Mechanical and tribological properties of three-component high-strength solid-lubricant polyimide based composites

Abstract

In order to design high-strength solid-lubricant composites for applications in friction units, the mechanical and tribological properties of polyimide (PI) based composites reinforced with long annealed carbon fibers and filled with commercially available solid-lubricant fillers of various nature (10 wt % PTFE, Gr, MoS2) under the conditions of metal-polymer and ceramic-polymer tribological mating were studied. It was shown that loading with long carbon fibers (CF) with the length of 2 mm and a content of 10 wt % increased the elastic modulus by 2.5 times, while the ultimate strength enlarged by 1.5 times. It was found that the highest wear resistance was characteristic for a three-component mixture composite with annealed CF and PTFE particles (in comparison with neat PI, the wear rate decreased by ∼419 times for metal-polymer and by ∼483 times for ceramic-polymer tribological couplings when tested by pin-on-disk scheme). Inorganic solid-lubricant fillers (Gr, MoS2) increased wear resistance of the composite by 35 (Gr) and 5 times (MoS2) for metal-polymer and ceramic-polymer mating, respectively. On the basis of a comparative analysis of various solid lubricant fillers some practical recommendations were given for the development of high-strength antifriction PI based composites for friction units using available reinforcing and solid lubricant fillers.