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Silicon carbide and boron carbide have become the most popular bulletproof ceramic materials

2024-08-20

Silicon carbide bulletproof ceramic

Silicon carbide has extremely strong covalent bonds and maintains high strength even at high temperatures. This structural characteristic endows silicon carbide ceramics with excellent strength, high hardness, wear resistance, corrosion resistance, high thermal conductivity, and good thermal shock resistance; At the same time, silicon carbide ceramics have a moderate price and high cost-effectiveness, making them one of the most promising high-performance armor and protective materials. SiC ceramics have broad development space in the field of armor protection, and their applications in individual soldier equipment and special vehicles are becoming more diversified. When used as protective armor material, considering factors such as cost and special application scenarios, ceramic panels arranged in small pieces are usually bonded with composite backing plates to form ceramic composite target plates, in order to overcome the failure of ceramics caused by tensile stress and ensure that only individual pieces are crushed when the projectile penetrates without damaging the entire armor.

Boron carbide is currently known as a superhard material with a hardness second only to diamond and cubic boron nitride, with a hardness of up to 3000 kg/mm2; Low density, only 2.52 g/cm3, which is one-third of steel; High elastic modulus of 450GPa; High melting point, approximately 2447 ℃; Its coefficient of thermal expansion is low and its thermal conductivity is high. In addition, boron carbide has good chemical stability, acid and alkali resistance, and does not react with acids, bases or most inorganic compound liquids at room temperature. It only has slow corrosion in hydrofluoric acid sulfuric acid and hydrofluoric acid nitric acid mixtures; And it does not wet or interact with most molten metals. Boron carbide also has excellent neutron absorption ability, which other ceramic materials do not possess. B4C has the lowest density among several commonly used armor ceramics, and its high elastic modulus makes it a good choice for military armor and space materials. The main problems with B4C are its high price (about 10 times that of alumina) and high brittleness, which limits its widespread application as single-phase protective armor.