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 - TY - CONF A1 - Hausberger, A. A1 - Major, Z. A1 - Theiler, Geraldine A1 - Gradt, Thomas A1 - Schwarz, T. T1 - Investigation on the friction and wear behaviour of thermoplastic polyurethanes by controlling the adhesion and deformation part of friction N2 - In this work, unfilled and graphite filled TPU materials were used to investigate the contribution of the adhesion and deformation component of friction. Pin-on-Disc tests were conducted in the air and under vacuum condition by using different surface roughness. T2 - 6. European Conference on Tribology CY - Ljubljana, Slovenia DA - 07.06.2017 KW - TPU KW - Friction KW - Wear KW - Adhesion KW - Deformation KW - Vacuum PY - 2017 SP - 4.02 - 1 EP - 4.02 - 2 AN - OPUS4-40763 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas 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 composite KW - Friction PY - 2018 AN - OPUS4-43899 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Friction and wear behaviour of graphite filled polymer composites in hydrogen environment N2 - High performance polymer composites have been intensively investigated for tribological applications in air, but rarely in hydrogen environment. Author's previous benchmark of composites in liquid hydrogen (LH2) showed that graphite filled polymers have beneficial friction behaviour in this extreme condition. Therefore, further investigations have been undertaken in hydrogen environment. This paper presents first results obtained with polyimide composites filled with different types (natural, synthetic) and amounts of graphite in air, vacuum and hydrogen environments. A particular attention is taken to the influence of hydrogen on graphite as well as on the polymer matrix. KW - Polymer composites KW - Polyimide KW - Graphite KW - Friction KW - Wear KW - Hydrogen environment KW - Vacuum PY - 2015 DO - https://doi.org/10.2474/trol.10.207 SN - 1881-2198 VL - 10 IS - 2 SP - 207 EP - 212 CY - Tokyo, Japan AN - OPUS4-33554 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR 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. KW - PEEK-Komposite KW - Wasserstoff KW - Vakuum KW - Graphit PY - 2017 SN - 0724-3472 VL - 64 IS - 6 SP - 52 EP - 59 AN - OPUS4-42919 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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, Geraldine A1 - Gradt, Thomas T1 - Comparison of the sliding behavior of several polymers in gaseous and liquid hydrogen N2 - The development of hydrogen technologies entails high safety requirements in distribution and dispensing infrastructure. Therefore, it is necessary to pursue research on material compatibility in hydrogen, especially for critical parts with tribological issues. The focus of this study is to evaluate the influence of hydrogen on a wider range of commercially available polymer materials. Thereby, the friction and wear behavior of different grades of TPE, POM, PA66, PA12, PPA, PEEK, PPS, PTFE, PAI, PI and PBI were investigated against a rotating steel disk (AISI 304). Filled and unfilled polymers from different suppliers were evaluated at room temperature in air, vacuum and hydrogen gas (H2) as well as in liquid hydrogen at - 253°C (LH2). The sliding behavior of the polymer materials is discussed by means of surface analyses, whereby special attention is paid to the formation of a transfer film. According to the results at ambient temperature, the effect of hydrogen environment on the tribological behavior of neat polymers may be related to lack of moisture, but also to saturated hydrocarbons in gaseous hydrogen. In liquid hydrogen, the best tribological performances were achieved with neat PA polymers as well as PPS and PI composites. KW - Polymers KW - Composites KW - Sliding wear KW - Hydrogen KW - Cryogenic temperature PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597123 DO - https://doi.org/10.2474/trol.18.217 SN - 1881-2198 VL - 18 IS - 5 SP - 217 EP - 231 PB - Japanese Society of Tribologists AN - OPUS4-59712 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Comparison of the sliding behaviour of several polymers in hydrogen N2 - The work presented here deals with the friction and wear behaviour of polymer materials in hydrogen. Commercially available grades of PEEK, PA, PPA, PAI, PI and PBI were investigated at room temperature in air and hydrogen gas (H2) as well as in liquid hydrogen at -253°C (LH2). T2 - 7th World Tribology Congress, WTC 2022 