The lubricity and reinforcement of carbon fibers in polyimide at high temperatures

Transfer film formation mechanism and tribochemistry evolution of a low-wear polyimide/mesoporous silica nanocomposite in dry sliding against bearing steel

“…Chang et al [30] correlated layer thickness of transfer films with tribological properties of polymer composites as a function of transfer film efficiency factor so that the friction and wear of the sliding system could be analyzed, resulting in a Stribeck type diagram. Nevertheless, while improved transfer film quality has been explained as one major reason for the enhancement of triobological properties of PI-matrix composites [1,2,[6][7][8][9][10], the transfer film formation mechanism of PI-matrix composites still remains neglected. In most cases, transfer films are regarded as a consequence of tribological behavior and studies considering the formation and evolution of the transfer film as a process of tribological behavior are rarely found.…”

“…In a dry sliding process against a metal, large PI wear debris or plates are easily sheared off because the rigidity of main chains and some are transferred on surfaces of metal counterpart, causing high friction and wear of pure PI. Such triobofilms are generally thick, lumpy and weakly bonded with metal pieces [1,6]. The incorporation of different micro/nanofillers such as carbon fibers, glass fibers, aramid fibers, ceramics and solid lubricants has been reported to contribute to over 50% increase in the wear resistance of PI [7][8][9].…”

“…In-situ polymerization method was employed initially to enhance tribological properties of PI composites, but with contrary outcomes obtained, possibly induced by combined effects of approaches, reinforcing agents and interfacial design [21,22]. Many reinforcing mechanisms [2,[6][7][8][9][10][11][12][13] were proposed to explain the reason for enhancing tribological properties of PI composites, consisting of the formation of high-quality triofilms, lubricity and preferential load bearing of fillers, as well as enhanced mechanical properties. Within diverse mechanisms, the improved quality of transfer films consistently gives rise to the improvement of tribological properties of PI composites.…”

An investigation on the mechanical and tribological properties of carbon fiber/polyimide composites at elevated temperatures

“…b–d and b. As discussed in our previous study, during the high temperature sliding process, the carbon fiber can be further graphitized to form better graphite structures under the action of high pressure and high shear stress, which promotes the formation of transfer films on the counterfaces, with consequently low friction coefficient . Moreover, partial transfer film can further transfer back to the surface of polymer composites and form a friction film during the repeated sliding process (Fig.…”

Improving tribological properties of phenolic resin/carbon fiber composites using m‐Si3N4@PANI core–shell particles

“…For instance, metal‐based friction composites, ceramic‐enhanced friction composites, and fiber‐enhanced friction composites have been developed. Among the fiber composites, carbon fiber friction composites possess the advantages of high dimensional stability, high strength, good wear resistance, high heat resistance, and good thermal conductivity . These excellent properties have determined that carbon fiber friction composites will receive widespread attention worldwide.…”