Synthesis of Boron Carbide Nano Powder by Solid State Reaction

Boron carbide(B4C) powder was synthesized by solid state reaction of hexagonal boron nitride with carbon black(or graphite).The phase assemblages of synthesized powders were influenced by carbon source,at-mosphere and temperature.Boron carbide powder with an average particle size of about 100 nm was obtained using carbon black as the carbon source at 1900℃ for 5 h in vacuum.The relative density of the sintered sample(2000℃/30 MPa/1 h) derived from the synthesized powder reached 97.9%,while that prepared from the commer-cial powder was 93.1%.The better sinterability of the synthesized powder than the commercial one can be attrib-uted to the finer particle size,lower oxygen content and the twin structure of the powder.