High-temperature synthesis and characterization of boron suboxide (B6O) and boron containing hard materials

Abstract Boron-rich phases like boron carbide and boron suboxide (nominally B6O), with high hardness, low density and chemical inertness, are used as an excellent thermal conducting material, as abrasives and for other high-wear applications. In addition, their application as a nuclear material is especially significant. This study presents a synthetic method for preparation of B6O at temperatures between 1200° and 1800°C. The synthesis was done in an argon atmosphere by using amorphous boron and boric acid in appropriate molar ratio. The evolution of the phase composition during thermal treatment was investigated by X-ray diffraction. A sample obtained at 1800°C consisted of B6O and B4C phases, revealing the intense reaction of B6O with carbon substrate in a vacuum. Sintering behaviour of the synthesized boron suboxide was followed with a scanning electron microscope