Preparation of boron suboxide nanoparticles and their processing

Abstract

Crystalline boron suboxide B 6O particles with size in the range of 1.5-2 μm and crystalline size in the range of 32-40 nm were prepared by calcination at 1400°C for one hour of precursors prepared by wet mixing amorphous boron with water solution of B 2O 3 followed by evaporation and drying. The XRD analysis showed that formation of B 6O started at 1350°C and well crystallized powder was obtained at 1400°C at ambient pressure. The synthesis temperature corresponded to the literature data but formation process was three times quicker. Decrease of molar ratio B/B 2O 3 from 16 to 14 in the precursor mixture reduced nonstoichiometry of prepared B 6O although simultaneously it increased admixture of B 2O. The characteristic shape of the particles was starlike plates. During the spark plasma sintering process, the densification of boron suboxide started at 1500°C and fully dense bodies (98%) were fabricated at 1900°C within five minutes.