Experimental investigation of the wear mechanisms of thin PDA/PTFE coatings

The wear mechanisms of thin polydopamine (PDA)/polytetrafluoroethylene (PTFE) coatings on stainless steel substrates were studied. Scratch, durability, and wear progression tests were performed on samples with three PTFE topcoat thicknesses. It was found that the wear process involved plastic deformation, plowing, adhesive spalling, large-area delamination, and abrasive wear. Thicker PTFE coatings had a lower initial coefficient of friction but a higher initial wear rate, which was attributed to the larger amount of loosely connected PTFE nanoparticles. The thickest coating had a slightly longer wear life due to the delayed delamination from the PDA layer.