Application and characteristics of boron carbide

Boron carbide is the superhard material whose hardness is only second to diamond and cubic boron nitride, with hardness up to 3000 kg/mm2.  Low density, only 2.52g /cm3, is 1/3 of steel;  High elastic modulus, 450 GPa;  High melting point, about 2447℃;  Its thermal expansion coefficient is low, high thermal conductivity.  

Boron carbide is a kind of nonmetallic ceramic material, gray black, has many excellent physical and chemical properties, such as good self-polishing and self-lubrication ability, can be used as special bearing material;  Low density and good mechanical properties, is the first choice of bulletproof armor material;  It has strong corrosion resistance, almost does not interact with any acid and alkali, so it is an excellent corrosion resistant material.  

In addition, boron carbide has good chemical stability, acid and alkali corrosion resistance, at room temperature does not react with acid and alkali and most inorganic compound liquid, only in hydrofluoric acid - sulfuric acid, hydrofluoric acid - nitric acid mixture has slow corrosion;  And most of the molten metal does not wet, do not act.  Boron carbide also has a good ability to absorb neutrons, which other ceramic materials do not have.  

In recent years, boron carbide has been used more and more in automobile, navigation and aviation, nuclear industry and other fields, expanding its application range.  The neutron absorption performance of boron carbide mainly depends on B10 in boron carbide. B10 has a high neutron capture cross section, and its capture energy spectrum width is only second to gadolinium, samarium, cadmium and other elements.  Boron carbide has become an increasingly popular nuclear reactor material due to its high neutron capture cross section.  

Application of boron carbide

Boron carbide is mainly used in structural materials, chemical raw materials, electrical properties, nuclear properties, composite ceramics and other aspects.  In terms of structural materials, due to its high hardness, it can be used as an abrasive for the processing of all kinds of hard metals, corundum or glass, and can also be made of wear-resistant and corrosion-resistant boron carbide devices. In addition, the external application of boron carbide materials can also be used as cutting edge, mortar and so on.  It can also be used as light armor and bulletproof vest for helicopters.  

In the chemical raw materials can be used as steel or other alloy boronizing agent on the surface of steel, to generate iron boride thin layer to enhance the strength and wear resistance of the material, but also can be used for some metal friction materials additives;  In the reduction - chemical method to get boride powder, boron carbide as a boron source, TiB2, ZrB2, GrB2 powder, also can produce boron halide, hydrogen boride, etc., known as the "boron carbide method" to prepare powder.  

In the nuclear performance, the advantages of strong absorption capacity of neutrons are used as functional components of neutron absorption materials, such as control rod, regulating rod, accident rod, safety rod and shielding rod.  The application of boron carbide composite ceramics can improve its sintering behavior by adding sintering additives, and obtain low price and good quality boron carbide products. It can also be made into composite materials. It has been applied in the field of industrial nozzle, pump seal and hot extrusion die, and is a high temperature corrosion resistant and wear-resistant material with wide application prospects.