Boride

A boride is a chemical compound in which boron is bonded to a more electropositive element, typically a metal. Binary borides cover a range of stoichiometries such as MB, MB2 and M2B, where M represents a metal. Borides can also form with nonmetals in some systems, and many boride phases are studied for their distinctive properties.

Most borides are refractory ceramics characterized by very high melting points, great hardness and corrosion resistance. The boron sublattice often forms covalent networks that strengthen the structure, while metallic components can provide electrical conductivity in certain borides. Some borides are notable for additional properties, such as the superconductivity of magnesium diboride (MgB2), discovered in 2001, which is a diboride rather than a traditional ceramic.

Occurrence and synthesis are dominated by synthetic preparation, since many borides do not occur as common minerals. They are typically produced by high-temperature solid-state reactions between boron and the metallic element, sometimes using reducing conditions or specialized routes such as chemical vapor deposition, arc melting or mechanical alloying. While natural borides exist, most industrial borides are engineered materials designed for specific performance.

Applications and significance vary with composition. Titanium diboride (TiB2) and related diborides are used as wear-resistant coatings and cutting-tool materials because of their hardness and thermal stability. Other borides serve as ultra-high-temperature ceramics, neutron-absorbent materials for nuclear applications, or components in electronic and superconducting devices. The boride family remains a focus of research for advanced coatings, refractory materials and energy-related technologies.