In the field of modern protective technology, advanced ceramic materials have become a core component of composite armor systems due to their excellent mechanical properties. Ballistic ceramics function through their ultra-high hardness and compressive strength, creating "erosion" and "blunting" effects upon high-velocity projectile impact, effectively dissipating kinetic energy. Currently, the three most widely used types are high-purity alumina (Al2O3), silicon carbide (SiC), and silicon nitride (Si3N4) . These materials are characterized by low density, high hardness, and high elastic modulus, making them indispensable for personal protection, vehicle armor, and aerospace components.

Alumina ceramic is currently the most cost-effective and widely used ballistic material. Specifically, 99.7% purity alumina exhibits excellent mechanical strength and hardness. Technical data indicates that 99.7% alumina ceramic has a density of approximately 3.90-3.92 g/cm³, a Vickers hardness exceeding 24 GPa, a flexural strength of about 313-350 MPa, and a compressive strength reaching approximately 3500 MPa . Formed via pressureless sintering or hot pressing, this material effectively withstands multi-hit scenarios and is widely used in structural components and armor inserts.

Compared to alumina, silicon carbide ceramic offers higher hardness and lower density, making it an ideal choice for mid-to-high-end protective equipment. Silicon carbide typically achieves a hardness above 28 GPa, a flexural strength nearing 700 MPa, and a density below 3.2 g/cm³, reducing protective weight while providing excellent ballistic resistance . Research indicates that even under weak support conditions, silicon carbide ceramics demonstrate significantly higher protective efficiency against 7.62mm armor-piercing projectiles than metallic materials; increasing ceramic thickness enhances its self-constraining effect, thereby improving energy dissipation . The advancement of pressureless sintering technology has further promoted the adoption of silicon carbide ballistic materials.

Silicon nitride ceramic holds a unique advantage in ballistic applications due to its high fracture toughness and strength. The inherent brittleness of conventional ceramics is a major limitation for ballistic use; however, silicon nitride, through layered structural design or whisker toughening, can significantly extend crack propagation paths and consume more fracture energy . For instance, silicon nitride materials fabricated with whiskers and rare earth oxides not only possess high hardness but also achieve significantly improved fracture toughness . This enables silicon nitride to maintain structural integrity under multi-hit impacts or complex stress conditions, making it suitable for critical components like high-performance ballistic inserts .

In summary, the selection of ballistic ceramic materials depends on specific performance requirements and budget constraints. 99.7% alumina offers a balance of reliable protection and cost-effectiveness; silicon carbide meets the demands for lightweight and high hardness; and silicon nitride represents a design direction towards high toughness and extended service life. With continuous advancements in material processing technologies, these advanced ceramics will play an increasingly vital role in future multi-scenario protection applications .