What Are the Lubricating Properties of Graphite?

When it comes to lubrication properties, graphite is a top performer. Also known as black lead, graphite is a crystalline form of carbon and features a layered structure. While graphite is known for its lustrous shine, it’s also a highly effective solid lubricant. Below, we take a closer look at the impressive lubricating properties of graphite.

The power of crystalline carbon

While graphite is made of pure carbon, it features a different structure to the element. Graphite is layered, with each horizontal sheet made up of hexagon-shaped sets of six carbon atoms. While the carbon atoms are strongly bonded together, the forces between each layer are weak. This allows them to easily “slide” over each other with minimal resistance. It’s this feature that gives graphite its slippery surface and makes it such a high-performing solid lubricant.

Unlike oil, grease and penetrating lubricants, graphite doesn’t leave behind a sticky residue. This eliminates the risk of attracting dirt, dust and other contaminants. Graphite also forms a much stronger bond to the substrate surface, making it the lubricant of choice when traits like wear resistance and longevity are a priority. 

Combining graphite with solvent

Combining graphite powder with a solvent is one of the easiest and most effective ways to utilise its lubrication properties. When blended with a fast-evaporating solvent, graphite can be easily applied to surfaces. Once applied, the solvent quickly evaporates and leaves behind a slippery, long-lasting protective film.

Graphite in the aerospace industry

Exceptional longevity and durability put graphite on the radars of aerospace engineers several decades ago. The industry is incredibly demanding, with extreme speeds, altitudes and temperatures placing components under immense pressure. Graphite stepped up as a high-performance lubricant capable of withstanding these harsh conditions. Metcar® is one example of ultra-specialised graphite, with the product widely used across the oil and gas, petrochemical and utilities sectors, as well as in the aerospace industry.  

Back on solid ground, graphite is used to lubricate gaskets, conveyor belts and transfer belts. It’s an effective lubricant for gears, chains, wheels and rollers. Lack of residue also makes graphite useful for locks, where viscous lubricants like oil and grease are unsuitable.

Graphite is one of the most common materials used for solid lubricants, though it’s not the only option available to operators. Find out more about oils, greases and penetrating lubricants in our complete guide, ‘What Are the Chemical & Physical Properties of Lubricants’.