Lamellar solid lubricants such as graphite, layered transition metal dichalcogenides and lubricious oxides are examined, and the limits of manipulating their propertis by doping are reviewed. The electronic structures of the host and the dopants interacting within a layered lattice are correlated with the characterically anisotropic electrical and thermal conductivities, shear modulus, shear strength and chemical reactivity. Factors controlling the critical resolved shear stress of asingle crystallite and those influencing the more global behavior of particles sheared within a lubricant film are compared, highlighting the effects of adsorbates chemisorbed on the grains during interaprticle sliding. The adhesion of these films to their underlay is explained in terms of activated bonding between the basal planes or the edge sites of the grains and the load-bearing substrate. The gamut of knowledge trancending the customary regime of engineering tribology down to the atomic-level fundamentals is a highly effective dagnostic tool that helps solve tough problems by better selection or additive-induced improvement of layered-lattice-type solid lubricants.
展开▼
