Boron carbide
From Wikipedia, the free encyclopedia
| Boron carbide | |
|---|---|
| Image:Boron carbide.jpg | |
| General | |
| Systematic name | Boron carbide |
| Other names | Tetrabor B4-C B4C Black Diamond |
| Molecular formula | B4C |
| Molar mass | 55.255 g/mol |
| Appearance | Black powder. |
| CAS number | [] |
| Properties | |
| Density and phase | 2.52 g/cm3, solid. |
| Solubility in water | Insoluble. |
| Melting point | 2350 °C (2623.15 K) |
| Boiling point | >3500 °C (>3773.15 K) |
| Structure | |
| Molecular shape | ? |
| Coordination geometry |
? |
| Crystal structure | Rhombohedral |
| Dipole moment | ? D |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Harmful, irritant. |
| NFPA 704 |
0
0
0
|
| Flash point | Non-flammable. |
| R/S statement | R: R20, R36, R37. S: S9, S36. |
| RTECS number | ? |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Other anions | ? |
| Other cations | ? |
| 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 radio-nuclides make 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.
[edit] Applications
- 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 in nuclear reactors.
[edit] References
- Carbide, Nitride and Boride Materials Synthesis and Processing ISBN 0-412-54060-6
