Boron carbide

From Wikipedia, the free encyclopedia

This article or section is in need of attention from an expert on the subject.

WikiProject Physics or the Physics Portal may be able to help recruit one.

If a more appropriate WikiProject or portal exists, please adjust this template accordingly.

Boron carbide
IUPAC name	Boron carbide
Other names	Tetrabor B4-C B4C Black Diamond
Identifiers
CAS number	[12069-32-8]
Properties
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.
Structure
Crystal structure	Rhombohedral
Hazards
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.