What Is Graphite Lubricant?

by Ma Wen Jie
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There are many types of lubricants, ranging from motor oil to exotic lubricants like lithium-based ones. Some modern materials can be impregnated with lubricant, eliminating the need to lubricate moving parts. Graphite lubricants are unusual in that they can work both as a dry lubricant and in a liquid base.

Purpose of Lubricants

Lubricants reduce friction between two surfaces. When two surfaces have too much friction, they might not be able to move. By adding lubricant, mechanical systems are less susceptible to problems related to friction. One of those problems is heat. Components that rub against each other without lubricant will create more heat than components in which the friction is reduced through lubrication.

What is Graphite?

Graphite is a form of carbon. Graphite is silvery black with a dull metallic luster. Graphite is a mineral that is very soft. On the Mohs hardness scale, it falls between 1 and 2. Because of this softness and tendency to flake, it works very well as a dry lubricant.

Dry Lubricants

Graphite as a dry lubricant requires atmospheric contact for optimal performance. Water vapor in the air reduces molecular bonding of the graphite, causing it to slip, thereby reducing friction. The downside of graphite as a lubricant is that it does not bond well to the surfaces it lubricates. It easily falls off and needs to be applied often.

Liquid Lubricants

There are a different types of liquid graphite lubricants. One is graphite suspended in a liquid base that will evaporate when the liquid is painted on a surface. When the liquid evaporates, it will leave a thin layer of pure graphite to lubricate the surface. Graphite grease is a form of graphite lubricant that is designed to stick to a surface, such as when used on an exposed bearing. The grease will help keep the graphite in place so it can work.

Advantages of Graphite

Graphite has advantages in situations where wet lubricants might not be practical, such as where electricity might be a hazard. Another situation is when lubricating porous substances such as wood. Wood is easily stained by oil or other common lubricants. Graphite can dissipate more heat than some other lubricants. For example, graphite grease can often handle more heat than natural bearing grease.

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