Materials used in armor have come a long way since ancient times when hides and skins were first used to protect the body.
For many years, armors were produced using various metals and alloys. In modern times, these metal suits have given way to armors made from super strong synthetic fibers and super strong synthetic hard materials. The latest super strong materials to be considered are ceramics.
Ceramic armor can be used to protect vehicles as well as individual personnel, and dates back to 1918. Ceramics are known to be some of the of the hardest materials, and unlike materials such as Kevlar (which uses its fibers to "catch" the bullet), ceramics break the bullet. The strongest and lightest ceramic is boron carbide.
Ceramic plates or trauma plates are used as inserts in soft ballistic vests. It is hard enough to ensure that a bullet or other weapon is deflected, meaning the armor material pushes out on the bullet with nearly the same force with which the bullet pushes in, thus preventing the armor from being penetrated. Ceramic plates provided to the U.S. military are called Enhanced Small Arms Protective Inserts (ESAPI).
The downside to the use of ceramic is that it cannot sustain successive impacts without quickly losing some of its protective value. However, advanced ceramic technology has eliminated that problem by minimizing the size of the ceramic tiles to be as small as possible, with the matrix elements having a minimal practical thickness of about 1 in. (25 mm).
What Materials are Used in Ceramic Armor?
The commercially manufactured ceramics for armor include materials such as boron carbide, aluminium oxide, silicon carbide, titanium boride aluminiumnitride, and Syndite(synthetic diamond composite). Boron carbide composites are primarily used for ceramic plates to protect against smaller projectiles, and are used in body and helicopters. Silicon carbide is primarily used to protect against larger projectiles.
Commercially, a variety of sintered, reaction-bonded and hot pressed ceramic materials are available, for example, Hexoloy® Silicon Carbide (SiC). Likewise common ceramic body armor components in the market are CeraShield™ High-Density Aluminum Oxides, CeraShield Silicon Carbides, and CeraShield Boron Carbides.
Mechanical Properties of Ceramic Armor
The mechanical properties of a few types of ceramic armors are displayed in the table below:
| Ceramic Armor |
Grain Size (µm) |
Density (g/cc) |
Knoop Hardness (100g load)-Kg/mm2 |
Compressive Strength @ RT (MPa x 106 lb/in2) |
Modulus of Elasticity @RT (GPa x 106 b/in2) |
Poisson Ratio |
Fracture Toughness @ RT MPa xm1/2 x103 lb/in2 /in 1/2 |
| Hexoloy® Sintered |
4-10 |
3.13 |
2800 |
3900
560 |
410
59 |
0.14 |
4.60-4.20 |
| Saphikon® Sapphire |
N/A |
3.97 |
2200 |
2000 |
435 |
0.27-0.30 |
N/A |
| Norbide® Hot Pressed |
8 |
2.51 |
2800 |
3900
560 |
440 |
0.18 |
3.1 |
Applications of Ceramic Armor
The following are some of the key applications of ceramic armor:
- The ballistic protection applications of the ceramic armor include transport aircraft armor protection, land vehicles armor protection, AC-130U gunships armor protection, helicopter armor protection, and body armor (XSAPI, ESAPI, SAPI for military and police protection). For example Hexoloy-Silicon Carbide SiC specifically provides ballistic armor protection and bullet-resistant composite armor for military personal, vehicles, aircraft and police.
- Marine-grade ceramic armor for use in medium and small size boats.
- Protection for VIP vehicles
Benefits of Ceramic Armor
The key benefits of a ceramic armor are listed below:
- Provides high performance armor protection
- High hardness and low weight
- Superior lightweight material for composite armor protection applications - a basic ceramic composite armor systems is approximately half the weight, of a similar steel-based systems (five times stronger than steel and 70% lighter)
- Controlled microstructures to ensure durability and performance
- Consistently reliable defense to unexpected threats
- Capable of defeating high velocity projectiles
- CeraShield™ ceramics when used along with an appropriate backing system, can overcome various threats including armor-piercing rounds and IEDs
- Design flexibility
- Excellent resistance to creep and stress rupture at temperatures up to 1650°C (3000°F).
Body Armor - Steel vs Ceramic
Sources
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