TRIBOLOGICAL CHARACTERISTICS OF AMORPHOUS-CARBON FILMS INVESTIGATED BY POINT CONTACT MICROSCOPY

Wear marks and frictional force distribution on amorphous carbon films, fluorinated amorphous carbon films, silicon-containing amorphous carbon films, and fluorinated silicon-containing amorphous carbon films were investigated by point contact microscopy. Film surfaces were also analyzed by x-ray photoelectron spectroscopy. The fluorinated silicon-containing (40%) amorphous carbon film has the highest strength of the tested films. CF4 plasma treatment fluorinated the silicon-containing (40%) amorphous carbon film, and significantly reduced its frictional coefficient to less than 0.3. The surface of fluorinated silicon-containing (40%) amorphous carbon film is composed of carbon, silicon, fluorine, and oxygen. Carbon, silicon, and fluorine show the plural chemical states of SiC and CFx. This increases film strength and enhances the lubricating effect of the fluorinated silicon-containing (40%) amorphous carbon film.