physics - Boron carbide

General
Boron carbide
Chemical formula	B₄C
Molecular weight	55.25 amu
Appearance	Dark gray or black solid or powder.
CAS number	12069-32-8 (B4-C)
MSDS	Boron carbide MSDS
Other names
Tetrabor B4-C B4C Black Diamond
Physical properties
Density and phase at STP	2.5 g/cm³ (?)
Solubility	None
Specific gravity	2.51
Crystal structure	Rhombohedral
Thermal decomposition	? K (? °C)
Phase behavior
Melting point	2,623 K (2,350° C)
Boiling point	3,773 K (3,500° C)
Triple point	? K (? °C) ? bar
Critical point	? K (? °C) ? bar
Heat of fusion (Δ_fusH)	? kJ/mol
Entropy of fusion (Δ_fusS)	? J/mol·K
Heat of vaporization (Δ_vapH)	? kJ/mol
Safety
Ingestion	?
Inhalation	?
Skin	?
Eyes	?
OSHA Permissible Exposure Limit (PEL)	? ppm
NIOSH Immediate Danger to Life and Health (IDLH)	? ppm
Precautions
Hazards: ? Personal protection: ? Reacts with: ? Storage: ?
Solid properties
Standard enthalpy change of formation (Δ_fH⁰_solid)	-62.68 kJ/mol
Standard molar entropy (S⁰_solid)	26.77 J/mol·K
Heat capacity (C_p)	? J/mol·K
Density	2.5 g/cm³
Liquid properties
Δ_fH⁰_liquid	51.88 kJ/mol
S⁰_liquid	69.21 J/mol·K
C_p	? J/mol·K
Density	? g/cm³
Gas properties
Δ_fH⁰_gas	? kJ/mol
S⁰_gas	? J/mol·K
C_p	? J/mol·K
Except where noted, all data was produced under conditions of standard temperature and pressure.

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 fourth hardest material known behind cubic boron nitride, diamond, and ultrahard fullerite.

Discovered in the 19th Century as a bi-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 in an electric arc furnace.

Applications

Personal and vehicle anti-ballistic armor plating.
Grit blasting nozzles.
High-pressure water jet cutter nozzles.
Scratch and wear resistant coatings.
Cutting tools and dies.
Abrasives.
Neutron absorber in Nuclear Reactors.

Boron carbide

Applications

See Also