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Boron carbide

Boron carbide
IUPAC name Boron carbide
Other names Tetrabor
Black Diamond
CAS number 12069-32-8
Molecular formula B4C
Molar mass 55.255 g/mol
Appearance Black powder.
Density 2.52 g/cm3, solid.
Melting point

2350 °C (2623.15 K)

Boiling point

>3500 °C (>3773.15 K)

Solubility in water Insoluble.
Crystal structure Rhombohedral
MSDS External MSDS
Main hazards Harmful, irritant.
Related Compounds
Related compounds Boron nitride
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

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, it was not until the 1930s that the material was studied scientifically. 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.


  • Personal and vehicle anti-ballistic armor plating, small-arms protective inserts.
  • Grit blasting nozzles.
  • High-pressure water jet cutter nozzles.
  • Scratch and wear resistant coatings.
  • Cutting tools and dies.
  • Abrasives such as used in grinding wheels.
  • Neutron absorber and control rod material in nuclear reactors.


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


    This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Boron_carbide". A list of authors is available in Wikipedia.
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