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• Time of issue:2019-10-24 22:02
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(Summary description)Alumina ceramics

In the 1980s, the ceramics used in armor systems were mainly alumina (also called bauxite) ceramics. Alumina ceramics have excellent performance and relatively low manufacturing costs, and a very thin ceramic layer can defend against small arms ammunition. In the UK, the first mass-produced body armor used alumina ceramic fenders.

After 1995, countries have invested a lot in improving the performance of alumina ceramics, but the improvement of its protective performance has always been limited. Nevertheless, due to its light weight, alumina ceramics are still widely used in some aircraft protection or body armor.

Boron carbide ceramics

In addition to alumina, other ceramic armor materials are also emerging. Among them, the most striking is the boron carbide ceramics that have been used since the 1960s. Boron carbide ceramics have ultra-high hardness and an amazing price. Therefore, this kind of ceramic is only used in some special occasions that have higher requirements on protective performance, such as the crew seat of the U.S. military's V22 "Osprey" rotary-wing aircraft. In addition, the Enhanced Body Armor (EBA) used by the British army also uses boron carbide ceramics, which can defend against 12.7mm steel core armor-piercing projectiles. There is also a "blunt trauma" protective layer inside the EBA, which protects the human body from blunt trauma when the ceramic is impacted but not penetrated and the lining is deformed, thereby protecting the vital organs of the human body from damage.

British BAE Systems Advanced Ceramics Branch produces boron carbide ceramics, which have been used as protective inserts for the U.S. Army's "Interceptor" body armor. By 2002, a total of 12,000 sets of Interceptor body armor were put into the field.

Of course, boron carbide ceramics also have its shortcomings. Facts have shown that its protection against high-speed warheads made of high-density materials is not satisfactory. This is due to the change of the physical properties of the boron carbide ceramic when the high-hardness and high-speed bullet impacts it.
Although the protection effect of boron carbide ceramics on hard core armor-piercing projectiles is not ideal, its protection on ordinary steel core armor-piercing projectiles is still relatively easy.

Silicon carbide ceramics

The hot-pressed silicon carbide ceramics introduced by BAE Systems in the United Kingdom and Ceradyne in the United States have better protection effects. Silicon carbide ceramics are fired at high temperature (up to 2000°C) under high pressure to obtain ultra-high strength, which is much stronger than the warhead, which shatters immediately after impact to release its kinetic energy quickly. Tests have proved that this ceramic has a good protective effect on small arms ammunition and armor-piercing shells with stabilized tail fins, and the price is relatively low.

A good armor material can be made by pressing silicon carbide ceramics and metal together by a hot pressing process. The purpose of the hot pressing process is to use different physical changes when the metal and ceramic are heated and cooled to generate a large stress inside the silicon carbide ceramic, thereby obtaining ultra-high strength. In addition, the resistance to multiple blows of hot-pressed silicon carbide ceramics has also been improved.

Silicon carbide ceramics can also be produced by a chemical reaction process, which can precisely control the size of the ceramic, but because some metal impurities generated by the chemical reaction will remain in the ceramic, thus reducing the strength of the ceramic. Silicon carbide ceramics produced by chemical reaction processes can be used in less threatened armor systems.

Other ceramics
In addition to the above ceramics, there are other ceramics that can be used for armor materials, such as aluminum nitride ceramics, silicon nitride ceramics, tungsten carbide ceramics, titanium diboride ceramics, etc. Silicon nitride ceramics and aluminum nitride ceramics are rarely used in armored systems. Tungsten carbide ceramics are expensive, but have high density (about 6 times that of silicon carbide ceramics), high strength, and have a good protective effect on armor-piercing bullets. Tungsten carbide is suitable for occasions where the volume of the armor material is required but the quality of the armor is not required. The performance of titanium diboride ceramics is also very good, and the density is higher than that of silicon carbide. Like tungsten carbide, titanium diboride is electrically conductive and can be processed electrochemically, whereas it is difficult to cut with other methods. Like tungsten carbide, the expensive price limits the application of titanium diboride ceramics.