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 - 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 - 4400204-4 PB - Inst. CY - New York, NY, USA AN - OPUS4-26384 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 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 - Theiler, Géraldine A1 - Gradt, Thomas T1 - Benchmarking of polymer materials for tribological applications in hydrogen N2 - The focus of this study is to evaluate the influence of hydrogen on the friction and wear behavior of a wide range of polymer materials. Thereby, the tribological performance of filled und unfilled polymers from different suppliers were compared at room temperature in air and hydrogen gas (H2) as well as in liquid hydrogen at -235°C (LH2). T2 - 23rd International Conference on Wear of Materials CY - Online meeting DA - 26.04.2021 KW - Polymers KW - Hydrogen KW - Friction KW - Wear PY - 2021 AN - OPUS4-52651 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 - 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 - 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 - 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 composite KW - Friction PY - 2018 AN - OPUS4-43899 LA - eng 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 - CONF A1 - Theiler, Géraldine 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 - JOUR A1 - Theiler, Géraldine 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 - 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 - 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, Géraldine 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 - CONF A1 - Gradt, Thomas A1 - Theiler, Géraldine 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 - 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 - 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 - 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 - 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 - Theiler, Géraldine 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 - Gradt, Thomas A1 - Theiler, Géraldine 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 - 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 - 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 -