Electromagnetic properties of carbon and graphite

Artificial graphite is needless to say that it is a good conductor of electricity, and it is so-called polycrystalline graphite in structure. Polycrystalline graphite is a carbon material with good graphitization properties obtained by heating at high temperature. Carbon materials are generally obtained by heating and treating organic matter in a reducing atmosphere, an inert atmosphere or in a vacuum. The carbon material obtained by the heat treatment below 1000°C is better regarded as an insulator than a carbonized material. Only when the carbonized material is heated above 1000°C, the specific resistance drops rapidly, and it becomes a good conductor of electricity. The polycrystalline graphite obtained by processing in this way is still a carbon material in a sense after all, and artificial graphite needs to be processed at temperatures above 2500°C under normal pressure. It is a very interesting and profound problem that carbon materials and carbides change with their electrical properties during simultaneous heat treatment.

A solid that is a good conductor of electricity, such as metal, has an electric load. A solid is composed of atoms, which have a nucleus and electrons. It is easy to imagine that the electrical load of a solid in this case is the existence of unconstrained free electrons in the atoms that make up the solid, called conduction electrons. For neutral and isolated atoms, electrons are stabilized with various inherent energy states. When such atoms aggregate into a solid, the conduction electrons that can conduct electricity belong to the outermost electrons, that is, valence electrons.