The key to answering the question, “why are electrodes often made of graphite?”, is to consider the structure of graphite. In graphite, the carbon atoms are arranged in layers, retaining their structure through the use of covalent bonds. A significant feature of graphite’s structure is the number of delocalized electrons which are present. Graphite requires only three of its outer energy electrons to bond, leaving the fourth free to act in a delocalized manner. Delocalized electrons are not readily associated with a particular atom and move freely. These electrons enable graphite to exhibit a high level of conductivity, explaining why the material is frequently used for electrodes.

As well as being an excellent conductor, there are several other reasons why graphite is a common choice for electrodes. Graphite has a very high melting point, enabling it to be used to conduct electricity in high temperature reactions without changing state. With such a high degree of stability, graphite can be used when other materials would be unsuitable. Another explanation to answer the question, “why is graphite used in electrodes?” relates to its relative cost and prevalence. Graphite can be created synthetically and there are also extensive deposits which are mined worldwide. As an easily obtainable material that has the properties necessary for electrodes, graphite is therefore a cost-effective, convenient option, providing another reason why graphite is used to make electrodes.

 

 

 

E6013 WELDING ELECTRODE RODS FOR CARBON STEEL

Electrodes can be made from any conductive material. Depending on the nature of the application, electrodes may be made from graphite, noble metals (gold, silver or platinum). Copper, titanium and brass are also commonly utilized.

Synthetic graphite electrodes can be constructed from a wide range of carbon-containing materials. These include acetylene, petrochemicals and coal. The carbon in these compounds is converted into graphite’s signature structure through extreme heating. To form graphite, the carbon needs to be heated to temperatures exceeding 3000°C. This process is called graphitization.