TY - GEN A1 - Jacobasch, Stefan A1 - Duffner, Eric A1 - Goedecke, Thomas A1 - Portella, Pedro Dolabella A1 - Mair, Georg W. A1 - Schendler, Thomas A1 - Gradt, Thomas A1 - Askar, Enis A1 - Bartholmai, Matthias A1 - Schröder, Volkmar A1 - Maiwald, Michael A1 - Holtappels, Kai A1 - Tschirschwitz, Rico A1 - Neumann, Patrick P. T1 - Unser Beitrag zum Thema Wasserstoff N2 - Die BAM ist nahezu über die gesamte Wertschöpfungskette hinweg wissenschaftlich tätig. Von der sicheren und effizienten Wasserstofferzeugung (POWER-to-GAS), über die (Zwischen-)Speicherung von Wasserstoff in Druckgasspeichern bis hin zum Transport bspw. mittels Trailerfahrzeug zum Endverbraucher. Komplettiert werden die Aktivitäten der BAM durch die sicherheitstechnische Beurteilung von wasserstoffhaltigen Gasgemischen, die Verträglichkeitsbewertung von Werkstoffen bis hin zur Detektion von Wasserstoffkonzentrationen über geeignete Sensorik, auch mittels ferngesteuerter Messdrohnen (sog. UAV-Drohnen). Zudem untersucht die BAM proaktiv Schadensrisiken und Unfallszenarien für die Sicherheitsbetrachtung, um mögliche Schwachstellen aufzeigen und potenzielle Gefährdungen erkennen zu können. KW - Wasserstoff KW - Wasserstofferzeugung KW - Energiespeicherung KW - Gasdetektion KW - Risikoanalyse KW - Power-to-Gas KW - Explosionsschutz KW - Tribologie KW - Druckgasspeicher KW - Glasspeicher KW - Gassensorik KW - Mini-UAV PY - 2019 SP - 1 CY - Berlin AN - OPUS4-47960 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, Thomas A1 - Vierneusel, B. A1 - Gradt, Thomas A1 - Tremmel, S. A1 - Wartzack, S. A1 - Szücs, Z. A1 - Arendt, I. T1 - Optimierte MoS2-PVD-Schichten für wechselnde Umgebungsbedingungen N2 - Der Festschmierstoff Molybdändisulfid ist insbesondere für Extremanwendungen ein gerne eingesetzter Werkstoff, problematisch ist jedoch der negative Einfluss von Feuchtigkeit. Bei mittels PVD-Verfahren abgeschiedenen MoS2-Schichten ergibt sich jedoch die Möglichkeit, durch Anpassung der Beschichtungsparameter vorwiegend basal ausgerichtete Schichten herzustellen, die auch an Luft ein verbessertes tribologisches Verhalten zeigen. N2 - The solid lubricant molybdenum disulfide is a well known material for extreme conditions, but Problems arise due to a negative effect of humidity. However, by using a PVD process, deposition parameters can be optimized to gain coatings with a more textured structure orienting the basal planes parallel to the Substrate surface. Therefore, an improved tribological behavior even under moist conditions can be achievcd. KW - MoS2-coatings KW - PVD-process KW - Tribology KW - Moisture KW - Cryogenic temperatures KW - MoS2-Beschichtungen KW - PVD KW - Tribologie KW - Luftfeuchte KW - Kryogene Temperaturen PY - 2013 SN - 0724-3472 VL - 60 IS - 4 SP - 18 EP - 23 PB - Expert Verlag CY - Renningen AN - OPUS4-29995 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, Thomas A1 - Gradt, Thomas A1 - Vierneusel, B. A1 - Tremmel, S. A1 - Wartzack, S. T1 - Tribological behavior of MoS2 in hydrogen environment N2 - The solid lubricant molybdenum disulfide is a well known material for extreme conditions where conventional oil or grease lubrication is not feasible (vacuum, high pressures). However, under reactive environments e.g. high humidity or hydrogen MoS2 is prone to premature failure. By using a PVD process, deposition parameters can be optimized to gain coatings with a more textured structure orienting the basal planes parallel to the Substrate surface, A similar concept has been used by Koch et al. for coatings developed to withstand the extreme operational conditions of the WENDELSTEIN W7-X fusion experiment. Therefore, an improved tribological behavior even under adverse conditions can be achieved. T2 - WTC 2013 - 5th World tribology congress CY - Torino, Italy DA - 08.09.2013 KW - Tribologie KW - Festschmierstoffe KW - MoS2 KW - Wasserstofftechnologie PY - 2013 SP - 1 EP - 3 AN - OPUS4-31156 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Deutsch, Cornelius A1 - Gradt, Thomas A1 - Orts Gil, Guillermo A1 - Schneider, Thomas A1 - Dmitriev, A.I. T1 - Tribological screening tests for the selection of raw materials for automotive brake pad formulations N2 - A modified pin-on-disc test was applied to determine tribological properties of typical brake pad constituents. Ball-milling of these ingredients together with iron oxide and graphite provided model materials displaying the main features of real third bodies. Solid lubricants like graphite affected the friction and wear behaviour of Fe3O4 powders considerably whereas further addition of hard nanoparticles induced only minor effects. This was corroborated by comparison with modelling results. MoS2 played a dual role. Depending on special conditions, this ingredient either reduced or increased friction. The latter could be explained, after nanoscopic characterization, by oxidation and destruction of the wear-protecting tribofilm. KW - Brake pad formulation KW - Raw materials KW - Third body KW - Pin-on-disc test PY - 2014 DO - https://doi.org/10.1016/j.triboint.2014.01.017 SN - 0301-679X VL - 73 SP - 148 EP - 155 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-30221 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Österle, Werner A1 - Deutsch, Cornelius A1 - Dörfel, Ilona A1 - Gradt, Thomas A1 - Häusler, Ines A1 - Orts-Gil, G. A1 - Prietzel, C. A1 - Schneider, Thomas T1 - Final outcome of a fundamental research project on tribofilms formed during automotive braking, Part 1: Experimental studies N2 - In order to obtain a better understanding of the role of tribofilms during automotive braking, their structures were investigated and the essential features identified. Next, different ingredient combinations were studied by preparing some model materials with simpler compositions than real tribofilms. A test method was developed for verifying the tribological properties of the model materials and for comparison with results obtained with numerical sliding simulations of such structures. Prerequisites of good brake Performance properties were identified. Although the coefficient of friction could be varied in a wide ränge, smooth sliding conditions could only be achieved with values smaller than 0.4. Tests with artificial third body powders turned out to be useful as screening method for the selection of raw materials for brake pad formulations. T2 - EuroBrake 2014 CY - Lille, France DA - 13.05.2014 KW - Tribofilm KW - Third body KW - Pad ingredients KW - Ball milling KW - Pin-on-disc test PY - 2014 SN - 978-0-9572076-4-6 SP - 1 EP - 8 PB - FISITA CY - London AN - OPUS4-35039 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gradt, Thomas A1 - Aßmus, Kristin A1 - Börner, Helmut A1 - Schneider, Thomas T1 - Apparatus for friction tests of support elements in fusion devices N2 - Spacers and supports belong to the critical elements in the structure of a nuclear fusion device, particularly, when they are installed in the vacuum or superconducting magnet system of the reactor. These supports have to sustain high loads while allowing a certain amount of tangential movement with low friction and without any stick-slip motion. Vacuum and cryogenic environments are extremely hostile for smooth sliding systems, because conventional liquid lubricants cannot be employed, and only a very limited number of materials for dry sliding systems under these conditions are available. In order to test the friction behaviour of support elements in the field coils of the fusion experiment WENDELSTEIN 7-X, a test rig was build which allows testing in liquid helium environment at 4.2 K, with a normal force up to 150 kN, and a sliding velocity of 0.1 mm/s in oscillating motion. First tests have shown that the apparatus is appropriate for simulating the sliding behaviour of support elements. As an example, a result of an earlier model test of an MoS2-coating is shown. KW - Tribologie KW - Vakuum KW - Kernfusion KW - Festschmierstoffe PY - 2008 DO - https://doi.org/10.1088/1742-6596/100/6/062032 SN - 1742-6588 SN - 1742-6596 VL - 100 IS - 062032 SP - 1 EP - 4 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-17369 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gradt, Thomas A1 - Schneider, Thomas A1 - Lingertat, J. A1 - Hathiramani, D. A1 - Junghanns, P. A1 - Aßmus, Kristin A1 - Schauer, F. T1 - Cryogenic vacuum tests of scaled down narrow support elements for the W7-X coil system KW - Wendelstein 7-X KW - Magnet system KW - Narrow support elements KW - Friction KW - MoS2 PY - 2009 DO - https://doi.org/10.1016/j.fusengdes.2008.11.075 SN - 0920-3796 VL - 84 IS - 2-6 SP - 840 EP - 843 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-19662 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lingertat, J. A1 - Gradt, Thomas A1 - Hathiramani, D. A1 - Junghanns, P. A1 - Laux, M. A1 - Meine, Kerstin A1 - Schauer, F. A1 - Schneider, Thomas T1 - Tribological performance of MoS2 coatings in liquid helium and at high loads N2 - The main part of a narrow support element (NSE) of the W7-X superconducting coil system is an aluminium bronze pad, PVD coated on its spherical surface with MoS2, which slides against the flat surface of the stainless steel coil housing, coated with MoS2 spray. The operational requirements of the NSEs are: vacuum of p < 10-6 mbar, temperature T ~4 K, maximum load P ~1500 kN, typical displacement ≤5 mm, smooth sliding and no stick-slip events. The paper describes test results obtained with a downscaled NSE at T = 4.2 and 77 K. During the test the NSEs were submerged in liquid helium and nitrogen, respectively. Whereas the LN2 test ran smoothly for up to ~15,000 cycles, the test in LHe showed stick-slip from the very first cycle. The stick-slip disappeared after ~50 cycles. Post mortem analysis of the tested parts revealed that in case of LHe the sprayed MoS2 film was removed during the first 30-100 cycles by blistering and flaking. The reason for the loss of adhesion at LHe temperature is not known, several possible causes are under discussion. Further experiments under vacuum and at T ~4 K are being prepared which are expected to help in clarifying the issue. KW - Stellarator KW - Wendelstein 7-X KW - Mechanical structure KW - Narrow support elements KW - MoS2 KW - Lubrication KW - T=4K PY - 2009 DO - https://doi.org/10.1016/j.fusengdes.2009.01.069 SN - 0920-3796 VL - 84 IS - 7-11 SP - 1192 EP - 1196 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-19745 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas A1 - Schneider, Thomas A1 - Lingertat, J. A1 - Hathiramani, D. T1 - MoS2-Schmierung für hochbelastete Stützelemente zwischen supraleitenden Magnetspulen T2 - 49. