How Boron Nitride Improves Aluminum Extrusion

:: Thursday, June 15, 2023 :: Posted By Maryam Moravej

The aluminium market is surging. Market research suggests the industry will grow by 5.5% annually over the next five years1.

As the tremendous expansion continues, aluminum producers are exploring how new methods and materials can enhance efficiency and elevate product quality.

That’s true for an important step in the process: Aluminum extrusion—where aluminum profiles are carefully shaped to exact specifications.

Boron nitride is quickly becoming the preferred release and lubrication agent in the industry.

By using our highly pure borate products, you can produce boron nitride coatings and powders that will enhance extrusion quality, reduce waste, and lower carbon emissions.

Boron nitride benefits in aluminum extrusion

The excellent release and lubrication properties are primary reasons why boron nitride is extremely useful in the aluminum extrusion process.

Because extrusion requires a high degree of precision, a great release agent is critical to upholding extrusion speed, productivity, and quality of your profile. Any surface imperfections such as scratches, dents, die lines, or oxidation marks can render your profile useless.

A dry or liquid boron nitride coating facilitates a smooth release and avoids dummy block surfaces sticking to the rear face of the billet. That ensures the extrusion butt stays attached to the die prior to shearing.

Boron nitride also offers several more advantages in extrusion such as:

  • Doesn’t cause smoking (unlike carbon-based releasing agents)
  • Keeps a cleaner working environment
  • Reduces the frequency of equipment maintenance

Note: A liquid boron nitride application may be preferable because it often results in less overspray and consumable costs. In contrast, a dry application requires maintaining a full electrostatic charge, which can lead to overapplication and upkeep challenges for both the boron nitride applicator and billet loading equipment.

Temperature and thermal shock resistance
Boron nitride’s ability to withstand extreme temperature changes without degrading prevents the billet from sticking or seizing.

Chemically inert
Because boron nitride is chemically inert, it’s compatible with aluminum and other elements found in different types of alloys. This reduces the risk of adverse reactions to profiles.

While toxicity is a primary concern with other release agents, boron nitride powders are safe and don’t pose any respiratory risks when handling.

Electrical insulation properties
Due to its electrical insulating properties, boron nitride can be electrostatically applied to your dummy block or billet. This application is quick and easy.

Why boron nitride is a superior release agent

Using boron nitride as a release agent substantially improves the safety of the aluminum extrusion process. Plus, the compound is more efficient than its counterparts and doesn’t need to be applied before every cycle.

Previously, the aluminum casting and extrusion industry relied on petroleum-based release agents: Greases and oil-based graphite suspensions, and acetylene. However, these products possess considerable drawbacks.

Greases and oil-based suspensions
Some aluminum extruders turn to these suspensions because of their cheaper price point. However, greases can cause more problems and increase costs later.

These types of suspensions are manually intensive and can only be applied by hand. Not only that, but they are highly flammable when subjected to high temperatures. Such propensity can lead to explosions that create blisters and holes in the extruded profile.

Acetylene (carbon black)
Acetylene differs from grease and oil-based suspensions because it’s more automatic and doesn’t require manual labor. But this method isn’t perfect.

As an aluminum billet makes its way to the extrusion press, acetylene is ignited to generate carbon black, a release agent. Carbon black is carcinogenic, which means careful safety measures must be in place to protect workers.

Another common acetylene flaw is found when the aluminum profile has distinct, detailed edges. Carbon black is prone to stick to these edges, leaving a permanent black mark on an otherwise pristine piece.

What boron products are used?

Determining which boron product is right for you starts by examining your process. Typically, extruders apply boron nitride either through a powder or water-based suspension.

Producing a boron nitride powder involves either boric oxide or boric acid. We recommend two of our highly pure products: Boric oxide or Optibor®.

Why partner with us?

Your processes are sensitive and therefore demand high-quality inputs that support your operational efficiency. By choosing U.S. Borax as a partner, you can expect every batch of borate products to be pure.

Consistency like this enables defect-free aluminum extrusion while improving safety and productivity.

Beyond exceptional product quality, we’re committed—along with our parent organization, Rio Tinto—to advancing sustainability efforts.

We encourage you to explore the START program and the low carbon aluminum production practices behind it. START is bringing more transparency to sourcing materials such as aluminum, which will empower more sustainable choices in the future.

If you have any questions about borate products for boron nitride, please contact our technical team.


1 Aluminum Market Report | Vantage Market Research


U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 650 customers with more than 1,800 delivery locations globally. We supply around 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

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