 DO - https://doi.org/10.1002/pen.25995 SN - 0032-3888 VL - 62 IS - 7 SP - 2143 EP - 2155 PB - Wiley AN - OPUS4-54708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolmangadi, Mohamed Aejaz A1 - Szymoniak, Paulina A1 - Smales, Glen Jacob A1 - Bermeshev, M. A1 - Schönhals, Andreas A1 - Böhning, Martin T1 - Molecular mobility of polynorbornenes with trimethylsiloxysilyl side groups: Influence of the polymerization mechanism N2 - We report dielectric and calorimetric studies on metathesis and addition-type polytricyclononenes, both based on the same monomer bearing three pendant OSiMe3 groups. For the addition-type polymer, dielectric spectroscopy reveals a β*-process related to the microporosity, whereas for its metathesis counterpart, the segmental dynamics manifests as an α-process related to a glass transition. Besides active dielectric processes, a significant conductivity contribution is detected for both samples which for the microporous additiontype polymer is three orders of magnitude greater than for the metathesis polymer. The broadband dielectric spectroscopy is complemented by detailed calorimetric investigations, comprising DSC, FSC, and TMDSC. The calorimetric methods detected the glass transition for the metathesis polymer in agreement with the observed dielectric α-process. Furthermore, the already reported gas transport properties for both polymers are compared, setting them in correlation with the observed molecular mobility and conductivity behavior. The discussed results reflect significant differences in molecular mobility of the two polymers affecting the appearance of microporosity which strongly determines the gas transport properties. KW - Microporous polymers KW - Molecular mobility KW - Electrical conductivity KW - Membrane polymers KW - Gas separation PY - 2022 DO - https://doi.org/10.22079/JMSR.2021.538060.1495 SN - 2476-5406 VL - 8 IS - 3 SP - 1 EP - 9 PB - Membrane Processes Research Laboratory (MPRL) CY - Tehran AN - OPUS4-54303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schönhals, Andreas A1 - Szymoniak, Paulina A1 - Kolmangadi, Mohamed Aejaz A1 - Böhning, Martin A1 - Zamponi, M. A1 - Frick, B. A1 - Appel, M. A1 - Günther, G. A1 - Russina, M. A1 - Alentiev, D. A1 - Bermeshev, M. A1 - Zorn, R. T1 - Microscopic dynamics of highly permeable super glassy polynorbornenes revealed by quasielastic neutron scattering N2 - The molecular dynamics of addition-type poly(tricyclononenes) with Si-substituted bulky side groups has been investigated by a combination of neutron time-of-flight and neutron backscattering spectroscopy methods on a time scale from 0.1 ps to ca. 3 ns. The investigated poly(tricyclononenes) PTCNSi1 and PTCNSi2g both bear a high microporosity which makes them promising candidates for active separation layers for gas separation membranes. At least for larger gas molecules it is assumed that the pathways for diffusion require an enlargement of pre-existing micropores in terms of an activated zone. A low temperature relaxation process was found for both polymers by the performed neutron scattering experiments. This process was assigned to the methyl group rotation. It was analysed in terms of a jump diffusion in a three-fold potential. The analysis of the dependence of the elastic incoherent structure factor on the scattering vector yields the number of methyl groups which might be immobilized. For PTCNSi1 (3 methyl groups in the monomeric unit) it was found that all methyl groups take part in the methyl group rotation whereas for PTCNSi2g (6 methyl groups in monomeric unit) a considerable number of methyl groups are blocked in their rotation. This immobilization of methyl groups is due to the sterically demanding arrangement of the methyl groups in PTCNSi2g. This conclusion is further supported by the result that the activation energy for the methyl group rotation is three times higher for PTCNSi2g than that of PTCNSi1. KW - Highly permeably polynorbornenes KW - Polymers of intrinsic microporosity KW - Gas separation membranes KW - Quasielastic neutron scattering PY - 2021 DO - https://doi.org/10.1016/j.memsci.2021.119972 SN - 0376-7388 VL - 642 PB - Elesevier B.V. AN - OPUS4-53508 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Valet, Svenja A1 - Burkert, Andreas A1 - Ebell, Gino A1 - Babutzka, Martin T1 - Determination of the corrosion product layer resistance on zinc and electrolytically galvanized steel samples by using gel electrolytes N2 - Although zinc and zinc coatings have been widely used for corrosion protection for decades new zinc coatings are constantly being developed. Characterizing the corrosion protectiveness of these new coatings, however, should not be underestimated. While exposure tests are time intensive, cyclic tests can only be used for a very limited field of application. Thus, electrochemical measurements provide both an efficient and an effective alternative. Conventional aqueous bulk electrolytes influence the surface layers of a tested zinc coating and are therefore not reliable. Gel electrolytes, however, have evolved over the last few years, are minimally invasive and provide reliable results. This work describes experiments with gel electrolytes made of agar. Unlike previous work, it proposes a composition of gel electrolyte for minimally invasive description of the protective power of naturally formed oxide layers on zinc and zinc coatings. Therefore, as a first part, the gel electrolyte made of agar is verified as a method for zinc and zinc-coated samples. Afterwards, this paper introduces the corrosion product layer resistance RL as a promising parameter to evaluate the protective power of zinc coatings. Results are verified with EIS and FTIR measurements. An example on a representative zinc coating demonstrates the practical application. KW - Gel electrolytes KW - Agar KW - Zinc coatings KW - Atmospheric exposure KW - Corrosion PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526053 DO - https://doi.org/10.1016/j.electacta.2021.138191 SN - 0013-4686 VL - 385 SP - 138191 PB - Elsevier Ltd. AN - OPUS4-52605 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emamverdi, Farnaz A1 - Yin, Huajie A1 - Smales, Glen Jacob A1 - Harrison, W. J. A1 - Budd, P. M. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Polymers of intrinsic microporosity - Molecular mobility and physical aging revisited by dielectric spectroscopy and X‑ray scattering N2 - Polymers of intrinsic microporosity (PIMs) are promising candidates for the active layer in gas separation membranes due to their high permeability and reasonable permselectivity. These appealing properties originate from a microporous structure as a result of inefficient segment packing in the condensed state due to a combination of a ladder-like rigid backbone and sites of contortion. However, this class of polymers suffers from a significant decrease in the permeability with time due to physical aging, whereby typically, the permselectivity increases. The initial microporous structures approach a denser state via local rearrangements, leading to the reduction of the permeability. Hence, a detailed characterization of the molecular mobility in such materials can provide valuable information on physical aging. In this work, the dielectric behavior of PIM-1 films and their behavior upon heating (aging) were revisited by isothermal frequency scans during different heating/cooling cycles over a broad temperature range between 133 and 523 K (−140 to 250 °C). In addition, the obtained results were compared with data of samples that were annealed at ambient temperatures over different time scales. Multiple dielectric processes were observed: several relaxation processes due to local fluctuations and a Maxwell−Wagner−Sillars polarization effect related to the microporosity. The temperature dependence of the rates of all processes follows the Arrhenius law where the estimated activation energy depends on the nature of the process. The influence of the thermal history (aging) on the processes is discussed in detail. KW - Polymers of intrinsic microporosity PY - 2022 DO - https://doi.org/10.1021/acs.macromol.2c00934 VL - 55 SP - 7340 EP - 7350 PB - American Chemical Society CY - Washington, DC AN - OPUS4-55485 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hattwig, Martin A1 - Wandrey, Peter-Andreas ED - Ziegler, Kurt ED - Becker, Gerhard Wilhelm T1 - Sicherheit bei der Herstellung und beim Transport oxidierend wirkender Stoffe und organischer Per-Verbindungen T2 - Grundsätze der Chemischen Sicherheitstechnik und ihre Anwendung in der Praxis CY - Berlin, Germany DA - 08.10.1981 PY - 1982 SP - 61 EP - 70 CY - Berlin AN - OPUS4-36229 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Thoralf A1 - Heyn, Andreas A1 - Fenker, M. A1 - Balzer, Martin T1 - Investigation on defect morphology and corrosion behaviour of TiMgN hard coatings on steel substrate N2 - Nitride hard coatings, such as Titanium nitride and chromium nitride coatings are widely used for applications focussing on wear protection and decorative purposes. Also these coatings are often applied on low alloyed steel substrates. The inevitable contact of the coated components with the environment through pores and coating defects bears the danger of corrosion of the steel substrate followed by further delamination of the coating and a loss of function of the component. A new attempt to increase the corrosion behaviour of those physically deposited hard coating systems is the implementation of magnesium. The positive effect of magnesium could be verified already electrochemically. Performed experiments on TiMgN have shown that corrosion resistance could drastically improved with increasing Mg content of the TiMgN up to 30 at% compared to steel substrates with applied titanium nitride hard coatings. Besides the clarification of the electrochemical and phenomenological effect of the magnesium on the corrosion behaviour, an additional aim of this work is the investigation of the coating defects, defect morphologies and their influence on the local corrosion behaviour. For this the incorporation of the magnesium and its effects on the coating material, the influence of coating growth related defects and the effect of the coating structure on the corrosion behaviour should be experimental examined by using innovative surface and material analysis methods such as FIB and TEM. Furthermore the evolution of the coating defects should be investigated by combing confocal microscopy with a new developed exposure test method using the electrochemical indication test KorroPad. The function of the KorroPad test, which was developed and patented [1] at the BAM for the detection of corrosion sensitive steel surfaces by indicating dissolution of iron ions [1], allows the detection and identification of critical coating defects