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{{short description|Brand name of a cubic form of boron nitride (cBN)}}

'''Borazon''' is a brand name of a cubic form of [[boron nitride]] (cBN). Its color ranges from black to brown and gold. It is one of the hardest known materials, along with various forms of [[diamond]] and other kinds of boron nitride. Borazon is a [[crystal]] created by heating equal quantities of [[boron]] and [[nitrogen]] at temperatures greater than 1800&nbsp;°C (3300&nbsp;°F) at 7&nbsp;[[gigapascal|GPa]] (1&nbsp;million [[pound-force per square inch|lbf/in<sup>2</sup>]]).

Borazon was first produced in 1957 by [[Robert H. Wentorf, Jr.]], a [[physical chemistry|physical chemist]] working for the [[General Electric]].<ref>{{cite journal| author = R. H. Wentorf| title =Cubic Form of Boron Nitride| journal = J. Chem. Phys. | volume = 26 | page = 956 | year = 1957| doi =10.1063/1.1745964| issue = 4| bibcode =1957JChPh..26..956W}}</ref> In 1969, General Electric adopted the name Borazon as its [[trademark]] for the material. The trademark is now owned by Diamond Innovations, doing business as [https://www.hyperionmt.com Hyperion Materials & Technologies, Inc.], and Borazon is manufactured only by Hyperion Materials & Technologies.<ref>{{Cite web|last=|first=|date=|title=TESS -- Error|url=http://tsdr.uspto.gov/documentviewer?caseId=sn72387519&docId=ACR20170621231013#docIndex=0&page=1|url-status=live|archive-url=https://web.archive.org/web/20200722191235/http://tsdr.uspto.gov/documentviewer?caseId=sn72387519&docId=ACR20170621231013 |archive-date=2020-07-22 |access-date=2020-07-22|website=tmsearch.uspto.gov}}</ref>

==Uses and production==
Borazon has a number of uses {{clarify|date=September 2020 |reason=As in "made-from" or rather used in the manufacturing process?}}, 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.{{Confusing|reason=Are these parts actually made from Borazon. Or is this just a random list of parts that can be polished with a Borazon grinding wheel?|date=September 2020}}

Prior to the production of Borazon, [[diamond]] was the preferred [[abrasive]] used for grinding very hard [[superalloys]] but it could not be used effectively on [[steel]]s because carbon tends to dissolve in iron at high temperatures. [[Aluminium oxide]] was the conventional abrasive used on hardened steel tools.<ref name="patent">[http://www.patentstorm.us/patents/5308367-description.html Description of Borazon and Borozon as prior art in patent from 31 December 1969]{{dead link|date=November 2016 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

Borazon replaced aluminium oxide for grinding hardened steels owing to its superior abrasive properties, comparable to that of diamond.<ref name="patent"/> Borazon is used in industrial applications to shape tools, as it can withstand temperatures greater than 2000&nbsp;°C (3632&nbsp;°F), much higher than that of a pure diamond at 871&nbsp;°C (1600&nbsp;°F).<ref name=BN>{{cite book| title = Landolt-Börnstein - Group VIII Advanced Materials and Technologies: Powder Metallurgy Data. Refractory, Hard and Intermetallic Materials| chapter =  13.5 Properties of diamond and cubic boron nitride | year = 2002 | volume = 2A2| doi = 10.1007/b83029| isbn = 978-3-540-42961-6| pages = 118–139| editor1-last = Beiss | editor1-first = P | editor2-first = R | editor2-last = Ruthardt | editor3-first = H | editor3-last = Warlimont }}</ref> Other uses include [[jewellery]] designing, [[glass]] 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.<ref name="patent"/>

==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 (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|Randall Garrett's]]'s short story "Thin Edge" (Analog, Dec 1963)<ref>{{cite web |title=Thin Edge |url=http://www.isfdb.org/cgi-bin/title.cgi?55426 |website=Internet Speculative Fiction Database |publisher=IFSDB |accessdate=24 May 2020}}</ref> 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]].

==See also==
*[[Abrasive machining]]

==References==
{{reflist}}

==External links==
* [http://www.winstonbrill.com/bril001/html/article_index/articles/51-100/article61_body.html Discovering a Material That's Harder Than Diamond] by [[Robert H. Wentorf, Jr.]]
* [http://biotsavart.tripod.com/bci.htm Boron in Materials Technology]
* [https://www.hyperionmt.com/en/products/Abrasives/ Borazon(R) CBN]

[[Category:Synthetic materials]]
[[Category:Superhard materials]]
[[Category:Boron compounds]]
[[Category:Nitrides]]