Superhard boron suboxide (B6O): Crystal structure, synthesis, properties, applications, and materials based thereon

A review of reported data on the crystal structure, synthesis, and properties of boron suboxide B₆O, which is a superhard material (hardness of up to 55 GPa, as measured in single crystals), and composites based on it is presented. Methods for the synthesis of B₆O with a icosahedral structure and for the growing of crystals at high temperature and high pressure are described. The mechanical and operational characteristics of composite materials based on B₆O are summarized; the resistance of B₆O to oxidation is analyzed, and the properties of B₆O–diamond and B₆O–B₄C composite materials are described.