for further microscopic investigation. Additional to that the KorroPad test simulates an accelerated exposure test by simultaneous absence of the disadvantages of typical short time exposure test like salt spray tests. Thus it allows a monitoring and analysis of the evolution of the critical coating defects and their influence on the local corrosion behaviour and the overall corrosion mechanisms. The results of this work should contribute to the development of new hard coatings with improved corrosion protection properties and also to a better understanding of the corrosion mechanisms of coated steel substrates. T2 - EUROCORR 2014 - European corrosion congress CY - Pisa, Italy DA - 08.09.2014 KW - Metallic coatings KW - Cathodic protection KW - Corrosion PY - 2014 SN - 978-3-89746-159-8 SP - O EP - 7473, 384 AN - OPUS4-31482 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin A1 - Reinemann, Steffi A1 - Heyn, Andreas T1 - Nachweis von Verarbeitungsfehlern bei nichtrostenden Stählen durch elektochemische Korrosionsuntersuchungen N2 - In diesem Beitrag soll an drei anschaulichen Beispielen dargestellt werden, wie sich Verarbeitungsfehler bei nichtrostenden Stählen auf das Korrosionsverhalten auswirken und zu unerwarteten Schäden führen können. Mit Hilfe von geeigneten elektrochemischen Verfahren werden Proben von drei unterschiedlichen nichtrostenden Stählen charakterisiert. An einem martensitischen nichtrostenden Stahl wird der Einfluss der Wärmebehandlung gezeigt, da dieser besonders empfindlich auf eine falsche Parameterwahl reagiert. Mit zwei austenitischen Stahlgüten wird verdeutlicht, wie sich Gefügeinhomogenitäten, die im Verarbeitungsprozess und bei der Stahlerzeugung entstehen, auf die Passivierung und das Lochkorrosionsverhalten auswirken. Dabei wird der Oberflächenzustand bei allen Untersuchungen gleich gehalten, um eine Rückführung des Korrosionsverhaltens auf die Gefügeinhomogenitäten durch den Vergleich mit Referenzchargen zu ermöglichen. T2 - 15. Sommerkurs Werkstoffe und Fügen am Institut für Werkstoff- und Fügetechnik CY - Magdeburg, Germany DA - 12.09.2014 PY - 2014 SN - 978-3-940961-85-3 SP - 197 EP - 206 AN - OPUS4-31475 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Thoralf A1 - Heyn, Andreas A1 - Balzer, Martin A1 - Fenker, M. T1 - Untersuchungen zum Einfluss von Magnesium auf das Korrosionsverhalten von TiMgN - Hartstoffbeschichtungen auf Stahlsubstraten N2 - Hartstoffbeschichtungen werden heutzutage in vielen praktischen Bereichen zur Verbesserung der Verschleißbeständigkeit und aus dekorativen Gründen auf verschiedenste Stahlbauteile aufgebracht. Beim unvermeidlichen Kontakt mit einem umgebenden wässrigen Medium über Schichtporen und-fehler sind die beschichteten metallischen Substratwerkstoffe jedoch der Gefahr lokaler Korrosion ausgesetzt, was mittel-oder langfristig zum Funktionsverlust der Bauteile führen kann. Ein neuartiger Ansatz zur Veränderung der mechanisch-technologischen, optischen sowie elektrochemischen Eigenschaften hartstoffbeschichteter Bauteile ist der Einbau des Elements Magnesium in den physikalisch abgeschiedenen Überzug (z.B. TiN). Untersuchungen von Fenker et al., die die Charakterisierung dieser neuartigen TiMgN-Überzüge zum Ziel hatten, konnten zeigen, dass sich mit zunehmenden Mg-Gehalt die Farbe des Überzugs von dem typischen goldgelb des TiN über violett, blau bis hin zu metallisch grau verändert und weiterhin die Oxidationsbeständigkeit deutlich gesteigert wird. Weiterhin zeigte sich in 24-stündigen neutralen Salzsprühtest, dass sich die Korrosionsbeständigkeit der mit TiMgN beschichteten Stähle mit steigendem Mg-Gehalt deutlich verbessern und die Korrosion des Stahlsubstrats zeitlich verzögert wird. Ausgehend von diesen phänomenologischen Beobachtungen wurden drei verschiedene Arbeitshypothesen über die elektrochemische Wirkungsweise des Magnesiums im TiMgN-Schichtsystem entwickelt, die ursächlich für die verbesserte Korrosionsbeständigkeit seien können. Die drei Arbeitshypothesen sind: · Potentialanpassung: Das Mg verringert das Freie Korrosionspotential der Schicht, welches sich dem des Stahlsubstrates annähert, womit Lochkorrosion verhindert bzw. verzögert wird. · Galvanische Anode/Opferanode: Das elektrochemisch unedlere Mg in dem Schichtsystem geht bei Vorhandensein von freiliegendem Fe bevorzugt in Lösung und schützt so den Stahl als galvanische Anode. · Versiegeln kleiner Schichtdefekte: Ausgefallene Korrosionsprodukte von Mg verschließen vorübergehend Schichtdefekte und verhindern bzw. verzögern das Vordringen des Korrosionsmediums zum Stahl. T2 - 15. Sommerkurs Werkstoffe und Fügen am Institut für Werkstoff- und Fügetechnik CY - Magdeburg, Germany DA - 12.09.2014 PY - 2014 SN - 978-3-940961-85-3 SP - 187 EP - 196 AN - OPUS4-31476 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rosemann, P. A1 - Babutzka, Martin A1 - Müller, Thoralf A1 - Heyn, Andreas T1 - Einfluss von Mikrostruktur und Oberflächenbearbeitung auf die Korrosionsbeständigkeit martensitisch nichtrostender Stähle N2 - Die Qualität von Schneidwaren aus martensitisch nichtrostenden Stählen (MNS) hängt neben ihrer härtebedingten Schneidleistung wesentlich von ihrer Korrosionsbeständigkeit ab, die dauerhaft das hochwertige optische Erscheinungsbild gewährleisten soll. Zur Prüfung der Korrosionsbeständigkeit hat sich bei Schneidwaren aus MNS die Anwendung des Wechseltauchversuchs etabliert, dessen Ausweitung aufwendig und dessen Ergebnisse oftmals fragwürdig sind. In den letzten Jahren wurden daher neue elektrochemische Methoden entwickelt, um das Korrosionsverhalten von MNS objektiver zu bewerten. Diese neuen Untersuchungsmethoden ermöglichen eine genauere Erfassung der teilweise stark schwankenden Korrosionsbeständigkeit von MNS und bilden damit die Grundlage zur Aufklärung der Ursachen dieser Schwankungen. Im Rahmen des IGF-Vorhabens 16636 BG wurden dazu das elektrochemische Rauschen (ECR), das KorroPad und die elektrochemisch potentiodynamische Reaktivierung (EPR) eingesetzt, um die werkstoffseitigen Einflüsse der Mikrostruktur und den Einfluss der Oberflächenbearbeitung auf die Korrosionsbeständigkeit zu untersuchen. Es wurden dazu an drei weit verbreiteten MNS (1.4116, 1.4034 und 1.4021) je acht verschiedene Oberflächenzustände hergestellt und das Korrosionsverhalten untersucht. Um die dabei aufgetretenen Unterschiede im Lochkorrosionsverhalten zwischen den drei Werkstoffen zu erklären, wurde der EPR-Test eingesetzt, der lokale ChromVerarmung im Gefüge als werkstoffbedingte Ursache von Lochkorrosionsanfälligkeit nachweist. Mit der Kombination der Ergebnisse aus EPR, ECR und KorroPad war es möglich, die unterschiedliche Lochkorrosionsanfälligkeit direkt der unterschiedlich stark ausgeprägten Chromverarmung der drei MNS zuzuordnen. Der Einfluss der Chromverarmung auf die Lochkorrosionsanfälligkeit ist dabei deutlich größer als der Effekt der Oberflächenbearbeitung, der nur bei gering ausgeprägter Chromverarmung ersichtlich ist. Damit wurde gezeigt, dass nur bei Betrachtung aller Einflussgrößen sichere Aussagen zur Korrosionsbeständigkeit und zu den Ursachen der Lochkorrosionsanfälligkeit von MNS möglich sind. T2 - 15. Sommerkurs Werkstoffe und Fügen am Institut für Werkstoff- und Fügetechnik CY - Magdeburg, Germany DA - 12.09.2014 PY - 2014 SN - 978-3-940961-85-3 SP - 179 EP - 186 AN - OPUS4-31477 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schmigalla, S. A1 - Dittmar, Martin A1 - Heyn, Andreas T1 - Möglichkeiten der elektrochemischen Instrumentierung bei der Untersuchung des Erosionskorrosionsverhaltens metallischer Werkstoffe N2 - Unter praktischen Einsatzbedingungen unterliegen die Konstruktionswerkstoffe in Anlagenkomponenten mit strömenden, feststoffhaltigen Medien, wie sie in vielen Anwendungsgebieten wie z.B. im Bereich der Erdölförderung und -Verarbeitung, der Kraftwerkstechnik sowie dem Bergbau auftreten, einer kombinierten mechanischen und korrosiven Beanspruchung. Da Bauteilschäden in den erwähnten Bereichen aufgrund der dort verarbeiteten Medien vielfach mit einer akuten Gefährdung von Mensch und Umwelt infolge des Austritts der transportierten Medien einhergehen, ist es erforderlich, genaue Erkenntnisse über das Werkstoffverhalten unter kombinierter erosiv-korrosiver Beanspruchung zu erlangen. Bisherige Standardprüfverfahren zur Untersuchung des Erosionskorrosionsverhaltens basieren üblicherweise auf der Bestimmung von Abtragsraten aus gravimetrisch bestimmten Masseverlusten unter definierten Prüfbedingungen. Unter Hochrechnung der ermittelten Abtragsraten wird versucht, Aussagen über das langfristige Werkstoffverhalten zu treffen und die voraussichtliche Betriebsdauer von Anlagenkomponenten abschätzen zu können. Durch die Ermittlung integraler Werte über die gesamte Versuchsdauer bleiben jedoch zeitliche Änderungen in den Bedingungen, wie sie unter praktischen Einsatzbedingungen zu erwarten sind, unberücksichtigt. Zudem können aus der Bestimmung von Abtragsraten unter Standardprüfbedingungen keine Rückschlüsse auf die Ursachen des Materialabtrags sowie auf mögliche Wechselwirkungen zwischen der mechanischen sowie korrosiven Beanspruchungskomponente getroffen werden. Die Entwicklung eines elektrochemisch instrumentierten Versuchsaufbaus kann hier einem Informationszugewinn im Hinblick auf die wirkenden Mechanismen unter kombinierter erosiv-korrosiver Beanspruchung generieren und somit einen entscheidenden Beitrag zur Abschätzung des langfristigen Werkstoffverhaltens unter Einsatzbedingungen und folglich auch zur Verbesserung der Bauteilsicherheit leisten. T2 - 15. Sommerkurs Werkstoffe und Fügen am Institut für Werkstoff- und Fügetechnik CY - Magdeburg, Germany DA - 12.09.2014 PY - 2014 SN - 978-3-940961-85-3 SP - 165 EP - 178 AN - OPUS4-31478 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rosemann, P. A1 - Babutzka, Martin A1 - Heyn, Andreas A1 - Halle, T. T1 - Influence of heat treatment on corrosion resistance of martensitic stainless steels 1.4034 and 1.4021 N2 - In the last years, new approaches for the evaluation of the corrosion resistance of stainless steels were developed which allow short term corrosion testing with increased information content. This work analyses the extensive influence of heat treatment on microstructure and the resulting corrosion resistance of the martensitic stainless steels 1.4034 and 1.4021 with advanced methods. Different heat treatments at various austenitization temperatures up to 1100°C and the effect of different cooling rates were evaluated; the last has not yet been studied in literature at all. The resulting corrosion behaviour in relation to the different carbon content in the two used alloys and the applied heat treatment will be presented and discussed. The applied methods of investigation were conventional evaluation of the critical pitting corrosion potential (PP), modified electrochemical