Abstract:
MoS
2-Ti composite film with columnar microstructure was fabricated by unbalanced magnetron sputtering, and was irradiated by an atomic oxygen (AO) beam with 5eV kinetic energy and total fluence of 6.0×10
22 atoms/cm
2. The MoS
2-Ti composite film exhibited a “blanket-like” surface morphology after AO irradiation. The MoS
2 phase on the film surface (within the depth of ~30 nm) and titanium suboxides (e.g. TiO
2-x, where 0<
x<2) inside the film were oxidized by AO into MoO
3 and TiO
2, respectively, leaving the MoS
2 beneath the top 30 nm oxidation layer uninfluenced were oxidized to MoO
3 and TiO
2, leaving unchanged chemical state of element Mo in the film. After AO irradiation, initial friction coefficient and wear rate increased from 0.018 to 0.03 and 4.49 × 10
−17 m
3/(N·m) to 5.5 × 10
−17 m
3/(N·m), respectively, and its friction mechanism was transformed from adhesion to abrasion.