Borazon is a brand name of a cubic form of

boron nitride Boron nitride is a thermally and chemically resistant refractory compound of boron and nitrogen with the chemical formula B N. It exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexago ...

(cBN). Its color ranges from black to brown and gold. It is one of the hardest known materials, along with various forms of

diamond Diamond is a Allotropes of carbon, solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Diamond is tasteless, odourless, strong, brittle solid, colourless in pure form, a poor conductor of e ...

and other kinds of boron nitride. Borazon is a

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...

created by heating equal quantities of

boron Boron is a chemical element; it has symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the boron group it has three ...

and

nitrogen Nitrogen is a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

at temperatures greater than 1800 °C (3300 °F) at 7 GPa (1 million lbf/in²). Borazon was first produced in 1957 by Robert H. Wentorf, Jr., a physical chemist working for the

General Electric General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston. Over the year ...

. In 1969, General Electric adopted the name Borazon as its

trademark A trademark (also written trade mark or trade-mark) is a form of intellectual property that consists of a word, phrase, symbol, design, or a combination that identifies a Good (economics and accounting), product or Service (economics), service f ...

for the material. The trademark is now owned by Diamond Innovations, doing business a
Hyperion Materials & Technologies, Inc.
and Borazon is manufactured only by Hyperion Materials & Technologies.

Uses and production

Borazon has a number of uses , such as: cutting tools, dies, punches, shears, knives, saw blades, bearing rings, needles, rollers, spacers, balls, pump and compressor parts, engine and drive train components (e.g. camshafts, crankshafts, gears, valve stems, drive shafts, CV joints, piston pins, fuel injectors, turbochargers, and aerospace and land-based gas turbine parts such as vanes, blades, nozzles, and seals), surgical knives, blades, scissors, honing, superfinishing, cylinder liners, connecting rods, grinding of steel and paper mill rolls, and gears. Prior to the production of Borazon,

was the preferred abrasive used for grinding very hard superalloys but it could not be used effectively on

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

s because carbon tends to dissolve in iron at high temperatures.

Aluminium oxide Aluminium oxide (or aluminium(III) oxide) is a chemical compound of aluminium and oxygen with the chemical formula . It is the most commonly occurring of several Aluminium oxide (compounds), aluminium oxides, and specifically identified as alum ...

was the conventional abrasive used on hardened steel tools.Description of Borazon and Borozon as prior art in patent from 31 December 1969
/ref> Borazon replaced aluminium oxide for grinding hardened steels owing to its superior abrasive properties, comparable to that of diamond. Borazon is used in industrial applications to shape tools, as it can withstand temperatures greater than 2000 °C (3632 °F), much higher than that of a pure diamond at 871 °C (1600 °F). Other uses include

jewellery Jewellery (or jewelry in American English) consists of decorative items worn for personal adornment such as brooches, ring (jewellery), rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the ...

designing,

glass Glass is an amorphous (non-crystalline solid, non-crystalline) solid. Because it is often transparency and translucency, transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window pane ...

cutting and laceration of diamonds. CBN-coated grinding wheels, referred to as Borazon wheels, are routinely used in the machining of hard ferrous metals, cast irons, and nickel-base and cobalt-base superalloys. They can grind more material, to a higher degree of accuracy, than any other abrasive. The limiting factor in the life of such tools is typically determined not by wear on the cutting surface but by its break-down and separation from the metal core resulting from failure of the bonding layer.

Cultural references

A Borazon drill is used in the TV miniseries and film '' Quatermass and the Pit''. In this story an alien spacecraft is unearthed in London and the drill is used in an attempt to open a sealed bulkhead. The shell of the object is so hard that even the Borazon drill makes no impression, and when the attempt is made, vibrations cause severe distress in people around the object. In Ivan Yefremov's novel '' Andromeda: A Space-Age Tale'' (written 1954–1956, published Jan 1957) boron nitride named ''borazon'' is routinely used in sublight engine parts and spaceship surface coating. In Randall Garrett's's short story "Thin Edge" (Analog, Dec 1963) a fictional borazon-tungsten cable of extraordinary tensile strength is a central plot element. The cable is developed by asteroid miners for a tow-rope for hauling asteroids. The protagonist cuts through cell bars and booby-traps his room using a single strand of the wire, similar to a monomolecular wire.

References

{{reflist

External links

Discovering a Material That's Harder Than Diamond
by Robert H. Wentorf, Jr.
Boron in Materials Technology

Borazon(R) CBN
Synthetic materials Superhard materials Boron compounds Nitrides

Uses and production

Cultural references

See also

References

External links