BORAX CRITICAL TO PROTECTING AMERICAN TANKS
by Harold Hough
It may be hard to equate the super strong armor of the M-1 Abrams Tank with the mining in Death Valley or laundry products, but they have a lot more in common that we would think. In fact, what makes it so hard to destroy an American tank has more to do with borax than steel.
Unlike the tanks of World War Two, Korea, and Vietnam, top of the line Western tanks like the American Abrams and the British Challenger rely on ceramics to stop high speed penetrator rounds or shaped explosive ammunition that are their major enemy. The armor is called Chobham Armor and it was invented in Britain.
Although the exact design of Chobham Armor is a secret, it is known to be composed of ceramic tiles encased within a metal matrix and bonded to a backing plate and several elastic layers. Due to the extreme hardness of the ceramics used, they offer superior resistance. They shatter light weight projectiles, literally wear out and stop higher speed penetrators as they go into the armor and destroy the symmetry of an exploding shaped charge.
A key to this hardness is boron carbide, which is nearly as hard as a diamond. A ceramic made of boron carbide is lighter, and harder than other ceramics, even though it is more expensive. These ceramics can have a protection value 25 times greater than a sheet of steel of the same weight. And, since boron absorbs neutrons, it provides the tank crew protection from nuclear blasts.
Boron carbide comes from a family of borate compounds usually called borax. Fortunately, this is one strategic material that the US has in abundance. Borax (formerly US Borax) is a part of the Rio Tinto Group and operates California's largest open pit mine in Boron, California - one of the richest borate deposits on the planet. The company supplies nearly half the world's demand for refined borates.
Borax began doing business about 130 years ago and today mines at its open pit operation in Boron, CA. This mine, which currently supplies nearly half of the world's borax was discovered in 1925 and went into production in 1927. Originally, it was an underground mine for mining tincal ore; the principle sodium borate mineral. In the late 1950s it became an open pit operation for mining both tincal and kernite, which is used for manufacturing borates and boric acid.
At the same time the mine became an open pit operation, processing facilities were built on site. This expansion allowed it to become one of the major suppliers of borates and boric acid. Most of the processing of the borates for agriculture, industrial, and specialty applications occurs at Boron and at a second refining and distribution operation in Wilmington, CA.
Borax is used in more than armor. Borax is commonly though of as a laundry detergent, and for good reason. Borates have unique properties that help stain removal and bleaching, while softening water and boosting surfactant performance. Borates also control bacteria and fungi.
Although the Boraxo/Borateem/20-Mule Team product lines were sold to Dial Corporation in 1988, there are still many products that Borax produces. It's a critical component in fertilizer because boron is an essential micronutrient for plants, vital to their growth and development. Without sufficient boron, plant fertilization, seeding and fruiting are not possible.
Although boron compounds are used in the latest ceramic tank armor, that is also one of its oldest uses, as evidenced by Chinese ceramics from the tenth century AD. Borates are used to initiate glass formation and reduce glass viscosity, helping to form a smooth surface; and to reduce thermal expansion, facilitating a good fit between the glaze or enamel and the item it covers. Borates in glazes and enamels also increase the refractive index, or luster; enhance durability and resistance to chemicals; and help dissolve coloring agents.
As a ceramic armor, boron carbide has been outstanding. Although some Abrams tanks have been disabled by enemy fire in places like Iraq, its ceramic armor has protected it occupants. No American has been killed by an enemy while in an Abrams tank.