potentiodynamic reactivation (mEPR) and the "KorroPad" (KP) technique. The performance of modified EPR and its interpretation were optimized to provide additional information about the general passivation ability and the extent of chromium depletion as result of applied heat treatment. The aim using PP and KP was the correlation between the Parameters of the mEPR with the changes in the pitting corrosion resistance. Furthermore the results will demonstrate the functionality and usability of the short term corrosion test methods mEPR and KP in order to increase their acceptance within the scientific community. The results indicate a surprisingly large influence of both austenitization temperature and cooling rate on the corrosion resistance within all three used test methods, which can explain the different corrosion behaviour of martensitic stainless steels in earlier investigations. T2 - EUROCORR 2014 - European corrosion congress CY - Pisa, Italy DA - 08.09.2014 KW - Martensitic stainless steel KW - KorroPad KW - Pitting corrosion KW - Polarisation PY - 2014 SN - 978-3-89746-159-8 SP - O EP - 7455, 146 AN - OPUS4-31481 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hasenstab, Andreas A1 - Krause, Martin A1 - Hillemeier, B. A1 - Rieck, C. T1 - Ultraschallecho-Messungen an Holz N2 - In der Praxis kann Fäulnis in Holzkonstruktionen ein großes Problem darstellen. Ein Fäulnisbefall kann zu einer Schädigung in der Gesamtkonstruktion führen. Zusammen mit der TU Berlin wurden an der Bundesanstalt für Materialforschung und -prüfung (BAM) Versuche mit Ultraschallecho zur Detektion von Bauteilrückwänden und verdeckten Hohlstellen durchgeführt. Hierbei werden Sender und Empfänger auf einer Bauteilseite angekoppelt, was eine große Anwendungsvielfalt ermöglicht. Im Rahmen der Versuche an der BAM wurden zylindrische Longitudinalwellenprüfköpfe in Zweikopftechnik mit 100 kHz angeregt und an den Probekörpern mit verschiedenen Koppelmitteln angekoppelt. Die Messergebnisse wurden graphisch als B-Bilder dargestellt und ausgewertet. Dabei zeigte sich, dass die Rückwand der fehlerfreien Probekörper klar geortet wird und eingebrachte Hohlstellen besonders gut detektiert werden können. KW - Zerstörungsfreie Prüfung KW - Ultraschallecho KW - Holz PY - 2006 DO - https://doi.org/10.1007/s00107-006-0124-x SN - 0018-3768 VL - 64 SP - 475 EP - 481 PB - Springer CY - Berlin AN - OPUS4-23056 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin A1 - Lehmann, Jens A1 - Burkert, Andreas T1 - The KorroPad - A novel test method for assessing the pitting corrosion susceptibility of stainless steel surfaces N2 - Pitting corrosion is one of the most common mechanisms of local passivity breakdown on stainless steels. Electrochemical methods have preferentially been applied for the evaluation of pitting corrosion resistance of stainless steels in laboratory. Nevertheless, some of them are not reliable enough and in general the application of electrochemical methods in the field becomes difficult because of a required deep understanding of corrosion phenomena and measurement technology. A new approach for the evaluation of the pitting corrosion susceptibility of stainless Steel surfaces in the laboratory as well as in the field is frequently demanded by representatives of the metalworking industry. Therefore, the KorroPad-test was invented and patented as part of a research project at the BAM Federal Institute for Materials Research and Testing in Germany. T2 - EUROCORR 2015 - European corrosion congress CY - Graz, Austria DA - 06.09.2015 KW - KorroPad KW - Pitting corrosion KW - Stainless steel PY - 2015 SP - Paper 5_730, 1 AN - OPUS4-34297 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martin, Tina A1 - Nordsiek, S. A1 - Weller, Andreas T1 - Low-frequency impedance spectroscopy of wood N2 - The method of low-frequency impedance spectroscopy has been successfully applied in Earth sciences to characterize soils and rocks. The method uses the diagnosing power of complex electrical resistivity in a frequency range between 1 mHz and 1 kHz. In our study, the potential of this method has been explored for the investigation of wood. We observed remarkable differences in the resulting spectra of complex resistivity for different European and Tropical tree species. The data processing of the acquired low-frequency impedance spectra yields integrating parameters. The comparison of the integrating parameters with the mean pore diameter that has been separately determined for the tropical tree species indicates clear correlations. An additional investigation has revealed remarkable difference in the complex resistivity spectra between oil bearing and non-oil bearing sandal wood. This result and the relations between electrical parameters and structural parameters of wood indicate the prospective potential of low-frequency impedance spectroscopy. KW - Holz KW - Spektroskopie KW - ZfP KW - SIP KW - Nondestructive KW - Low-frequency impedance spectroscopy KW - Spectral induced polarization PY - 2015 DO - https://doi.org/10.5171/2015.910447 SP - 1 EP - 9 PB - IBIMA Publ. AN - OPUS4-34811 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Thoralf A1 - Burkert, Andreas A1 - Heyn, A. A1 - Balzer, Martin A1 - Fenker, M. T1 - Investigation on the improved corrosion behavior of TiMgN hard coating on steel substrate T2 - EUROCORR 2015 - European corrosion congress CY - Graz, Austria DA - 06.09.2015 KW - Hard coatings KW - TiMgN KW - Corrosion PY - 2015 SP - paper 11.1_693 AN - OPUS4-34618 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Feldmann, Rüdiger A1 - Zoёga, Andreas A1 - Milmann, Boris A1 - Krause, Martin T1 - Ortung tiefliegender Bewehrung durch Ultraschall mit bildgebender Phasenauswertung N2 - Die Ortung von schlaffer Bewehrung in Beton erfolgt routinemäßig mit bildgebenden Radar- oder Wirbelstromverfahren. Die Anwendung dieser Verfahren ist aber begrenzt, wenn es sich um die Ortung tiefliegender Bewehrung (ab ca. 30 cm) oder um jungen Beton handelt. Grund ist die Schwächung der Radarpulse durch oberflächennahe Bewehrung oder durch die Betonfeuchte. Das bildgebende Ultraschallechoverfahren bietet den Vorteil, dass die Ultraschallpulse in diesen Fällen eine wesentlich höhere Eindringtiefe erreichen. Im vorliegenden Beitrag wird eine Fallstudie vorgestellt, bei der mehrlagig eingebrachte Bewehrungseisen in einer nur einseitig zugänglichen 60 cm dicken Betonplatte geortet werden sollten, um eine Kernbohrung ohne Verkanten der Bohrkrone durchzuführen. Zur Ortung der Bewehrung wurde das Ultraschallechoverfahren mitScherwellen der Mittenfrequenz 50 kHz mit einem automatisch arbeitenden Bauwerksscanner eingesetzt. Aus den flächig aufgenommenen Messdaten wurde mit der Rekonstruktionsrechnung nach dem Prinzip der synthetischen Apertur (SAFT, Synthetic Aperture Focusing Technique) die Position der Bewehrungseisen bildhaft ortsgenau dargestellt. Dies gelingt mit einer Auswertungsoption, bei der die Phase der reflektierten Ultraschallpulse ermittelt und farbcodiert dargestellt wird (Phasenauswertung). Damit lassen sich Reflexionen der Bewehrung eindeutig von eventuellen Fehlstellen oder Rückwandechos unterscheiden. T2 - Fachtagung Bauwerksdiagnose 2014 CY - Berlin, Germany DA - 13.02.2014 KW - Ultraschallecho-Verfahren KW - SAFT KW - Bewehrung KW - Beton KW - Abbildungsverfahren PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351056 UR - https://www.ndt.net/?id=15885 SN - 1435-4934 VL - 19 IS - 8 SP - 1 EP - 11 PB - NDT.net CY - Kirchwald AN - OPUS4-35105 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Thoralf A1 - Heyn, Andreas A1 - Babutzka, Martin A1 - Rosemann, P. T1 - Examination of the influence of heat treatment on the corrosion resistance of martensitic stainless steels N2 - Martensitic stainless steels are commonly used in cutlery fabrication requiring high hardness and sufficient corrosion resistance. The heat treatment process affects the mechanical and electrochemical behavior of martensitic stainless steels due to the precipitation of chromium carbides. Depending on the heat treatment the corrosion resistance of these steels can vary strongly, and improper heat treatment parameters can lead to a weak pitting corrosion resistance. The aim of this work is to identify heat treatment parameters influencing the corrosion resistance of martensitic stainless steels by using three different electrochemical testing methods. To this purpose, five different heat treatments were applied to the alloys 1.4116 and 1.4034. In addition to the determination of the critical pitting potentials and the modified double-loop electrochemical potentiodynamic reactivation tests (DL-EPR) a new KorroPad indicator test was used assessing the pitting corrosion behavior. The results showed that all methods used were in good agreement for verifying the influence of the various heat treatment parameters on the corrosion behavior and to identify the effect of heat treatment conditions on the pitting corrosion resistance. KW - DL-EPR KW - Heat treatment KW - KorroPad KW - Martensitic stainless steel KW - Pitting corrosion PY - 2015 DO - https://doi.org/10.1002/maco.201407861 SN - 0947-5117 SN - 1521-4176 VL - 66 IS - 7 SP - 656 EP - 662 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-33621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin A1 - Burkert, Andreas A1 - Heyn, A. T1 - Korrosionsuntersuchungen mit gelartigen Elektrolyten zur Beschreibung der Korrosionsschutzwirkung von Zinküberzügen N2 - Ein neuer Ansatz bei elektrochemischen Korrosionsuntersuchungen kann durch den Einsatz von gelartigen Elektrolyten als Alternative zu wässrigen Prüfelektrolyten beschritten werden. Gelartige Elektrolyte ermöglichen minimalinvasive Untersuchungen an natürlich gebildeten Zinkdeckschichten. Dadurch können korrosionsrelevante Kennwerte ermittelt werden, die Aussagen zur Deckschichtbildung und zur Stabilität der gebildeten Deckschichten unter verschiedenen klimatischen Bedingungen erlauben. In diesem Beitrag wird anhand verschiedener Deckschichtzustände an Zink der Mehrwert von Untersuchungen mit gelartigen Elektrolyten für die Korrosionsforschung verdeutlicht. T2 - 16. Tagung "Korrosionsschutz in der maritimen Technik" CY - Hamburg, Germany DA - 25.01.2017 KW - Deckschichtbildung KW - Layer formation KW - Gelartige Elektrolyte KW - Gel-type electrolytes KW - Korrosionsprüfung KW - Corrosion testing KW - Zinkdeckschichten KW - Zinc coatings PY - 2017 SN - 978-3-935406-64-2 VL - 16 SP - 35 EP - 44 AN - OPUS4-39041 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin A1 - Burkert, Andreas A1 - Heyn, A. T1 - Corrosion investigations on zinc coatings by using gel-type electrolytes N2 - In the presentation different zinc coatings are presented and investigated. Their naturally formed protective layers are electrochemically characterized and corrosion