Tribological performance of 3D printed plastics coated with self-lubricating coatings

This study focused on improving the tribological properties of Fused Deposition Modeling (FDM) printed plastic components by applying self-lubricating tungsten-sulfur-carbon (W-S-C) coatings. Test samples were fabricated using polyamide (PA) and carbon fiber reinforced polyamide (CF-PA) filaments. W–S–C coatings with two different carbon contents (∼36 and ∼48 at.%) were deposited onto 3D-printed PA and CF-PA substrates, with coating thickness varied for the ∼36 at.% C system. Coating characterization techniques included scanning electron microscopy (SEM), wavelength dispersive spectroscopy (WDS), X-ray diffraction (XRD), nanoindentation, scratch testing, and reciprocating ball-on-disk tribometry against a steel counterbody. The results showed a significant enhancement in the tribological properties of the coated samples. The coated PA samples exhibited a 65% reduction in coefficient of friction (CoF) and a wear rate 24 times lower than the uncoated PA samples. Similarly, the coated CF-PA samples demonstrated a substantial 55% reduction in CoF and a wear rate 10 times lower than the uncoated CF-PA samples. The thicker coatings demonstrated superior tribological performance compared to the other coatings, showcasing their effectiveness in improving the tribological characteristics of both PA and CF-PA samples.