Boron carbide in ballistic ceramics

Boron carbide is an important wear-resistant and high hardness structural ceramic material in new ceramics. As boron and carbon are non-metallic elements, and the atomic radius is close to the combination of different from the general gap compounds, so boron carbide ceramics have a high melting point, ultra-high hardness, low density, wear-resistant and corrosion-resistant and many other unique properties, in the field of national defence, nuclear energy, aerospace, machinery, abrasion-resistant technology, is increasingly showing its broad prospects for the development of applications.

At present, AlO-based bullet-resistant ceramics have been used in the “502 project” and “212 project”, but in the body of the chariot side parts of the AlO-based ceramic composite armour, its weight reduction effect is not obvious, and the use of high-performance boron carbide ceramic composite armour of the same thickness Armour than AlO-based bulletproof ceramic quality reduction of 15% to 20%, while the bulletproof performance is further improved.

Therefore, the key equipment project ceramic composite armour development project on high-performance, low-cost boron carbide ballistic ceramics put forward an urgent need.
As boron carbide ceramics with lightweight, ultra-high hardness and high modulus of elasticity characteristics, bulletproof vests, bulletproof helmets and bulletproof armour is the best material, the beginning of the application of boron carbide ceramics as ceramic armour materials. Compared with other bulletproof materials (such as SiC, Al2O3), boron carbide ceramics are lighter and harder, especially suitable for helicopter gunships and other aircraft as ballistic armour materials, which can effectively resist shells. Therefore, B4C ceramics are generally only used in some special occasions with high requirements for protective performance.

Thus, the development and application of high-performance, low-cost boron carbide bulletproof ceramic materials can greatly improve the performance of related weapons and equipment, with significant military and economic benefits. Boron carbide bulletproof ceramic material application direction for the key equipment engineering, future main battle tanks, infantry fighting vehicles, airborne airborne vehicles and other light armoured vehicles, as well as armed helicopters belly plate, boat superstructure armour protection.

Industrial boron carbide strength and toughness is relatively low, which is mainly due to the coarse organisation (250um), defects, densities are not high due to the improvement of sintering density, grain refinement and other basic pathways can significantly improve the strength, but the fracture toughness increase is not very large, which is related to the limitations of the single-phase material itself. Therefore, to reduce the tendency of boron carbide through the crystal fracture, increase fracture toughness, take the “composite” road seems to be the last choice. A large number of studies have shown that the composite additives can greatly reduce the sintering temperature and pressure, under high temperature and high pressure conditions, to obtain high density boron carbide ceramics, and have excellent mechanical properties. The prospect of composite materials is very attractive, but the question is to choose what kind of way to achieve the “composite” purpose, in short, boron carbide materials can be more widely used in engineering depends on the solution of the three basic problems: sintering temperature reduction; strength and fracture toughness of the improvement of antioxidant behaviour.

It is an eternal law of nature that structure determines performance. For the new boron carbide material system, its performance depends on the microstructure, which is closely related to the chemical composition, winding process and phase reaction process. In view of the characteristics of boron carbide ceramics and the importance of ceramics as ballistic armour, so boron carbide ceramics research work, the country has achieved great results, the study of a new type of boron carbide ceramics for bulletproof, from raw material formulations, sintering process to the finished product made of finished products, performance testing of a series of work have achieved good results. The developed high-performance boron carbide ceramics reached the enterprise standard and the U.S. Army military standard, its technical level of the first domestic, fill the gaps in the country, up to the advanced level in the international arena, to provide a new type of lightweight and high-performance bulletproof armour products.