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendungen CY - Göttingen, Deutschland DA - 2008-09-22 KW - Tribologie KW - Molybdändisulfid KW - Stick-Slip KW - Supraleitung KW - Kernfusion PY - 2008 SN - 978-3-00-025676-9 VL - I SP - 13/1 EP - 13/10 AN - OPUS4-18366 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gradt, Thomas A1 - Schneider, Thomas A1 - Lingertat, J. A1 - Hathiramani, D. A1 - Schauer, F. T1 - MoS2-Schmierung für hochbelastete Stützelemente zwischen supraleitenden Magnetspulen KW - Kernfusion KW - Supraleitende Magnete KW - Kryotribologie KW - Vakuumtribologie KW - Stick-Slip KW - MoS2 PY - 2009 SN - 0724-3472 VL - 56 IS - 5 SP - 24 EP - 28 PB - Expert Verlag CY - Renningen AN - OPUS4-20726 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Vierneusel, B. A1 - Schneider, Thomas A1 - Tremmel, S. A1 - Wartzack, S. A1 - Gradt, Thomas T1 - Humidity resistant MoS2 coatings deposited by unbalanced magnetron sputtering N2 - MoS2 is a suitable solid lubricant for environments free of oxygen or water vapor (i.e. vacuum). Humid air degrades film properties due to oxidation accompanied by high wear and increasing coefficients of friction. The present study aims at the further development of sputtered pure MoS2 coatings, extending their applicability to varying environmental conditions by increasing the resistance against humidity. The systematic coating development process is supported by using an experimental Box–Behnken design with variations of the deposition parameters cathode voltage, target/substrate distance, temperature and argon gas pressure. In contrast to common one-factor-at-a-time (OFAT) studies, this approach enables a determination of interactions between deposition process parameters and tribological–mechanical MoS2 film properties. The tribological improvement focuses on a maximization of wear resistance in air and vacuum measured in ball-on-disk experiments. The evaluated mechanical properties are hardness, elastic modulus and residual stresses. These stresses were determined by the substrate curvature method. The study reveals that the residual stress state in the films and the hardness-to-modulus ratio are crucial for their tribological performance in humid air and vacuum environments. After a detailed determination of the relationships between deposition conditions and film properties, some selected microstructural analyses are presented which show that a substantially basal orientation of the lattice has positive effects on wear but also causes anisotropic film properties which result in fissile fracture of the coating if strong shock or point loads occur. KW - Unbalanced magnetron sputtering KW - MoS2 KW - Humidity resistance KW - Residual stress PY - 2013 DO - https://doi.org/10.1016/j.surfcoat.2013.07.019 SN - 0257-8972 VL - 235 SP - 97 EP - 107 PB - Elsevier B.V. AN - OPUS4-29729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, Thomas A1 - Vierneusel, B. A1 - Gradt, Thomas A1 - Tremmel, S. A1 - Wartzack, S. A1 - Szücs, Z. A1 - Arendt, I. T1 - Optimierte MoS2-PVD-Schichten für wechselnde Umgebungsbedingungen N2 - Der Festschmierstoff Molybdändisulfid ist insbesondere für Extremanwendungen, bei denen konventionelle Öl- oder Fettschmierung nicht in Frage kommen (Vakuum, hohe Pressungen) ein gerne eingesetzter Werkstoff. Problematisch ist jedoch der negative Einfluss von Feuchtigkeit, wodurch die Einsetzbarkeit von M0S2 unter Normalbedingungen leidet. Bei mittels PVD-Verfahren abgeschiedenen MoSa-Schichten ergibt sich jedoch die Möglichkeit, durch Anpassung der Beschichtungsparameter vorwiegend basal ausgerichtete Schichten herzustellen, die auch an normal feuchter Luft ein verbessertes tribologisches Verhalten zeigen. MoSa-Schichten sind darüber hinaus auch für Anwendungen bei extrem tiefen Temperaturen interessant, da hier kein Schmierstoff zur Verfügung steht, der ähnlich günstige Reibeigenschaften aufweist. Für bewegliche Stützelemente zwischen supraleitenden Magnetspulen des Kernfusions-Experiments Wendelstein 7-X waren bis zu 7 pm dicke Schichten entwickelt worden, die jedoch durch das notwendige langsame Aufwachsen für andere Anwendungen nicht wirtschaftlich herzustellen waren. Hier sollen neue, im Rahmen eines Kooperationsprojekts entstandene MoS2-PVD-Schichten vorgestellt werden, die bei wechselnden Umgebungsbedingungen noch gute tribologische Eigenschaften liefern, jedoch durch ihre Dicke von 1-2 pm und hoher Aufwachsrate kostengünstig sind. N2 - The solid lubricant molybdenum disulfide is a well known material for extreme conditions where conventlonal oll or grease lubrication is not feasible (vacuum, high pressures). Problems arise due to a negative effect of humidity which is a drawback for the suitability of M0S2 under normal conditions. However, by using a PVD process, Deposition parameters can be optimized to gain coatings with a more textured structure orienting the basal planes parallel to the Substrate surface. Therefore, an improved tribological behavior even under moist conditions can be achieved. MoS2-coatings additionally are interesting candidates for being applied under cryogenic temperatures, since no lubricant is available having similarly favorable frictional properties. Up to 7 pm thick coatings have been developed especially for sliding support elements between superconducting magnets of the fusion-experiment Wendelstein 7-X, however, the extremely slow deposition rate precluded its utilization on more common tribo-systems due to cost considerations. Here, new MoS2-coatings are presented which were developed in a cooperational project, giving good tribological results under variing environments but are more cost effective being only 1-2 pm in thickness and faster in film growth.. T2 - 53. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß CY - Göttingen, Germany DA - 24.09.2012 PY - 2012 SN - 978-3-00-039201-6 SP - 46/1 EP - 46/12 CY - Aachen AN - OPUS4-26724 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gradt, Thomas A1 - Schneider, Thomas T1 - Tribological performance of MoS2 coatings in various environments N2 - Molybdenum disulfide (MoS₂) is a well-known solid lubricant for tribosystems running in vacuum or dry gases. Problems arise due to its sensitivity to humidity, which is a drawback for its application under ambient conditions. However, by using a physical vapor deposition (PVD) process, deposition parameters can be optimized not only to gain a coatings structure with favorable frictional properties but also to minimize the sensitivity to attack by water molecules. Therefore, an improved tribological behavior even under moist conditions can be achieved. MoS₂coatings are also candidates for being applied at cryogenic temperatures. They already have proven their suitability, e.g., for sliding support elements between superconducting magnets of the nuclear fusion-experiment Wendelstein 7-X. However, these coatings were exclusively produced for this particular application and the utilization for more common tribosystems may be precluded due to cost considerations. In view of a wider range of applications, pure and Cr containing PVD-MoS₂ coatings with an optimized structure were tested under varying environments including hydrogen gas and cryogenic temperatures. Results of the most promising variant are presented in this paper. KW - Solid lubrication KW - MoS2 KW - Extreme environments KW - Hydrogen KW - Cryogenic einvironment PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-381460 DO - https://doi.org/10.3390/lubricants4030032 SN - 2075-4442 VL - 32 IS - 4 PB - MPPI AG CY - Basel, Switzerland AN - OPUS4-38146 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Giovannozzi, A. A1 - Gradt, Thomas A1 - Häusler, Ines A1 - Rossi, A. A1 - Wetzel, B. A1 - Zhang, G. A1 - Dmitriev, A.I. T1 - Exploring the potential of Raman spectroscopy for the identification of silicone oil residue and wear scar characterization for the assessment of tribofilm functionality N2 - We applied a combination of Raman spectroscopy (RS) and cross-sectional transmission electron microscopy (X-TEM) to identify silicone oil residues and tribofilms at steel disc surfaces after tribological testing. Neither chemical cleaning nor mechanical removal of a 50 µm thick surface layer produced a surface without any silicone residue. Nevertheless, long-term tribological properties are not affected due to silicone degradation which has been proved by Raman spectroscopy. Excellent anti-wear and anti-friction properties of a nanocomposite at severe stressing conditions correlated with the formation of a silica-based tribofilm containing amorphous and graphite-like carbon nanoparticles. Since reliable carbon quantification by analytical TEM is difficult, RS is a useful complementary method for carbon identification at wear scars. KW - Raman spectroscopy KW - Cross-sectional TEM KW - Silicone oil residue KW - Tribofilm PY - 2015 DO - https://doi.org/10.1016/j.triboint.2015.04.046 SN - 0301-679X VL - 90 SP - 481 EP - 490 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-33421 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kröll, Mirco A1 - Grundtner, R. A1 - Pagano, F. A1 - Nyberg, E. A1 - Heino, V. A1 - Spaltmann, Dirk A1 - Gradt, Thomas T1 - Auswirkungen von vereinheitlichten Prozeduren auf tribologische Versuche N2 - Anerkannte Institutionen stellen ihre Kompetenzen auf dem Gebiet tribologischer Charakterisierungen Industrie und Forschung zur Verfügung (https://www.i-tribomat.eu/). Ein Aspekt hierbei ist eine tribologische Datenbank. Um die nötige Qualität der Daten sicherzustellen, sind vereinheitlichte Prozeduren erforderlich, in deren Auswirkungen dieser Vortrag einen Einblick gibt. T2 - 62. Tribologie-Fachtagung der Gesellschaft für Tribologie e. V. CY - Online meeting DA - 27.09.2021 KW - Datenbank KW - Tribologische Daten KW - Europäisches Tribologie-Zentrum PY - 2021 SN - 978-3-9817451-6-0 VL - 15 SP - 15/1 EP - 15/4 AN - OPUS4-53430 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hübler, Daniela A1 - Gradt, Thomas T1 - Effect of different binders and secondary carbides on NbC cermets T1 - Einfluss unterschiedlicher Binder und Sekundärkarbide auf NbC-Hartmetalle N2 - Due to the rapidly increasing price of tungsten carbide and the significant health risks associated with the wear products of WC-Co (Co3O4 and Wo3), an alternative is required. Niobium carbide (NbC) is well suited as a cutting tool due to its high melting point and low solubility in iron. So far, NbC-Ni cermets best met the requirements of high hardness and toughness. Various secondary carbides such as VC, Mo2C, TiC, but also WC were added to further improve the hardness. N2 - Aufgrund des rasanten Preisanstiegs von Wolframcarbid und signifikanter Gesundheitsrisiken, die mit den Verschleißprodukten von WC-Co-Hartmetallen (Co3O4 and Wo3) einhergehen, wird eine Alternative benötigt. Niobcarbid (NbC) ist als Zerspanwerkzeug aufgrund seiner hohen Schmelztemperatur und seiner geringen Löslichkeit in Eisen gut geeignet. Im Vergleich zu reinem NbC, führte eine vollständige Substitution von WC zu NbC-Co zu einem Anstieg der Zähigkeit und Festigkeit. Als alternative Binder wurden anschließend Nickel- und Eisengebundene Binder untersucht. Obwohl eisengebundene Hartmetalle im Vergleich zu NbC-Ni Hartmetallen eine ökonomische und kostengünstigere Alternative darstellen würden, zeigten sie einen höheren Reibkoeffizienten und eine höhere Verschleißrate. Bisher erfüllen die NbC-Ni-Hartmetalle die Anforderungen hinsichtlich einer hohen Härte und Zähigkeit am besten. Verschiedene Sekundärkarbide, wie VC, Mo2C, TiC, aber auch WC wurden zusätzlich hinzugefügt, um die Härte weiter zu steigern. Elementanalysen der NbC-Ni-MeC Hartmetalle (Me = Metall) zeigten, dass der Binder eine kubisch-flächenzentrierter Mischkristall ist, während die NbC Phase ein Mischkristall des Typs (Nb, Me)C ist. KW - Niobium carbide (NbC) KW - Cutting tool KW - Binders PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547202 DO - https://doi.org/10.1007/s10010-022-00583-1 SN - 0015-7899 VL - 86 IS - 2 SP - 197 EP - 211 PB - Springer CY - Berlin AN - OPUS4-54720 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Reibungszahlen von Holz-Holz- und Holz-Stahl-Kontakten für Stoßdämpfer von CASTOR-Behältern N2 - Holz wird vielfach in Stoßdämpfern von Transportbehältern