In many cop movies or military movies, many police officers or soldiers wear thick bulletproof vests. Bulletproof vests not only make soldiers look cool but also protect their lives in critical moments. Judging from the current technological conditions, bulletproof vests are the most important light equipment to ensure the life safety of soldiers. Wearing them can greatly improve the combat enthusiasm of the police or soldiers in the war, and it can also make the police or soldiers more courageous to face threats, to effectively complete the combat mission. It can be said that the bulletproof vest is the confidence of the soldiers. Few people dare to face the battlefield with a real gun without wearing a bulletproof vest. Bulletproof vests are also one of the important inventions of modern weapons.
In the impression of many people, hard steel is one of the best materials to resist bullets because it is strong enough. In another impression, ceramics can't stand the impact of bullets anyway. Surprisingly, however, the material used to make modern bulletproof vests is not very hard steel, but ceramics that break at the touch. What are the considerations that go against common sense when using ordinary ceramics for bulletproof vests? The reason is as follows.
We all know that the properties of materials are relative. Although the steel plate is strong, it is heavy. If a steel plate that can block bullets is made into a bulletproof vest, the weight of the two steel plates at the front and the rear of the bulletproof vest will seriously limit the soldier's mobility in action. If the thickness of the steel plate is reduced to reduce the weight, the bulletproof effect cannot be effectively achieved.
The ceramic inserts of body armor can use a variety of materials, the more common are alumina, silicon carbide, and boron carbide. Ceramics are bulletproof because of their high specific stiffness, high specific strength, and chemical inertness in many environments. What is better than metal is that metal material will plastically deform and absorb energy when resisting the impact of the bullet, while ceramics will hardly undergo plastic deformation, and the bullet will be passivated or even broken due to its own high strength and hardness characteristics. The bulletproof layer is made of bulletproof ceramic and high-strength and high-modulus fiber composite board. When the high-speed projectile collides with the ceramic layer, the ceramic layer shatters or cracks and diffuses around the bullet impact point to consume most of the energy of the projectile. The modulus fiber composite board further dissipates the remaining energy of the projectile. Therefore, the application of advanced ceramics in armor systems is very attractive and has become a protective armor widely used in body armor, vehicles, aircraft, and other equipment.
