TY - JOUR A1 - Friedrich, K. A1 - Klein, P. A1 - Theiler, Geraldine A1 - Ye, L. A1 - Mai, Y.W. T1 - PEEK- and PTFE- Based Composites for Tribology Applications in a Range between Liquid Helium and Room Temperature N2 - This study deals with the development of PEEK (polyehteretherketone) and PTFE (polytetrafluoroethylene) based composites, optimized for low friction and low wear performance under extreme environments. It is demonstrated that the incorporation of a harder polymer component into PTFE (such as PEEK particles), a short fiber reinforcement (e.g. carbon fibers CF), and internal lubricants (e.g. PTFE particles), helps to reduce the friction and to improve the wear resistance over a very wide temperature range. KW - Composites KW - Tribology KW - PEEK KW - PTFE KW - Temperature KW - Friction KW - Wear PY - 2007 SN - 1013-9826 VL - 334-335 SP - 597 EP - 600 PB - Trans Tech Publ. CY - Aedermannsdorf AN - OPUS4-15045 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 - 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 - 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 - Brice, H. A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Frictional behavior of material couples in superconducting MRI magnet systems at 4.2 K N2 - Windings in superconducting magnets operating at 4.2 K are highly susceptible to quenching caused by small frictional heat inputs. Small movements in the magnet system are inevitable during ramping due to the increasing electromagnetic forces. Friction pairs of polymer based materials have been investigated at 4.2 K to gain an understanding of their sliding behavior in conditions representative of superconducting MRI systems. The results indicate that polymer-polymer pairs experience unstable sliding behavior with repeated stick-slip whereas polymer-aluminum couples have stable sliding behavior up to high contact pressures of 20 MPa. KW - Cryotribology KW - Friction KW - MRI magnets KW - Stick-slip PY - 2012 DO - https://doi.org/10.1109/TASC.2011.2175683 SN - 1051-8223 VL - 22 IS - 3 SP - 4400204-1 EP - 4400204-4 PB - IEEE CY - New York, NY AN - OPUS4-26384 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 - CONF A1 - Theiler, Geraldine T1 - Effects of UV radiation on the friction behavior of thermoplastic polyurethanes N2 - The effects of UV radiation and humidity condition on the frictional properties of TPU materials are presented in this paper. Photooxidative degradation of polymer leads to deterioration of physical and mechanical properties, which affect its tribological behavior significantly. Unfilled TPUs lose their anti-slip properties. T2 - The 6th World Tribology Congress (WTC 2017) CY - Beijing, China DA - 17.09.2017 KW - TPU KW - UV radiation KW - Friction PY - 2017 AN - OPUS4-42440 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine T1 - Effects of UV radiation on the friction behavior of thermoplastic polyurethanes N2 - The effects of UV radiation and humidity condition on the frictional properties of TPU materials are presented in this paper. Photooxidative degradation of polymer leads to deterioration of physical and mechanical properties, which affect its tribological behavior significantly. Unfilled TPUs lose their anti-slip properties. T2 - The 6th World Tribology Congress CY - Beijing, China DA - 17.09.2017 KW - TPU KW - UV radiation KW - Friction PY - 2017 SP - 1 EP - 4 AN - OPUS4-42443 LA - eng 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 - JOUR A1 - Theiler, Geraldine A1 - Wachtendorf, Volker A1 - Elert, Anna Maria A1 - Weidner, Steffen T1 - Effects of UV radiation on the friction behavior of thermoplastic polyurethanes N2 - The effects of weathering exposure on unfilled and filled thermoplastic polyurethanes (TPU) materials are described as performed under different humidity conditions. For this purpose, a weathering device was used with UV-A 340 nm lamps at a constant temperature of 40 °C. The effects of environmental (UV and humidity condition) degradation on the frictional properties of TPU materials are presented along with surface analyses to characterize the chemistry of the degradative process. Photooxidative degradation of unfilled polymer leads to deterioration of physical and mechanical properties, which affects its tribological behavior significantly. Due to crosslinking, the stiffness of the material increases, reducing drastically the friction coefficient of unfilled TPUs. The frictional behavior of glass fiber reinforced TPU is less affected by radiation. KW - Photooxidation KW - UV radiation KW - Friction KW - TPU KW - Humidity PY - 2018 DO - https://doi.org/10.1016/j.polymertesting.2018.08.006 SN - 0142-9418 SN - 1873-2348 VL - 70 SP - 467 EP - 473 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-45709 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 - 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 - 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 - 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 - CHAP A1 - Friedrich, K. A1 - Theiler, Geraldine A1 - Klein, P. ED - Sinha, S. K. T1 - Chapter 9: Polymer composites for tribological applications in a range between liquid helium and room temperature N2 - This chapter deals with the development of polyetheretherketone (PEEK) and polytetrafluoroethylene (PTFE)-based composites, optimized for low friction and low wear performance under extreme environments. It is demonstrated that the incorporation of a harder polymer component into PTFE (such as PEEK particles), a short fiber reinforcement (e.g. carbon fibers (CFs)) and internal lubricants (e.g. PTFE particles) helps to reduce the friction and to improve the wear resistance over a very wide temperature range. KW - Polymer composites KW - Friction KW - Wear KW - Cryogenic temperature PY - 2018 SN - 978-981-3227-78-1 SN - 978-981-3227-80-4 SP - 307 EP - 343 PB - World Scientific Publishing Co. Pte. Ltd. AN - OPUS4-46321 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine 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 - 09.01.2018 KW - Friction KW - Wear KW - Hydrogen KW - PEEK PY - 2018 AN - OPUS4-43902 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine T1 - Friction and wear characteristics of polymers in gaseous and liquid hydrogen N2 - The presentation deals with the investigation of polymer composites for their suitability for friction systems in gaseous and liquid hydrogen. T2 - 59. Tribologie-Fachtagung CY - Goettingen, Germany DA - 24.09.2018 KW - Friction KW - Wear KW - Polymer composites KW - Hydrogen KW - Cryogenic temperature PY - 2018 AN - OPUS4-46184 LA - eng 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 N2 - In the present work it was shown that the the aim of the presented tests is to investigate polymer composites for their suitability for friction systems in gaseous and liquid hydrogen. T2 - 59. Tribologie-Fachtagung CY - Göttingen, Germany DA - 24.09.2018 KW - Friction KW - Wear KW - Polymer composites KW - Hydrogen KW - Cryogenic temperature PY - 2018 SN - 978-3-9817451-3-9 SP - 60/1 EP - 60/4 AN - OPUS4-46178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Geraldine T1 - Sliding performance of polymer materials in hydrogen and methane N2 - In this talk, the sliding performance of polymer materials in hydrogen and methane are presented. The influence of the environmental conditions is discussed in terms of material composition, counterface, transfer film formation, and triboreactions. T2 - International Tribology Conference/ITC CY - Sendai, Japan DA - 17.09.2019 KW - Friction KW - Wear KW - Polymer composites KW - Hydrogen KW - Methane PY - 2019 AN - OPUS4-49148 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 -