The effect of the synthesis temperature and time on the formation of boron suboxide

Boron suboxide (B₆O), offering a good balance between abundance of its constituents and promising tribological performance, is intriguing. Applications such as cutting tools, high-wear resistant coatings, and ballistics would benefit from such properties, however a feasible synthesis method is yet to be realized. The synthesis of B₆O under atmospheric pressure is a challenging pursuit, and there is insufficient thermodynamic data for the formation of boron suboxide in the literature. In this study, boron suboxide powder was synthesized by reducing B₂O₃ by amorphous boron. Phase analysis of the formation of boron suboxide was demonstrated within the temperature range of 1200–1350 °C. The amorphous phase beside boron suboxide is present for all temperature treatments, but the best fitting crystalline phase was observed of the powder synthesized at 1300 °C. The powder was also heat treated at 1300 °C for various hours (2–6 h), and the crystalline phase was only observed for the powder heat treated for 4 h. The morphology of synthesized powder exhibited a star-like morphology. The production of B₆O-TiB₂ composite powder by reduction of TiO₂ by amorphous boron with the excess addition of boron is also reported in this study.