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 BN. It exists in various crystalline forms that are isoelectronic to a similarly structured carbon lattice. The hexagon ...
(cBN). Its color ranges from black to brown and gold, depending on the chemical bond. It is one of the hardest known materials, along with various forms of
diamond
Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, ...
and kinds of boron nitride. Borazon is a
crystal created by heating equal quantities of
boron
Boron is a chemical element with the 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 th ...
and
nitrogen
Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at sevent ...
at temperatures greater than 1800 °C (3300 °F) at 7
GPa
Grading in education is the process of applying standardized measurements for varying levels of achievements in a course. Grades can be assigned as letters (usually A through F), as a range (for example, 1 to 6), as a percentage, or as a numbe ...
(1 million
lbf/in2).
Borazon was first produced in 1957 by
Robert H. Wentorf, Jr., a
physical chemist
Physical chemistry is the study of macroscopic and microscopic phenomena in chemical systems in terms of the principles, practices, and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mecha ...
working for the
General Electric Company
The General Electric Company (GEC) was a major British industrial conglomerate involved in consumer and defence electronics, communications, and engineering. The company was founded in 1886, was Britain's largest private employer with over 250 ...
. In 1969, General Electric adopted the name Borazon as its
trademark
A trademark (also written trade mark or trade-mark) is a type of intellectual property consisting of a recognizable sign, design, or expression that identifies products or services from a particular source and distinguishes them from others ...
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, compressor parts, engine & 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,
diamond
Diamond is a solid form of the element carbon with its atoms arranged in a crystal structure called diamond cubic. Another solid form of carbon known as graphite is the chemically stable form of carbon at room temperature and pressure, ...
was the preferred
abrasive
An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away by friction. While finishing a material often means polishing it to gain a smooth, reflec ...
used for grinding very hard
superalloys
A superalloy, or high-performance alloy, is an alloy with the ability to operate at a high fraction of its melting point. Several key characteristics of a superalloy are excellent mechanical strength, resistance to thermal creep deformation, ...
but it could not be used effectively on
steel
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant t ...
s because carbon tends to dissolve in iron at high temperatures.
Aluminium oxide was the conventional abrasive used on hardened steel tools.
[Description of Borazon and Borozon as prior art in patent from 31 December 1969](_blank)
/ref>
Borazon replaced aluminium oxide for grinding hardened steels owing to its superior abrasive properties, comparable to that of diamond.jewellery
Jewellery ( UK) or jewelry (U.S.) consists of decorative items worn for personal adornment, such as brooches, rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the clothes. From a western pe ...
designing, glass
Glass is a non-crystalline, often transparent, amorphous solid that has widespread practical, technological, and decorative use in, for example, window panes, tableware, and optics. Glass is most often formed by rapid cooling (quenching) o ...
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 series and film ''Quatermass and the Pit
''Quatermass and the Pit'' is a British television science-fiction serial transmitted live by BBC Television in December 1958 and January 1959. It was the third and last of the BBC's ''Quatermass'' serials, although the chief character, Profe ...
''. 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
Ivan Antonovich (real patronymic Antipovich) Yefremov ( ru , Ива́н Анто́нович (Анти́пович) Ефре́мов; April 23, 1908 – October 5, 1972; last name sometimes transliterated as Efremov) was a Soviet paleonto ...
'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)monomolecular wire
Monomolecular wire is a type of wire consisting of a single strand of strongly bonded atoms or molecules, like carbon nanotubes.
In science
Organic molecular wires have been proposed for use in optoelectronics.
In fiction
Among the earliest des ...
.
See also
*Abrasive machining
Abrasive machining is a machining process where material is removed from a workpiece using a multitude of small abrasive particles. Common examples include grinding, honing, and polishing. Abrasive processes are usually expensive, but capable of t ...
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