Boron carbide body armor

The hardness of boron carbide (carbon hexaboride) is not well defined because it is made as sintered compacts which have variable densities, compositions, and defect densities. It is very hard (up to 4400kg/mm2), and of relatively low density, so it has been used extensively as body-armor (McColm,... 

Boron carbide is a relatively inexpensive hard material, which is used for its mechanical properties of strength and extreme hardness in armor-plates for body protection, in sandblast nozzles, and as an abrasive for grinding and cutoff wheels. In nuclear plants, boron carbide is used as the neutron absorbing material of the control rods. 

Most applications at this time are sponsored by the military. Boron carbide, with its low density (but higher eost), is used successfully in body armor and helicopter armor. Silicon carbide has been used in prototype quantities for land vehieles, but no large-scale production is planned at this stage. 

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