Ceramic protective armor and its protective mechanism

Boron carbide ceramics are mainly B4C ceramics. Chemical formula is B4C, hexagonal crystal system, dark color. The melting point is 2450℃, the theoretical density is 2.52g/cm3, and the Vickers hardness is 49.5GPa, which is inferior to diamond and cubic boron nitrite in nature. It also has a large thermal neutron capture cross section. It can be used to process gemstones, ceramics, molds, turning tools and bearings, etc. It can also be used as neutron absorbent of sandblasting nozzle and atomic reactor, and can be used as ceramic protective armor material.

1. Ceramic protective armor and its protective mechanism

Compared with other material protective armor, ceramic armor has the advantages of high hardness, light weight, and strong defense ability to warhead and ammunition fragments, has become a widely used in body armor, vehicles, aircraft and other equipment protective armor. Nowadays, most ceramic armor is bonded with low hardness and low density viscous polymer between the lining. When the shock wave of ammunition spreads to the interface of ceramic and polymer adhesive layer, the shock wave produces strong stretching and destroys the ceramic layer, and the polymer adhesive layer is damaged by strong shearing. By pulling and shearing, the ceramic layer is separated from the lining. At the same time, the warhead and ammunition fragments shatter under pressure, forming a conical fracture zone. It is because of the high hardness of ceramics that the shock wave energy of warheads and ammunition fragments can be decomposed into a larger protective area. Thus preventing warhead and ammo fragments, protecting personnel vital parts.

The general development trend of armor materials is toughening, lightweight and multifunctional. Ceramic material is an important branch of bulletproof material, which has high hardness, high compressive strength and excellent ballistic performance under high stress. Under the impact of the bullet (speed > 700 ~ 800m/s), the ceramic front is broken and the remaining energy is absorbed by the soft reinforcement material (nylon cloth layer, etc.) on the reverse side, which must be able to support the ceramic material fragments and the bullet itself after the impact.