Differences in nano-topography and tribochemistry of ZDDP tribofilms from variations in contact configuration with steel and DLC surfaces

Abstract In this work, we evaluated the effect of counter-body material (the same or dissimilar) and contact configuration (moving stationary body), at similar tribological conditions, on tribochemical nanotopography characteristics adsorbed surface films. Zinc dialkyldithiophosphate (ZDDP), best performing anti-wear additive, was used in self-mated steel/steel DLC/DLC contacts, which were compared with mixed steel/DLC DLC/steel contacts 1-h 6-h sliding tests. The macroscale (tribometer) nanoscale (atomic force microscopy) friction, thickness, topography, chemical (attenuated total reflection-Fourier transform infrared spectroscopy X-ray photoelectron spectroscopy) properties tribofilms studied. results revealed unexpectedly large differences all studied tribofilm parameters; is because are completely different; includes composition, known to have a crucial nano- macro-scale properties. These clearly demonstrate that material, additives, common operating parameters, is, pressure, velocity, temperature, crucially affect ZDDP as well position moving within contact, moving/stationary bodies.