relevant values are determined by using a gel pad based on polysaccharide. The corrosion relevant values allow the differentiation of various zinc coating systems and can describe the current protective effect provided by the coating. It is shown that gel-type electrolytes influence protective layers and coatings considerably less than corresponding bulk electrolytes. From the results it is evident that gel-type electrolytes represent a viable and promising field in corrosion research. T2 - 7th Kurt-Schwabe-Symposium CY - Mittweida, Germany DA - 04.09.2016 KW - zinc coatings KW - gel-type electrolytes KW - corrosion invetsigations PY - 2016 SP - 19 AN - OPUS4-37411 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin A1 - Burkert, Andreas A1 - Heyn, A. T1 - Korrosionsuntersuchungen mit gelartigen Elektrolyten an natürlich gebildeten Zinkdeckschichten N2 - Ein neuer Ansatz bei elektrochemischen Korrosionsuntersuchungen kann durch den Einsatz von gelartigen Elektrolyten als Alternative zu wässrigen Prüfelektrolyten beschritten werden. Gelartige Elektrolyte ermöglichen minimalinvasive Untersuchungen an natürlich gebildeten Zinkdeckschichten. Dadurch können korrosionsrelevante Kennwerte ermittelt werden, die Aussagen zur Deckschichtbildung und zur Stabilität der gebildeten Deckschichten erlauben. In diesem Beitrag wird anhand verschiedener Deckschichtzustände an Zink der Mehrwert von gelartigen Elektrolyten für die Korrosionsforschung verdeutlicht. N2 - A new approach in electrochemical corrosion testing includes the use of gel-type electrolytes as an alternative to aqueous test electrolytes. Gel-type electrolytes enable minimally invasive studies of naturally formed zinc coatings. Thus, corrosion-relevant parameters can be determined that allow conclusions on layer formation and layer stability. This contribution will clarify the value of gel-type electrolytes for corrosion research at the example of various coatings on zinc. T2 - Tagung Werkstoffprüfung 2016 CY - Neu-Ulm, Germany DA - 01.12.2016 KW - Zinkdeckschichten KW - Zinc coatings KW - Korrosionsprüfung KW - Corrosion testing KW - Gelartige Elektrolyte KW - Gel-type electrolytes KW - Deckschichtbildung KW - Layer formation PY - 2016 SN - 978-3-514-00830-4 SP - 125 EP - 130 PB - Verlag Stahleisen GmbH CY - Düsseldorf AN - OPUS4-38578 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konnertz, Nora A1 - Ding, Yi A1 - Harrison, W.J. A1 - Budd, P.M. A1 - Schönhals, Andreas A1 - Böhning, Martin T1 - Molecular mobility and gas transport properties of nanocomposites based on PIM-1 and polyhedral oligomeric phenethyl-silsesquioxanes (POSS) N2 - Polymers with intrinsic microporosity (PIMs) are of great interest in the field of gas separation membranes. Already the first synthesized PIM-1 shows extraordinary permeability and selectivity. Unfortunately, PIM-1 is susceptible to physical aging and thus gradually loses its outstanding properties. In this study a polyhedral oligomeric silsesquioxane with phenethyl substituents (PhenethylPOSS) was used as a nanofiller (0–40 wt%) in the PIM-1 matrix to potentially improve the gas transport properties and prevent physical aging. The molecular mobility of the solution-cast nanocomposite films was analyzed by Broadband Dielectric Spectroscopy (BDS). Furthermore, gas permeability was determined with the time lag method (0–20 bar upstream pressure) at 35 °C for N2, O2, CH4 and CO2. KW - Broadband Dielectric Spectroscopy KW - Gas separation KW - Gas permeation KW - Polymers of intrinsic microporosity KW - Nanocomposite KW - POSS KW - PIM-1 PY - 2017 DO - https://doi.org/10.1016/j.memsci.2017.02.007 SN - 0376-7388 SN - 1873-3123 VL - 529 SP - 274 EP - 285 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-39169 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin A1 - Burkert, Andreas T1 - Untersuchungen zur Versalzung von Metalloberflächen im maritimen Bereich N2 - Die Versalzung und Verunreinigung von Metalloberflächen durch chloridhaltige Aerosole hat eine große Bedeutung für das Korrosionsverhalten von beschichteten Metalloberflächen im maritimen Bereich und bei Offshore-Anwendungen. So ist z. B. zu klären, ob und in welchem Maße eine Versalzung der Oberfläche Einfluss auf die Haftung und Dauerhaftigkeit von Beschichtungen hat. Dafür sind Detailfragen zu klären, etwa mit welcher Versalzung nach welchem Zeitraum zu rechnen ist oder wie für systematische Untersuchungen eine definierte und reproduzierbare Versalzung im Labor nachgestellt werden kann. Der Beitrag widmet sich diesen Fragestellungen. Es werden Ergebnisse eines Feldversuches auf Helgoland gezeigt und ein einfaches Verfahren zur definierten Beladung von Metalloberflächen mit Chloriden im Labormaßstab vorgestellt. T2 - 17. Tagung "Korrosionsschutz in der maritimen Technik" CY - Hamburg, Germany DA - 24.01.2018 KW - Maritime Atmosphäre KW - Maritime atmosphere KW - Versalzung KW - Salinization PY - 2018 SN - 978-3-935406-65-9 VL - 17 SP - 87 EP - 102 AN - OPUS4-43937 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin A1 - Burkert, Andreas A1 - Heyn, A. T1 - Corrosion investigations on zinc coatings by using gel-type electrolytes N2 - A new approach to the assessment of the corrosion behaviour of zinc coatings under atmospheric conditions can be achieved using gel-type electrolytes as an alternative to standard aqueous test electrolytes. Gel-type electrolytes allow minimally invasive corrosion investigations on zinc coatings. They also provide the possibility to carry out corrosion investigations onsite. By using gel-type electrolytes corrosion-relevant characteristic values such as corrosion currents and polarization resistances can be determined. These allow to describe the formation and the stability of the formed corrosion product layers under various climatic conditions. With this knowledge, a prediction of the zinc coating life cycle is possible. In this contribution, the value of gel-type electrolytes for corrosion research on zinc coatings is presented. T2 - Intergalva 2018 CY - Berlin, Germany DA - 17.06.2018 KW - Deckschichtbildung KW - Layer formation KW - Gelartige Elektrolyte KW - Gel-type electrolytes KW - Korrosionsprüfung KW - Corrosion testing KW - Zinkdeckschichten KW - Zinc coatings PY - 2018 SP - 385 EP - 392 AN - OPUS4-45245 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yin, Huajie A1 - Chua, Y. Z. A1 - Yang, B. A1 - Schick, C. A1 - Harrison, W. A1 - Budd, P. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - First clear cut experimental evidence for a glass transition in a polymer with intrinsic microporosity: PIM-1 N2 - Polymers with intrinsic microporosity (PIMs) represent a novel, innovative class of materials with great potential in various applications from high-performance gas separation membranes to electronic devices. Here for the first time, for PIM-1, as the archetypal PIM, fast scanning calorimetry provides definitive evidence for a glass transition (Tg=715 K, heating rate 3·10^4 K/s) by decoupling the time-scales responsible for glass transition and decomposition. As the rigid molecular structure of PIM-1 prevents any conformational changes, small-scale bend and flex fluctuations must be considered the origin of its glass transition. This result has strong implications for the fundamental understanding of the glass transition and for the physical aging of PIMs and other complex polymers, both topical problems of materials science. KW - Polymers with intrinsic microporosity KW - Fast Scanning Calorimetry PY - 2018 DO - https://doi.org/10.1021/acs.jpclett.8b00422 SN - 1948-7185 VL - 9 IS - 8 SP - 2003 EP - 2008 PB - ACS AN - OPUS4-44683 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Erdmann, Maren A1 - Kupsch, Andreas A1 - Müller, Bernd R. A1 - Hentschel, Manfred P. A1 - Niebergall, Ute A1 - Böhning, Martin A1 - Bruno, Giovanni ED - Erdmann, Maren T1 - Diesel-induced transparency of plastically deformed high-density polyethylene N2 - High-density polyethylene becomes optically transparent during tensile drawing when previously saturated with diesel fuel. This unusual phenomenon is investigated as it might allow conclusions with respect to the material behavior. Microscopy, differential scanning calorimetry, density measurements are applied together with two scanning X-ray scattering techniques: wide angle X-ray scattering (WAXS) and X-ray refraction, able to extract the spatially resolved crystal orientation and internal surface, respectively. The sorbed diesel softens the material and significantly alters the yielding characteristics. Although the crystallinity among stretched regions is similar, a virgin reference sample exhibits strain whitening during stretching, while the diesel-saturated sample becomes transparent. The WAXS results reveal a pronounced fiber texture in the tensile direction in the stretched region and an isotropic orientation in the unstretched region. This texture implies the formation of fibrils in the stretched region, while spherulites remain intact in the unstretched parts of the specimens. X-ray refraction reveals a preferred orientation of internal surfaces along the tensile direction in the stretched region of virgin samples, while the sample stretched in the diesel-saturated state shows no internal surfaces at all. Besides from stretching saturated samples, optical transparency is also obtained from sorbing samples in diesel after stretching. KW - PE-HD Sorption KW - Cavitation KW - Diesel Fuel KW - X-ray refraction KW - WAXS KW - Internal Surfaces KW - Crystal Texture PY - 2019 DO - https://doi.org/10.1007/s10853-019-03700-8 SN - 1573-4803 SN - 0022-2461 VL - 54 IS - 17 SP - 11739 EP - 11755 PB - Springer US CY - US AN - OPUS4-48226 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zorn, R. A1 - Lohstroh, W. A1 - Zamponi, M. A1 - Harrison, W. A1 - Budd, P. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Molecular mobility of a polymer of intrinsic microporosity revealed by quasielastic neutron scattering N2 - Quasielastic neutron scattering by employing a combination of time-of-flight and backscattering techniques is carried out to explore the molecular mobility of a polymer of intrinsic microporosity (PIM-1) at microscopic time scales in comparison with a high-performance polyimide. Molecular fluctuations can change the structure of the temporary network of micropores and open or close pathways for gas molecules. Therefore, the investigation might help to understand the selectivity of PIMs in gas separation processes. The performed neutron scattering experiments provide evidence for a low-temperature relaxation process, which was assigned to methyl group rotation. This methyl group rotation was analyzed in terms of jump diffusion in a three-fold potential. The analysis results in a fraction of methyl groups which are immobilized. For PIM-1 it was found that the fraction of immobilized methyl groups decreases with increasing temperature up to 350 K. At higher temperatures the number of immobilized methyl group increases gain due to an underlying relaxation process. This motional process on a somewhat larger length scale might lead to a reversible structural rearrangement which partially hinders the strongly localized methyl group rotation. In addition, it was found that the activation energy for the methyl group rotation for PIM-1 and the polyimide is significantly higher than for conventional polymers. KW - Polymer of intrinsic microporosity KW - Quasielastic neutron scattering PY - 2020 DO - https://doi.org/10.1021/acs.macromol.0c00963 SN - 0024-9297 SN - 1520-5835 VL - 53 IS - 15 SP - 6731 EP - 6739 PB - American Chemical Society CY - Washington, DC AN - OPUS4-51147 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zorn, R. A1 - Szymoniak, Paulina A1 - Kolmangadi, Mohamed Aejaz A1 - Wolf, M. A1 - Alentiev, D. A1 - Bermeshev, M. