# Anisotropic conductivity of graphite: conductor and insulator by direction

Graphite is not a uniform dielectric: it conducts well in the basal plane and behaves like an insulator perpendicular to the layers. That anisotropy explains its role in EDM, brushes, and thermal components.

Source: https://esgraf.com/en/blog/benefits-graphite-dielectric-properties

Graphite is often described as conductive, but its electrical response depends on crystal orientation. In the basal plane electrons move easily; perpendicular to that plane conductivity drops by several orders of magnitude.

It is more accurate to speak of **anisotropy** than of a uniformly dielectric material. Perpendicular to the basal plane graphite approaches insulating behavior; in parallel it competes with good metallic conductors.

## Why does conductivity change?

The layered structure explains the difference. Each sheet forms a strong hexagonal network in plane. Between layers, weak van der Waals bonds limit charge transport vertically.

In industrial applications that dual behavior is useful: the same material can dissipate heat in one direction and insulate in another, depending on how the part is oriented in the process.

## Graphite and dielectric fluid in EDM

In electrical discharge machining (EDM), the **dielectric fluid** — typically a dielectric oil — prevents free conduction between electrode and workpiece until a controlled discharge occurs. The graphite electrode, by contrast, must conduct to channel current.

Do not confuse the roles: the oil insulates the working medium; the graphite electrode conducts the discharge. When the electrode absorbs some fluid, cut penetration may vary with dielectric viscosity, graphite porosity, and immersion time.

For EDM processes, ESGRAF supplies [graphite electrodes](https://esgraf.com/en/materials/technical-graphite/edm) calibrated by grade and application.

## Applications that use anisotropy

- **Brushes and electrical contacts:** conductivity in the wear plane.
- **Thermal components:** dissipation or insulation depending on part orientation in furnaces or glass lines.
- **EDM electrodes:** high conductivity and dimensional stability under repeated discharges.

## Limitations to consider

Grade, grain orientation, temperature, and atmosphere affect performance. Do not assume one graphite grade behaves like another without reviewing operating conditions.

## Information needed for a quote

To guide selection or prepare a quote, ESGRAF typically needs:

- Application and operating conditions (temperature, atmosphere, load).
- Dimensions, technical drawing, or CAD file when applicable.
- Required quantity.
- Requested grade or material currently in use.
- Observed issue with the previous part or lubricant, if any.

## Request a quote

[ESGRAF](https://esgraf.com/) offers solid and powder graphite for multiple industries. Share your application, dimensions, quantity, and drawings when available.

Call +52 (81) 8381 0381, +52 (81) 8381 0391, or [send a message](https://esgraf.com/en/contact).