für radioaktives Material eingsetzt. Dafür wird oftmals Fichtenholz verwendet. Die Reibung zwischen den dabei entstehenden Grenzflächen ist von entscheidender Bedeutung. Die Ergebnisse hierzu zeigen eine gleichmäßige, mit steigender Temperatur abfallende Reibung. T2 - 63. Tribologie Fachtagung CY - Göttingen, Germany DA - 26.09.2022 KW - Reibung KW - Hokz-Holz-Kontakte KW - Holz-Stahl-Kontakte KW - CASTOR-Behälter KW - Stoßdämpfer PY - 2022 AN - OPUS4-56018 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas A1 - Martin, Martin A1 - Gleim, Tobias T1 - Reibungszahlen von Holz-Holz- und Holz-Stahl-Kontakten für Stoßdämpfer von CASTOR-Behältern N2 - Holz wird vielfach in Stoßdämpfern von Transportbehältern für radioaktives Material eingesetzt. Dafür wird oftmals Fichtenholz verwendet, das in mehreren Lagen und senkrecht zueinander liegender Faserrichtung zwischen einer inneren und einer äußeren Stahlhülle eingebaut wird. Die Reibung zwischen den dabei entstehenden Grenzflächen ist von entscheidender Bedeutung für die Stoß- und Energieabsorption, z. B. bei einem Aufprall des Behälters auf eine harte Unterlage. Um detaillierte Informationen für entsprechende numerische Simulationen zu bekommen, wurden in dieser Arbeit die Reibungszahlen von Holz-Holz- und Holz-Stahl-Paarungen bei für derartige Behälter relevanten Beanspruchungsbedingungen im Temperaturbereich zwischen -40°C und 90°C gemessen. Die Ergebnisse zeigen eine gleichmäßige, mit steigender Temperatur abfallende Reibung, wobei die Werte für Holz-Stahl-Paarungen zwischen 0,43 bei -40°C und 0,22 bei 90°C sowie für Holz-Holz-Kontakte zwischen 0,3 bei -40°C und 0,24 bei 90°C liegen. T2 - 63. Tribologie-Fachtagung 2022 CY - Göttingen, Germany DA - 26.09.2022 KW - Reibung KW - Holz-Holz-Kontakte KW - Holz-Stahl-Kontakte KW - CASTOR-Behälter KW - Stoßdämpfer PY - 2022 SN - 978-3-9817451-7-7 SP - 23/1 EP - 23/4 AN - OPUS4-56021 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Tribologisches Verhalten von a-C:H- und ta-C-Schichten in Methan- und Wasserstoffumgebung N2 - Verschleißfeste Kohlenstoffschichten mit niedriger Reibung sind hervorragend für Anwendungen in der Erdgas- und Wasserstofftechnologie geeignet. Einige Varianten versagen jedoch in inerter Umgebung, was für die praktische Anwendung sehr nachteilig ist. Im Vortrag werden Beispiele aus Modellversuchen für verschiedene Varianten, auch für Flüssigmethan-Umgebung gezeigt. T2 - Workshop: Nachhaltigkeit durch Tribologische Schichten CY - Karlsruhe, Germany DA - 17.05.2022 KW - Reibung KW - Kohlenstoffschichten KW - Methan KW - Wasserstoff KW - Tribologie PY - 2022 AN - OPUS4-56014 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - MoS2-Coatings for support elements in the Wendelstein 7-X nuclear fusion experiment N2 - The magnetic plasma confinement system of the nuclear fusion experiment “Wendelstein 7-X”, which recently produced the first plasma, consists of 20 planar and 50 non-planar superconducting coils. To keep them precisely in position, these coils contact each other at special support elements. The supports are operated in high vacuum at a temperature of about 4 K, and when the magnetic field is ramped up, forces up to 1500 kN and sliding motion of some mm occurs. Because mechanical disturbances may cause severe failures, only low friction without any stick-slip behaviour is tolerable. In pre-tests a PVD-MoS2-coating had proven to be the optimum solution. It was tested with downsized samples in reciprocating motion in liquid nitrogen (T = 77 K) and liquid helium (T = 4,2 K). In long-term tests in liquid nitrogen this coating showed stable sliding for up to 14.900 friction cycles without coating failure. However, in liquid helium an unexpected stick-slip effect occurred, whose origin could not be clarified so far. T2 - BAM Kolloquium Abteilung Werkstofftechnik CY - Berlin, Germany DA - 09.06.2016 KW - Kernfusion KW - Magnetischer Einschluss KW - Supraleitende Magnete KW - Tribologie KW - Festschmierstoffe KW - Magnetic confinement KW - Tribology KW - Lubricants KW - Superconducting magnet KW - Nuclear fusion PY - 2016 AN - OPUS4-38140 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wolter, Christian A1 - Österle, Werner A1 - Gradt, Thomas T1 - Metal sulphides as friction stabilisers under variable humidity N2 - Neben Kohlenstoff werden Metallsulfide in jeder Standardrezeptur für Bremsbeläge als Reibungsstabilisatoren verwendet. Um deren Wirkung zu untersuchen, wurden verschiedene Pulvermischungen in einer Stift-Scheibe-Anordnung tribologisch beansprucht, um künstliche dritte Körper zu erzeugen und zu testen, deren definierte Zusammensetzungen aus drei wichtigen Bestandteilen einer realen Reibschicht bestehen: Magnetit, Graphit und div. Metallsulfide. N2 - Besides carbon, metal sulphides are used in every standard brake pad formulation as friction stabilisers. In order to investigate their impact, various powder mixtures were tribologically stressed in a pin-on-disc device in order to produce and test artificial third bodies. containing the three main components of a real friction film, namely magnetite, graphite and a metal sulphide of interest. Since the sliding behaviour is influenced by the relative humidity the powder mixtures are tested at low, medium and high moisture levels. The tests revealed that the presence of graphite dominates the friction behaviour as well as the humidity sensitivity. The powders were prepared by either manual mixing or high energy ball-milling. Interestingly, all ball-milled blends provided coefficients of friction within the desired range for braking, which was attributed to the effect of zirconia particles from wear debris of the milling balls. The zirconia particles prevent the formation of solid lubricant films on the surfaces and support a homogeneous mixture of all constituents of the powder. Optimum brake performance is gained by an optimum combination of solid lubricants and abrasives. T2 - 57. Tribologie-Fachtagung CY - Göttingen, Germany DA - 26.09.2016 KW - Friction KW - Metal sulphides KW - Brake pad formulation PY - 2016 SN - 978-3-9817451-1-5 SP - 1.5/1 EP - 1.5/6 AN - OPUS4-37838 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Dörfel, Ilona A1 - Wollenschläger, Nicole A1 - Gradt, Thomas A1 - Wolter, Christian A1 - Reinstädt, Philipp A1 - Zeigmeister, U. A1 - Dmitriev, A. I. A1 - Nikonov, A. Y. T1 - Potential of different nickel coatings for optimizing the sliding behavior of electrical connectors N2 - The potential of several nickel coatings was investigated by reciprocating sliding tests against copper thus simulating the plug-socket system of an electrical connector. KW - Electrical connectors KW - Electro-plated nickel coatings KW - Electroless Ni-P KW - Cold-welding KW - Tribooxidation PY - 2018 DO - https://doi.org/10.1016/j.triboint.2018.01.006 SN - 0301-679X SN - 1879-2464 VL - 120 SP - 491 EP - 501 PB - Elsevier Ltd. AN - OPUS4-44468 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gradt, Thomas A1 - Scheuerlein, Ch. A1 - Lackner, F. A1 - Savary, F. T1 - Friction coefficient between the Ti6Al4V loading pole and the 316LN steel shims of the HL-LHC 11 T magnets N2 - The paper deals with a tribosystem in the magnet system of the Large Hadron Collider High Luminosity upgrade (HL-LHC) project. KW - Accelerator magnets KW - Friction KW - Molybdenum disulphide KW - Solid lubricants KW - Superconducting magnets PY - 2018 DO - https://doi.org/10.1109/TASC.2018.2792469 VL - 28 IS - 3 SP - 4005703 PB - IEEE AN - OPUS4-44621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Genga, R. M. A1 - Glaser, D. A1 - Rokebrand, P. A1 - Cornish, L. A. A1 - Woydt, M. A1 - Gradt, Thomas A1 - Janse van Vuuren, A. A1 - Polese, C. ED - von Leipzig, K. ED - Sacks, N. ED - McClelland, M. T1 - Laser shock peening: A NbC based cermet enhancement alternative for improved GCI interrupted face-milling N2 - Attempts were made to improve the properties and machining performance of NbC based cermet cutting inserts for face milling of grey cast iron (GCI) (BS 1452/GG35) by spark plasma sintering (SPS), use of sub-stoichiometric NbC (NbC₀ˏ₈₈), Cr₃C₂ and Mo₂C additives and laser shock peening (LSP). The microstructure, hardness, fracture toughness and Young’s modulus of WC–Co, NbC₀ˏ₈₈-Co and NbC₀ˏ₈₈-Ni cermet-based inserts were investigated for machining performance. Additions of Mo₂C and manufacture by SPS significantly refined the NbC₀ˏ₈₈-Ni/Co cermet’s carbide grain size from ~5.0 μm to <0.9 μm, which increased the hardness (by ~4GPa) and wear resistance. Laser shock peening (LSP) improved the fracture toughness of all the inserts, from 10% (in the SPS WC based in cermets) to ~100% (in the LPS NbC based cermets). Uncoated cutting inserts were manufactured from the sintered cermets in an SNMA (double sided square insert without a chipformer on the cutting edge) shape (12.7 × 12.7 × 4.3 mm³, 1.6 mm nose radius). The inserts were used for interrupted face-milling of GCI at cutting speeds (ν˛) ranging from 100 m/minute (400 rpm)–500 m/minute (2000 rpm) and depths of cut (ɑₚ) of 0.2–1.0 mm. The insert wear was measured after every pass and analyzed by annular dark field scanning transmission electron microscopy (ADF-STEM). Cutting temperatures were measured with a high-speed thermal camera and forces were measured using a Kistler dynamometer. During machining at ν˛ = 200 m/minute and ɑₚ = 1.0 mm, WC–Co inserts had the lowest flank wear rate (FWR), although LSP significantly improved the tool life of the NbC₀ˏ₈₈-Ni inserts, significantly reducing the FWR from 148.63 μm/minute to 99.79 μm/minute (by ~33%) and the average resultant force from 1257 ± 15 N to 535 ± 15 N. During machining at ν˛ = 500 m/minute and ɑₚ = 0.2 mm, LSP significantly lowered the FWRs of the NbC₀ˏ₈₈ inserts, giving better tool life than all the WC based inserts. Generally, LSP improved the NbC₀ˏ₈₈ inserts’ tool life, reducing the flank wear rate by up to 33% during roughing and 63% during finishing. T2 - 8th International Conference on Competitive Manufacturing (COMA ’22) CY - Stellenbosch, South Africa DA - 09.03.2022 KW - Niobium carbide KW - Laser shock peening KW - Face milling KW - Tool wear PY - 2023 SN - 978-3-031-15602-1 SN - 978-3-031-15601-4 SN - 978-3-031-15604-5 DO - https://doi.org/10.1007/978-3-031-15602-1_62 SN - 2194-0525 SN - 2194-0533 N1 - Serientitel: Lecture notes in production engineering – Series title: Lecture notes in production engineering SP - 871 EP - 889 PB - Springer CY - Cham AN - OPUS4-62689 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pirker, F. A1 - Toth, I. A1 - Cihak-Bayr, U. A1 - Grundtner, R. A1 - Vernes, A. A1 - Benedicto, J. A1 - Spaltmann, Dirk A1 - Gradt, Thomas A1 - Alberdi, A. A1 - Alonso, I. A1 - Bayón, R. A1 - Igartua, A. A1 - García, Á. A1 - Pagano, F. A1 - Bravo, I. A1 - Kogia, M. A1 - Dykeman, D. A1 - Liedtke, S. A1 - Minami, I. A1 - Nyberg, E. A1 - Soivio, K. A1 - Ronkainen, H. A1 - Majaniemi, S. A1 - Heino, V. A1 - Gkagkas, K. A1 - Mont, L. A1 - Amigorena, I. T1 - Tribological characterisation services for materials - i-TRIBOMAT N2 - Um den Entwicklungsprozess von neuen Komponenten zu beschleunigen, ist die Vorrausage der Eigenschaften der eingesetzten Werkstoffe im Betrieb der Komponenten von enormer Bedeutung. Um neue Werkstoffe hinsichtlich Ihrer Performance (in einer Komponente) bewerten zu können, ist deshalb die Entwicklung neuer innovativer Methoden notwendig. Diese Methoden können auch unter dem Begriff „lab-to-field“ oder „materials“ – up-scaling