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Low frequency vibrational density of state of highly permeable super glassy polynorbornenes – The Boson peak N2 - Inelastic incoherent neutron time-of flight scattering was employed to measure the low frequency density of states for a series of addition polynorbornenes with bulky side groups. The rigid main chain in combination with the bulky side groups give rise to a microporosity of these polymers in the solid state. The microporosity characterized by the BET surfaces area varies systematically in the considered series. Such materials have some possible application as active separation layer in gas separation membranes. All investigated materials show excess contributions to the Debye type density of states characteristic for glasses known as Boson peak. The maximum position of the Boson peak shifts to lower frequency values with increasing microporosity. Data for PIM-1 and Matrimid included for comparison are in good agreement to this dependency. This result supports the sound wave interpretation of the Boson peak. KW - Polynorbornes KW - Neutron Scattering PY - 2020 DO - https://doi.org/10.1039/d0cp03360j SN - 1463-9076 VL - 22 IS - 33 SP - 18381 EP - 18387 PB - Royal Chemical Society AN - OPUS4-51165 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kolmangadi, Mohamed Aejaz A1 - Szymoniak, Paulina A1 - Smales, Glen Jacob A1 - Alentiev, D. A1 - Bermeshev, M. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Molecular Dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase Separation N2 - For the first time, dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbones and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl) is reported. Generally, this class of polymers has some potential for applications in the field of gas separation membranes. Two dielectrically active processes are observed at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter is related to the glassy dynamics of the flexible -Si(OR)3 side groups, creating a nanophase separation in both the alkyl chain rich and backbone rich domains. This is confirmed through temperature modulated DSC measurements and X-ray scattering experiments. The glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC, are determined for the first time using Fast Scanning Calorimetry employing both fast heating and cooling rates. This is complimented with scattering experiments that show how the size of the alkyl chain rich domains increases with chain length. Alongside these results, a significant conductivity contribution was observed for all poly(tricyclononenes) with -Si(OR)3 side groups, which is interpreted in terms of a percolation model. KW - Polynorbornenes KW - Broadband Dielectric Spectrscopy KW - Advanced calorimetry PY - 2020 DO - https://doi.org/10.1021/acs.macromol.0c01450 VL - 53 IS - 17 SP - 7410 EP - 7419 PB - ACS AN - OPUS4-51196 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Babutzka, Martin A1 - Müller, Thoralf A1 - Mietz, Jürgen A1 - Burkert, Andreas T1 - Investigation of the influence of iron‐containing abrasives on the corrosion behaviour of the aluminium alloy AlSi1.2Mg0.4 N2 - The corrosion resistance of aluminium surfaces is closely linked to the surfacecstate after a grinding process. For years, iron‐containing abrasive materials were suspected to lead to increased corrosion susceptibility after processing of aluminium surfaces. To prove a possible correlation between the iron content of an abrasive and the corrosion behaviour of aluminium components, scientific investigations and experimentally practical corrosion tests are necessary. For the current investigation, specimens of a technical Al‐Si alloy from the same batch were used. The test specimens were mechanically ground with various resin‐bonded model abrasives containing different iron contents. The performed corrosion tests did not reveal a negative influence of the different iron‐containing abrasives on the corrosion behaviour of the Al–Si alloy. However, the most sensitive measuring method (electrochemical noise) showed differences in the surface activity depending on the type of abrasive. KW - Aluminium KW - Corrosion KW - Corrosion testing KW - Grinding PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506762 DO - https://doi.org/10.1002/maco.202011657 SN - 0947-5117 SN - 1521-4176 VL - 71 IS - 10 SP - 1667 EP - 1679 PB - Wiley‐VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-50676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konnertz, Nora A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Dielectric investigations of nanocomposites based on matrimid and polyhedral oligomeric phenethyl-silsesquioxanes (POSS) N2 - Matrimid and Matrimid/PhenethylPOSS nanocomposites films were prepared by solution casting. They can be considered as potential membrane materials for gas separation. Theire dielectric properties were investigated using Broadband Dielectric Spectroscopy (BDS) in combination with standard techniques. Matrimid shows one relaxation process assigned as beta*-relaxation and a conductivity contribution. The relaxation process has a high activation energy of 99 kJ/mol. Thus this process is supposed to be of cooperative nature due to a π-π stacking of the phenyl rings of Matrimid. The influence of the thermal history on Matrimid was analyzed with BDS as well where an annealing effect is found. The Matrimid/PhenethylPOSS nanocomposites show up to a concentration of about 4 wt% PhenethylPOSS a miscibility on a molecular level. For higher concentrations a phase separated structure was indicated. The conductivity of both systems is explained by π-π stacking of the phenyl rings which enhances charge transport. KW - Matrimid KW - POSS KW - Nanocomposites KW - Broadband dielectric spectroscopy PY - 2016 DO - https://doi.org/10.1016/j.polymer.2016.02.060 SN - 0032-3861 VL - 90 SP - 89 EP - 101 PB - Elsevier Science AN - OPUS4-35616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Konnertz, Nora A1 - Böhning, Martin A1 - Schönhals, Andreas A1 - Ding, Yi T1 - Molecular mobility and gas transport properties of PIM-1 and nano composites based on PIM-1 and phenethylPOSS N2 - Polymers with intrinsic microporosity are of highly interest in the field of gas separation membranes. Especially the first synthesized PIM-1 shows extraordinary permeabilities and selectivities. Unfortunately, PIM-1 tends to physical aging and loses its good properties. Physical aging is related to the molecular mobility of PIM-1 which was here investigated by broadband dielectric spectroscopy (BDS). Besides the studies on pure PIM-1 a polyhedral oligomeric silsesquioxane with phenethyl substituents (PhenethylPOSS) was used as nanofiller (0 - 40 wt-%) in the PIM-1 matrix to improve the gas transport properties and prevent physical aging. The molecular mobility of the solution casted nano composite films was analyzed by BDS as well. Furthermore, gas transport properties were determined with the time lag method (0 - 20 bar) in a temperature range of 35°C to 65°C with N2, O2, CH4 and CO2. T2 - 80. Jahrestagung der DPG und DPG-Frühjahrstagung CY - Regensburg, Germany DA - 06.03.2016 KW - PIM-1 PY - 2016 AN - OPUS4-35541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Thoralf A1 - Lehmann, Jens A1 - Babutzka, Martin A1 - Burkert, Andreas ED - Borsutzki, M. ED - Moninger, G. T1 - Bewertung werkstofftechnischer Einflussfaktoren auf die Passivschichtstabilität nichtrostender Stähle mittels Korrosionsschneltest N2 - Mit Hilfe des KorroPad-Prüfverfahrens konnten verschiedene umgebungs- sowie prozessbedingte Einflüsse in Parameterstudien gezielt untersucht werden. So konnte der negative Einfluss von korundbasierten Schleifmitteln auf die Passivschichtausbildung nachgewiesen werden. Weiterhin konnte mittels KorroPad die Wirksamkeit verschiedener Oberflächenbearbeitungsverfahren bei der Schweißnahtnachbearbeitung untersucht und daraus Erkenntnisse für die Prozessoptimierung gewonnen werden. In den hier gezeigten Untersuchungen hat sich das KorroPad-Prüfverfahren für die Beschreibung der Passivschichtstabilität als hervorragend geeignet erwiesen. N2 - By using the KorroPad test a wide ränge of environmental and process-related factors couid be investigated in parameter studies. Thus, the negative influence of corundum-based abrasives on passive layer formation was proven. Furthermore the effectiveness of different surface treatments for weld seam reworking was investigated and thus process optimization was possible. The investigations demonstrate that the KorroPad test method is highly suitable for the evaluation of passive layer stability. T2 - Tagung Werkstoffprüfung 2014 - Fortschritte in der Werkstoffprüfung für Forschung und Praxis CY - Bad Neuenahr, Germany DA - 03.12.2015 KW - Rapid corrosion test KW - Surface treatment KW - Quality control KW - Stainless steel KW - Korrosionsschnelltest KW - Oberflächenbehandlung KW - Qualitätskontrolle KW - Nichtrostender Stahl PY - 2015 SN - 978-3-514-00816-8 SP - 95 EP - 100 PB - Verlag Stahleisen CY - Düsseldorf AN - OPUS4-35233 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Konnertz, Nora A1 - Ding, Yi A1 - Harrison, W.J. A1 - Budd, P.M. A1 - Schönhals, Andreas A1 - Böhning, Martin T1 - Molecular mobility of the high performance membrane polymer PIM-1 as investigated by dielectric spectroscopy N2 - The increasing demand for energy efficient separation processes fosters the development of new high performance polymers as selective separation layers for membranes. PIM-1 is the archetypal representative of the class of polymers of intrinsic microporosity (PIM) which are considered most promising in this sector, especially for gas separations. Since their introduction, PIMs stimulated a vast amount of research in this field and meanwhile evolved to the state of the art in membrane