Uses of the Graphite

The usefulness of graphite depends upon its peculiar softness and scaliness, as well as upon its chemical inertness, infusibility, and conductivity for electricity. For the manufacture of black-lead pencils natural graphite itself was formerly used, being cut up into strips of the required size. Now, however, powdered graphite is mixed into a paste with fine clay, and the mixture is pressed through a hole so as to form a thread.

Graphite crucibles are made from a mixture of powdered graphite and fine clay. They are moulded like pottery and then fired. They are employed for melting metals, and especially in the manufacture of crucible steel.

A well-known application of graphite is for protecting iron - e.g. grates - from rust. It is also used in electrotyping, the surface on which electrodeposition of metal is to take place being covered with a layer of graphite, which is a conductor.

It is likewise employed as a lubricant for machinery, and as a coating for gunpowder to prevent absorption of moisture. The efficiency of the powder is, however, somewhat diminished by the graphite.