Superlubricity

Supra lubricity ( English: superlubricity ) is a phenomenon in which friction can disappear almost completely. Supra lubricity occurs when two crystalline surfaces although dry but another inappropriate slide over each other (see incommensurability from the Department of Crystallography ). The effect was postulated as early as 1991, but could be measured only in 2004 with great accuracy between two graphene surfaces. The similarity of the term supra lubricity with terms such as superconductivity and superfluidity is misleading, as various loss mechanisms can lead to finite (usually small ) frictional forces.

The atoms in graphite are oriented in a hexagonal manner and form an atomic mountain and valley landscape that looks like an egg carton. If the two graphene surfaces ( every 60 degrees ) are in registry with each other, the friction force is high. If the two surfaces are rotated out of the registry, the friction is greatly reduced. It's like two egg cartons which can slide easily over one another when they are rotated relative to each other.

A state of ultra-low friction can also be achieved when a sharp tip slides over a flat surface and the pressure is below a certain threshold value is held, a function of the felt with the tip of the surface potential of the rigidity of the applied material. The threshold can be improved considerably by the excitation of the slider system at its resonant frequency. This suggests that a practical way to limit wear on NEMS (nano -electro-mechanical systems) is.