Corrosion, surface, and tribological behavior of electrophoretically deposited polyether ether ketone coatings on 316L stainless steel for orthopedic applications

Electrophoretic deposition (EPD) of polyether ether ketone (PEEK) coatings on metallic implants has recently attracted a great deal of interest; however, further investigation into their corrosion, surface, and tribological properties is required for their clinical application. Using Potentiodynamic polarization and Mott-Schottky analysis of PEEK coatings, we analyzed the electrochemical corrosion behavior of electrophoretically deposited PEEK coatings on 316L stainless steel (SS) substrates. In addition, the tribological behavior of the coatings was determined through pin-on-disc and scratch testing. Initially, the EPD parameters were optimized using a Taguchi Design of Experiment (DoE) approach. The coatings exhibited irregular shaped grains along with ∼66 μm of thickness. Fourier transform infrared spectroscopy confirmed the presence of functional groups ascribed with PEEK. The coatings were moderately hydrophobic and had an average roughness of ∼2 μm. The corrosion studies demonstrated promising features of current density and corrosion potential, indicating that corrosion resistance significantly improves with PEEK coating. Electrochemical impedance spectroscopy also confirmed the corrosion resistance of PEEK coating. The coatings exhibited a slightly lower wear resistance than SS samples, but still possessed adequate wear and scratch resistance for biomedical applications. The current study confirmed that the PEEK coatings on metallic implants is effective for orthopedic applications where corrosion and tribology are major concerns.