Ultralow friction

Transition from Stick-Slip to Continuous Sliding in Atomic Friction Entering a New Regime of Ultralow Friction. 

The friction coefficient drops to a value below 0.05, characteristic of ultralow friction. This is a well known phenomenon encountered when using MoDDP additives in lubricating tests (Tung et al., 1988 Zheng et al., 1986). This demonstrates that the ultralow friction is mainly due to a tribochemical transformation of the solid reaction film. In the ASE spectrum analysis a molybdenum sulfide tribofilm formed on the wear scar showed a S Mo peak ratio near 9, which is in agreement with a pure MoS2 spectrum. 

For constracting mobile mechanical devices, molecular surfaces need to be engineering. The controlled and reversible telescopic extension of multiwaU nanotubes was demonstrated, realizing ultralow-friction nanoscale linear bearings and constant-force nanosprings. Measurements performed in situ on individual custom-engineered nanotubes inside a high-... 

Lee, S. Spencer, N. D. Achieving Ultralow Friction by Aqueous, Brush-Assisted Lubrication. In Superlubricity, Erdemir A., Jean-Michel Martin, J.-M., Eds. Elsevier Amsterdam, 2007 Chapter 21. 

Lee, S., Spencer, N.D. Achieving ultralow friction by aqueous, brush-assisted lubrication. In Erdemir, A., Martin, J.M. (eds.) Superlubricity, pp. 365-396. Elsevier, Amsterdam (2007)... 

Joly-Pottuz, L., Dassenoy, F., Vacher, B., Martin, J. M. and Mieno, T., Ultralow friction and wear behaviour of NiA -based single walled carbon nanombes (SWNTs), Tribology International, 37 (11-12), 2004,1013-1018. Gavillet, J., Loiseau, A., Ducastelle, F., Thair, S., Bernier, R, Stephan, O., Thibault, J. and Charher, J. C., Microscopic mechanisms for the catalyst assisted growth of single walled carbon nanotubes. Carbon, 40 (10), 2002, 1649-1663. 

Erdemir, A., Bindal, C., and Fenske, G. R., Formation of ultralow friction surface films on boron carbide, Appl. 

Fig. 20.8 a Superfluidity of water droplet in CNTs of different diameters [68] and b ultralow-friction nanoscale linear bearing made of multi-walled CNT [69]... 

The demoDstratioD of ultralow friction between multi-walled CNT layers is a valuable confirmation that they will be useful mechanical components in molecular nanotechnology such as molecular bearing. 

The occurrence of quantum friction is a kinetic process of energy dissipation E — fr S with fr being the friction force and s the sliding distance) due to the phonon (heat) and electron excitation (electron-hole pair production) during sliding [76], A state of ultralow friction is reached when a sharp tip slides over a flat surface and the applied pressure is below a certain threshold, whose value is dependent on the surface potential sensed by the tip and the stiffness of the contacting materials [73, 77, 78],... 

A. Socoliuc, R. Bennewitz, E. Gnecco, E. Meyer, Transition from stick-slip to continuous sliding in atomic friction entering a new regime of ultralow friction. Phys. Rev. Lett. 92(13), 134301 (2004)... 

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