zusammengefasst werden. D. h. Werkstoffe werden im Labor charakterisiert, und deren Eigenschaften mittels z.B. Simulation auf die Komponentenperformance hochskaliert (upscaling). i-TRIBOMAT ist ein EU gefördertes Projekt (H2020, GA Nr. 814494) mit dem Ziel ein Open Innovation Test Bed für tribologische Werkstoffcharakterisierung aufzubauen und entsprechende Services von der tribologischen Charakterisierung neuer Werkstoffe bis hin zu Simulationsmodellen zur Vorrausage der Perfomance von Komponenten der Industrie anzubieten. Durch die Bündelung von Knowhow und Infrastruktur zu Charakterisierung sowie den Aufbau einer digitalen Plattform, wird i-TRIBOMAT das weltgrößte Open Innovation Test Bed für tribologische Werkstoffcharakterisierung. N2 - The prediction of the properties of the materials used in the operation of components is of enormous importance, in order to accelerate the development process of new components. To evaluate new materials in terms of their performance (in a component), the development of new innovative methods is necessary. These methods can also be summarized under the term lab-to-field or materials – upscaling, meaning materials being characterised in a laboratory and their properties being upscaled to the component performance by means of e.g. simulation. i-TRIBOMAT is a EU funded project (H2020, GA Nr. 814494) aiming at building an Open Innovation Test Bed for tribological material characterization and offering corresponding services from tribological characterization of new materials to simulation models for predicting the performance of industrial components. By bundling the infrastructure, know-how for characterization and building a digital platform, i-TRIBOMAT becomes the world’s largest open innovation test bed for tribological material characterization. T2 - 22nd International Colloquium Tribology CY - Esslingen, Germany DA - 28.01.2020 KW - Tribologie KW - Lab-to-field up-scaling KW - Werkstoffdatenbank KW - Geteilte Infrastruktur KW - Tribo-Analytik KW - Intelligente tribologische Werkstoffcharakterisierung KW - Lab-to-field upscaling KW - Tribology KW - Intelligent tribological material characterization KW - Materials database KW - Shared infrastruture KW - Tribo-analytics PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576762 DO - https://doi.org/10.30419/TuS-2020-0026 SN - 0724-3472 SN - 2941-0908 VL - 67 IS - 5-6 SP - 35 EP - 50 PB - Expert CY - Tübingen AN - OPUS4-57676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Österle, Werner A1 - Dmitriev, A.I. A1 - Gradt, Thomas A1 - Häusler, Ines A1 - Hammouri, Basem A1 - Morales Guzman, Pablo Israel A1 - Wetzel, B. A1 - Yigit, D. A1 - Zhang, G. T1 - Exploring the beneficial role of tribofilms formed from an epoxy-based hybrid nanocomposite N2 - The composition and nanostructure of a beneficial tribofilm formed during sliding of a hybrid nanocomposite against steel were characterized comprehensively. A similar nanostructure was produced by high energy ball milling of the three identified tribofilm constituents: silica, hematite and graphite. By supplying powders to a pin-on-disc test it has been shown that neither silica, nor hematite, nor a mixture of both provide the low coefficient of friction (COF) observed for the hybrid composite. Only if graphite was blended with the oxides, the low COF was obtained. Thus, a film of finely dispersed stable inorganic wear products containing 15 vol% graphite provides low friction and wear in the considered case. KW - TEM KW - Nanocomposite KW - Tribofilm KW - Ball milling KW - Pin-on-disc test PY - 2015 DO - https://doi.org/10.1016/j.triboint.2015.03.006 SN - 0301-679X VL - 88 SP - 126 EP - 134 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-33035 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rodrigues, A.C.P. A1 - Österle, Werner A1 - Gradt, Thomas A1 - Azevedo, César Roberto de Farias T1 - Impact of copper nanoparticles on tribofilm formation determined by pin-on-disc tests with powder supply: Addition of artificial third body consisting of Fe3O4, Cu and graphite N2 - Copper, magnetite and graphite particles were mixed in order to observe their impact on the coefficient of friction (CoF) during pin-on-disc tests and on the tribofilm formation after testing. Pure magnetite powder provided a value of CoF of 0.4. Magnetite-copper mixtures tested at 400 °C revealed lower CoF values (~0.4) than those at room temperature (~0.6). Magnetite-graphite and magnetite-graphite-copper mixtures presented lower CoF values (~0.3). All systems formed a magnetite-based tribofilm and patches of metallic copper were found on the tribosurfaces of the mixtures containing copper. Carbon layers and graphite nanoinclusions were observed in the graphite mixtures. The incorporation of zirconia particles, a by-product of ball milling mixing, prevented the selective transfer of graphite and copper to the tribosurfaces of some of the samples. KW - Brake pad materials KW - Sliding friction KW - Transfer layer KW - Surface analysis KW - Model friction tests PY - 2017 DO - https://doi.org/10.1016/j.triboint.2017.02.014 SN - 0301-679X VL - 110 SP - 103 EP - 112 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-40104 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gräning, Dirk A1 - Gradt, Thomas T1 - Sliding wear of martensitic steels in hydrogen – X30CrMoN15-1 and 100Cr6 – the role of water traces N2 - Die Untersuchung befasste sich ursprünglich mit dem Einfluss von gasförmigem Wasserstoff bei Normaldruck auf den Verschleiß von martensitischen Stählen. Dabei wurde als Gegenkörper eine Al2O3-Kugel verwendet, da dieser Werkstoff inert und zugleich hart ist und somit immer einen geringen Abtrag aufweisen sollte. Um 1 ppm Wasserstoff ohne thermomechanische Unterstützung in reines α-Eisen zu drücken, wird nämlich ein Druck von 15·105 MPa(~15 Mbar) benötigt. In der Versuchsreihe wiesen die Al2O3-Kugel in N2- und H2-Atmosphäre einen hohen Verschleiß auf, während bei Luft-Versuchen die Spur klein und der Verschleiß an der Scheibe groß war. Durch Streuungen und daraus folgenden Untersuchungen zeigte sich, dass Wasserstoff keinen merkbaren Einfluss hatte, Wasserspuren im Gas aber dafür umso deutlicher den Verschleiß beeinflussten. N2 - Initially the primary objective of the project has been the investigation of the influence of gaseous hydrogen on the wear of martensitic steels under heavy tribological stress. As a counter body an Al2O3 ball has been used because the material is inert and hard so that a low amount of wear was expected. If only the gas pressure is responsible for the absorption of hydrogen from the gas to pure α-iron it would require 15·105 MPa (~15 Mbar) to press 1 ppm into the material. In the test series the Al2O3 balls showed in N2 and H2 atmosphere a higher wear compared to aerial experiments which showed a smaller wear track and a severer wear for the disc. Because of scattering and thereof following investigations it was shown that hydrogen has no noticeable influence but water traces in the gas are manipulating the outcome of the tests distinctly. T2 - 57. Tribologie-Fachtagung CY - Göttingen, Germany DA - 26.09.2016 KW - Tribology KW - Hydrogen environment KW - Alumina KW - Martensitic steel KW - Adsorbed water film PY - 2016 SN - 978-3-9817451-1-5 VL - 2016 SP - 1.3/1 EP - 1.3/6 AN - OPUS4-40105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Gradt, Thomas A1 - Aßmus, Kristin T1 - Tribological Behaviour of Solid Lubricants at Low Temperatures N2 - Supporting elements between large superconducting magnets like the field coils in WENDELSTEIN 7-X have to sustain high loads while allowing a certain amount of tangential movement without any stick-slip motion. In model tests with reciprocating friction in liquid helium and vacuum a PVD-MoS2-coating has proven its suitability for these components. It showed a very stable sliding behaviour with a friction coefficient below 0.1 without coating failure under all test conditions. KW - Tribologie KW - Festschmierstoffe KW - MoS2 KW - Kryotechnik KW - Vakuumtechnik KW - Kernfusion PY - 2006 SN - 978-80-239-8883-3 VL - 1 SP - 173 EP - 176 CY - Prague, Czech Republic AN - OPUS4-17398 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - MoS2-Schmierung für hochbelastete Stützelemente zwischen supraleitenden Magnetspulen T2 - Tribologie-Fachtagung CY - Göttingen, Germany DA - 2008-09-22 PY - 2008 AN - OPUS4-18128 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Cryogenic vacuum tests of scaled down narrow support elements for the W7-X coil system T2 - 25th Symposium on Fusion Technology CY - Rostock, Germany DA - 2008-09-15 PY - 2008 AN - OPUS4-18129 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Friction and wear behaviour of stainless steels in liquid hydrogen T2 - International Hydrogen Energy Development Forum 2010 CY - Fukuoka, Japan DA - 2010-02-03 PY - 2010 AN - OPUS4-21078 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Test rig for static and dynamic friction tests at cryogenic temperatures T2 - Symposium on Vacuum based Science and Technology CY - Greifswald, Germany DA - 2007-09-05 PY - 2007 AN - OPUS4-17481 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Vakuumtribologie T2 - Technologietag Berliner Glas "EUV-Lithographie" CY - Berlin, Germany DA - 2008-04-30 PY - 2008 AN - OPUS4-18190 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Reibungsmindernde Schichten in der Vakuumtechnik T2 - 1. Workshop "Oberflächentechnik in der Produktion - Schichten in geschmierten und ungeschmierten Systemen" CY - Dresden, Germany DA - 2008-10-17 PY - 2008 AN - OPUS4-18191 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Gradt, Thomas ED - Czichos, Horst ED - Habig, K.-H. T1 - Vakuumtribologie KW - Tribologie KW - Kryotechnik KW - Vakuumtechnik KW - Festschmierstoffe KW - Polymerkomposite PY - 2010 SN - 978-3-8348-1810-2 SP - 586 EP - 598 PB - Springer-Vieweg CY - Wiesbaden ET - 3. Aufl. AN - OPUS4-22076 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Gradt, Thomas ED - Czichos, Horst ED - Habig, K.