The basic principle of armor protection is to consume projectile energy, slow it down and render it harmless. Most conventional engineering materials, such as metals, absorb energy through structural deformation, while ceramic materials absorb energy through a micro-fragmentation process.

The energy absorption process of bulletproof ceramics can be divided into 3 stages.

(1) Initial impact stage: projectile impact on the ceramic surface, so that the warhead blunt, in the ceramic surface crushed to form a fine and hard fragmentation in the process of energy absorption.

(2) Erosion stage: the blunted projectile continues to erode the fragmentation area, forming a continuous layer of ceramic fragments.

(3) Deformation, cracking, and fracture stage: finally, tensile stresses are generated in the ceramic causing it to shatter, followed by the deformation of the backing plate, with all remaining energy absorbed by the deformation of the backing plate material. During the impact of the projectile on the ceramic, both the projectile and the ceramic are damaged.

What are the material performance requirements for bullet-proof ceramics?

Because of the brittle nature of the ceramic itself, it fractures rather than deforms when impacted by a projectile. Under tensile loading, fracture occurs first at non-homogeneous locations such as pores and grain boundaries. Therefore, in order to minimize microscopic stress concentrations, armor ceramics should be of high quality with low porosity and fine grain structure.