How Is Boron Used In The Automotive Industry?
The automotive industry has changed dramatically over the past 100 years. With electric vehicles becoming more popular, new material is needed for battery electrodes that can accommodate these changes. Boron is an excellent candidate because of its ability to efficiently transmit electrons while also being lightweight and inexpensive. It’s not just used in batteries; it’s also used as a coolant for engines and brakes, as well as being a strengthening agent for steel alloys.
Industrial Fluids And Lubricants
Borates are well established and widely used in the manufacture of industrial and automotive fluids, such as lubricants, hydraulic fluids, water treatment chemicals, closed system heat exchanger fluids, antifreeze, brake fluids, fuel additives, and metalworking fluids. In these fluids, borates impart numerous benefits:
- Corrosion inhibition
- Buffering action
- Freezing-point reduction
- Boiling-point elevation
- Stabilization of thermal oxidation
- Prevention of sludge formation
- Reduction in moisture sensitivity
Many boron-containing lubricating oils are consumed in automotive (eg, motor oil, transmission fluids) and aviation applications. Others are used in industrial applications (eg, greases, gearbox, and metal-forming lubricants) or in non-lubricating uses, such as working fluid in hydraulic pumps.
Borates In Automotive Uses
Borates’ anticorrosive properties are also prized in the automotive industry. Most passenger automobiles use a mixture of water and antifreeze to remove approximately 50% of the heat generated by internal combustion engines. The antifreeze solutions used in these radiator systems must feature:
- A low freezing point
- A high boiling point
- An efficient heat-transfer medium
- Corrosion inhibition
- Chemical stability
- Low toxicity
An aqueous solution of ethylene glycol or propylene glycol meets most of these requirements. But glycol-based antifreeze can oxidize to produce corrosive organic acids in automotive coolant systems. In antifreeze, the buffering action of borates keeps the pH of these fluids above 7, preventing the acid formation and inhibiting corrosion. 20 Mule Team Borax borax decahydrate or Neobor ®, together with other components, serves this purpose. These products are readily soluble in glycols, are non-toxic, and can be handled safely.
In moisture-sensitive brake fluids (generally made from triethylene glycol monoalkyl ethers), borates act to prevent vapor-lock. The borate ester of the glycol ethers is a good partial replacement for glycol ethers. Borate esters are made by reacting triethylene monoalkyl ethers and Optibor boric acid under proper conditions. The absorption of moisture into the brake fluid converts the borate esters back to boric acid and glycol ethers. The released boric acid remains dissolved in the fluid and so has a minimum effect on the boiling point. Brake fluids with a borate ester content of 63% (or 4.4% boric oxide B ) can meet U.S. Department of Transportation (DOT) specifications and the needs of higher-performance vehicles.
In fuel additives, borate esters have been used to help prevent pre-ignition and keep carburetors clean. In aviation fuel, borates have been used to help prevent bacterial and fungal growth in storage or use tanks, yielding a clean-burning fuel.
In addition to their corrosion-inhibitive properties, boron-containing additives have detergent and anti-rust properties, are anti-knocking, and have low sludge formation. Along with the ability to provide lubrication, reduction of carbonaceous deposits, these properties make them valuable in automotive oils and lubricants. Borax.com
Boron alloy steels include carbon, a low alloy including HSLA, carbon-manganese, and tool steels.
Because of boron’s high neutron absorption boron is added to stainless steels used in the nuclear industry – up to 4% but more typically 0.5 to 1%.
Boron steels find use in the car industry, typically as strengthening elements such as around the door frames, and in reclining seats. As of the mid-2000s, it was in common use by European car manufacturers.
The introduction of boron steel elements introduced issues for accident scene rescuers as its high strength and hardness resisted many conventional cutting tools (hydraulic shears) in use at that time.
Flat boron steel for automotive use is hot stamped in cooled molds from the austenitic state (obtained by heating to 900-950C). A typical steel 22MnB5 shows a 2.5x increase in tensile strength after this process, from a base of 600MPa. Stamping can be done in an inert atmosphere, otherwise abrasive scale forms – alternatively a protective Al-Si coating can be used.
aluminized steel ). Introduction of high tensile strength hot-stamped mild manganese boron steel (22MnB5) (up to proof strength ultimate tensile strength 1500MPa) allowed weight saving through downgauging in the European car industry.
Boron steel is used in the shackles of some padlocks for cut resistance Boron steel padlocks of sufficient shackle thickness (15mm or more) are highly hacksaw, bolt cutter, and hammer-resistant, although they can be defeated with an angle grinder.
Boron-containing Polymer Has Electric Vehicle Energy Storage Potential
Wang and his team used bA low-cost, flexible polymer that can tolerate high temperatures could provide energy storage in electric vehicles, according to researchers from Penn State University in Pennsylvania. The polymer is a composite whose key ingredient, boron nitride, allows it to withstand temperatures up to 248°C under the application of high voltages.
The composite is a dielectric substance; that is, it stores electric charge when exposed to an electric field. In electric vehicles, they are used to release current quickly for start-up or to convert DC from batteries into AC to run an electric motor.
Generally, high-temperature applications require ceramic dielectrics, but these are heavy and brittle, according to Penn State professor of materials science and engineering, Qing Wang, who led the research. Polymer dielectrics are lighter but have tended to degrade in performance or melt at high temperatures, necessitating a cooling system, which adds further weight and complexity.
Boron nitride, a two-dimensional substance similar in structure to graphene which has been shown to have dielectric properties, in the form of ‘nanosheets’ about 2nm thick and 400nm across as the active agent in a cross-linked polymer nanocomposite with benzenecyclobutene, a polymer used in electronics. The composite can be made by just mixing the boron nitride and the polymer precursor, then curing with heat or light to create the cross-linked structure. Because the nanosheets are so small, the polymer remains flexible.
The team claims in a paper in Nature that the polymer can be photo-patterned and have “outstanding high-voltage capacitative energy storage capabilities at record temperatures,” with electrical conduction several orders of magnitude lower than existing polymers; the boron nitride dissipates heat. The dielectric properties remain after the several bending cycles, the team adds.