- Chem.a white powder, BN, formed by heating boron in nitrogen. In its ordinary form, it has a structure of stacked layers of hexagonal rings, very similar to that of graphite, and is used as a refractory electrical insulator. Cf. Borazon.
* * *(chemical formula BN), synthetically produced crystalline compound of boron and nitrogen, an industrial ceramic material of limited but important application, principally in electrical insulators and cutting tools. It is made in two crystallographic forms, hexagonal boron nitride (H-BN) and cubic boron nitride (C-BN).H-BN is prepared by several methods, including the heating of boric oxide (B2O3) with ammonia (NH3). It is a platy powder consisting, at the molecular level, of sheets of hexagonal rings that slide easily past one another. This structure, similar to that of the carbon mineral graphite (see the Figure), makes H-BN a soft, lubricious material; unlike graphite, though, H-BN is noted for its low electric conductivity and high thermal conductivity. H-BN is frequently molded and then hot-pressed into shapes such as electrical insulators and melting crucibles. It also can be applied with a liquid binder as a temperature-resistant coating for metallurgical, ceramic, or polymer processing machinery.C-BN is most often made in the form of small crystals by subjecting H-BN to extremely high pressure (six to nine gigapascals) and temperature (1,500° to 2,000° C, or 2,730° to 3,630° F). It is second only to diamond in hardness (approaching the maximum of 10 on the Mohs hardness scale) and, like synthetic diamond, is often bonded onto metallic or metallic-ceramic cutting tools for the machining of hard steels. Owing to its high oxidation temperature (above 1,900° C, or 3,450° F), it has a much higher working temperature than diamond (which oxidizes above 800° C, or 1,475° F).
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Boron nitride — IUPAC name Boron nitride Identifiers … Wikipedia
boron nitride — n. a white, powdery compound, BN, of boron and nitrogen, with high electrical resistance: it can be compressed, under a million pounds of pressure, to form Borazon … English World dictionary
boron nitride — noun : any binary compound of boron and nitrogen; especially : a fluffy white crystalline powder BN made in various ways (as by the reaction of ammonia and fused boric oxide) and used chiefly as a lubricant and electric insulator * * * Chem. a… … Useful english dictionary
boron nitride — boro nitridas statusas T sritis chemija formulė BN atitikmenys: angl. boron nitride rus. бор азотистый; бора нитрид … Chemijos terminų aiškinamasis žodynas
boron nitride — noun A binary compound of boron and nitrogen, of empirical formula BN; exists in forms analagous to the allotropes of carbon, many of which are inorganic polymers … Wiktionary
boron nitride — Смотри нитрид бора … Энциклопедический словарь по металлургии
boron-nitride diffusion source — boro nitrido difuzijos šaltinis statusas T sritis radioelektronika atitikmenys: angl. boron nitride diffusion source vok. Bornitriddifusionsquelle, f rus. источник диффузии на основе нитрида бора, m pranc. nitrure de bore en source de diffusion,… … Radioelektronikos terminų žodynas
boron nitride pellicle — boro nitrido plėvelė statusas T sritis radioelektronika atitikmenys: angl. boron nitride pellicle vok. Bornitridfilm, m rus. плёнка нитрида бора, f pranc. pellicule de nitrure de bore, f … Radioelektronikos terminų žodynas
Boron — (pronEng|ˈbɔərɒn) is a chemical element with atomic number 5 and the chemical symbol B. Boron is a trivalent nonmetallic element which occurs abundantly in the evaporite ores borax and ulexite. Boron is never found as a free element on… … Wikipedia
nitride — /nuy truyd, trid/, n. Chem. a compound, containing two elements only, of which the more electronegative one is nitrogen. [1840 50; NITR + IDE] * * * ▪ chemical compound Introduction any of a class of chemical compounds in which nitrogen is… … Universalium