Abstract: A novel bismaleimide resin (5406 resin) and its composites with nanometer Si3N4 were prepared. the effect of the content of nanometer Si3N4 on the properties of 5406 resin and its composites was investigated. }Che resin 5406 had high modulus, good heat properties, especially a low viscosity allowing the fine dispersion of the nanoparticles and the casting of the composite precursors. the composite with nanometer Si3N4 exhibited considerably lower friction coefficient and wear rate than the neat 5406 resin. SEM indicated that the wear mechanism of the composites of 5406/Si3N4 was essentially adhesion wear, while that of the neat 5406 resin was mainly plastic deformation.

Key words: bismaleimide, friction, wear, wear mechanism, nanometer silicon nitride