High performance composite films assembled on metal substrates with graphene oxide.

Friction and wear seriously affect the performance, service life and stability of metal moving parts. In this work, a novel GO composite film grafted with POCl 3 was fabricated on metal substrates, including SS, Ti and Al. These films showed excellent tribological properties, including high carrying capacity, low friction coefficient (COF) and low wear volume on the macroscale. A tribofilm composed of GO nanoflakes and metallic phosphate was formed in the wear track of SS substrate. In addition, amorphous carbon and metallic phosphate were the main components of the transfer layer formed on the surface of the steel ball. The excellent tribological properties were dominated by GO, and the great wear resistance was attributed to the formation of metallic phosphates during the friction process. Simulation results showed that the oxygen of metallic phosphate was derived from GO modified with POCl 3 rather than air. Taking the synergistic effect of GO and POCl 3 into account when designing nanocomposite films is of great value in industrial applications. • GO composite films was assembled on stainless steel (SS), titanium alloy (Ti) and aluminum alloy (Al). • GO-based composite films grafted with POCl 3 exhibited the best tribological performance. • A tribofilm and a transfer layer were formed in the wear track of SS substrates and steel balls. • The calculation results confirmed that the synergistic effect of GO and POCl 3. [ABSTRACT FROM AUTHOR]