-H. T1 - Tieftemperaturtribologie KW - Tribologie KW - Kryotechnik KW - Vakuumtechnik KW - Festschmierstoffe KW - Polymerkomposite PY - 2010 SN - 978-3-8348-1810-2 SP - 599 EP - 610 PB - Springer-Vieweg CY - Wiesbaden ET - 3. Aufl. AN - OPUS4-22078 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Wolfgang A1 - Gradt, Thomas A1 - Ostrovskaya, Y. T1 - Tribologische Eigenschaften von Festschmierstoffen in tiefkalten Medien T2 - BAM-Sonderheft 2003 "Polymere Verbundwerkstoffe zwischen Raumtemperatur und 4,2 K" ; 2. Symposium im DFG-Projekt: Eigenschaften von PTFE- und PEEK-Matrix-Werkstoffen bei tribologischer Beanspruchung CY - Berlin, Deutschland DA - 2003-02-27 PY - 2003 SP - 28 EP - 32 AN - OPUS4-2671 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Tribologisches Verhalten von Gleitlacken für kryogene Anwendungen T2 - Reibung, Schmierung und Verschleiß, 44. Tribologie-Fachtagung CY - Göttingen, Germany DA - 2003-09-22 PY - 2003 AN - OPUS4-3089 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübner, Wolfgang A1 - Gradt, Thomas A1 - Aßmus, Kristin A1 - Pyzalla, A. A1 - Pinto, H. A1 - Stuke, S. T1 - Hydrogen absorption by steels during friction T2 - Hydrogen and Fuel Cells Conference and Trade Show ; Hydrogène et Piles à Combustible Conférence et Foire Commerciale CY - Vancouver, Canada DA - 2003-06-08 PY - 2003 SP - 1 EP - 11(?) PB - CHA CY - Toronto AN - OPUS4-3319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Tribologische Eigenschaften von Festschmierstoffen in tiefkalten Medien T2 - 2. Symposium im DFG-Projekt: Eigenschaften von PTFE- und PEEK-Matrix-Werkstoffen bei tribologischer Beanspruchung / BAM-Sonderheft 2003 "Polymere Verbundwerkstoffe zwischen Raumtemperatur und 4,2 K" CY - Berlin, Germany DA - 2003-02-27 PY - 2003 AN - OPUS4-4308 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gradt, Thomas A1 - Hübner, Wolfgang A1 - Ostrovskaya, Y. T1 - Tribologisches Verhalten von Gleitlacken für kryogene Anwendungen KW - Kryotechnik KW - Vakuumtechnik KW - Gleitlacke KW - Reibungszahlen KW - Schichtlebensdauer KW - MoS2 KW - Polyharnstoff PY - 2004 SN - 0724-3472 VL - 51 IS - 6 SP - 37 EP - 40 PB - Expert Verlag CY - Renningen AN - OPUS4-6923 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Gradt, Thomas A1 - Hübner, Wolfgang A1 - Ostrovskaya, Y. T1 - Tribologisches Verhalten von Gleitlacken für kryogene Anwendungen PY - 2003 SN - 3-00-003404-8 SP - 25/1 EP - 25/10 PB - GfT CY - Moers AN - OPUS4-2659 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Tribologisches Verhalten von Verschleißschutzschichten in H2- und CH4-Umgebung T2 - Tribologie-Fachtagung CY - Göttingen, Germany DA - 2005-09-26 PY - 2005 AN - OPUS4-10958 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Tribological behaviour of solid lubricants at low Temperatures T2 - CryoPrague 2006 CY - Prague, Czech Republic DA - 2006-07-17 PY - 2006 AN - OPUS4-13632 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Stick-Slip-Verhalten von Kunststoff-Kompositwerkstoffen in Vakuumumgebung T2 - Tribologie-Fachtagung 2006 CY - Göttingen, Germany DA - 2006-09-25 PY - 2006 AN - OPUS4-13634 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas A1 - Aßmus, Kristin T1 - Stick-Slip-Verhalten von Kunststoff-Kompositwerkstoffen in Vakuumumgebung T2 - 47. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendungen CY - Göttingen, Germany DA - 2006-09-25 KW - Tribologie KW - Trockenreibung KW - Polymerwerkstoffe KW - Vakuumumgebung KW - Stick-Slip KW - Temperatureinfluss PY - 2006 SN - 3-00-019670-6 SP - 53/1 EP - 53/12 CY - Aachen AN - OPUS4-14479 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gradt, Thomas A1 - Hübner, Wolfgang T1 - Tribologisches Verhalten von Verschleißschutzschichten in H2- und CH4-Umgebung KW - Trockenreibung KW - Gleitlacke KW - DLC-Schichten KW - Wasserstoff-Umgebung KW - Erdgas-Umgebung KW - Dry friction KW - AF-coatings KW - DLC-coatings KW - Hydrogen environment KW - Natural gas environment PY - 2006 SN - 0724-3472 VL - 53 IS - 5 SP - 7 EP - 12 PB - Expert Verlag CY - Renningen AN - OPUS4-14480 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gradt, Thomas A1 - Aßmus, Kristin T1 - Stick-Slip-Verhalten von Kunststoff-Kompositwerkstoffen in Vakuumumgebung KW - Trockenreibung KW - Polymer-Kompositwerkstoffe KW - Vakuumumgebung KW - Stick-Slip KW - Temperatureinfluss PY - 2007 SN - 0724-3472 VL - 54 IS - 1 SP - 14 EP - 18 PB - Expert Verlag CY - Renningen AN - OPUS4-14720 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Apparatus for friction tests of support elements in fusion devices T2 - 17th International Vacuum Congress (IVC-17) CY - Stockholm, Sweden DA - 2007-07-01 PY - 2007 AN - OPUS4-16258 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Gradt, Thomas ED - Kuo, C.-H. T1 - Tribological behaviour of solid lubricants in hydrogen environment N2 - In a future energy supply system based on renewable sources hydrogen technology will play a key role. Because the amount of energy from renewable sources, such as wind or solar power, differs seasonally and regionally, an energy storage method is necessary. Hydrogen, as an environmentally friendly energy carrier, can fill this gap in an ideal way, in particular for mobile applications (Wurster et al., 2009). Already today, in Germany the amount of hydrogen as a byproduct in chemical industry is enough for fuelling about 1 Mio passenger cars1. Excess electrical power can be used to produce hydrogen by electrolysis. On demand, this hydrogen can be used for mobile or stationary fuel cells. Beside this new developing technology, hydrogen is used as fuel for rocket engines and in chemical industry since a long time. Table 1 comprises some physical parameters of hydrogen. It can be seen that hydrogen gas has a very low density which makes storage at high pressure or in liquid form (LH2) necessary. KW - Tribologie KW - Kryotechnik KW - Wasserstofftechnologie KW - Festschmierstoffe PY - 2011 UR - http://www.intechopen.com/articles/show/title/tribological-behaviour-of-solid-lubricants-in-hydrogen-environment SN - 978-953-307-371-2 DO - https://doi.org/10.5772/22286 IS - Chapter 11 SP - 271 EP - 286 PB - InTech AN - OPUS4-24534 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Tribotests on wear protective coatings in hydrogen environment T2 - International Hydrogen Energy Development Forum 2012 CY - Fukuoka, Japan DA - 2012-02-02 PY - 2012 AN - OPUS4-25568 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Gradt, Thomas ED - Wang, Q.J. ED - Chung, Y.-W. T1 - Cryogenic solid lubrication N2 - Cryogenic engineering comprises technical systems working at temperatures below 120 K (−153°C). This is the temperature range of the boiling points of permanent gases such as nitrogen (77 K), hydrogen (20 K), and helium (4.2 K). Liquid natural gas (LNG), which is, in addition to hydrogen, also discussed as an alternative fuel boils at 112 K and, therefore, is a cryogenic liquid as well. KW - Tribologie KW - Kryotechnik KW - Festschmierstoffe KW - Polymerkomposite KW - Verschleißschutzschichten PY - 2013 SN - 978-0-387-92896-8 SN - 978-0-387-92897-5 SN - 978-0-387-92898-2 IS - Chapter C SP - 641 EP - 647 PB - Springer Science + Business Media CY - New York AN - OPUS4-29516 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Veränderte Reibcharakteristik von MoS2-Schichten bei extrem tiefen Temperaturen T2 - 54. Tribologie-Fachtagung CY - Göttingen, Germany DA - 2013-09-30 PY - 2013 AN - OPUS4-29391 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas A1 - Börner, Helmut A1 - Hübner, Wolfgang T1 - Friction and Wear Testing for Cryogenic Engineering T2 - MAT 2001 ; International conference: material testing and research ; MAT Kongreß ; MAT Conference CY - Nuremberg, Germany DA - 2001-05-08 PY - 2001 IS - A5.5 SP - 129 EP - 133 PB - AMA Service GmbH CY - Wunstorf AN - OPUS4-1116 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Gradt, Thomas A1 - Börner, Helmut A1 - Hübner, Wolfgang T1 - Low temperature tribology at the federal institute for materials research and testing N2 - Friction systems running in cryogenic environment are critical in respect to wear and frictional heat generation because in this temperature range, conventional lubricants can't be applied. In order to test the friction and wear behaviour of appropriate solid lubricants and wear resistant material combinations in cryogenic environment, including liquid hydrogen, special test rigs have been constructed. These devices provide test conditions for tribological investigations at temperatures ranging from 4.2K to room temperature in liquid or gaseous environment at pressures between 10-3 mbar and 20 bar. Investigations on polymers, composites and metals with and without coatings show that there is a broad variety of appropriate materials for cryogenic friction units, but the behaviour of austenitic steels in such systems gives an example of non sufficient knowledge in this field. T2 - 9th ESMATS, European Space Mechanisms and Tribology Symposium CY - Liège, Belgium DA - 2001-09-19 PY - 2001 UR - http://adsabs.harvard.edu/abs/2001ESASP.480..317G SN - 92-9092-761-5 SN - 0379-6566 N1 - Serientitel: ESA SP – Series title: ESA SP IS - 480 SP - 317 EP - 320 PB - ESA Publ. Division CY - Noordwijk AN - OPUS4-1164 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Gradt, Thomas A1 - Börner, Helmut ED - Lehmann, J. T1 - Friction and Wear Testing in Liquid Hydrogen T2 - 4th HYPOTHESIS ; 4th International Symposium on Hydrogen Power - Theoretical and Engineering Solutions CY - Stralsund, Germany DA - 2001-09-09 KW - Tribology KW - Cryogenic engineering KW - Hydrogen environment KW - Test equipment KW - Steels PY - 2001 SN - 3-9807963-0-2 VL - 2 SP - 388 EP - 392 PB - Fachhochsch. CY - Stralsund AN - OPUS4-1165 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas A1 - Börner, Helmut A1 - Hübner, Wolfgang A1 - Ostrovskaya, Y. T1 - Friction and wear testing in cryogenic environment T2 - 3ème Colloque Européen sur la Technologie des Lanceurs ; 3rd European Conference on Launcher Technology CY - Strasbourg, France DA - 2001-12-11 PY - 2001 SP - 927 EP - 935 PB - CNES CY - Paris AN - OPUS4-1330 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübler, Daniela A1 - Höhne, Patrick A1 - Gradt, Thomas T1 - Influence of TiC content on the tribological behavior of NbC-Ni-TiC cermets N2 - Increasing demand for alternatives to tungsten carbide (WC) cemented carbides as cutting tools, due to the health risks of their wear products WO3 and Co3O4. Niobium carbide (NbC) has a high potential, due to its high wear resitance, high hot hardness and melting point (3520°C), and low solubility in iron alloys. T2 - 23rd International Conference on Wear of Materials CY - Online meeting DA - 26.04.2021 KW - Niobium carbide (NbC) KW - Cermets KW - Tribological behavior PY - 2021 AN - OPUS4-52560 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neumann, Martin A1 - Gleim, Tobias A1 - Gradt, Thomas T1 - Friction coefficients for wood-wood and wood-steel high pressure contact under temperatures between -40 °C and 90 °C N2 - Wood is widely used in impact limiters of Transport casks for radioactive material. Encapsulated by an outer and inner Steel structure, spruce wood is offen applied in layers of altemating direction. The friction at the interfaces between these layers is of crucial importance for the impact and energy absorption e.g., at an accidental impact of a cask against a hard component. In order to get detailed Information for corresponding numerical calculations, in this study the friction coefficient for the combinations wood-wood and wood-steel was measured in the temperature ränge between -40 °C and 90 °C according to the relevant stress conditions for such casks. Results show decreasing friction with increasing temperature, ranging from 0.43 at -40 °C to 0.22 for 90 °C for wood-steel combinations and from 0.3 at -40 °C to 0.24 at 90 °C to for a wood-wood combination. KW - Wood KW - Friction KW - Transport cask KW - Radioactive material PY - 2023 DO - https://doi.org/10.24053/TuS-2023-0007 SN - 0724-3472 VL - 70 IS - 2 SP - 5 EP - 12 PB - expert verlag AN - OPUS4-57787 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neumann, Martin A1 - Gleim, Tobias A1 - Gradt, Thomas A1 - Wille, Frank T1 - Friction coefficients for wood-wood and wood-steel interfaces in impact limiters for transport casks N2 - Wood is widely used in impact limiters of transport casks for radioactive material. Encapsulated by an outer and inner steel structure, spruce wood is often applied in layers of alternating direction. The friction at the interfaces between these layers is of crucial importance for the impact and energy absorption e.g., at an accidental impact of a cask against a hard target. In order to get detailed information for corresponding numerical calculations, in this study the friction coefficient for the combinations wood-wood and wood-steel was measured in the