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What is Graphite ?
Origin
Long time after the era of the Celts, who already had used graphite in the production of ceramics, English shepherds in the year 1565 found a glossy anthracite-coloured mineral that was excellently suited for drawing and writing, and they gave it the name "plumbago". It was only in 1779 that a Swedish chemist discovered that this material was a type of carbon and not of lead. The name commonly used today is derived from the Greek word for to write: Graphein
Carbon
Large quantities of carbon can be found in the sun and in the atmosphere of most planets. Although on the earth the content of carbon is less than 0.1 percent, it still is the basis of organic chemistry and of life itself. This is because of graphite's property to form composites with itself and with other elements such as oxygen, hydrogen, or nitrogen. Crystalline carbon is only known in four allotropic forms:
GRAPHITE, DIAMONDS, FULLERENES, and NANOTUBES
Types of Graphite
Graphite is chemically inert, eco-friendly, and absolutely safe. It is classified as microcrystalline and macrocrystalline natural graphite and synthetic graphite. Six hexagonally arranged carbon atoms form the basic unit of the graphite crystal. The twodimensional lattices are highly stable within themselves, but they can be easily shifted against each other.
Crystal Structure
The basic units of the graphite crystal - six hexagonally arranged carbon atoms - form two-dimensional lattices that interact with each other. This crystal structure results in a number of special properties that make graphite a raw material with a great variety of applications.
These properties predestine the "black gold" for a great variety of applications: Excellent electric and thermal conductivity, outstanding lubrication properties, high resistance to temperature and oxidation, and the ability to form intercalation compounds.
Properties
Excellent conductivity
The thermal and electric conductivity of graphite is based on free electrons. This property is determined by the size and the good degree of order of the crystallites
Outstanding lubrication properties
Graphite has an excellent lubrication effect because the layers in the crystal lattice can be easily shifted against each other. The outstanding properties of graphite especially become obvious under high temperatures and pressures.
Resistance to oxidation and cyclic temperature stress
With its excellent degree of crystallisation, graphite is highly resistant to oxidation and to most chemical agents, which is why graphite is predestined for preferred application in the field of fireproof materials.
Formation of intercalation compounds
The bonding strength between the layer planes allow the intercalation of certain molecules in the graphite lattice. This intercalation property is the basis for the application of graphite in the fields of special lubricants and rechargeable batteries.
Characterisation
Graphite grades can be characterised by six interrelated and mutually influencing parameters: Purity, crystallinity, particle size, particle shape, surface, and porosity. Selective influencing of these parameters results in the optimal combination of properties for the respective application
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