Low-temperature synthesis of boron carbide powder from condensed boric acid-glycerin product

摘要

Crystalline boron carbide (B_4C) powder was synthesized by the carbothermal reduction of a condensed product formed from boric acid (H_3BO_3) and glycerin (C_3H_8O_3). The condensed product was prepared by dehydration after directly mixing equimolar amounts of H_3BO_3 and glycerin, which was followed by pyrolysis in air to obtain a precursor powder from which the excess carbon had been eliminated. The prepared precursor powder had a bicontinuous boron oxide (B_2O_3)/carbon network structure. Crystalline B_4C powder without residual carbon was successfully synthesized from this precursor powder by heating at 1250 ℃ for 5 h in an Ar flow.