technology for gas separation. The major obstacle for extending the practical membrane application is their strong tendency to physical aging. For the first time, investigations by broadband dielectric spectroscopy (BDS) addressing molecular dynamics and conductivity in PIM 1 are presented. As chain packing during film formation from the casting solution and physical aging are key factors determining the separation performance of PIMs as membrane materials, characterization of the molecular mobility in such materials as revealed by BDS will provide valuable information for further development and optimization. KW - PIM-1 KW - BDS broadband dielectric spectroscopy KW - Relaxation KW - Membrane PY - 2016 DO - https://doi.org/10.1021/acsmacrolett.6b00209 SN - 2161-1653 VL - 5 IS - 4 SP - 528 EP - 532 PB - ACS American Chemical Society CY - Washington, DC, USA AN - OPUS4-35798 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rosemann, P. A1 - Müller, Thoralf A1 - Babutzka, Martin A1 - Heyn, Andreas T1 - Influence of microstructure and surface treatment on the corrosion resistance of martensic stainless steels 1.4116, 1.4034, and 1.4021 N2 - In the last years, new approaches for the evaluation of the corrosion resistance of martensitic stainless steels were developed, which allow nearly non-destructive as well as short-term corrosion testing. This work analyzes the sensitive influence of microstructure and surface treatment on the corrosion resistance. The effect of alloy composition and microstructure, which is always present in addition to the influence of various surface treatments will be evaluated and discussed. The corrosion behavior was investigated with conventional evaluation of the pitting potential, electrochemical potentiodynamic reactivation (EPR), electrochemical noise (EN), and the 'KorroPad' (KP) technique. EPR provided information about the passivation ability and the extent of chromium content reduction due to chromium carbide precipitation in the microstructure. The use of EN and KP aims to detect the influence of different surface treatment parameters on the corrosion resistance in a nearly non-destructive way. Furthermore the results shall demonstrate the functionality and convenience of the short-term corrosion test methods EN and KP in order to gain more acceptance within the scientific community. The results will allow the extraction of surface treatment effects on the corrosion behavior of the martensitic stainless steels 1.4116, 1.4034, and 1.4021. KW - Corrosion resistance KW - Electrochemical noise KW - Martensitic stainless steel KW - Electrochemical potentiodynamic reactivation KW - KorroPad KW - EPR-Test KW - Heat treatment PY - 2015 DO - https://doi.org/10.1002/maco.201307276 SN - 0947-5117 SN - 1521-4176 VL - 66 IS - 1 SP - 45 EP - 53 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-32572 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yin, Huajie A1 - B, Yang A1 - Chua, Y. Z. A1 - Szymoniak, Paulina A1 - Carta, M A1 - Malpass-Evans, R A1 - McKeown, N A1 - Harrison, W A1 - Budd, P A1 - Schick, C A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Effect of backbone rigidity on the glass transition of polymers of in-trinsic microporosity probed by fast scanning calorimetry N2 - Polymers of Intrinsic Microporosity (PIMs) of high performance have developed as materials with a wide application range in gas separation and other energy-related fields. Further optimization and long-term behavior of devices with PIMs require an understanding of the structure-property relationships including physical aging. In this context the glass transi-tion plays a central role, but with conventional thermal analysis a glass transition is usually not detectable for PIMs be-fore their thermal decomposition. Fast scanning calorimetry provides evidence of the glass transition for a series of PIMs, as the time scales responsible for thermal degradation and for the glass transition are decoupled by employing ultrafast heating rates of tens of thousands K s-1. The investigated PIMs were chosen considering the chain rigidity. The estimated glass transition temperatures follow the order of the rigidity of the backbone of the PIMs. KW - Polymers of intrinsic microporosity KW - Fast scanning calormetry PY - 2019 DO - https://doi.org/10.1021/acsmacrolett.9b00482 SN - 2161-1653 VL - 8 IS - 8 SP - 1022 EP - 1028 PB - ACS Publications AN - OPUS4-48617 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin A1 - Burkert, Andreas A1 - Heise, Svenja A1 - Heyn, A. T1 - Korrosionsuntersuchungen mit gelartigen Elektrolyten an Zink - Eine innovative Prüfmethodik N2 - Ein neuer Ansatz bei elektrochemischen Korrosionsuntersuchungen kann durch den Einsatz von gelartigen Elektrolyten als Alternative zu wässrigen Prüfelektrolyten beschritten werden. Gelartige Elektrolyte ermöglichen minimalinvasive Untersuchungen an natürlich gebildeten Zinkdeckschichten. Dadurch können korrosionsrelevante Kennwerte ermittelt werden, die Aussagen zur Deckschichtbildung und zur Stabilität von atmosphärisch gebildeten Deckschichten erlauben. In diesem Beitrag wird anhand verschiedener Untersuchungen an Reinzink der Mehrwert von gelartigen Elektrolyten für die Korrosionsforschung und -prüfung verdeutlicht. Darüber hinaus werden neue Erkenntnisse zur Deckschichtbildung von Zink unter atmosphärischen Bedingungen vorgestellt. T2 - GfKORR-Jahrestagung 2019 CY - Frankfurt a. M. DA - 12.11.2019 KW - Zink KW - Gelartige Elektrolyte KW - Korrosionsuntersuchungen KW - Deckschichtbildung PY - 2019 SN - 978-3-935406-71-0 SP - 53 EP - 64 AN - OPUS4-49642 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Burkert, Andreas A1 - Babutzka, Martin T1 - Korrosionsschutz durch Deckschichtbildung und Passivität N2 - Metallene Konstruktionswerkstoffe reagieren infolge ihres thermodynamisch instabilen Zustandes mehr oder weniger stark mit Stoffen aus der Umgebung. Eine große Rolle bei diesen Reaktionen spielt das Feuchtigkeitsangebot an der Metalloberfläche, welches nicht zwingend mit einem sichtbaren Wasserfilm einhergehen muss. An der Atmosphäre bilden sich an sauberen Metalloberflächen bei etwa 80 % relativer Luftfeuchte, bei versalzten Oberflächen auch schon ab etwa 25 % r. F., Feuchtfilme aus. Im Feuchtfilm laufen grundsätzlich die gleichen elektrochemischen Reaktionen ab, wie diese von wässrigen Medien bekannt sind. Dabei geht das Metall zunächst in Ionenform und in nachgelagerten Reaktionen in einen thermodynamisch stabilen Zustand in Form unterschiedlichster Oxid- und Hydroxidverbindungen über. Die so entstehenden Korrosionsprodukte können im Feuchtigkeitsfilm begrenzt löslich oder unlöslich sein und lagern sich auf den Oberflächen der Konstruktionswerkstoffe häufig als feste Korrosionsprodukte ab bzw. wachsen dort auf. Je nachdem wie die Korrosionsprodukte strukturell zum Untergrund passen, können sich dichte, sehr gut haftende Schichten ausbilden oder poröse, dicke Schichten ohne nennenswerte Haftung aufwachsen. Wachsen dichte, porenfreie Schichten mit guter Haftung auf, die im umgebenden Medium unlöslich sind, wird die weitere Auflösung des Metalls stark gehemmt. Man spricht dann von der Ausbildung schützender Deckschichten bzw. von Passivschichten auf welcher der Korrosionsschutz und damit die Dauerhaftigkeit vieler Konstruktionswerkstoffe beruhen. Kaesche bezeichnete die Passivität sehr treffend als „optimalen Grenzfall des Korrosionsschutzes durch Schichten von Korrosionsprodukten“. Aus technischer Sicht hält Kaesche eine Unterscheidung von Deckschichten bzw. Passivschichten für nicht zwingend erforderlich, da beide die Korrosionsgeschwindigkeit in gleichem Maß herabsetzen können. Die Übergänge zwischen den meist dickeren und dadurch sichtbaren Deckschichten und den meist dünnen, nicht sichtbaren Passivschichten sind fließend. T2 - 18. Tagung "Korrosionsschutz in der maritimen Technik" CY - Hamburg, Germany DA - 30.01.2019 KW - Korrosionsschutz KW - Überzüge KW - Deckschichten KW - Passivität PY - 2019 SN - 978-3-935406-70-3 VL - 18 SP - 25 EP - 38 AN - OPUS4-47307 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yin, Huajie A1 - Chapala, P. A1 - Bermeshev, M. A1 - Schönhals, Andreas A1 - Böhning, Martin T1 - Molecular Mobility and Physical Aging of a Highly Permeable Glassy Polynorbornene as Revealed by Dielectric Spectroscopy N2 - Polymeric membranes represent a cost- and energy efficient solution for gas separation. Recently superglassy polymers with high free volume outperform many conventional dense polymers in terms of gas permeability and selectivity. However, such polymers are prone to pronounced physical aging, resulting in a dramatic reduction in the gas permeability. Molecular mobility of polymer segments plays an important role in the physical aging and the gas transport performance of polymeric membranes. Molecular mobility and physical aging of a representative superglassy polynorbornene with very high gas permeability, PTCNSi2g, was monitored by using dielectric spectroscopy with state-of-the-art high-resolution analyzers. This work helps to shed some light on the structure−property relationship of superglassy polymers on a molecular level and to provide practical “design rules” for the development of high performance polymers for gas separation. KW - Molecular mobility KW - Gas separation membrane KW - Broadband dielectric spectroscopy KW - Polymer KW - Physical ageing PY - 2017 DO - https://doi.org/10.1021/acsmacrolett.7b00456 SN - 2161-1653 VL - 6 IS - 8 SP - 813 EP - 818 PB - ACS CY - Washington DC, USA AN - OPUS4-41354 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Babutzka, Martin A1 - Burkert, Andreas A1 - Heyn, A. T1 - Korrosionsuntersuchungen mit gelartigen Elektrolyten zur Beschreibung der Korrosionsschutzwirkung von Zinküberzügen N2 - Ein neuer Ansatz bei elektrochemischen Korrosionsuntersuchungen kann durch den Einsatz von gelartigen Elektrolyten als Alternative zu wässrigen Prüfelektrolyten beschritten werden. Gelartige Elektrolyte ermöglichen minimalinvasive Untersuchungen an natürlich gebildeten Zinkdeckschichten. Dadurch können korrosionsrelevante Kennwerte ermittelt werden, die Aussagen zur Deckschichtbildung und zur Stabilität der gebildeten Deckschichten erlauben. In diesem Beitrag wird anhand verschiedener Deckschichtzustände an Zink der Mehrwert von gelartigen Elektrolyten für die Korrosionsforschung verdeutlicht. T2 - 16. Sommerkurs Werkstoffe und Fügen am Institut für Werkstoff- und Fügetechnik CY - Magdeburg, Germany DA - 08.09.2017 KW - Deckschichtbildung KW - Gelartige Elektrolyte KW - Korrosionsprüfung KW - Zinkdeckschichten KW - Corrosion testing KW - Gel-type electrolytes KW - Layer formation KW - Zinc coatings PY - 2017 SN - 978-3-944722-58-0 DO - https://doi.org/10.24352/UB.OVGU-2017-75 SP - 119 EP - 127 AN - OPUS4-41898 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Babutzka, Martin