This research describes the friction behavior of pulsed laser-deposite
d tungsten disulfide films. A ball-on-flat apparatus, in which a 440C
stainless steel ball was held on a rotating dish coated with a WS2 fil
m, was used as the test configuration. Friction measurements were made
in dry nitrogen and in laboratory air. Wear surfaces were characteriz
ed by scanning electron microscopy and Raman spectroscopy. The frictio
n coefficient of the film in dry nitrogen was 0.04, and in laboratory
air it rose to between 0.10 and 0.15. In the dry nitrogen case, fricti
on induced some degree of crystallinity into the otherwise amorphous f
ilm, while rubbing in air mostly resulted in oxidation of the film. Tr
ansfer films formed in a dry environment were smooth, tenacious and fi
rmly adherent to the steel counterface. By contrast, the films formed
in air were patchy and powdery in nature.