TY - CONF A1 - Hübner, Wolfgang A1 - Gradt, Thomas A1 - Theiler, Geraldine A1 - Aßmus, Kristin A1 - Ostrovskaya, Y. T1 - Werkstoff-Untersuchungen für technische Anwendungen in flüssigem Wasserstoff T2 - 1. Deutscher Wasserstoff-Energie-Tag 2002 CY - Essen, Deutschland DA - 2002-10-12 PY - 2002 IS - CD-ROM SP - 1 EP - 8 AN - OPUS4-1973 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Géraldine 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 - 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 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 - CONF A1 - Gradt, Thomas A1 - Theiler, Géraldine 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 - Gradt, Thomas T1 - Tribological characteristics of polyimide composites in hydrogen environment N2 - The influence of hydrogen environment on the friction and wear behavior of polyimide (PI) composites was investigated for two different PI-types (PI1 and PI2) filled with natural or synthetic graphite. Sliding tests were run against AISI 52100 steel and the worn surfaces as well as the transfer film were analyzed by means of SEM, EDX and Infrared Spectroscopy. Results indicate that the chemical structure of the polyimide has a major influence on the tribological behavior. While the friction of PI2 remains rather stable in all environments, PI1 showed very low friction in hydrogen without any lubricant. The lubricity of graphite was found to be more effective in hydrogen than in moist air. KW - Sliding friction KW - Polyimide KW - Graphite KW - Hydrogen PY - 2015 DO - https://doi.org/10.1016/j.triboint.2015.06.001 SN - 0301-679X VL - 92 SP - 162 EP - 171 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-33555 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 - 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 - 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 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Tribological behaviour of graphite filled polyimide composites in hydrogen environment T2 - ECCM16 - 16th European conference on composite materials CY - Seville, Spain DA - 2014-06-22 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 - 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 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 - Gradt, Thomas A1 - Theiler, Géraldine 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 - 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 - Theiler, Geraldine A1 - Gradt, Thomas A1 - Banova, Z. A1 - Schlarb, A.K. 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 - 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 - JOUR A1 - Theiler, Géraldine 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 - 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 - 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 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. ------------------------------------------------------------------------------------------------------------------------------------------- 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 - 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 -