temperature range between -40°C and 90°C according to the relevant stress conditions for such casks. Results show decreasing friction with increasing temperature, ranging from 0.43 at -40°C to 0.22 for 90°C for wood-steel combinations and from 0.3 at -40°C to 0.24 at 90°C to for a wood-wood combination. T2 - 20th International Symposium on the Packaging and Transportation of Radioactive Materials CY - Juan-les-Pins, France DA - 11.06.2023 KW - Wood KW - Friction KW - Transport cask PY - 2023 SP - 1 EP - 11 AN - OPUS4-57334 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hausberger, A. A1 - Major, Z. A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Observation of the adhesive - and deformation - contribution to the friction and wear behaviour of thermoplastic polyurethanes N2 - In this study unfilled and graphite filled thermoplastic polyurethanes (TPU) were investigated in tribological pin-on-disc tests. KW - TPU KW - Friction KW - Wear KW - Adhesion KW - Deformation KW - Vacuum PY - 2018 DO - https://doi.org/10.1016/j.wear.2018.07.006 SN - 0043-1648 SN - 1873-2577 VL - 412-413 SP - 14 EP - 22 PB - Elsevier CY - Amsterdam AN - OPUS4-45897 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas A1 - Theiler, Geraldine T1 - Polymerwerkstoffe für Tribosysteme in tiefkalt verflüssigtem Erdgas N2 - Der Beitrag handelt von der Eignung von Polymeren für Anwendungen in LNG. Um dies zu testen, wurde das tribologische Verhalten von PEEK-, PTFE-, PI-, und UHMW-PE-basierten Werkstoffen im Gleitkontakt gegen CrNi-Stahl untersucht. T2 - 59. Tribologie-Fachtagung CY - Göttingen, Germany DA - 24.09.2018 KW - Alternative Kraftstoffe KW - CNG KW - LNG KW - Trockenreibung KW - Polymerkomposite PY - 2018 SN - 978-3-9817451-3-9 SP - 59/1 EP - 59/4 AN - OPUS4-46177 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Materials for tribosystems in hydrogen technology N2 - In this presentation tribological investigations on steels, polymers and coatings in gaseous and liquid hydrogen are shown. For steels the results of show that although martensitic steel may suffer from hydrogen embrittlement, application e.g. in roller bearings is possible. On the other hand, martensitic transformation of austenitic steels may cause problems in the application of these materials. Furthermore, the tribological performance of polymer composites with and without solid lubricant fillers in gaseous and liquid hydrogen was investigated. In particular, PEEK- and PTFE-matrix compounds showed low friction and sufficient low wear under these conditions. Among the solid lubricants, carbon-based materials are appropriate for hydrogen applications. Several variants of DLC and ta-C materials were tested. Beside the results for hydrogen, also a comparison with CH4-environment is shown. T2 - ÖTG-Symposium 2021 CY - Online meeting DA - 18.11.2021 KW - Hydrogen environment KW - Liquid hydrogen KW - Austenitic stainless steels KW - Polymer composites KW - DLC PY - 2021 AN - OPUS4-53793 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weihnacht, V. A1 - Makowski, S. A1 - Brückner, A. A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Tribologie und Anwendung trocken laufender ta-C-Schichten N2 - Superharte ta-C Kohlenstoffschichten sind durch niedrige Reibung und extreme Verschleißbeständigkeit für Anwendungen auf ungeschmierten Gleitpaarungen, z.B. trocken laufenden Getrieben prädestiniert. In tribologischen Untersuchungen im trockenen Gleitkontakt mit reversierender bzw. einsinniger Bewegungsrichtung wurden Reibungs- und Verschleißkoeffizienten in Abhängigkeit der Luftfeuchtigkeit und im Hochvakuum bestimmt. In den durchgeführten Oberflächenuntersuchungen von Schicht und Gegenkörper zeigten sich interessante Phänomene hinsichtlich Transfer- bzw. Triboreaktionsschichten. Obwohl die Ergebnisse eine Verschlechterung der ta-C-Eigenschafien mit abnehmender Luftfeuchtigkeit zeigen, sind die Reibungs- und Verschleißeigenschaften im Hochvakuum zum Teil erstaunlich positiv. KW - Tribologie KW - Verschleißschutzschichten KW - ta-C KW - DLC KW - Reibung KW - Verschleiß KW - Trockenreibung KW - Vakuumtribologie KW - Friction KW - Wear KW - Dry-running condition KW - Vacuum tribology PY - 2012 SN - 0724-3472 VL - 59 IS - 6 SP - 41 EP - 44 PB - Expert Verlag CY - Renningen AN - OPUS4-28004 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Friction and wear behaviour of polymers in liquid hydrogen N2 - The tribological behaviour of polymer composites were investigated in liquid hydrogen at -253°C and compared with previous results obtained in gaseous hydrogen at ambient temperature. KW - Polymers KW - Friction KW - Wear KW - Hydrogen KW - Cryogenic temperature PY - 2018 DO - https://doi.org/10.1016/j.cryogenics.2018.05.002 SN - 0011-2275 VL - 93 SP - 1 EP - 6 PB - Elsevier CY - Amsterdam AN - OPUS4-44886 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Hübner, Wolfgang A1 - Gradt, Thomas A1 - Klein, P. A1 - Friedrich, K. T1 - Friction and wear of PTFE composites at cryogenic temperatures N2 - This paper presents investigations on the tribological behaviour of PTFE composites against steel at cryogenic temperatures. The results showed that the friction coefficient decreases with temperature down to 77 K, but did not follow a linear evolution further down to extreme low temperatures. It can be stated that the cryogenic environment has a significant influence on the tribological performance of the polymer composites. The effect of low temperatures was more clearly detected at low sliding speed, where friction heat is reduced. A change in wear mechanism from adhesive to abrasive was observed in this case. SEM and AFM analyses showed that the PTFE matrix composites investigated under these experimental conditions have transferred material onto the disc down to very low temperatures. Chemical analyses indicate the presence of iron fluorides. KW - PTFE composites KW - Cryogenic tribology KW - Transfer film PY - 2002 DO - https://doi.org/10.1016/S0301-679X(02)00035-X SN - 0301-679X VL - 35 IS - 7 SP - 449 EP - 458 PB - Butterworth-Heinemann CY - Oxford AN - OPUS4-1866 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gradt, Thomas A1 - Theiler, Geraldine T1 - Tribological behaviour of solid lubricants in hydrogen environment N2 - For further development of hydrogen technology, it is necessary to have a sufficient number of materials for safe and reliable operation available. Frictional contacts exposed to hydrogen, are critical because of vanishing protective oxide layers in the presence of a chemical reducing environment. Furthermore, liquid lubricants are often not applicable, because of purity requirements, or very low temperatures in the case of liquid hydrogen. Thus, for numerous tribosystems in hydrogen technology, solid lubrication is the only possible method for reducing friction and wear. Therefore, investigations on the tribological behaviour of friction reducing materials, such as PTFE, graphite, DLC and MoS2, in inert and hydrogen environment were carried out. The results show that solid lubricants, applied as coatings or as components in polymer composites, are able to reduce friction and wear in gaseous as well as in liquid hydrogen. However, some materials are very sensitive to the environmental medium. KW - Hydrogen environment KW - Low temperatures KW - Solid lubricants KW - Coatings KW - Polymer composites PY - 2011 DO - https://doi.org/10.247/trol.6.117 SN - 1881-2198 VL - 6 IS - 2 SP - 117 EP - 122 CY - Tokyo, Japan AN - OPUS4-23252 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Tribological behaviour of graphite filled polyimide composites in hydrogen environment N2 - The tribological behaviour of graphite filled polyimide composites against steel (AISI 52100) was investigated in air, vacuum and hydrogen environments. Composites consist of two polyimides filled with different types and amount of graphite. Friction and wear measurements were performed at 0.2m/s and 3.1MPa at ambient temperature. Worn surfaces and morphology of the material transfer on the steel counter-face were investigated by optical microscopy and SEM analyses. Results reveal that the polyimide structure has an important influence on the friction behaviour of graphite filled composites in hydrogen environment. T2 - ECCM16 - 16th European conference on composite materials CY - Seville, Spain DA - 22.06.2014 KW - Polyimide composites KW - Graphite KW - Hydrogen environment KW - Vacuum PY - 2014 SN - 978-84-616-9798-4 SP - Paper 1137, 1 EP - 8 AN - OPUS4-31181 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas A1 - Theiler, Geraldine T1 - Influence of solid lubricant fillers on the tribological behaviour of peek composites in vacuum T2 - ESMATS 2009 - 13th European space mechanisms and tribology symposium CY - Vienna, Austria DA - 2009-09-23 KW - Tribologie KW - Vakuum KW - Polymere KW - Kompositwerkstoffe KW - Festschmierstoffe PY - 2009 SP - 1 EP - 4 CY - Vienna, Austria AN - OPUS4-19913 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Influence of the Temperature on the Tribological Behaviour of PEEK Composites in Vacuum Environment N2 - This paper describes tribological experiments carried out with polyetheretherketone (PEEK), filled with carbon fibres and solid lubricants (polytetrafluoroethylene (PTFE), graphite or MoS2), against steel discs. Oscillating sliding tests were performed in high vacuum environment in the temperature range between -40°C and +160°C. Results indicate that MoS2 filled PEEK show the best tribological performance in vacuum. Particularly, in the lower temperature range and at higher loads the friction behaviour is improved by the MoS2 content. KW - Polymerkomposite KW - Vakuum KW - Reibung KW - Verschleiß PY - 2008 DO - https://doi.org/10.1088/1742-6596/100/7/072040 SN - 1742-6588 SN - 1742-6596 VL - 100 IS - 072040 SP - 1 EP - 4 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-17368 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Mechanical and Tribological Properties of Polymer Composites at Cryogenic Temperatures N2 - This paper presents the mechanical and tribological properties of Polytetrafluoroethylene (PTFE) and Polyetheretherketone (PEEK) matrix composites filled with short carbon fibers in cryogenic environments. Tensile tests were performed at room temperature (RT) in air and in LN2. Tribological experiments were carried out with a pin-on-disc configuration at RT, in LN2, in LH2 and in LHe. PEEK composites have a better tribological performance than PTFE materials especially regarding the wear resistance. T2 - 21st International Cryogenic Engineering Conference `06 (ICMC `06) CY - Prague, Czech Republic DA - 2006-07-17 KW - Tribologie KW - Zugfestigkeit KW - Polymerkomposite KW - Kryotechnik KW - PEEK KW - PTFE PY - 2006 SN - 978-80-239-8884-0 SN - 0151-1637 VL - 2 SP - 47 EP - 51 CY - Prague, Czech Republic AN - OPUS4-17397 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Theiler, Geraldine A1 - Gradt, Thomas ED - Wilson, Andrew T1 - Tribological Behaviour of PEEK Composites in Vacuum Environment N2 - For tribological components working under extreme conditions, such as vacuum, or broad temperature ranges, it is often a problem to achieve acceptable durability of their friction parts. Thus, new material requirements are involved for these tribo-systems, in particular regarding operability and reliability. At BAM, several projects were conducted in the recent years, dealing with the tribological properties of friction couples at