Kingcera silicon carbide ceramic bulletproof sheet
With the development of technology, modern weapons are more and more destructive, and people pay more and more attention to bulletproof materials. As a very popular bulletproof material at present, special ceramics have played an important role in the field of bulletproof. Special ceramics have the characteristics of high strength, high hardness, low density, corrosion resistance, and high wear resistance. They are lighter in weight and less loaded than metal bulletproof materials, and have obvious advantages in individual bulletproof equipment such as bulletproof vests. At present, bulletproof ceramics mainly including alumina, zirconia, silicon carbide, boron carbide, aluminum nitride, silicon nitride, and titanium boride have been offered for engineering application. Among them, silicon carbide is a ceramic material that has been applied and studied more at home and abroad in recent years, and using silicon carbide as a bulletproof material has become a hot research topic in domestic and oversea recent years.
1、Advantages of silicon carbide ceramic bulletproof sheets
There are three materials used more in bulletproof ceramics: alumina, silicon carbide and boron carbide. Alumina ceramic bulletproof sheet (know as white sheet commonly) has the lowest hardness (HRA90) and high density among the three, but the price is cheap; boron carbide ceramic bulletproof sheet has the highest hardness, low density, and the best performance among the three, but the price is also far than the other two materials. In comparison, silicon carbide ceramic bulletproof sheet (know as black sheet commonly) has a hardness of up to HRA92 and a density of only 82% of that of alumina bulletproof sheet. The price is moderate, so it is widely used.
Silicon carbide (SiC) mainly has two crystal structures, namely cubic β-SiC and hexagonal α-SiC. It is a compound with strong covalent bonds, and the ionic type of its Si--C bond is only 12 %. Therefore, compared with other ceramics such as alumina and boron carbide, it has better mechanical properties, oxidation resistance, higher wear resistance and lower friction coefficient. In addition, it has good thermal stability and high temperature Excellent properties such as high strength, small thermal expansion coefficient, high thermal conductivity, and good thermal shock and chemical corrosion resistance are favored by military experts from various countries and are widely used.
However, its fatal shortcoming of low toughness is still an urgent problem to be solved. The molecular structure and characteristics of silicon carbide determine that it has low toughness. When it hit by a bullet, its ultra-high strength can completely resist the huge kinetic energy of the bullet and shatter the bullet instantly. Cracks or even fragments occur at the moment of impact, which makes the silicon carbide ceramic plate can only be used as a one-time insert plate, and usually cannot withstand multiple consecutive shots. However, many researchers in the field of material molecular science have stated that the shortcoming of silicon carbide's low toughness can theoretically be compensated and overcome by controlling the sintering process and ceramic fiber weaving. This will greatly broaden the application range of silicon carbide in the field of bulletproof, making it an ideal material for the manufacture of bulletproof equipment.
Kingcera silicon carbide ceramic bulletproof sheet
2、Bulletproof principle of silicon carbide ceramic bulletproof plate
The basic principle of armor protection is to dissipate the energy of the bullet, slow it down and render it harmless. Most traditional engineering materials, such as metal materials, absorb energy through plastic deformation of the structure, while ceramic materials absorb energy through the process of micro-fracture.
The energy absorption process of silicon carbide bulletproof ceramics can be roughly divided into three stages:
1. Initial impact stage: the bullet hits the ceramic surface, blunts the bullet, and absorbs energy during the process of crushing the ceramic surface to form small and hard fragment areas;
2.Erosion stage: the blunted bullet continues to erode the fragment area, forming a continuous layer of ceramic fragments;
3. Deformation, crack and fracture stage: Finally, tensile stress is generated in the ceramics to break the ceramics, and then the back plate is deformed, and the remaining energy is all absorbed by the deformation of the back plate material. When the bullet hits the ceramic, both the bullet and the ceramic are damaged.
Measured from performance, price, development prospects, etc., silicon carbide bulletproof ceramics have high research value, and will be more and more widely used in the field of bulletproof!
