Introduction
Ballistic materials play an important role in modern protection. Ballistic vests and armored vehicles rely on them. Critical sites like nuclear power plants also depend on these materials to defeat explosive fragments and gunfire. The industry of ballistic materials is still improving. You may have noticed that the requirements for these products are steadily growing. This article will introduce commonly used ballistic materials, helping you decide which one best suit your needs.
Applications of Bulletproof Materials to Make Bulletproof VestsBallistic Testing Standards and Protection Levels
Before going into the details of the ballistic materials, it is essential to know about testing standards and protection levels. The most referenced standard today is the U.S. National Institute of Justice. NIJ classifies armors into five protection levels: IIA, II, IIIA, III, and IV. The “A” indicates a level that provides better protection than the previous level but does not meet the next higher level.
By material type, soft body armor typically corresponds to level IIIA and below. Hard plates and ballistic protection systems are generally rated III and above and are used together with ballistic inserts.
Each level is designed to defeat different types of ammunition: Level IIA soft armor is lightweight and concealable and can defeat 9 mm and .40 S&W handgun rounds. Level II is also lightweight and concealable but affords a higher level of ballistic protection than IIA and can defeat short-barrel 9 mm and .357 Magnum handgun rounds. Level IIIA soft armor has great flexibility and can defeat rounds such as .357 SIG and .44 Magnum coming from longer-barrel handguns. Level III hard armor incorporates either metal or composite plates and is rated for defeating 7.62 mm full-metal-jacketed rifle bullets. Level IV hard armor is the highest level currently standardized for military use and is specifically designed to defeat .30 caliber armor-piercing rifle bullets.
NIJ Ballistic Protection Levels
Level | Armor Category | Typical Materials / Form | Concealable? | Example Threats |
IIA | Soft body armor | Textile/fiber soft armor (e.g., Kevlar layers) | Yes | 9 mm, .40 S&W (handgun rounds) |
II | Soft body armor | Enhanced fiber soft armor | Yes | Short-barrel 9 mm, .357 Magnum (handgun rounds) |
IIIA | High-performance soft armor | Multi-layer high-performance fibers or soft composite systems | Yes | .357 SIG, .44 Magnum (longer-barrel handguns) |
III | Hard armor plates | Metal or composite hard plates (used as inserts) | No | 7.62 mm full-metal-jacket (FMJ) rifle bullets |
| IV | Hard armor plates (top military level) | High-hardness ceramic / composite multi-layer plates (with backing) | No | .30 caliber armor-piercing rifle rounds |
Armor rating is closely tied to the properties of ceramic materials. Hardness affects how a projectile is blunted, density and areal density determine equipment weight and user mobility, and fracture toughness relates to the material’s resistance to multiple hits.
Common Ballistic Materials and Their Applications
Common ballistic materials have three main categories.
a) Soft High‑Polymer Fiber Materials
These materials are seldom used on their own to defeat high-velocity rifle rounds, but normally act as the textile backing of body armor or a backing behind ceramic plates, where fibers absorb and dissipate the projectile energy through tensile stretching, shear, and fiber breakage.
Aramid fibers are considered a big success in ballistic protection. They solve the weight and bulk problems of vests with high strength and toughness.
Ultra-high-molecular-weight polyethylene (UHMWPE) confers even better performance. It is lighter than aramid, offering better energy absorption. Today, it is used by many forces in lightweight body armor and helmets.
b) Hard Ceramic Materials
Hard ceramics are at the heart of modern ballistic armor. Having very high hardness and strength, they consume and absorb projectile kinetic energy by fracturing on impact.
Silicon carbide (SiC) is the most widely used one for body armor. Its balanced performance, high hardness and reasonable cost render it a highly cost-effective choice for soldier plates and armored vehicle panels.
Boron carbide (B4C) is one of the top ballistic ceramics. Its hardness is second to diamond, and has the lowest density of common ballistic ceramics, thus enabling extremely light protection. However, it is also very expensive and is thus generally reserved for high‑end applications such as helicopters and specialized vehicles.
Alumina (Al2O3) is the traditional lowest‑cost ballistic ceramic. Its hardness and protection performance are lower than SiC and B4C. For the same protection level, it is heavier. Al2O3 is suitable for cost‑sensitive applications or where the highest protection is not required.
Other ceramics, such as silicon nitride (Si3N4), excel in thermal‑shock resistance. They are commonly used in high‑temperature parts in engine than for mainstream ballistic applications.
c) Composite Systems
In modern ballistic solutions, composite systems that combine complementary advantages are widely adopted to overcome the limitation of using only one material. The most common one is a hard‑strike‑face/soft‑backing arrangement. A front ceramic plate, normally SiC or B4C, among others, serves to fracture and blunt the projectile, while residual energy and fragments are caught and trapped by a rear backing made of UHMWPE or aramid fibers. It is this hard‑front and soft‑back composite that provide the protection required, with minimization of weight and improvement of performance.
The Operation of the Bulletproof ArmorAdvanced hybrids, including metal/ceramic laminates, nano‑phase ceramics, and other engineered composites, are under continuous development with a view toward further enhancement of toughness and ballistic performance.
Which is the Best Ballistic Material?
