In situ Synthesizing Carbon-Based Film by Tribo-Induced Catalytic Degradation of Poly-α-Olefin Oil for Reducing Friction and Wear.

Reducing friction and wear in a convenient and economical way has always been desired for industrial production. Here, a carbon-based film with excellent friction-reducing and antiwear abilities was formed in situ from the degradation of poly-α-olefin oil (PAO10) on the friction interfaces of the MoN/Pt coating sliding against the Si3N4 ceramic ball during the rubbing process. The MoN/Pt coating was prepared on stainless steel by direct current magnetron sputtering, in which an active 10 nm Pt layer grew well on the MoN layer. The MoN/Pt coating, lubricated by trace amounts of 5 mL PAO10 oil, exhibited a super low friction coefficient of 0.042 and an extremely low wear rate of 1.08 × 10-8 mm3 (N m)-1 after a long duration of applied friction under a high Hertz contact stress of 1.7 GPa. Raman spectra and transmission electron microscopy images revealed that the carbon-based film was composed of amorphous carbon phase dotted with sporadic Pt, MoO3, and SiO2 crystal phases. Molecular dynamics simulations illustrated that the MoN/Pt coating had catalytic action and resulted in the degradation of PAO10 during the rubbing process, which corresponded to the formation of the amorphous carbon-based film on the wear surfaces.