Low-Friction and Wear-Resistant Polyether Ether Ketone Composite Coatings for High-Pressure High-Temperature Applications

The mechanical and tribological properties of polyether ether ketone (PEEK) based polymer nanocomposite films, consisting of  boron nitride and tungsten carbide fillers, were studied toward application as low-friction and wear-resistant coatings under high-temperature, high-pressure conditions. Dry nanocomposite powders of different compositions were synthesized by ball milling, and applied on steel substrates, to obtain well-adherent coatings with mono- and multilayered architectures. Coating properties such as modulus, hardness, dynamic coefficient of friction, and wear were correlated to the type, particle size and concentration of the filler, polymer crystallinity, coating microstructure, and surface roughness. The analytical techniques used for the study included nanoindentation, linear reciprocating ball-on-flat tribometry, differential scanning calorimetry, laser diffraction, X-ray diffraction, and scanning electron microscopy. Using optimized filler size, composition, and processing conditions, highly wear-resistant coatings with friction coefficients (against steel) of about 0.2 and indentation modulus of about 14 GPa were obtained. The corresponding values for unfilled PEEK coatings were found to be 0.48 and 4 GPa, respectively. This talk will discuss the relationship between the properties of the composite coatings with their composition, processing, and microstructure.