Borates in Automobiles

:: Wednesday, January 12, 2022 :: Posted By Orion Graham

Your car is a complex system made up of thousands of parts. Many of those parts contain borates. Serving a multitude of functions, borates in automobiles are critical to ensuring the safety, durability, reliability, and quality we depend on to get us to our destinations.

From headlights to motor oil to primary components of your car such as the aluminium body, boron is a key element.

Reinforcing the body and frame

If your car has an aluminum body and steel frame, you can thank borates, which are used in many common metallurgical applications. Manufacturers add borates to aluminum and steel, where they act as a grain refiner and hardening agent. During smelting, borates facilitate the formation of flux, enabling the removal of impurities.

In other words, borates help make your car body and alloy frame stronger and more resistant to corrosion.

Facing increased demand for lighter and more fuel-efficient cars, manufacturers are replacing metal body parts for composite parts. Composites are typically made from fiberglass and a polymeric resin. When textile fiberglass is produced, borates are used to make the process more cost-and-energy efficient by reducing the melting and fiberizing temperature.

Download Technical bulletin: Borates in metallurgical applications

Improving visibility with borosilicate glass

One of the most widely used applications for borates today is in the manufacture of borosilicate glass. Comprised of silica and 5-20% boric oxide (boron trioxide), borosilicate glass is prized for its strength and formability. It’s also resistant to heat, chemicals, shocks, and scratches.

Sealed headlights and halogen bulbs

Automotive manufacturers use borosilicate glass in sealed headlights and the halogen bulbs for your car.

High quality and consistency are crucial in glass production for lighting and bulbs. Glass manufacturers must ensure they’re adding the appropriate type and amounts of borates for their formulations, otherwise they risk uneven melting performance, which negatively affects the chemical and physical properties of the finished glass.

Touch screen displays

Automotive manufacturers looking to entice consumers offer advanced technology inside cars such as touch screen displays with navigation and entertainment features.

Specialized borosilicate glass is used in the production of thin-film-transistor liquid-crystal displays (TFT LCD) because it forms thinner and lighter screens, a major selling point in the market.

Download Technical bulletin: Borates in glasses

Borates in automotive fluids and lubricants

Heat, corrosion, and sludge are among the primary enemies of cars. To prevent them from causing major damage, manufacturers use borates in automotive fluids including motor oil, hydraulic fluids, fuel additives, lubricants, and antifreeze.

Fuel additives

Boric acid can serve as a lubricating additive in fuel, which can reduce friction inside your car’s pistons. Less friction means your engine will lose less energy and run more efficiently. When borate esters are included in fuel additives, they help to keep carburetors clean and prevent pre-ignition.

Motor oil

No one wants sludge buildup in their car’s engine. In motor oil, boron improves lubrication properties and prevents sludge from forming.


In addition to protecting engines in extreme cold, antifreeze keeps them from running too hot. Borates used in antifreeze solutions found in most radiators today provide these benefits:

  • A low freezing point
  • A high boiling point
  • Corrosion inhibition
  • Efficient transfer of heat
  • Low toxicity

Brake fluid

Hydraulic brake fluids are moisture sensitive. If the temperature rises past the fluid’s boiling point, a driver can experience a loss of brake power—also called vapor lock. Borate esters are used in some brake fluids to lower the boiling point and prevent vapor lock.

Learn more about borates in industrial fluids and lubricants

Borates’ role in polymers and rubber

In automobiles, polymers are found throughout multiple systems, including a car’s electrical system (wires and cables), carpet and upholstery, and foam insulation.

However, polymers are extremely flammable and any products using polymers may benefit from specialized borate compounds that can act as flame retardants and promote char formation. Borates are often found in a wide array of flame retardant additives to prevent polymers from igniting and burning.

Fire retardant capabilities are increasingly important as electric vehicle popularity increases. These vehicles contain more wires, cables, and connectors than their non-electric counterparts. Plus, the battery of an electric vehicle poses a higher fire risk.


In tires, borates promote adhesion between the rubber and steel belt. Adding zinc borate to a tire’s rubber composition creates a strong, durable adhesion to the metallic part of the tire.

Learn more about borates in polymers, plastics, and elastomers

Electric vehicles: Boron in batteries and capacitors

The world is turning its attention toward reducing carbon emissions, and electric vehicles play a key part. These vehicles require lithium-ion batteries that rely on borate compounds for safety, performance, and long life. Borates are found in the electrolyte solution that enables lithium-ion battery capacitors to create and hold a charge—making them indispensable in battery production.

Learn more about boron in batteries and capacitors

Boron and lithium sourcing

Interestingly, lithium and boron are found in similar geologies. Currently, our U.S. Borax team is working on a breakthrough method for extracting lithium from waste rock at our Boron, California operations.

Learn more about U.S. Borax and sustainable lithium

Driving quality and performance in automobiles

Boron plays a role in every one of your car's complex systems. We are proud to provide a full range of borate products to support the automotive industry—and keep you driving wherever you need to go.




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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