Formation of a protective film on a copper friction surface in the presence of fullerene C60

The influence of C-60 additive in industrial oil on the structure of the friction surface of copper foil in a steel-copper sliding friction pair is investigated by wide-angle x-ray diffraction, scanning electron microscopy, and hardness testing. The presence of C-60 in the lubricant leads to the formation of a thin film (of thickness < 1000 Angstrom) on the friction surface of the copper, where it protects the surface layers of the latter against major structural changes and helps to improve the tribological characteristics. (C) 1999 American Institute of Physics. [S1063-7842(99)02011-5].