Effect of Lubrication on Friction and Wear Properties of PEEK with Steel Counterparts

Abstract

Poly-Ether-Ether-Ketone (PEEK) has been widely used for tribological applications with steel counterparts because of its superior mechanical and self-lubricating properties. Fluid lubrication has the potential to further improve the performance of PEEK/steel contacts but its effect has been shown to depend on the operating conditions. To elucidate these aspects and establish the mechanism of fluid lubrication, the friction and wear properties of the PEEK/steel contacts in both dry and poly-α-olefin (PAO) lubricated conditions were investigated by tribological tests and surface analytical techniques. The nanoindentation measurements showed that lubrication with PAO had a softening effect on the wear track of PEEK, but no correlation was established with the wear of PEEK. The tribological behavior, for both dry and lubricated contacts, was correlated with the thickness of PEEK transfer films on the steel counterparts. The thickness of these films, as determined by Electron Probe Micro Analysis (EPMA) and X-ray Photoelectron Spectroscopy (XPS), was controlled by the rates of their formation and removal and depended on the operating conditions. Moreover, lubrication with PAO inhibited not only the formation but also the removal of PEEK transfer films. This study thus sheds light on the mechanism of fluid lubrication of the PEEK/steel contacts.

Effect of Friction Reducers with Unreinforced PEEK and Steel Counterparts in Oil Lubrication

“…While Tatsumi [38,39] attempted to elucidate the mechanism of tribofilm formation, our experimental work aimed to show the potential of friction reducers combined with conventionally marketed base oils (Mineral (Group III)) with special focus on nonconventional couplings under operating conditions very similar to those used in reality (higher temperature).…”

“…Currently, there is limited research available on the effects of friction reducers in PEEK contacts during oil lubrication. At room temperature, Tatsumi et al [38] demonstrated that lubrication with a poly-α-olefin (PAO)-based oil not only inhibited the formation of PEEK transfer films but also prevented their removal in the PEEK-steel contact. In another study [39], FRs blended with a PAO-based lubricant were investigated and a mechanism was proposed.…”

Friction and wear performance of polyether ether ketone (PEEK) polymers in three lubrication regimes

“…For PEEK-based materials, particularly PEEKcf20, we noticed from Alicona's measurements a lapping effect, i.e., a smoothing of the peaks in the material at the location of the wear track. Some authors in the literature have noted the formation of tribofilm in dry condition using other tribometers (MTM) under more harsh external conditions [13].…”

Correlating surface topography of relaxed layer of ZA/ZrB2 in situ composites to wear and friction

“…Lubrication acts as a protective film between the asperities of counter surface, resulting in less friction and wear [20]. Tatsumi et al [21] have investigated the effect of lubricants on the tribology of PEEK with steel counter surface and reported that lubrication reduces friction and softening effect on wear track. Under lubrication conditions, bronze-based alloys are extensively used for tribological applications, especially in automobile and machinery parts [22,23].…”