Influence of temperature and load on the friction coefficient between carbon fibers

In the article, a study was carried out on a microtribometer according to the “crossing cylinders” contact scheme: the effect of temperature in the range from 23 to 300°C and normal load in the range from 0.2 to 1 N on the coefficient of sliding friction between carbon fibers. Carbon fibers were synthesized in different ways from polyacrylonitrile polymer and differed in finishing temperature, namely: 1400°C and 2800°C. The fiber surface before and after tribological tests was studied using SEM and AFM microscopes. Tribological experiments have shown that the coefficient of friction depends on the nature and technology of carbon fiber manufacturing, as well as its heat treatment, which affects both the adhesion properties and the surface roughness of the fiber. Reducing the microrelief of the surface of the original fiber with a simultaneous increase in its adhesive properties is one of the ways to increase the coefficient of friction between the fibers and, as a result, contributes to an increase in the level of friction for carbon-carbon friction composites.