A1 - Mietz, Jürgen A1 - Burkert, Andreas T1 - Investigation of the salinization of steel surfaces in marine environment N2 - The salinization and contamination of metal surfaces by chloride-containing aerosols is of great importance with regard to corrosion phenomena of damaged coated metal surfaces and stainless steels in the maritime sector and in offshore applications. Detailed questions have to be answered to clarify whether and to what extent salinization of the surface has an influence on the adhesion and durability of coatings in repairing applications and on pitting occurrence on stainless steels under atmospheric conditions. The questions arise which degree of salinization is reached after which period of time and how a defined and reproducible salinization can be simulated in the laboratory for further systematic investigations. The article is dedicated to these questions. Results of a field trial on the Island of Heligoland are presented and a simple procedure for a defined loading of metal surfaces with chlorides at a laboratory scale using a design of experiments (DoE) approach is introduced. KW - Maritime Atmosphäre KW - Versalzung KW - Maritime atmosphere KW - Salinization PY - 2018 DO - https://doi.org/10.1002/maco.201810636 SN - 0947-5117 SN - 1521-4176 VL - 70 IS - 6 SP - 1016 EP - 1025 PB - Wiley-VCH Verlag CY - Weinheim AN - OPUS4-47727 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Langklotz, U. A1 - Babutzka, Martin A1 - Schneider, M. A1 - Burkert, Andreas T1 - The combination of minimally invasive electrochemical investigations and FTIR‐spectroscopy to analyze atmospheric corrosion product layers on zinc N2 - The present work describes the combination of electrochemical investigations by using a gel‐type electrolyte with Fourier‐transformed infrared spectroscopy to investigate partially extremely thin corrosion product films on titanium‐zinc. The gel pad method enables the determination of corrosion relevant parameters such as the potential and the linear polarization resistance without altering the corrosion product layers, which are extremely prone to re‐dissolution when freshly formed. Complementary infrared spectroscopy enables the determination of main compounds of even very thin surface layers of few tenth of nanometers with a certain lateral resolution. It was found that zinc forms mostly zinc carboxy‐hydroxides such as hydrozincite, under various exposure conditions. The protective properties of these hydrozincite layers depend on the structure of the corrosion product film rather than on its thickness. In mid‐term exposure tests, shallow corrosion pits were found even in the absence of corrosive agents such as chloride. KW - Gel-type electrolytes KW - Gelartige Elektolyte KW - Zinc coatings KW - Zinkdeckschichten KW - Korrosionsprüfung KW - Corrosion testing KW - FT-IR PY - 2019 DO - https://doi.org/10.1002/maco.201810696 SN - 0947-5117 SN - 1521-4176 VL - 70 IS - 7 SP - 1314 EP - 1325 PB - Wiley-VCH Verlag CY - Weinheim AN - OPUS4-47728 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Reinemann, Steffi A1 - Lehmann, Jens A1 - Rosemann, Paul A1 - Babutzka, Martin A1 - Bohlmann, Tatjana A1 - Burkert, Andreas T1 - Optimierung industrieller Korundschleifprozesse zur Sicherstellung der Korrosionsbeständigkeit nichtrostender Stähle N2 - Durch eine breite Beteiligung von Schleifmittelherstellern, -anwendern und wissenschaftlichen Einrichtungen im projektbegleitenden Ausschuss (PA) konnte der vielschichtige Themenkomplex „Schleifen“ im Kontext zu den Projektzielen umfassend untersucht werden. Es wurden praxisrelevante Parameterfelder definiert, die eine erfolgreiche Aufklärung der Projektfragestellung ermöglichten. Im Zuge der Untersuchungen wurde ein signifikanter Einfluss beim Einsatz von Granulatschleifbändern auf das Korrosionsverhalten geschliffener Oberflächen festgestellt. Damit zeigten geschliffene Oberflächen regelmäßig eine schlechtere Korrosionsbeständigkeit als Oberflächen, die mit sonst gleichen Parametern mit einlagig gestreuten Bändern bearbeitet wurden. Die durch einige Untersuchungsergebnisse aus vorangegangenen AiF-Vorhaben ursprünglich verfolgte These, dass Unterschiede in der Korrosionsbeständigkeit auf die Kornart der Schleifmittel Korund bzw. SiC zurückzuführen ist, konnte nur bedingt bestätigt werden. Bei den systematischen Untersuchungen innerhalb dieses Projektes erwies sich der Einfluss der Kornart im Vergleich zum Einfluss des Schleifbandtyps (Granulat bzw. einlagig gestreutes Korn) als weniger relevant. Durch weiterführende Untersuchungen konnten auf Oberflächen, die mit Granulatschleifbändern bearbeitet wurden, große Materialaufplattungen aus Eigenmaterial festgestellt werden. Das Eigenmaterial wird dabei im Schleifprozess zunächst abgetragen und aufgrund der Topografie des Schleifbandes zeitweise auf den Bändern festgehalten. Später lösen sich diese Materialanhäufungen vom Band ab und können prozessbedingt durch Wärme- und Krafteinwirkung auf den bearbeiteten Oberflächen aufgeplattet werden. Durch REM und KorroPad Untersuchungen ließen sich Bereiche mit solchen Eigenmaterialaufplattungen eindeutig als wesentliche Ausgangspunkte für Korrosionsprozesse identifizieren. Das aufgeplattete Material ist stark verformt, thermisch beeinflusst und bildet eine Spaltgeometrie zur Bauteiloberfläche aus. Diese Veränderungen führen zur Störung der Passivschichtausbildung in diesen Bereichen und verursachen damit eine erhöhte Korrosionsanfälligkeit der Oberflächen. Durch gezielte Nachbearbeitungsprozesse ist es möglich, die Eigenmaterialaufplattungen von den Oberflächen zu entfernen. Im Rahmen des Vorhabens wurde dazu eine Nachbearbeitung mittels Schleifvlies geprüft, die zu einer Entfernung der Eigenmaterialaufplattungen und damit zu einer Wiederherstellung der erwarteten Korrosionsbeständigkeit führte. Wird der Endschliff von Oberflächen mit einlagig gestreutem Korn ausgeführt, sind ebenfalls keine korrosionsrelevanten Materialaufplattungen zu erwarten. Die in einem vorhergehenden AiF Vorhaben IGF 17136 N/1 entwickelte Methode der KorroPad-Prüfung konnte auch hier erfolgreich für die Untersuchung der Auswirkung unterschiedlicher Prozessparameter auf die Korrosionsbeständigkeit der Oberflächen eingesetzt werden. Zudem erwies sich das EPR-SL-Verfahren als ein weiterer Ansatz, um die Passivschichtstabilität verschieden geschliffener Oberflächen vergleichend untersuchen zu können. Mit den nun vorliegenden Erkenntnissen können kmU künftig durch Anpassungen und Optimierung von Schleifprozessen eine gute Korrosionsbeständigkeit der bearbeiteten Oberflächen sicherstellen. Die Optimierung der Prozessparameter und -schritte kann durch den Einsatz der KorroPad-Prüfung Inhouse erfolgen und somit die laufende Fertigung im Rahmen der Qualitätsprüfung überwacht und dokumentiert werden. KW - KorroPad KW - Korrosion KW - Korrosionsbeständigkeit KW - Korrosionsschutz KW - Verfleckungen KW - Nichtrostender Stahl KW - Schleifen KW - Oberfläche PY - 2019 SP - 1 EP - 74 AN - OPUS4-47729 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reinemann, Steffi A1 - Rosemann, P. A1 - Babutzka, Martin A1 - Lehmann, Jens A1 - Burkert, Andreas T1 - Influence of grinding parameters on the corrosion behavior of austenitic stainless steel N2 - Samples of the austenitic stainless steel grade X5CrNi18‐10 (1.4301, AISI 304) were ground industrially with various grinding parameters to study their influence on corrosion resistance. The ability of the mechanically ground surfaces to form a stable passive layer was evaluated by KorroPad test and a modified electrochemical potentiodynamic reactivation test based on a single loop (EPR‐SL). Furthermore, the surfaces were characterized by surface analytical methods. The main influence was determined regarding abrasive belt type. Surfaces mechanically ground with granulate abrasive belts constantly had a lower corrosion resistance than surfaces ground with single‐coated grain. The granulate abrasive belts generated more sensitized surface areas and left formations of welded sample material on the mechanically ground surfaces. A post‐treatment with a nonwoven abrasive proved to be an effective finishing process by which the surface defects and sensitized material got removed and the surfaces regained the expected corrosion resistance. KW - Abrasive belt KW - Austenitic stainless steel KW - Electrochemical potentiodynamic reactivation KW - Grinding KW - KorroPad KW - Surface KW - Corrosion PY - 2019 DO - https://doi.org/10.1002/maco.201910874 SN - 0947-5117 SN - 1521-4176 VL - 70 IS - 10 SP - 1776 EP - 1787 PB - Wiley-VCH Verlag CY - Weinheim AN - OPUS4-47871 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emamverdi, Farnaz A1 - Huang, J. A1 - Szymoniak, Paulina A1 - Bojdys, M. J. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Structure and molecular mobility of phosphinine-based covalent organic frameworks – glass transition of amorphous COFs N2 - Two-dimensional covalent organic frameworks (COFs) based on phosphinine and thiophene building blocks have been synthesized with two different side groups. The materials are denoted as CPSF-MeO and CPSF-EtO where CxxF correspond to the covalent framework, whereas P and S are related to heteroatoms phosphorous and sulfur. MeO and EtO indicate the substituents, i.e. methoxy and ethoxy. Their morphologies were studied by scanning electron microcopy and X-ray scattering. The absence of crystalline reflexes in the X-ray pattern reveal that both materials are amorphous and can be considered as glasses. Furthermore, N2 adsorption measurements indicate substantial Brunauer–Emmett–Teller (BET) surface area values pointing to the formation of three-dimensional pores by stacking of the aromatic 2D layer. An analysis of the porosity of both COFs showed a mean radius of the pores to be of ca. 4 nm, consistent with their chemical structure. The COFs form nanoparticles with a radius of around 100 nm. The thermal behavior of the COFs was further investigated by fast scanning calorimetry. These investigations showed that both COFs undergo a glass transition. The glass transition temperature of CPSF-EtO is found to be ca. 100 K higher than that for CPSF-MeO. This large difference in the glass transition is discussed to be due to a change in the interaction of the COF sheets induced by the longer ethoxy group. It might be assumed that for CPSF-EtO more individual COF sheets assemble to larger stacks than for CPSF-MeO. This agrees with the much larger surface area value found for CPSF-EtO compared to CPSF-MeO. To corroborate the results obtained be fast scanning calorimetry dielectric measurements were conducted which confirm the occurrence of a dynamic glass transition. The estimated temperature dependence of the relaxation rates of the dielectric relaxation and their absolute values agrees