▎ 摘　　要

NOVELTY - High thermal conductivity polyimide nano-friction material comprises 100 pts. wt. polyimide, 0.5-2 pts. wt. graphene, 0.5-1 pt. wt. multi-walled carbon nanotube and 0.1-1 pt. wt. nano-copper powder. USE - The high thermal conductivity polyimide nano-friction material is useful in ultrasonic motor rotor (claimed). ADVANTAGE - The composite material: has high thermal conductivity, thus has a low wear rate in a high-temperature environment, simple preparation method, convenient operation, low cost, and easy industrial large-scale preparation; is also easy to process into thin slices for use in rotary ultrasonic motors, which can increase the service life of the ultrasonic motor in a high-temperature environment. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing high thermal conductivity polyimide nano-friction material, comprising (i) ultrasonically dispersing graphene, multi-walled carbon nanotubes and nano-copper powder in acetone for 30 minutes, then adding polyimide powder, ball milling with a ball mill for 4 hours, (ii) drying in a vacuum drying oven at 80 degrees C, crushing and sieving to obtain mixed powder, (iii) hot pressing the mixed powder under the pressure of 10-20 MPa, maintaining the temperature at 375-390 degrees C for 1-2 hours, then cooling down with the furnace to obtain polyimide nano-friction material and (iv) slicing the polyimide nano-friction material produced in step (iii), pasting and surface treating.