Dry film lubricants, often under-discussed in the broad spectrum of lubrication, are becoming increasingly vital in numerous industries, from automotive to aerospace and from electronics to food processing. These lubricants offer distinct advantages that differentiate them from traditional oils and greases.
So, what exactly are dry film lubricants, and what are their benefits and applications? Can they be used in combination with standard lubricants and if so, am I already using them?!
What are Dry Film Lubricants?
Dry film lubricants are materials that, when applied to a surface, provide a layer of solid lubrication. Unlike traditional liquid or semi-liquid lubricants, they do not rely on oils or greases to provide lubrication.
Instead, they provide a continuous, thin layer of solid particles, such as graphite, molybdenum disulfide (moly), hexagonal boron nitride (micro-ceramic), or polytetrafluoroethylene (PTFE), which minimizes friction between two surfaces.
It is important to note, however, that there are some greases and lubricants that use dry film lubricants in combination with standard oil and greases. In these cases, the standard lubricant almost only acts as a delivery agent for the dry lubricant. Some excellent examples of this would be MOS2 (moly) grease or LI400 (micro-ceramic) grease!
Benefits of Dry Film Lubricants
Here are a few benefits of dry film lubricants.
- Operating under extreme conditions: Dry film lubricants can function in extremely hot and cold temperatures, whereas conventional lubricants might either evaporate or freeze.
- Reduced contamination: Since these lubricants are dry, there’s a lower risk of attracting and retaining contaminants like dirt and dust, which can lead to wear and damage. This makes dry film lubricants excellent in high dust applications like roller chain lubrication!
- Long-lasting: Dry film lubricants have a long life span. They don’t degrade quickly, reducing the frequency of re-application. Many dry film lubrication apply like paint, creating a long-lasting protective coating that also provides lubrication!
- Resistance to chemicals and corrosion: Many dry film lubricants offer excellent chemical resistance, making them suitable for environments where chemical exposure is a concern.
Common Types of Dry Film Lubricants
Following are the four types of dry film lubricants:
- Graphite: One of the most well-known dry lubricants, graphite is stable at high temperatures and offers good conductivity. It’s often used in locks, hinges, and high-temperature applications.
- Molybdenum Disulfide (MoS2): Offering excellent load-bearing capabilities, MoS2 can perform under extreme pressure and has a low coefficient of friction. In fact, MOS2 is used in a lot of high-pressure construction greases for tractors, loaders, excavators, and bulldozers!
- PTFE (Teflon): Best known as the non-stick coating for cookware, PTFE provides an ultra-low coefficient of friction and is chemically inert, making it suitable for many applications. PTFE is an excellent multi-purpose dry film lubricant, especially in low to mild-heat applications!
- Hexagonal Boron Nitride (Micro Ceramic): The newest player in the dry film lube industry is HBN, commonly known as micro-ceramic. The amazing thing about micro-ceramic is that it is extremely durable! It can withstand extreme temperatures and pressures in some of the harshest environments because of its insanely tough chemical structure and the fact that it is chemically inert (it doesn’t react with other chemicals). Additionally, it is extremely stable, all of which make it one of the most exciting technologies in the lubricant industry.
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Applications of Dry Film Lubricants
Here are a few applications of dry film lubricants.
- Aerospace: Given their ability to function under extreme conditions, dry film lubricants are invaluable in the aerospace industry. They can withstand the cold vacuum of space and the intense heat of re-entry.
- Automotive: Dry lubricants are used in brake systems, transmissions, and even as coatings for certain engine parts to reduce wear.
- Agriculture: Anytime there is a dusty environment dry film lubricants can offer a huge advantage, which is why they are becoming very popular in the ag industry.
- Electronics: With their excellent conductivity properties, certain dry film lubricants are utilized in electrical contacts and connectors.
- Food Processing: Some FDA-approved dry film lubricants are used in food processing equipment, where traditional lubricants might contaminate the food product.
How are Dry Film Lubricants Applied?
The application of dry film lubricants can vary based on the specific product and use-case scenario. Common methods include spraying, brushing, or dipping. Some require a curing process, which could be achieved through heat or simply air drying. It’s vital to ensure proper adhesion to the substrate for effective performance.
In combination with oils and greases, you simply use the grease or oil like normal and the dry film lubricant is delivered by the wet lubricant—pretty neat!
While dry film lubricants offer numerous advantages, they have limitations. The biggest limitation is cost. For this reason, we see exponentially more wet lubricants than dry lubricants, but many combination lubricants are now hitting the market and in time dry film lubricants will play a bigger role.
In conclusion, dry film lubricants serve as an indispensable tool in many industries due to their unique properties and performance capabilities. Whether you’re dealing with extreme conditions, aiming for long-lasting performance, or simply trying to avoid contamination, these lubricants could be the answer. As technology advances, we can anticipate further innovations and wider adoption of dry film lubricants in various applications.