Lexicon of Materials - E

Our dictionary of materials consists of technical terms, which are explained in detail using easily understood language. Please click on a letter of your choice to reach the relevant material.
 

Graphite construction materials made from expanded natural graphite for the building industry.

See also: Expanded graphite

The Material

Synthetic graphite has unique properties thanks to its special crystalline structure. Graphite electrodes functioning as conductors in electric arc furnaces can withstand temperatures up to 3,000 °C. Graphite cathodes used as conductors can resist electro-chemical and mechanical stress in the aluminum electrolysis cell for 5 to 7 years at temperatures of almost 1,000 °C – and still remain highly energy efficient.

The Properties

  • extremely temperature resistant
  • high electric conductive
  • high chemical stability
  • thermal shock resistant

The Manufacturing Process

Coke and pitch are mixed, molded into form, and carbonized and then graphitization follows. The typical graphite crystal lattice is formed during this high-temperature processing step at approx. 2,500 – 3,000 °C.

The base material for the manufacture of expanded graphite is natural graphite. This is converted into a graphite intercalation compound. By thermal decomposition of the intercalation compounds, expanded, high-bulking graphite flakes occur which are calendered into flexible graphite foils or are compressed into sheets.

Details on properties, manufacturing, and typical applications of expanded natrual  graphite can be found under

SIGRAFLEX® Expanded graphite

Graphite produced in an extrusion process. In contrast to isostatically molded graphite, extruded graphite has lower strength but higher thermal conductivity. Extruded graphite is primarily used in electronics, industrial and high-temperature applications.

Details on properties, manufacturing, and typical applications of isostatic graphite can be found under SIGRAFINE® Fine grain graphite