Tribological behavior of silicon and oxygen co-doped hydrogenated amorphous carbon coatings on polyether ether ketone.

Polyether ether ketone (PEEK) is widely used for polymer-metal sliding pairs due to its excellent characteristics such as self-lubrication, and chemical stability. However, PEEK is prone to be worn easily when it comes to friction with metal, which is the most critical limitation for the development of PEEK/metal tribo-pairs. In this study, the tribological properties of silicon and oxygen co-doped amorphous hydrogenated carbon (a- C:H:Si:O) coating on PEEK substrates were focused, where the a-C:H was used for comparison simultaneously. Results revealed that both a-C:H and a-C:H:Si:O coated PEEK displayed a high hardness over 6 GPa and enhanced the tribological resistance. Noted that even the PEEK coated with a-C:H coating behaved the lowest wear rate of 1.82 × 10−7 mm3/Nm, co-doping Si and O improved the adhesion strength between coating and PEEK substrate together with the lubricity. In particular, the a-C:H:Si:O coatings with the concentration of 3.96– 7.49 at. % for Si and 3.07– 6.07 at. % for O showed excellent stability with a wear rate of (2.9 ± 0.4) × 10−7 mm3/Nm, due to the formed compacted tribo-film over the counterpart. The results bring forward a promising strategy to enhance the wear resistance of PEEK/metal sliding components for harsh tribological applications. [Display omitted] • a-C:H:Si:O coatings with highly controllable composition were deposited on PEEK by PECVD. • The a-C:H and a-C:H:Si:O coated PEEK obtained a high hardness over 6 GPa and an improved tribological performance. • Good mechanical properties of a-C:H:Si:O coating and dense tribofilm formed account for the good lubricity. [ABSTRACT FROM AUTHOR]