cryogenic temperature and in vacuum environment. This paper describes the vacuum and ultra high vacuum tribometers constructed at BAM and presents experiments carried out with polymer composites. The experiments presented were performed with PEEK, filled with solid lubricants, against 304 steel with a pin-on-disc configuration in oscillating sliding. Friction tests were carried out in vacuum in the temperature range between -40°C and +160°C and in ultra high vacuum at room temperature. KW - Tribologie KW - Vakuum KW - Polymere KW - Kompositwerkstoffe KW - Festschmierstoffe PY - 2007 SN - 92-9291-217-6 SN - 1609-042X SP - 1 EP - 5 AN - OPUS4-17399 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas A1 - Theiler, Geraldine T1 - Tribological properties of polymer composites for applications in LNG environment N2 - In a first test series, the friction and wear properties of 6 polymeric candidate materials for application in LNG tribosystems were tested. The most favorable properties showed PTFE composite, filled with carbon fibers and PEEK, which showed low and stable friction and a wear coefficient in the order of 10-7 mm3N-1m-1. PTFE containing PEEK composites seem to be also appropriate for LNG applications. Admixtures of graphite as solid lubricant result in lower wear. Contrary, a lubricating mechanism of MoS2 was not observed. The PI-materials showed comparatively high friction and medium wear. T2 - 21th International Colloquium Tribology CY - Stuttgart/Ostfildern, Germany DA - 09.01.2018 KW - Tribology KW - PEEK KW - PTFE composites KW - Friction PY - 2018 SP - 1 EP - 2 AN - OPUS4-43900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Hübner, Wolfgang A1 - Gradt, Thomas A1 - Klein, P. T1 - Friction and Wear of Carbon Fibre Filled Polymer Composites at Room and Low Temperatures PY - 2004 SN - 0933-5137 SN - 1521-4052 VL - 35 IS - 10/11 SP - 683 EP - 689 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-6866 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - High performance polymer materials for tribological applications in hydrogen and methane N2 - The development of hydrogen technologies is a key strategy to reduce greenhouse gas emission worldwide. Power-to-Gas is a challenging solution, in which hydrogen and methane can be used in mobility, industry, heat supply and electricity generation applications. This presentation deals with the tribological behaviour of polymer materials in hydrogen and methane, both in gas and in liquefied form. T2 - ECOTRIB 2019, MaTri'19 CY - Vienna, Austria DA - 12.06.2019 KW - Slidng wear KW - Polymer materials KW - Hydrogen KW - Methane PY - 2019 SN - 978-3-901657-60-3 SP - 228 EP - 229 AN - OPUS4-48253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Tribological Research in Germany - Overview and Examples from the Federal Institute for Materials Research and Testing (BAM) N2 - The talk gives a historical introduction and introduces some of the biggest and most important research institutes in Germany dealing with tribology at Universities, scientific societies and companies. Some examples for research projects and focus areas are given. As an example for a research institute with a long history in tribological research the activities of BAM in Berlin are presented. T2 - Joint Tribology Symposium of Kyushu University and Yokohama National University KY7 CY - Fukuoka, Japan DA - 01.02.2019 KW - Friction KW - Lubrication KW - Wear PY - 2019 AN - OPUS4-47345 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Influence of cryogenic hydrogen environment on the tribological properties of materials N2 - The presentation gives an overview over the LH2-activities during 20 years of tribological research in cryogenic environments at BAM. T2 - 2019 Hydrogenius & I2CNER Tribology Symposium CY - Fukuoka, Japan DA - 30.01.2019 KW - Friction KW - Wear KW - Hydrogen KW - Cryogenic Engineering KW - Hydrogen Embrittlement PY - 2019 AN - OPUS4-47339 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Harsha, A. P. A1 - Gradt, Thomas T1 - On the sliding wear behavior of PEAK composites in vacuum environment N2 - The tribological behavior of neat and filled PEEK and PEKK composites were compared in air and vacuum conditions. Very low friction and wear coefficient were obtained at low sliding speed while severe wear occurred at high speed. Experimental results are discussed by analysing the transfer film and wear debris. KW - PEAK KW - Composites KW - Wear KW - Friction KW - Vacuum PY - 2019 DO - https://doi.org/10.1115/1.4042271 SN - 0022-2305 SN - 0742-4787 VL - 141 IS - 4 SP - 044502-1 EP - 044502-7 PB - ASME AN - OPUS4-47298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spaltmann, Dirk A1 - Kogia, M. A1 - Liedtke, S. A1 - Dykeman, D. A1 - Gradt, Thomas T1 - Challenges for the design of a universal tribological database for materials N2 - Renowned institutions in the field of tribology combine their testing and analytical capabilities with experts in materials/process information management technology to provide the respective Services in Europe (i-TRIBOMAT). This requires a centralized materials information management system or the standardised capture, consolidation and harmonization of tribological information. T2 - 60. Tribologe-Fachtagung CY - Goettingen, Germany DA - 23.09.2019 KW - Database KW - Tribology KW - Digital KW - LIMS PY - 2019 SN - 978-3-9817451-4-6 SP - 37/1 EP - 37/5 PB - GfT (Gesellschaft für Tribologie) CY - Jülich AN - OPUS4-49147 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shapovalov, Oleg A1 - Gaal, Mate A1 - Hönig, Gerald A1 - Gradt, Thomas A1 - Weiss, S. T1 - Temperature dependence of the propagation speed of a longitudinal wave in different solids for use as a wedge material in an extreme-temperature-resistant ultrasonic transducer N2 - In special cases of angle beam ultrasonic measurement – e.g. defect detection in hot solids as well as flow measurement of liquid gases or energy storage mediums – the applied transducer has to withstand extreme temperatures. Since the irradiation angle into the specific material is determined not only by wedge design, but also by the speed of sound in both the wedge material and the tested object, the developer must take into account the speed of the wave propagation in a wedge material over the whole temperature range of transducers application. In this study we investigate the temperature dependence of the speed of longitudinal wave propagation in 10 different materials in the range from -200 °C to 400 °C. The investigated materials belong to different material classes (ceramics, glass, as well as ferrous and non-ferrous metals) and are all temperature-resistant up to at least 600 °C, and therefore applicable as wedge materials in an ultrasonic transducer for use at extreme temperatures. T2 - 23rd International Congress on Acoustics CY - Aachen, Germany DA - 09.09.2019 KW - Ultrasonic Transducer KW - Speed of sound KW - Longitudinal Wave KW - Temperature PY - 2019 SP - 4776 EP - 4782 AN - OPUS4-48980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Friction and wear behaviour of graphite filled polymer composites in hydrogen environment N2 - Ensuring a sustainable energy supply is currently one of the most important areas for industry and research institutions. Hydrogen technology is a promising candidate, but its broad extension requires extremely high reliability and safety in all areas for common applications as automobiles and stationary fuel cells. Particularly components containing tribosystems are critical parts. T2 - WTC 2013 - 5th World tribology congress CY - Torino, Italy DA - 08.09.2013 PY - 2013 SP - Paper 868, 1 EP - 2 AN - OPUS4-30942 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - PEEK-Komposite für Reibsysteme in der Vakuumtechnik T2 - Fachtagung der Gesellschaft für Tribologie 2007 CY - Göttingen, Germany DA - 2007-09-24 PY - 2007 AN - OPUS4-17482 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Gradt, Thomas A1 - Banova, Z. A1 - Schlarb, A.K. T1 - PEEK-Komposite für Reibsysteme in der Vakuumtechnik N2 - Aim of the investigation is to characterize selected PEEK-composites in vacuum environment. Oscillating sliding friction was investigated with a pin-on-disc configuration in high vacuum (10-5 mbar) at room temperature, -40 °C, +100 °C and +160 °C. The contact pressure was 1 MPa and 7 MPa respectively , the maximum sliding velocity 0.1 m/s. Furthermore, tests in ultra high vacuum (10-9 mbar) were carried out with flat and spherical pins at 1 MPa and 60 MPa respectively. Among the tested materials MoS2 filled PEEK shows the best tribological performance in vacuum. Particularly, in the lower temperature range and at higher loads the friction behaviour is improved by MoS2 content. KW - Vakuum KW - Polymer composite KW - Tribology KW - PEEK Komposite KW - Hochvakuum KW - Temperatureinfluss KW - MoS2 KW - Grafit KW - PEEK composites KW - High vacuum KW - Influence of the temperature KW - Graphite PY - 2008 SN - 0724-3472 VL - 55 IS - 5 SP - 25 EP - 30 PB - Expert Verlag CY - Renningen AN - OPUS4-18306 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Wear Resistant MoS2/ta-C Coatings for Applications in Various Environments T2 - 19th International Vacuum Congress (IVC-19) CY - Paris, France DA - 2013-09-09 PY - 2013 AN - OPUS4-29126 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Hübner, Wolfgang A1 - Gradt, Thomas A1 - Klein, P. A1 - Friedrich, K. T1 - Tribologisches Verhalten der Werkstoffpaarung Polymerverbundwerkstoff/Stahl bei tiefen Temperaturen KW - Kryotechnik KW - Polymerkomposite KW - PTFE KW - PEEK KW - Flüssigwasserstoff KW - Flüssighelium KW - Reibungszahlen KW - Übertrag PY - 2005 SN - 0724-3472 VL - 52 IS - 1 SP - 20 EP - 25 PB - Expert Verlag CY - Renningen AN - OPUS4-12645 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Influence of hydrogen environment on the tribological performance of polymer composites T2 - WHEC 2006 - 16th World Hydrogen Energy Conference CY - Lyon, France DA - 2006-06-13 KW - Polymer composites KW - Tribological behaviour KW - Low temperatures KW - Hydrogen environment PY - 2013 SN - 978-1-62276-540-9 SP - CD #153 / 654 EP - 662 PB - International Association for Hydrogen Energy CY - Lyon AN - OPUS4-12646 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - MoS2-filled PEEK composite as a self-lubricating material for aerospace applications T2 - 40th Aerospace mechanisms symposium CY - Cocoa Beach, FL, USA DA - 2010-05-12 KW - PEEK composite KW - MoS2 KW - Friction KW - Ultra high vacuum KW - Aerospace PY - 2010 IS - NASA/CP-2010-216272 SP - 347 EP - 351 CY - Hanover, MD, USA AN - OPUS4-22047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas A1 - Theiler, Geraldine A1 - Hale, H. T1 - Reibeigenschaften von Polymerfolien in Flüssighelium N2 - Starke Magnetfelder, wie sie z.B. für die Magnetresonanztomografie (MRT) notwendig sind, werden durch supraleitende Spulen erzeugt, die mit Flüssighelium auf eine Temperatur von -269°C gekühlt werden. Die Reibungswärme, die z.B. bei kleinsten Bewegungen zwischen der Spule und deren Stützstruktur entsteht, kann bewirken, dass die kritische Temperatur des Supraleiters lokal überschritten wird und ein normalleitender Bereich entsteht. Aufgrund der bei Normalleitung entstehenden jouleschen Wärme kann sich dieser Bereich weiter erwärmen und schnell ausbreiten. Dieser Vorgang wird als Quench bezeichnet und führt zum schlagartigen Verdampfen des extrem teuren Kältemittels und zu Betriebsunterbrechungen von mehreren Tagen. Da diese Quenche durch Reibungswärme verursacht werden, ist es notwendig, das Reibverhalten der beteiligten Werkstoffe so zu optimieren, dass kein kritischer Betriebszustand erreicht wird. Dies betrifft in erster Linie Polymerfolien, die zur elektrischen Isolierung zwischen der Spule und der Stützstruktur notwendig sind. Neben zu hoher Reibung allgemein müssen ausgeprägte Haftreibungsspitzen und StickSlip-Effekte vermieden werden. Mit diesem Ziel wurde das Reibverhalten von PTFE-, PET- und Pl-Folien bei tiefen Temperaturen und den für diese Anwendung typischen niedrigen Gleitgeschwindigkeiten untersucht. Es zeigte sich, dass die Reibung zwischen Polymeroberflächen in Flüssighelium allgemein höher, aber stabiler als in Flüssigstickstoff ist. Allerdings hängt das Reibverhalten erheblich von der Werkstoffpaarung ab. Der Stick-Slip-Effekt nimmt bei allen untersuchten Polymer-Polymer-Paarungen mit wachsender Kontaktpressung zu. PET gegen PET hat das ungünstigste Reibverhalten und sollte bei hohen Pressungen vermieden werden. Zum Vergleich getestete Paarungen von Polymeren gegen Aluminium zeigten deutlich günstigeres Reibverhalten ohne signifikanten Stick-Slip. Deshalb sollte bei derartigen Anwendungen sichergestellt werden, dass die Gleitebene zwischen Polymer- und Metalloberfläche liegt. T2 - 55. