Properties, Applications and Product Information of Boron Carbide, B4C

C.T. Kang , Ph.D. 7si@7-stars-international.com
Last revised: 2001/8/22

Production Methods

Boron carbide is produced from boric acid or B2O3 and carbon containing materials in electric arc furnaces. Reaction is 2B2O3 + 7C = B4C + 6CO. ESK and Mudanjiang Second Abrasives Factory of China are the major producers in the world.
Another method to produce submicron boron carbide powders was invented by William Rafaniello and William Moore of The Dow Chemical Company. Details can be found in US Patent # 4,804,525.

Properties

Density: 2.51 g/cm³
Crystal structure: Rombohedral
Melting Point: around 2,450^oC
Very high hardness: It is the third hardest material next to diamond and cubic boron nitride (cBN).
Thermal expansion coefficient: 5 X 10^{-4 o}C^-1
High resistance to chemical attack
Boron carbide has a high neutron absorption cross-section -- for thermal neutron is around 4,000 barns. And the price is much less than pure boron.
Electrical conductive: electrical resistivity at 25oC is 0.1-10 ohm ^.cm

Applications

Wear resistant components: sandblasting nozzles
Refractory industry: as an antioxidant additives in magnesia-carbon bricks (MgO-carbon bricks)
Abrasives: lapping and polishing powders
Armor tiles: High-density boron carbide armor tiles, bullet proofing seats of Apache attack helicopters. Mainly produced by hot pressing.
Nuclear industry: neutron absorber, poison pellets. Example: US Patent 4,684,480. Title: Ceramic bonded neutron absorber plates of boron carbide and free carbon
Radiation protection & shielding
Reinforcement: Metal Matrix Composites (MMC), lightweight cermets, aluminum matrix boron carbide composite (B4C/Al) used for bicycle frames. Example: US Patent # 4,718,941 "Infiltration processing of boron carbide-, boron- and boride-reactive metal cermets"
Raw material: for producing other boron containing materials such as titanium boride, TiB2. Reaction: 2TiO2 + B4C + 3C = 2TiB2 + 4CO
Solid fuel: HTPB/Boron carbide based propellants for ducted rockets
Boriding agent: Boron carbide is one of the raw materials used in boriding agents. Boriding (Boronizing) is a surface treatment (pack cementation). Boride surface layer(s) is formed after the treatment. The hardness and the wear resistance of the surface are greatly improved.
Welding electrodes: Boron carbide containing welding rods are used to improve the wear resistance of surface

Mudanjiang Jingangzhuan Boron Carbide & Fine Ceramics Co., Ltd (Formerly Mudanjiang Second Abrasives Factory (MSAF)) :

One of the major boron carbide powder manufacturers in the world. It is also the largest, oldest, and most reputable boron carbide manufacturer in China.
Hundreds of tons B4C powders have been exported to Japan, US and other countries.

Partial List of Boron Carbide Powders Produced by MSAF

I. Particle Sizes: -100, -200, and -325 mesh

Chemical Compositions

wt. %	Grade "A"	Grade "B"	Grade "C"	Grade "D"
Total boron	> 76.5%	> 77.5%	> 78.5%	> 78.5%
Free boron	< 0.5%	< 0.4%	< 0.3%	< 0.2%
B2O3 Content	< 0.5%	< 0.4%	< 0.3%	< 0.2%
Total Carbon	> 18.5%	> 18.5%	> 18.5%	> 19.5%
Free Carbon	< 2.0%	< 2.0%	< 2.0%	< 2.0%
Fe2O3 content	< 0.6%	< 0.5%	< 0.4%	< 0.3%
Si content	< 0.5%	< 0.4%	< 0.3%	< 0.2%
B4C content	> 93.0%	> 94.0%	> 95.0%	> 96.0%
Total B + total C	> 95.0%	> 96.0%	> 97.0%	> 98.0%

II. Particle Size: - 10 microns (10 microns and finer)

Chemical Composition

	Grade "A"	Grade "B"
Total B	> 78.0%	> 78.0%
Total C	> 18.0%	> 19.5%
Total B + total C	> 96%	> 97.5%
Free Carbon	< 2.50%	< 1.7%
B2O3	< 0.25%	< 0.15%
Fe content	< 0.3%	< 0.2%
Si content	< 0.3%	< 0.2%

III. Other particle sizes, such as -25 microns and FEPA standards, are available also.

If you have any questions, please email to: C.T. Kang, Ph.D. 7si@7-stars-international.com

Mudanjiang Abrasives & Grinding Tools Co.
US Office
PO Box 512, Richland, WA 99352 USA
Tel: (509)946-2495, Fax: (509)943-9235

Products

You can hyperlink to the following web pages and find more information about these products which are handled by Seven Stars International, LLC.

Special Nozzles for Sandblasting, Spray Drying and Geo Jet

Boron Carbide, B4C: Properties, applications and products of boron carbide

Boron Carbide Nozzles and Inserts: Advantages and product information of boron carbide nozzles and inserts. Both nozzles and insert are produced by Malyn Industrial Ceramics, Inc..

Boriding Agents: Properties, applications of two boriding agents

Schunk-Inex Si / SiC Composite Radiant Tube: High temperature Si/SiC composite radiant / protective tubes for heat treatment industry

Schunk-Inex Si / SiC Tube(Chinese Big 5), Chinese GB Code Information about INEX Si/SiC tubes written in Chinese.

MCrAlY Coatings: High temperature corrosion resistant coatings.

Mechanical Seals and Seal Rings: Seal ring materials include: reaction bonded SiC, tungsten carbide, alumina and silicon nitride.

Boron Nitride, BN: Properties, applications and products of boron nitride powders.

MoSi2 Heating Element

Silicon Carbide: Properties, applications and products of silicon carbide, SiC.

Zirconia Powders: Information of two available ZrO2 powders.

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