To minimize free carbon residue in the boron carbide (B4C) powder, a modified sol-gel process is performed
where the starting materials as boric acid and citric acid compositions are adjusted. Because of boron loss
in the form of B2O2(g) during the reduction reaction of the stoichiometric starting composition, the final B4C
powders contain carbon residues. Thus, an excess H3BO3 is used in the reaction to compensate the loss and
to obtain stoichiometric powders. Parameters of production have been determined using x-ray diffraction
analysis and particle size analyses. The synthesized B4C powder using an excess boric acid composition
shows no trace of carbon.