FRICTIONAL-PROPERTIES OF CERAMICS, MOS2 COATED FILMS AND POLYETHYLENEFIBER-REINFORCED PLASTICS AT 4.2 K IN LIQUID-HELIUM

Frictional problems in superconducting magnets are related to the stab ility and reliability of the magnets, because frictional heating cause s quench of the magnet and the frictional resistance determines the li mit of the shear force at the contacting surfaces. To find those mater ials possessing low friction, the frictional properties of ceramics of ZrO2 and Si3N4, three different kinds of MoS2 coated films and polyet hylene fibre reinforced plastics (DFRPs) were examined at 4 K in liqui d helium under reciprocating sliding conditions. The two ceramics show ed similar tendencies in terms of friction. The organically bonded MoS 2 film exhibited the lowest coefficient of friction of 0.06, while the coefficient of friction of DFRP was lower than that of glass fibre re inforced epoxy (GFRP).