There is no best ballistic material. Compositing different materials is the main trend in modern ballistic armor industry. However, these composite systems remain relatively higher cost and more difficult to manufacture. For a balance of lightness, effectiveness, and cost, ceramic materials are recommended.
a) Best Performance: Boron carbide (B4C)
Boron carbide is the best-performance ballistic ceramic. Its very high hardness can blunt and even shatter projectiles. It is used in applications that need extreme performance and weight savings, for example, helicopter armor and special forces plates.
High Hardness
B4C has Mohs hardness of 9.46 with excellent penetration resistance. Its high elastic modulus that up to 400 GPa helps for stress wave transmission, contributing to its superior impact resistance.
Density and Mobility
With density of about 2.52 g/cm3, B4C is the lightest one of common ballistic ceramics. It brings the lightest armor for the same protection level, greatly improving mobility. However, low fracture toughness and its brittleness make it less effective against multiple impacts.
Higher Cost
B4C is expensive, priced at around $95-$120 per kg. It is about ten times the cost of alumina.
Processing and Manufacturing Requirements
The processing requirements for B4C are demanding. It must be manufactured under high-temperature and high-pressure sintering. Improper preparation can affect its density.
Chemical Stability and High-Temperature Resistance
B4C has excellent high-temperature resistance with a melting point of 2450℃. It is also resistant to acid and alkali corrosion, exhibiting strong chemical stability.
b) Best Value,Wide Adoption: Silicon carbide (SiC)
Silicon carbide ballistic ceramics have become the popular choice for its high cost performance. For those high-performance applications with limited budgets, like mainstream military body armor and armored vehicle plates, SiC is an ideal and widely used choice.
High Hardness and Strength
It possesses a Mohs hardness of about 9.5 with the flexural strength is as high as 400–600 MPa, which allows effective blunting of projectiles. The controlled micro‑fracturing of the ceramic absorbs kinetic energy and prevents penetration.
Low Density and Lightweight Design
SiC possesses a density of about 3.2 g/cm3, significantly lower than steel and alumina. For the same protection level, SiC plates are approximately 20% lighter than alumina ones. This contributes to weight reduction in individual equipment and vehicle armor, enhancing mobility.
Production Process of NKM Silicon Carbide Bulletproof PlateExcellent Energy Absorption
SiC ballistic plate works in three parts. In the impact stage, the projectile strikes the surface. The projectile nose is blunted and the ceramic material fractures to absorb energy. In the penetration, the projectile continues to abrade the fractured zone. In the final fracture stage, the broken ceramic, together with the backing, absorbs the remaining energy.
High Cost‑Performance
Current price for SiC is competitive at roughly 49–56 USD/kg, compared with the cost of boron carbide at about 98–112 USD/kg. With about 80% of the ballistic performance, SiC represents an exceptionally good value in many applications.
High-Temperature Stability
SiC has a high melting point at 2830℃ with good thermal conductivity, low coefficient of thermal expansion and superior thermal shock resistance. Therefore, SiC will be able to maintain excellent performance even at high temperatures and under extreme conditions.
Silicon Carbide Bulletproof Plates Manufactured by NKMc) Cost‑Effective Choice: Alumina (Al2O3)
Alumina is the most economical one with lower cost and easier processing. Its hardness and toughness are both lower than SiC and B4C. Thus, alumina plates find applications where protection requirements are moderate, budgets are tight, or huge quantities are needed.
Hardness and Penetration Resistance
With Mohs hardness of 9 and compressive strength of ≥1800 MPa, Al2O3 offers good wear resistance. Compared with B4C and SiC, its lower hardness makes it less capable of stopping high‑velocity, high‑energy projectiles.
High Density
Al2O3 has a relatively high density of about 3.6 g/cm³, making it the heaviest among these ballistic ceramics. For the same protection level, Al2O3 are bulkier, reducing mobility.
Low Fracture Toughness and Thermal Performance
Al2O3 has low fracture toughness and brittle, more likely to crack or shatter upon impact. Its thermal shock resistance is also poor, making it more prone to fluctuation under temperature changes.
The Lowest Cost
Al2O3 offers excellent cost‑effectiveness, priced at only $10–$12 per kg. It is one of the lowest‑cost ballistic ceramic materials available.
Mature Processing and Manufacturing
The manufacturing process of Al2O3 is mature and relatively simple. It is easy to achieve a smooth surface finish, stable dimensions, and efficient mass production.
Broad Applications
Al2O3 is widely used across various fields, including military protection, high‑risk civilian occupations, and critical infrastructure security.
There is no best material absolutely, but there is the most suitable material for your needs. If ultimate performance regardless of cost is the goal, then boron carbide is appropriate. If you want a high‑performance and cost balance, choose silicon carbide. If the cost is the overriding constraint, then alumina is acceptable. If you don’t want to make a limitation to a single material, a ceramic strike face combined with a high‑polymer fiber backing is currently one of the best practical ballistic solutions. Among ceramic options, silicon carbide brings the best balance between the cost and performance. It is therefore a primary recommendation.
With the emphasis on national security increasing, high-quality ballistic materials ensure effective protection in military defense and public safety, as well as in civilian fields. If you are looking for high-quality silicon carbide ballistic ceramics, contact Newthink New Materials. With 14 years of experience in the industry, NKM provides you with products and services you can rely on in building a protective barrier.
Reference
[3] Laible, R. (Ed.). (2012). Ballistic materials and penetration mechanics (Vol. 5). Elsevier.
