CORRELATION OF THE TRIBOLOGIC PROPERTIES OF VARIOUS GRAPHITE INTERCALATION COMPOUNDS TO THEIR ELECTRONIC STRUCTURE.

摘要

As far as lot of lamellar compounds (Graphite, MoS2, BN,...)[1,2] can be used either as solid lubricants or as nanoadditives in lubricating greases or oils in the form of stable dispersions of nanoparticles in the liquid or jellified base [3,4], the understanding of their friction properties remains of great interest. The specifity of the lamellar,structure is that basal layers, in which atoms are strongly bonded, are separated by van der Waals gaps through which interplanar interactions are weak (van der Waals interactions or weak orbital overlaps) [5]. The good friction properties of some lamellar compounds (MoS2, Graphite...) are then attributed to these low interlayer interactions leading to low critical shear rates along directions parallel to the layers. In this work, in order to investigate the structural / electronic parameters involved in the friction reduction processes, structural and electronic structure changes are monitored using intercalation of selected intercalant species The studied compounds are Graphite Intercalated Compounds (GIC) for which the intercalation of nucleophilic (metal chlorides) and electrophilic (alkaline metals) species in the van der Waals modifies the crystallographic and electronic structure of the host compound and consequently the interactions between basal slabs.