What is a Dry Lubricant? Exploring Its Characteristics and Benefits

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Dry lubricants are a fascinating subject that have gained popularity in various industries. With their unique characteristics and numerous benefits, they have become a go-to solution for many applications. So, what is a dry lubricant? In this blog post, we will delve into the world of dry lubricants, exploring their various characteristics and the advantages they offer. So, if you’re curious to learn more about this exciting topic, let’s dive right in!

What is a Dry Lubricant?

Dry lubricants are chemical substances that are solid and typically take the form of coatings or powders. Dry lubricants are essentially solid lubricants that exist in the solid state, yet they can still reduce friction between various surfaces even when they are in the solid state. This is one of the best qualities of a dry lubricant in and of itself because it satisfies the intended procedure without the use of any liquid medium.

Graphite and molybdenum disulfide are the two primary dry lubricants. Dry lubricants offer higher temperature lubrication whereas oil- and liquid-based lubricants still function at high temperatures. Dry lubricants are frequently utilized in applications like locks and dry-lubricated bearings. These substances function at temperatures more than 350 C (662 F) in a non-oxidizing/reducing environment. They become active in oxidizing conditions at 350 °C (662 °F), whereas molybdenum disulfide becomes active at 1100 °C (2012 °F).

Types of Dry Lubricants

Although there are many distinct types of solid lubricants, graphite, molybdenum disulfide (MoS2), hexagonal boron nitride, and tungsten disulfide are the four that are most frequently employed. Among these, molybdenum disulfide and graphite are the primary substances most frequently utilized as dry lubricants.

Graphite

Because the liquid lubricant helps particles stuck in the lock, complicating problems, graphite is a common choice for rock lubrication. In addition to being used in air compressors, air stops, bearings, open gears, piano movements, brass instrument valves, and rail couplings, graphite is also employed in the food business. Graphite is used to lubricate the internal moving elements of the cannon in sandy areas.

Graphite is the most appropriate type of lubricant for use in the air. Steam serves as the main lubricant for graphite. Because water absorption lowers the binding energy, the adhesion energy between graphite and the substrate is higher than the adhesion energy between graphite and its substrate. Due to the need for steam for lubrication, graphite is not an effective application in a vacuum. Due of graphite’s ability to carry electricity, it can encourage electrochemical corrosion.

Molybdenum Disulfide (MoS2)

When extracted, some sulfide-rich mines produce MoS2, which is then refined to a purity acceptable for the lubricant. The hexagonal crystal structure of MoS2 is similar to that of graphite, and it has the inherent quality of being simple to cut. Compared to graphite, MoS2 has better lubricating properties. MoS2 is effective in vacuum, whereas graphite is not. The maximum temperature of MoS2 is 400 °C due to limited oxidation.

Film thickness and grain size are significant factors that are appropriate for the substrate’s surface roughness. Impurities in MoS2 promote faster oxidation in smaller particles and increased abrasion wear in big particles. In contrast to tungsten disulfide, it is more cheap while serving the same purpose.

Hexagonal Boron Nitride

It can be utilized in spacecraft and is also referred to as white graphite. The most intriguing property of boron nitride in oxidizing conditions is its great temperature resistance at a use temperature of 1200 C. The material boron nitride has a high heat conductivity. Cubic boron nitride, which is extremely hard, is a component of abrasives and cutting tools.

Tungsten Disulfide

Thin stacks, commonly referred to as lamellar structures, are formed by the tungsten disulfide (WS2) molecule. Weak, readily breakable connections are used to hold these tiny layers together. As a result, there is very little drag or friction between the layers as they move side by side. The layers of the material offer reduced sliding friction when they are utilized on contact surfaces, effectively lubricating the surface.

There are a few various ways to apply tungsten disulfide (WS2) coatings, including sprays, polishes, gymnastics, and collisions. They are utilized in space vehicles and CV joints, but due to their expensive price, they are only found in a small number of dry-lubricated bearings.

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The Benefits of Dry Lubricant

Dry lubricants provide advantages over conventional lubricants comprised of petroleum-based materials like greases and oils. They can sustain much higher temperatures without thermal breakdown, operate as friction barriers that are much thinner and impermeable to high pressures, and have the potential to withstand much higher temperatures. Dry lubricants can operate effectively in temperatures as high as 662° F (350° C).

According to the particular use, a dry lubricant’s type is chosen. For instance, molybdenum disulfide can endure temperatures as high as 2,012°F (1,100°C), while some dry lubricants that can withstand extremely low temperatures, known as cryogenic temperatures, can liquefy gases like nitrogen.

Ball bearings are frequently coated with dry lubricants that have been deposited in the form of thin films. Even though it is only 0.0001 to 0.003 inches (0.00254 to 0.0762 millimeters) thick, the covering is strong. Some dry lubricants can also resist pressures of 250,000 pounds per square inch (17,237 bar) in a vacuum, which is the usual environment for liquid oxygen storage.

The Benefits of Dry Lubricant

Conclusion

In conclusion, a dry lubricant is a versatile and efficient solution for reducing friction in various applications. Its unique characteristics, such as low viscosity, high thermal stability, and resistance to moisture and contaminants, make it an ideal choice for situations where traditional lubricants may not be suitable.

The benefits of using a dry lubricant, including improved performance, extended equipment life, and reduced maintenance costs, make it a valuable tool in industries ranging from automotive and aerospace to manufacturing and electronics.

By understanding the characteristics and benefits of dry lubricants, individuals and businesses can make informed decisions and harness the advantages that this innovative lubrication technology has to offer.

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