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 JF - IEEE transactions on applied superconductivity 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 - CONF A1 - Theiler, Geraldine A1 - Brice, H. A1 - Gradt, Thomas T1 - Stick-slip behaviour of polymer films in LHe T2 - WTC 2013 - 5th World tribology congress 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 -