Influence of silicon carbide nanofibers on the properties of polytetrafluoroethylene-based composites

The results of the study of the silicon carbide nanofibers (SiC NF) structure obtained by chemical vapor deposition are presented, as well as their influence on the mechanical and tribotechnical properties of fluoroplastic-based composites. The studied fibers are of an average transverse size of 100 nm, a cubic 3C–SiC structure with an admixture of 6H and 4H–SiC phases, and also contain numerous stacking faults and twins. They are covered with a layer of amorphous silicon, possibly partially oxidized. It is established that the synthesis product processing in a ball mill contributes to the further uniform distribution of nanofibers in the polymer matrix. In this case, fibers with a diameter of 100 nm and less are converted into elongated particles with a length-to-diameter ratio l/d ~ 5-10. The SiC NF additives significantly increase mechanical and tribotechnical characteristics of fluoro¬plastic, especially wear resistance during friction without lubrication. For example, adding 15 mass% SiC NF leads to an increase in fluoroplastic hardness and Young’s modulus in three times, and wear resistance by two orders of magnitude while maintaining the low friction coefficient typical of fluoroplastic.