Microtribological properties of Ti-6Al-4V alloy treated with self-assembled dopamine and graphene oxide coatings

Ti-6Al-4V alloy is promising material as biomedical micro/nano electromechanical systems. However, its poor microtribological properties have a negative impact on the micromachine stability. In this study, enhancements in anticorrosion and microtribological performances under dry and SBF lubrication are realized by grafting graphene oxide (GO) on the alloy surface. We further demonstrate that based on a 3-aminopropyltriethoxysilane (APTES) transition layer, the GO-coated sample with dopamine (DA) adhesive layer (APTES-DA-GO) exhibits better properties than those of the APTES-GO. Moreover, the anticorrosion and tribological mechanisms of the GO-coated samples were discussed. Analyses of worn surfaces show that the relative slip of GO sheets and entrapment of wear particles of the surface topography are the main factors contributing to the improved tribological behaviour.