CY - Lyon, France DA - 10.07.2022 KW - Friction KW - Wear KW - Polymers KW - Hydrogen KW - Cryogenic PY - 2021 SP - 1 AN - OPUS4-62089 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Influence of counterface and environment on the tribological behaviour of polymer materials N2 - This paper focuses on the influence of the counterface materials on the sliding behaviour of polymer materials in hydrogen. Polyimide (PI), polyetheretherketone (PEEK) and Polytetrafluoroethylene (PTFE) materials were investigated against hardened 52100 martensitic bearing steel and 304 austenitic stainless steel with similar roughness (Ra = 0.2 μm). Results indicate that the friction and wear of PI and PEEK materials depend on the counterface material. This effect wasn’t observed for PTFE composites. While the tribological performance of polyimide is better against 52100 in hydrogen, improved sliding behaviour of PEEK materials is observed with 304 counterface, particularly at higher sliding speed. Surface analyses of the transfer film reveal that the influence of the counterface is primarily related to the chemical nature of the steel for PI and to the thermal conductivity of the disc for PEEK materials. KW - Friction KW - Wear KW - Polymers KW - Hydrogen Transfer Film PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515483 DO - https://doi.org/10.1016/j.polymertesting.2020.106912 VL - 93 SP - 106912 PB - Elsevier Ltd. AN - OPUS4-51548 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Environmental effects on the sliding behaviour of PEEK composites N2 - The sliding performance of PEEK materials against steel discs was investigated in air, vacuum and hydrogen environment. KW - Sliding friction KW - PEEK KW - Graphite KW - TiO2 KW - CNTs KW - Vacuum KW - Hydrogen PY - 2016 DO - https://doi.org/10.1016/j.wear.2016.09.019 SN - 0043-1648 SN - 1873-2577 VL - 368 SP - 278 EP - 286 PB - Elsevier B.V. AN - OPUS4-37927 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gradt, Thomas T1 - Influence of solid lubricant fillers on the tribological behaviour of PEEK composites in vacuum N2 - Polymer composites are widely used as dry sliding materials for economical reasons or in special cases where the application of liquid lubricants or greases is not possible. Examples can be found in space, vacuum, low temperature, or cleanroom environment. For such dry sliding tribosystems it is necessary to achieve acceptable low friction and endurance. Polytetrafluoroethylene (PTFE) has proved to be an outstanding material for the use in tribological applications in vacuum in the broad temperature range from - 260 °C to + 260 °C. A promising matrix material is polyetheretherketon (PEEK). Like PTFE, it is also resistant to many aggressive solvents and has a very low vapor pressure, making it suitable for vacuum applications. The tribological behaviour of PEEK and PEEK-matrix composites has been investigated in many studies. However, the number of studies of self lubricating PEEK composites filled with PTFE and other solid lubricants are limited for vacuum and ultra high vacuum environment. The paper presents results of high-vacuum friction tests of different carbon fibre reinforced PEEK composites filled with PTFE, and a further solid lubricant. The polymer samples were tested in pin-on-disc configuration against X5CrNi1810 steel (similar to AISI 304). Depending on sliding speed and temperature, friction coefficients as low as for PVD coatings have been observed. T2 - 13th European Space Mechanisms and Tribology Symposium (ESMATS 13) CY - Vienna, Austria DA - 2009-09-23 PY - 2009 AN - OPUS4-19892 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Friction and wear of PEEK composites in vacuum environment N2 - The sliding performance of PEEK composites was investigated in vacuum environment. Tests were performed with carbon fibre reinforced PEEK composites filled with PTFE, and MoS2 or graphite as further solid lubricant. Polymer samples were tested in a pin-on-disc configuration continuously sliding against CrNi-steel. Depending on sliding speed and temperature, the MoS2 filled composites showed high wear resistance and friction coefficients as low as PVD coatings. KW - PEEK composites KW - Vacuum KW - Friction KW - Wear KW - MoS2 KW - Graphite PY - 2010 DO - https://doi.org/10.1016/j.wear.2010.04.007 SN - 0043-1648 VL - 269 IS - 3-4 SP - 278 EP - 284 PB - Elsevier CY - Amsterdam AN - OPUS4-22046 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -