boron carbide ring is a dark gray non-metallic compound, mainly consisting of B4C, with an Mohs hardness of over 9.3. It has a high hardening potential, and it is used as a cutting tool and abrasive. It is also known for its ability to withstand extreme temperatures and resistance to most chemicals, including ionizing radiation and neutrons. In nuclear applications, it is useful in reactor control and shielding.

It is a semiconductor with an energy band gap determined by its composition and degree of order. Its electronic properties are dominated by hopping-type transport, and the band gap is generally p-type. It can be doped to modify its electronic properties.

In synthesis, boron carbide is formed by dissolving boric acid (H3BO3) in distilled water and mixing it with mono- or polysaccharides such as glucose, fructose, dextrin, or hydroxyethyl starch. The resulting solution is then mixed with amorphous carbon powder and dried by heat at elevated temperature to form a slurry that can be fed into pressureless sintering equipment.

During the sintering process, the boron carbide forms an outer zone around which a layer of unconverted boron ox-.ide and carbon crystals is formed. It is essential that this zone be carefully separated from the pure boron carbide product in order to maintain its purity. This can be accomplished by maintaining a controlled environment during the sintering process, and by careful selection of raw materials that are less likely to contain boron rich impurities.