How is flexible graphite made

From pencils and diamonds - everything to do with the versatile material graphite

Structure and properties of graphite

Graphite has a layer structure. In each layer, each carbon atom is bound to three others. This results in a two-dimensional network of hexagons. There are strong bonds within each layer, but the bonds between the different layers are very weak. In this way the layers can easily be shifted against each other and even separated. For this reason graphite is very soft and is therefore even used as a lubricant. However, graphite has other special properties:

Electrical conductivity of graphite

The fact that graphite is electrically conductive results from its atomic structure. Each carbon atom in a graphite crystal has four valence electrons, also called outer electrons, which can form bonds with neighboring atoms. However, only three of the four valence electrons form a bond, the fourth electron remains freely movable and thus enables electricity to be conducted.

Thermal conductivity of graphite

Graphite has excellent thermal conductivity and high temperature resistance at the same time. Graphite has no melting point, so that graphite changes directly from the solid to the gaseous state. This process is called sublimation. In a protective gas atmosphere, graphite becomes plastically deformable from a temperature of 2500 ° C. At temperatures of more than 3750 ° C, graphite sublimates even without the presence of oxygen.

Chemical resistance of graphite

Graphite is one of the most chemically resistant materials. It is resistant to almost all organic chemistry media. These typically include intermediate and / or end products in the petrochemical industry, coal processing, the plastics industry, the production of varnishes, paints, refrigerants and antifreeze, but also in the cosmetics and food industries.

Graphite is also resistant to most inorganic media, for example to non-oxidizing acids, alkalis, aqueous salt solutions and most technical gases.

Download: Chemical resistance of natural graphite