Boron carbide

Boron carbide

Chembox new
Name = Boron carbide
ImageFile =
ImageSize =
ImageName = Boron carbide
IUPACName = Boron carbide
OtherNames = Tetrabor
B4-C
B4C
Black Diamond
Section1 = Chembox Identifiers
CASNo = 12069-32-8
Section2 = Chembox Properties
Formula = B4C
MolarMass = 55.255 g/mol
Appearance = Black powder.
Density = 2.52 g/cm3, solid.
Solubility = Insoluble.
MeltingPt = 2350 °C (2623.15 K)
BoilingPt = >3500 °C (>3773.15 K)
Section3 = Chembox Structure
MolShape =
Coordination =
CrystalStruct = Rhombohedral
Dipole =
Section7 = Chembox Hazards
ExternalMSDS = [http://www.logitech.uk.com/MSDS/Files%5C0CON-024%20to%20028.pdf External MSDS]
MainHazards = Harmful, irritant.
Section8 = Chembox Related
OtherAnions =
OtherCations =
OtherCpds = Boron nitride

Boron carbide (chemical formula B4C) is an extremely hard ceramic material used in tank armor, bulletproof vests, and numerous industrial applications. With a hardness of 9.3 on the mohs scale, it is the fifth hardest material known behind boron nitride, diamond, ultrahard fullerite, and aggregated diamond nanorods.

Discovered in the 19th century as a by-product of reactions involving metal borides, however, its chemical formula was unknown. It was not until the 1930s that the formula was determined to be B4C [http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=CA339873&F=0&QPN=CA339873] . Boron carbide is now produced industrially by the carbo-thermal reduction of B2O3 (boron oxide) in an electric arc furnace.

Its ability to absorb neutrons without forming long lived radionuclides makes the material attractive as an absorbent for neutron radiation arising in nuclear power plants. Nuclear applications of boron carbide include shielding, control rod and shut down pellets. Within control rods, boron carbide is often powdered, to increase its surface area.

References

* Carbide, Nitride and Boride Materials Synthesis and Processing ISBN 0-412-54060-6

External links

* [http://www.npi.gov.au/database/substance-info/profiles/15.html National Pollutant Inventory - Boron and compounds]
* [http://webbook.nist.gov/cgi/cbook.cgi?ID=C12069328&Units=SI&Mask=2#Thermo-Condensed NIST Chemistry Database Entry for Boron Carbide]


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Look at other dictionaries:

  • boron carbide — n. a black, crystalline compound of boron and carbon, B4C, almost as hard as diamond: used as an abrasive and in control rods for nuclear reactors: see MOHS SCALE (sense 2) …   English World dictionary

  • boron carbide — Chem. a black, crystalline, extremely hard, water insoluble solid, B4C, used chiefly as a moderator in nuclear reactors, as an abrasive, and as a refractory. * * * ▪ chemical compound       (B4C), crystalline compound of boron and carbon. It is… …   Universalium

  • boron carbide — noun : any binary compound of boron and carbon; especially : a refractory shiny black crystalline solid B4C ranking next to the diamond in hardness made usually by heating boric oxide and coke in an electric furnace and used chiefly as powdered… …   Useful english dictionary

  • boron carbide — a compound, B4C, slightly harder than silicon carbide (q.v.), obtained by heating boron at very high temperature to effect its union with carbon; used as a neutron absorber in nuclear reactors, and as an abrasive agent in industry and dentistry …   Medical dictionary

  • boron carbide — noun A binary compound of boron and carbon, BC, that is a very hard ceramic, and is used in tank armour, bulletproof vests etc. Syn: Tetrabor …   Wiktionary

  • boron carbide — noun Date: circa 1909 a refractory shiny black crystalline compound B4C that is one of the hardest known materials and is used especially in abrasives and as a structural reinforcing material …   New Collegiate Dictionary

  • boron carbide — /bɔrɒn ˈkabaɪd / (say bawron kahbuyd) noun a black crystalline solid, B4C, which is the hardest known substance after diamond, and which is used as an abrasive and to form control rods in nuclear reactors …  

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  • Boron — (pronEng|ˈbɔərɒn) is a chemical element with atomic number 5 and the chemical symbol B. Boron is a trivalent nonmetallic element which occurs abundantly in the evaporite ores borax and ulexite. Boron is never found as a free element on… …   Wikipedia

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