Some machinable graphite parts.

Graphite is a natural mineral derivative of carbon. It is a native element, often the result of sedimentary carbon compounds, but also occurring in certain rocks containing organic carbon, in magma or as the result of the reduction of sedimentary carbon through the reduction of carbonates.

Graphite has a non-compact layered structure made up of hexagonally-shaped structures. These layers are known as graphene have an inter-layer distance of approximately 0.336 nm.

In each layer, the carbon atoms are strongly bonded together by molecular links whereas the layers are not strongly bonded together, which explains the material’s relative lack of hardness.

Physical properties

Graphite is the stable form of carbon at ordinary temperatures and pressures. This material has a black, shiny, submetallic appearance. Its hardness is low, between 1 and 2 on the Mohs scale. Due to its layered structures, all of its physical properties are anistropic. Indeed, its electrical conductivity varies greatly if measured between the layers or perpendicularly.

Applications

Graphite has many industrial applications in various natural or synthetic forms :

Mechanical Engineering: friction parts, seals, lubricants

Electrical manufacturing: brush motors

Reducers, particularly in the steel industry (blast coke furnaces)

Electrodes for the steel industry (electrical steel)

Moderators in nuclear reactors

Adsorbents in activated charcoal filter