Cubic boron nitride (CBN) is a synthetic compound with extreme hardness, heat stability, and chemical resistance. It is produced from boron and nitrogen compounds and used as an abrasive or cutting tool in industrial applications. CBN is stable at high temperatures and chemically stable in the presence of iron and nickel. Polycrystalline CBN is produced by sintering CBN particles with ceramic.
Cubic boron nitride (CBN) is a synthetic chemical compound made up of boron and nitrogen atoms in a one to one ratio. Unlike other types of boron nitride, it exists as a cubic crystal lattice, with its atoms arranged in a symmetrical cube-shaped structure like the crystal structure of diamond. Its material properties include extreme hardness, heat stability, and superior chemical resistance. Cubic boron nitride is the second hardest known material after diamond, making it useful in a wide variety of industrial applications, where it is often used as an abrasive or cutting tool.
All boron nitride compounds are produced synthetically, as they do not occur naturally. The process begins with boric acid, a compound of boron, oxygen and hydrogen, or boron trioxide, which is made up of boron and oxygen. Each of these compounds can be reacted with urea or ammonia, which contain nitrogen, to produce a boron nitride powder. The powder is crystallized through intense heat to form hexagonal boron nitride, which has a hexagonal crystal structure analogous to that of graphite, a precursor to synthetic diamond. The hexagonal boron nitride is then heat treated under high pressure to form cubic boron nitride.
CBN has several advantages as an industrial material. It is nearly as hard as diamond, making it useful for cutting and abrading metals and other substances. The heat resistance of CBN is also quite high. Diamond begins to decompose to carbon dioxide in air at approximately 1.472°F (approximately 800°C), while cubic boron nitride is stable in air up to approximately 2.552°F (approximately 1,400°C). In industrial grinding applications and other processes where intense heat is generated, CBN is preferred over diamond.
Another advantage of CBN as an alternative to diamond is its chemical stability in the presence of nickel, iron and related substances. Diamond is soluble in these metals, which means it reacts chemically with them and dissolves. This makes it useless as a tool for cutting iron or steel. CBN, on the other hand, does not react and can therefore be used to cut these materials.
The variety of CBN used in industrial cutting tools is known as polycrystalline cubic boron nitride (PCBN). PCBN is produced by sintering cubic boron nitride particles with ceramic. In sintering, boron nitride is placed in a furnace at high temperature and pressure which bonds it to the ceramic, fusing into the extremely hard substance used for grinding and cutting.
Protect your devices with Threat Protection by NordVPN
