From ancient to modern times, the core of all military activities is around a core of “spear and shield”, namely attack and defense. With the continuous progress of military technology, soft body armor has been far from meeting the operational requirements. People began to use hard materials with soft body armor, to achieve a higher level of defense, common materials are: steel plate, titanium alloy, B4C, Si3N4, SiC,Al2O3 and so on.
Steel plate is the first used in hard body armor material, although it greatly improves the protection level of soft body armor, but the protection ability is limited, can only defend against the attack of lead core bullets and ordinary steel core bullets, and there are too much weight easy to jump bullets and other shortcomings.
Ceramic material relative to steel plate is further improved, light weight density is less than half of steel plate, and there is no ricochet phenomenon.
Currently common bulletproof ceramic plate specifications: 250*300mm cambered assembly plate.
Common specifications of bulletproof ceramic sheet:
50*50 arc surface (370~400)
Hexagonal plane (side length 21mm)
Half piece, bevel Angle (25*50)
Performance requirements of bulletproof ceramics:
The bulletproof principle of ceramic and metal is very different, metal bulletproof plate is by plastic deformation to absorb the kinetic energy of the bullet, while ceramic bulletproof plate is by its rupture to absorb the kinetic energy of the bullet.
Bulletproof ceramics require more performance, such as: density, porosity, hardness, fracture toughness, elastic modulus, speed of sound, mechanical strength, any one performance can not have a direct and decisive relationship with the overall bulletproof performance, so the fracture mechanism is very complex, crack formation is caused by many factors, and the time is very short.
①Porosity should be as low as possible to improve hardness and elastic modulus, ceramic hardness must be higher than bullet flight hardness.
② Hardness directly determines the bullet-resistant performance of bulletproof plate.
③ The density directly determines the weight of the bulletproof plate, because of the limited weight capacity of individual soldiers, so hard body armor density requirements are the lighter the better.
④Classification of ceramic bulletproof plate: 95 alumina ceramic, 97 alumina ceramic, 99 alumina ceramic, etc.
Of the commonly used ceramic materials,B4C, Si3N4, SiC bullet-proof performance is outstanding, but the price is high, Al2O3 has low price, mature process, easy to control size, low sintering temperature, easy to mass production and other advantages, has become a common material in bulletproof ceramics.
Post time: Apr-24-2023