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendungen CY - Göttingen, Germany DA - 22.09.2014 PY - 2014 SN - 978-3-00-046545-1 VL - II SP - 41/1 EP - 41/10 AN - OPUS4-31529 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Einfluss von Wasserstoff auf das Gleitverhalten von graphitgefüllten Polymeren N2 - Die tribologischen Eigenschaften von graphitgefüllten Polyimiden gegen Stahl 100Cr6 wurden an Luft, im Hochvakuum (10'3 Pa), und in Wasserstoffumgebung bei verschiedenen Drücken (103 Pa, 104 Pa und 105 Pa) untersucht. Zwei unterschiedliche Polyimid-Typen wurden eingesetzt, wobei Typ und Menge des Graphits variiert wurden. Die Experimente wurden bei 3,1 MPa Kontaktdruck und einer Gleitgeschwindigkeit von 0,2 m/s bzw. 1 m/s durchgeführt. Die verschlissenen Oberflächen und die Morphologie des Materialübertrags auf die Stahl-Gegenfläche wurden mit Lichtmikroskopie, REM, TEM und FTIR untersucht. Der Vergleich der untersuchten Werkstoffe zeigt, dass sowohl die Matrix als auch der Graphitanteil einen Einfluss auf das Reibverhalten in den verschiedenen Umgebungen haben. T2 - 55. Tribologie-Fachtagung - Reibung, Schmierung und Verschleiß - Forschung und praktische Anwendungen CY - Göttingen, Germany DA - 22.09.2014 PY - 2014 SN - 978-3-00-046545-1 VL - II SP - 35/1 EP - 35/11 AN - OPUS4-31530 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Brice, H. A1 - Gradt, Thomas T1 - Stick-slip behaviour of polymer films in LHe N2 - Superconducting magnets are susceptible to quenching, even with the smallest amounts of energy disturbances due to the extremely low thermal capacity of materials at 4.2 K. Hence, small mechanical disturbances resulting in frictional heating can be sufficient to exceed the wire’s critical temperature, causing it to quench. Unfortunately, relative motion between surfaces in the magnet System is inevitable due to various forces present in the System, including winding pretension, differences in material thermal contraction and the large electromagnetic forces. Typically insulating polymers are present at this interface to achieve the required electrical insulation requirements. T2 - WTC 2013 - 5th World tribology congress CY - Torino, Italy DA - 08.09.2013 PY - 2013 SP - Paper 366, 1 EP - 4 AN - OPUS4-30940 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Reibeigenschaften von Polymerfolien in Flüssigkeiten T2 - 55. Tribologie-Fachtagung CY - Goettingen, Germany DA - 2014-09-22 PY - 2014 AN - OPUS4-31458 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Gradt, Thomas A1 - Banova, Z. A1 - Schlarb, A.K. T1 - PEEK-Komposite für Reibsysteme in der Vakuumtechnik KW - Vakuum KW - Polymer composite KW - Tribology PY - 2007 SN - 978-3-00-022603-8 VL - I SP - 19/1 EP - 19/12 CY - Aachen AN - OPUS4-17364 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Gradt, Thomas ED - Inaki Azkarate, ED - Estibaliz Ezponda, ED - Marco Nicola Carcassi, ED - Marangon, Alessia ED - Elena Rossi, T1 - Polymer composites for tribological applications in hydrogen environment N2 - In the development of hydrogen technology, special attention is paid to the technical problems of hydrogen storage. One possible way is cryogenic storage in liquid form. Generally cryotechnical machines need components with interacting surfaces in relative motion such as bearings, seals or valves, which are subjected to extreme conditions. Materials of such systems have to be resistant to friction-caused mechanical deformation at the surface, low temperatures and hydrogen environment. Since materials failure can cause uncontrolled escape of hydrogen, new material requirements are involved for these tribo-systems, in particular regarding operability and reliability. In the past few years several projects dealing with the influence of hydrogen on the tribological properties of friction couples were conducted at the Federal Institute for Materials Research and Testing, (BAM), Berlin. This paper reports some investigations carried out with polymer composites. Friction and wear were measured for continuous sliding and analyses of the worn surfaces were performed after the experiments. Tests were performed at room temperature in hydrogen as well as in liquid hydrogen. T2 - 2nd International Conference on Hydrogen Safety CY - San Sebastián, Spain DA - 2007-09-11 KW - Hydrogen KW - Polymer composite KW - Tribology PY - 2007 SN - 978-84-95520-15-9 SP - 1 EP - 9 CY - San Sebastián, Spain AN - OPUS4-18429 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Tribological behaviour of solid lubricants in hydrogen environment N2 - For further development of hydrogen technology it is necessary to have a sufficient number of materials for safe, reliable, and enduring service available. In this respect, tribosystems directly exposed to hydrogen are critical because of vanishing protective oxide layers in the presence of a chemical reducing environment. Furthermore, liquid lubricants are often not applicable, because of purity requirements, or very low temperatures in the case of liquid hydrogen. Thus, for numerous components in hydrogen technology, solid lubrication is the only possible method for reducing friction and wear. However, information about the suitability of particular friction reducing materials such as graphite, DLC, MoS2, and WS2 for hydrogen environment is very limited. Therefore, investigations on the tribological behaviour of these materials in liquid and gaseous hydrogen were carried out. The paper presents results for MoS2, WS2, and carbon coatings, and for PEEK matrix composites filled with PTFE, MoS2, or graphite. For comparison also results of tests in inert gases and liquid nitrogen and helium are shown. T2 - World Tribology Congress WTC IV CY - Kyoto, Japan DA - 2009-09-06 PY - 2009 AN - OPUS4-19893 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Gleitverhalten von PEEK-Kompositwerkstoffen in Wasserstoffumgebung N2 - Die Reibeigenschaften von PEEK-Materialien gegen Stahlscheiben wurden in Luft, Vakuum und Wasserstoffumgebung untersucht. Die Ergebnisse zeigen, dass reines PEEK umgebungsabhängig ist und die Desorption von Gasen im Vakuum zu hohen Verschleißraten führt. Die niedrigsten Verschleißraten sowohl in Vakuum als auch in einer Wasserstoffumgebung erzielen TiO2-Partikel. Ferner treten chemische Prozesse in den Materialien und im Tribokontakt auf und interagieren miteinander. T2 - 57. Tribologie-Fachtagung CY - Göttingen, Germany DA - 26.09.2016 KW - PEEK KW - Reibung KW - Wasserstoffumgebung PY - 2016 SN - 978-3-9817451-1-5 SP - 60/1 EP - 60/10 AN - OPUS4-37839 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Friction and wear characteristics of polymers in gaseous and liquid hydrogen N2 - The tribological characteristics of pure and graphite filled polymers were investigated in gaseous hydrogen at ambient temperatures and in LH2 at -253°C. It could be shown that the tribological properties of PI and PEEK materials is related to the formation of a transfer film. The influence of both hydrogen and cryogenic temperatures will be discussed in the presentation. T2 - 21th International Colloquium Tribology CY - Stuttgart/Ostfildern, Germany DA - 09.11.2018 KW - Friction KW - Wear KW - Hydrogen KW - PEEK PY - 2018 SP - 1 EP - 2 AN - OPUS4-43903 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas A1 - Theiler, Geraldine T1 - Tribological behaviour of solid lubricants in hydrogen environment T2 - World tribology congress 2009 CY - Kyoto, Japan DA - 2009-09-06 KW - Tribologie KW - Kompositwerkstoffe KW - Festschmierstoffe KW - Wasserstoff PY - 2009 SN - 978-4-9900139-9-8 IS - B1-122 SP - 15 AN - OPUS4-20137 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weihnacht, V. A1 - Brückner, A. A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - MoS2/ta-C-Kombinationsschichten hergestellt durch Laser-Arc-Technologie - Hochwertige Gleitschichten für extreme Umgebungen T1 - MoS2/ta-C coatings produced by laser-arc-technology N2 - Mittels lasergesteuerter gepulster Vakuumbogentechnologie (Laser-Arc) wurde eine reihe von reinen MoS2-Schichten sowie Kombinationsschichten aus MoS2 und tetraedrischem amorphen Kohlenstoff (ta-C) hergestellt. Mit diesen Schichtvarianten erfolgten tribologische Tests im Vakuum sowie in Atmosphäre. Dabei wurden im Hochvakuum reibungskoeffizienten bis zu 0,005 gemessen. Durch die Verwendung einer ta-C unterschicht konnte eine Lebensdauer von über 5×105 Lastzyklen erreicht werden. Zudem erwies sich diese unterschicht als vorteilhaft für das tribologische Verhalten der MoS2/ta-C Schichten unter atmosphärischen Bedingungen. N2 - A series of MoS2 and combined MoS2/ta-C coatings were prepared by lasercontrolled arc evaporation (Laser-Arc) in order to study the tribological coating behaviour under vacuum and atmospheric conditions. Very low friction coefficients down to 0.005 were measured under high vacuum. By using a ta-C underlayer beneath the MoS2 a increased lifetime up to 5×105 load cycles could be obtained. Also under atmospheric conditions the underlayer had a beneficial effect on coating performance. KW - MoS2 KW - ta-C Schichten KW - Reibung KW - Verschleiß KW - Vakuum Umgebungen PY - 2012 DO - https://doi.org/10.1002/vipr.201200500 SN - 0947-076X SN - 1522-2454 VL - 24 IS - 5 SP - 17 EP - 23 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-27207 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Polmeric materials for tribosystems in cryogenic liquefied natural gas (LNG) N2 - In order to test the suitability of polymers for LNG service, the tribological behaviour of materials based on PEEK, PTFE, PI and UHMW-PE sliding against CrNi steel was investigated. T2 - 59. Tribologie-Fachtagung CY - Goettingen, Germany DA - 24.09.2018 KW - CNG KW - LNG KW - Polymers KW - Friction PY - 2018 AN - OPUS4-46183 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hübner, Wolfgang A1 - Theiler, Geraldine A1 - Gradt, Thomas A1 - Klein, P. A1 - Friedrich, K. T1 - Der Einfluss kryogener Medien auf den Materialtransfer im Tribosystem Polymerkomposit/Stahl PY - 2001 SN - 0724-3472 VL - 48 IS - 6 SP - 8 EP - 12 PB - Expert Verlag CY - Renningen AN - OPUS4-12659 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -