Microscale friction and deformation behavior of polydopamine/polytetrafluoroethylene-coated 60NiTi from nanoscratch tests

• Low-load scratches compressed the polydopamine (PDA)/polytetrafluoroethylene (PTFE). PDA aggregates were by low-load and removed high-load ones. PDA/PTFE coating failed at a load corresponding to that of aggregate removal. Large initial wear depths reported in prior studies due compaction. The scratch behavior (PTFE) coatings has traditionally been studied using macro-scale tribometers. However, this study, nanoindenter is used on 60NiTi substrate investigate nanoscale deformation failure mechanisms under various loads. Nanoscratch tests also performed coated only with adhesive underlayer study Scanning electron microscope imaging provided further insights behavior. revealed strongly correlated removal particles underlayer. findings suggest compaction thin could be main reason for previously large depth tribology studies.