Boron Nitride

DescriptionBoron nitride is a material in which the extra electron of nitrogen (with respect to carbon) enables it to form structures that are isoelectronic with carbon allotropes.Boron nitride is an inorganic compound with a flat, hexagonal crystal similar to graphite, but with the carbon atoms replaced by boron and nitrogen atoms. The alternate boron and nitrogen atoms are linked to form interlocking hexagonal rings with three boron atoms and three nitrogen atoms, and the layers are held together by van der Waals forces. There is no boron-nitrogen bonding between the layers.The bond length is 1.466Å and the interlayer spacing is 3.331 Å. A spherical form (with a hexagonal crystal structure) is also available.Boron nitride can also be in cubic form in which alternately linked boron and nitrogen atoms form a tetrahedral bond network, similar to carbon atoms in diamond.

UsesBoron nitride used in the manufacture of high-temperature equipment parts due to its excellent thermal and chemical stability. It is used as a lubricant and an additive to cosmetics, paints, dental cements and pencil leads. It is also used to provide self lubricating properties to ceramics, alloys, resins, plastics and rubbers. In addition to this, it has many industrial applications such as xerographic process, laser printers, oxygen sensors and proton conductors. Cubic boron nitride is used as an abrasive material.

UsesBoron nitride is a material in which the extra electron of nitrogen (with respect to carbon) enables it to form structures that are isoelectronic with carbon allotropes. Also used in manufacture of alloys; in semiconductors, nuclear reactors, lubricants.Hexagonal boron nitride can be used as an electrical insulator; as thermocouple protection sheaths, crucibles and linings for reaction vessels; and as a coating for refractory molds used in glass forming and in superplastic forming of titanium. It can also be incorporated in ceramics, alloys, resins, plastics, and rubber to give them self-lubricating properties. Hexagonal boron nitride is used the formulation of coatings and paints for high temperature applications. It is also used as a substrate for semi-conductors, lens coatings, and transparent windows. https://www.cir-safety.org

Usesboron nitride is a synthetically manufactured white, talc-like powder that can reflect light, giving a product a sparkle effect. It is primarily used in color cosmetics to provide subtle shimmer; however, it can also be found in skin care formulations for enhancing product smoothness and slip.

General DescriptionBoron nitride in cubic form, known as Borazon, is a manufactured abrasive that was discovered by General Electric Co. Laboratories in 1957. Unlike manufactured diamond, Borazon does not have a natural counterpart. It is produced under temperatures and pressures similar to those required for diamond manufacture. Additionally, cubic boron nitride exhibits greater thermal stability compared to diamond. It remains stable at temperatures exceeding 1,371°C, while diamond reverts to graphite at temperatures above 816°C. Borazon has a Knoop hardness (K100) of 7800, which is higher than ordinary abrasives but lower than diamond.

PreparationBoron nitride is prepared by heating boric oxide with ammonia: B2O3 + 2NH3 → 2BN + 3H2O Alternatively, the compound can be prepared by heating boric oxide or boric acid with ammonium chloride or an alkali metal cyanide. Purified product can be obtained by high temperature reaction of boron halide with ammonia: BCl3 + NH3 → BN + 3HCl Boron nitride can also be made from the elements by heating boron and nitrogen at red heat.

Definitionboron nitride: A solid, BN, insolublein cold water and slowly decomposedby hot water; r.d. 2.25 (hexagonal);sublimes above 3000°C. Boronnitride is manufactured by heatingboron oxide to 800°C on an acid-solublecarrier, such as calcium phosphate,in the presence of nitrogen orammonia. It is isoelectronic with carbonand, like carbon, it has a veryhard cubic form (borazon) and asofter hexagonal form; unlikegraphite this is a nonconductor. It isused in the electrical industrieswhere its high thermal conductivityand high resistance are of especialvalue.