Comparative Study of Friction and Wear Performance of PEK, PEEK and PEKK Binders in Tribological Coatings

Abstract

Tribological coatings are widely used in industry, particularly when the conventional oil lubrication of sliding surfaces has to be replaced by maintenance-free contacts. This work studies the tribological performance of waterborne tribological coatings based on three binders of the polyaryletherketone (PAEK) family: polyetherketone (PEK), PEEK, and polyetherketoneketone (PEKK). Even though PEEK is a well-known commercial solution for this type of tribological coatings, PEK and PEKK have never been studied in such a context. PTFE particles were added to all coatings as a solid lubricant. High thermal resistance of the binder materials was confirmed, with decomposition starting above 550 °C, under either N2 or O2 atmosphere. XRD analysis showed that PEK and PEEK are semi-crystalline after being subjected to the coating curing conditions, while PEKK is amorphous. The coatings were successfully applied with thicknesses of 20–30 µm. Tribological measurements showed that the PEK-based coating possesses a coefficient of friction (COF) of 0.08 under high load and pressure conditions (hertzian point contact), which is lower than the reference PEEK-based coating (around 0.11). The PEKK-based coating showed an impressive wear resistance with almost no wear measured compared to the 105 µm wear obtained for PEEK-based coating, while showing a similar COF. These results suggest that PEK and PEKK seem to be interesting alternatives to PEEK and should be further studied for use in tribological coatings.

Use of high-performance polymeric materials in customized low-cost robotic grippers for biomechatronic applications: experimental and analytical research

“…The components made from PEKK can withstand higher operating temperatures without losing structural integrity, this being one critical factor in the highperformance and longevity of robotic grippers, which often work in varied and demanding thermal environments (Tadini et al, 2017). Additionally, the robust carbon structure in PEKK provides excellent wear resistance, reducing the rate of material degradation under mechanical stress and repetitive motions, thereby extending the service life of the robotic grippers (Pedroso et al, 2022).…”

Assessment of the Influence of Protective Polymer Coating on Panda Fiber Performance Based on the Results of Multivariant Numerical Simulation

“…The study of tribological properties of materials has been and remains a relevant topic for scientists in various fields [21][22][23][24][25][26][27][28]. In order to reduce the level of friction force magnitude, various modifications are introduced in the material composition [24][25][26], lubricants are used [27], etc. [28].…”

Characterization of the Polyetheretherketone Weldment Fabricated via Rotary Friction Welding

“…Results showed that an increase in quantity was obtained using a laser power of 15 mW. Pedroso et al [16] investigated the tribological performance of waterborne tribological coatings based on three binders of PEEK and polyetherketone. Results suggested that PEKK and polyetherketone seem to be attractive alternatives to PEEK.…”