Densification of boron carbide under high pressure

Additive-free boron carbide (B4C) powders were densified at 4 GPa using the high-pressure “anvil-type with hollows” apparatus in the temperature range of 1500–1900 °C. The boron carbide ceramics prepared by this method showed a hardness of 37 GPa, which is very close to the hardness of mono-crystal boron carbide. The study showed that the boron carbide grains are uniformly sized without observed grain growth in the sintered materials. Obtained results revealed that high-pressure sintering can be a very effective low-temperature densification method for the obtainment of additive-free B4C ceramics. Moreover, the process can be scaled-up for the production of large-size composites required in various cutting tools and other extreme condition applications.