Effect of Cellulose-Derived Structural Homogeneity of Precursor on the Synthesis and Morphology of Boron Carbide

Abstract

Crystalline boron carbide (B4C) powder was synthesized by carbothermal reduction of condensed boric acid-cellulose product and effect of structural homogeneity of precursor on low-temperature synthesis of B4C was investigated on basis of cellulose-derived structural development. The formation of condensed products was confirmed by FTIR and TGA analyses. The pyrolyzed products of cellulose precursor at 400 °C for 2 h were composed of fine dispersion of carbon fibers with B2O3 particles. The formation of carbon fibers favored conversion kinetics of B4C synthesis. The formation of crystalline B4C started and completed at 1100 and 1200 °C, which was one of the lowest temperatures reported for polymeric precursor route. Morphology of synthesized B4C transformed from polyhedral to equiaxed as synthesis temperature was raised from 1150 to 1200 °C. Nitrogen physisorption measurements revealed that synthesized B4C powders had mesopores with high surface area indicating large interfacial area of B2O3/carbon fibers resulting in more nucleation sites.