well with the data obtained by fast scanning calorimetry. Considering the fragility approach to the glass transition, it was further found that CPSF-MeO is a fragile glass former whereas CPSF-EtO behaves as a strong glass forming material. This difference in the fragility points also to distinct differences in the interaction between the 2D COF molecules in both materials. KW - Covalent Organic frameworks PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596770 DO - https://doi.org/10.1039/d3ma01123b SP - 1 EP - 10 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59677 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Szymoniak, Paulina A1 - Kolmangadi, Mohamed A. A1 - Juranyi, Fanni A1 - Böhning, Martin A1 - Zorn, Reiner A1 - Schönhals, Andreas T1 - Low-Frequency Vibrational Density of State of Janus-Polynorbornenes: The Dependence of the Boson Peak on the Nanophase-Separated Structure N2 - Inelastic incoherent neutron time-of-flight scattering was employed to investigate the low-frequency vibrational density of states (VDOSs) for a series of glassy Janus-poly(tricyclononenes), which consist of a rigid main chain and flexible alkyl side chains. Here, the length of the flexible side chains was systematically varied from propyl to octyl. Such materials have potential applications as active separation layers in gas separation membranes as a green future technology, especially for the separation of higher hydrocarbons. From the morphological point of view, the Janus polynorbornenes undergo a nanophase separation into alkyl side chain-rich nanodomains surrounded by a rigid polynorbornene matrix. Here, the influence of the nanophase-separated structure on the low-frequency VDOS is investigated from a fundamental point of view. The low-frequency VDOSs of these Janus polynorbornene show excess contributions to the Debye type VDOS known as the Boson peak (BP) for all side chain lengths. Due to the high incoherent scattering cross-section of hydrogen, most of the scattering comes from the alkyl side chain-rich domains. Compared to conventional glass-forming materials, in the considered Janus polynorbornenes, the BP has a much lower intensity and its frequency position is shifted to higher values. These experimental results are discussed in terms of the nanophase-separated structure where the alkyl chain-rich domains were constrained by the surrounding matrix dominated by the rigid backbone. With increasing alkyl chain length, the size of the alkyl chain-rich domains increases. The frequency position of the BP shifts linearly to lower frequencies with the size of these nanodomains estimated from X-ray measurements. The obtained results support the sound wave interpretation to the BP KW - Inelastic neutron scattering PY - 2023 DO - https://doi.org/10.1021/acs.macromol.3c00913 SN - 0024-9297 SP - 1 EP - 10 PB - ACS AN - OPUS4-57972 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Taffe, Alexander A1 - Maierhofer, Christiane A1 - Krause, Martin A1 - Gardei, André A1 - Niederleithinger, Ernst A1 - Hasenstab, Andreas A1 - Hemmleb, Matthias A1 - Wiggenhauser, Herbert A1 - Borchardt, Kerstin T1 - ZfPBau-Kompendium 2004 N2 - Dieses Kompendium ist ein kurzgefasster Abriss, ein Leitfaden und auch ein Handbuch der für den Einsatz im Bauwesen geeigneten zerstörungsfreien Prüfverfahren. In strenger, stets gleicher Gliederung wird jede der mehr als 100 Untersuchungsmethoden in einem eigenen Geräteblatt beschrieben. Hinzu kommen Querverweise zu alternativen Prüfmethoden sowie zahlreiche Hinweise auf einschlägige Fachliteratur und zu bekannt gewordenen Geräteherstellern, Lieferanten und Dienstleistern. PY - 2007 N1 - Das "ZfPBau-Kompendium 2004" war eine Datenbank, die von 2007 bis 2015 im Internet verfügbar war; sie wurde ersatzlos vom Netz genommen, als sie nicht mehr aktuell war – The "ZfPBau-Kompendium 2004" was a database that was accessible on the internet from 2007 to 2015; it was deleted without replacement when it wasn't up-to-date anymore PB - Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-1497 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Casperson, Ralf A1 - Knöppchen, Andreas A1 - Pohl, Rainer A1 - Zimne, Lutz A1 - Bode, Johannes A1 - Hollesch, Martin T1 - Manufacturing of reference defects for NDT using low-energy EDM N2 - For non-destructive testing (NDT) appropriate reference blocks are required in order to verify and calibrate a testing procedure. At BAM a special electric discharge machining (EDM) system has been developed which is able to manufacture artificial defects having a width down to 30 μm. Especially in the case of austenitic materials conventional EDM leads to a transformation of austenite to martensite. The martensite transformation causes a higher sensitivity of electromagnetic NDT methods (e. g. eddy current testing) at the artificial defects compared to natural defects of same size. The EDM system developed at BAM uses very low energy to avoid this material transformation. A side effect of the low-energy EDM is a lower surface roughness compared to conventional EDM. The artificial defects manufactured at BAM are measured optically and delivered with a certificate. A comparison of artificial defects shows the influence of material transformation on NDT and how differently the quality of the artificial defects can be. T2 - 19th World Conference on Non-Destructive Testing CY - Munich, Germany DA - 13.06.2016 KW - Reference defect KW - EDM KW - Electric discharge machining KW - Artificial defect PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365995 SN - 978-3-940283-78-8 VL - 157 SP - 1 EP - 10 PB - German Society for Non-Destructive Testing (DGZfP e.V.) CY - Berlin, Germany AN - OPUS4-36599 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Polte, Jörg A1 - Herder, Martin A1 - Erler, Robert A1 - Rolf, Simone A1 - Fischer, A. A1 - Würth, Christian A1 - Thünemann, Andreas A1 - Kraehnert, R. A1 - Emmerling, Franziska T1 - Mechanistic insights into seeded growth processes of gold nanoparticles N2 - A facile approach for the synthesis of monodisperse gold nanoparticles with radii in the range of 7 to 20 nm is presented. Starting from monodisperse seeds with radii of 7 nm, produced in the first step, the addition of a defined amount of additional precursor material permits distinct size regulation and the realization of predicted nanoparticle sizes. These information were derived from ex- and in situ investigations by comprehensive small angle X-ray scattering (SAXS), X-ray absorption near edge structure (XANES) and UV-Vis data to obtain information on the physicochemical mechanisms. The obtained mechanisms can be transferred to other seeded growth processes. Compared to similar approaches, the presented synthesis route circumvents the use of different reducing or stabilizing agents. The size of resulting nanoparticles can be varied over a large size range presented for the first time without a measurable change in the shape, polydispersity or surface chemistry. Thus, the resulting nanoparticles are ideal candidates for size dependence investigations. KW - Gold nanoparticles KW - SAXS KW - XANES KW - Growth mechanism PY - 2010 DO - https://doi.org/10.1039/c0nr00541j SN - 2040-3364 SN - 2040-3372 VL - 2 IS - 11 SP - 2463 EP - 2469 PB - RSC Publ. CY - Cambridge AN - OPUS4-22346 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Wilrich, Cordula A1 - Schröder, Volkmar A1 - Brandes, E. A1 - Schmidt, Martin A1 - Wandrey, Peter-Andreas A1 - Mix, K.-H. A1 - Wehrstedt, Klaus-Dieter A1 - Bender, H. A1 - Stephan, U. A1 - Eberz, A. A1 - Steinbach, J. A1 - Stoessel, F. T1 - Plant and process safety - 2. Hazardous materials and process conditions N2 - "Ullmann's Encyclopedia of Industrial Chemistry" is the benchmark reference in chemistry and chemical and life science engineering, covering inorganic and organic chemicals, advanced materials, pharmaceuticals, polymers and plastics, metals and alloys, biotechnology and biotechnological products, food chemistry, process engineering and unit operations, analytical methods, environmental protection, and much more. The present article is part of the topic collection "Environmental Protection and Industrial Safety". It covers plant and process safety, focusing on hazardous materials and process conditions. KW - Flammable gases and vapors KW - Combustibility of liquids KW - Dust explosions KW - Explosive condensed substances KW - Harmful effects of substances KW - Exothermic and pressure-inducing chemical reactions PY - 2012 SN - 978-3-527-30673-2 DO - https://doi.org/10.1002/14356007.q20_q01 SP - 1 EP - 50 PB - Wiley-VCH CY - Weinheim AN - OPUS4-58108 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emamverdi, Farnaz A1 - Huang, J. A1 - Mosane Razavi, Negar A1 - Bojdys, M. J. A1 - Forster, A. B. A1 - Budd, P. M. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Molecular Mobility and Gas Transport Properties of Mixed Matrix Membranes Based on PIM‑1 and a Phosphinine Containing Covalent Organic Framework N2 - Polymers with intrinsic microporosity (PIMs) are gaining attention as gas separation membranes. Nevertheless, they face limitations due to pronounced physical aging. In this study a covalent organic framework containing λ5-phosphinine moieties, CPSF-EtO were incorporated as a nanofiller (concentration range 0-10 wt%) into a PIM-1 matrix forming dense films with a thickness of ca. 100 μm. The aim of the investigation was to investigate possible enhancements of gas transport properties and mitigating effects on physical aging. The incorporation of the nanofiller occurred on aggregate level with domains up to 100 nm as observed by T-SEM and confirmed by X-ray scattering. Moreover, the X-ray data show that the structure of the microporous network of the PIM-1 matrix is changed by the nanofiller. As the molecular mobility is fundamental for gas transport as well as for physical aging, the study includes dielectric investigations of pure PIM-1 and PIM-1/CPSF-EtO mixed matrix membranes to establish a correlation between the molecular mobility and the gas transport properties. Using the time-lag method the gas permeability and the permselectivity were determined for N2, O2, CH4 and CO2 for samples with variation in filler content. A significant increase in the permeability of CH4 and CO2 (50 % increase compared to pure PIM-1) was observed for a concentration of 5 wt% of the nanofiller. Furthermore, the most pronounced change in the permselectivity was found for the gas pair CO2/N2 at a filler concentration of 7 wt%. KW - Polymers of Intrinsic Microporosity KW - Nanocomposites PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595031 DO - https://doi.org/10.1021/acs.macromol.3c02419 SN - 0024-9297 VL - 57 IS - 4 SP - 1829 EP - 1845 PB - ACS Publications AN - OPUS4-59503 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -