Graphite
Graphite is a form of carbon that is self-lubricating, electrically and thermally conductive, and stable at very high temperatures in non-oxidising atmospheres. It is used for EDM electrodes, bearings, seals, crucibles, furnace parts and brushes.
What it is
Fine-grain isostatic graphite machines easily into precise shapes such as EDM electrodes and seal rings. Its low friction and chemical inertness suit bearings and seals in dry or chemical conditions, and it withstands temperatures above 2,000 °C in inert atmospheres.
Graphite oxidises in air above about 400–500 °C, so high-temperature use is in vacuum or inert gas. Impregnated grades (resin, metal) reduce porosity for seals.
Typical applications
- EDM electrodes
- Mechanical seal rings and bearings
- Crucibles and moulds
- Vacuum furnace fixtures and heating elements
- Carbon brushes
Materials & grades
- Isostatic fine-grain graphite
- Extruded and moulded graphite
- Resin- or metal-impregnated graphite
Points to consider
- Machining produces fine conductive dust; control extraction.
- Brittle; design without thin, sharp features.
- Choose impregnated grades for leak-tight seals.
- Oxidises in hot air; use protective atmospheres.
Frequently asked questions
Why is graphite used for EDM electrodes?
It machines quickly, conducts electricity well and wears slowly in EDM, making precise electrodes cost-effective.
Can graphite be used at high temperatures?
Yes, above 2,000 °C in vacuum or inert gas, but it oxidises in air above about 400–500 °C.
Is graphite a good bearing material?
Yes, for dry or chemical environments, thanks to self-lubrication and chemical inertness.