Tribological properties of PEEK composites in ionic liquid lubricants

Tribological properties of PEEK composites in ionic liquid ([BMIM]PF6) were studied and compared with that under dry sliding condition as well as in anti-wear hydraulic oil (L-HM 46). The friction coefficient (μ) and wear rate (W) of PEEK composites in [BMIM]PF6 are reduced by a wide margin than that under dry sliding, and the reduction amplitudes of 11 and W are 73%-85% and 68%-96%, respectively. Under dry sliding, μ of MoS₂/PEEK (μ_MoS2PEFK,dry) is the lowest among PEEK composites, which is just half of Urtnicdm and W of Gr/PEEK under dry sliding (W_Gr/PEEK,dry) is 64% of W_PEEK,dry. But μ of pure PEEK in [BMIMJPF6 (μ_PEEK.IL) is only 31% of μ_{MoS2/PEEK,dry} and w of Pure PEEK in [BMIM]PF6 (W_PEEK,IL) is just 10% of W _GrPEEK,dry. As a kind of traditional lubricant, L-HM 46 also has a good lubrication effect on PEEK composites. But the lubrication effect of [BMIMJPF6 is better, with a reduction amplitude of 6%-26% in μ and a reduction amplitude of 4%-40% in W when compared with L-HM 46. In [BMIM]PF6 (or in L-HM 46), W of pure PEEK is the lowest among PEEK composites and μ of pure PEEK is just a little higher than that of MoS₂/PEEK. Results show that PEEK composites in [BMIM]PF6 have better tribological propertis than under dry sliding condition and in L-HM 46, and pure PEEK has superior tribological behavior than PEEK composites filled with internal lubricants in [BMIMJPF6.