Refractories boron

Next to Cr C2, TiC is the principal component for heat and oxidation-resistant cemented carbides. TiC-based boats, containing aluminum nitride, AIN, boron nitride, BN, and titanium boride, TiB2, have been found satisfactory for the evaporation of metals (see Boron compounds, refractory boron compounds Nitrides). 

The main chemical products produced from these minerals are (a) boron oxides, boric acid and borates, (b) esters of boric acid, (c) refractory boron compounds (borides, eu .), (d) boron halides, (e) boranes and carbaboranes and (f) organoboranes. The main industrial and domestic uses of boron compounds in Europe (USA in parentheses) are ... 

Boron forms B—N compounds that are isoelectronic with graphite (see Boron compounds, refractory boron compounds). The small size also has a significant role in the interstitial alloy-type metal borides boron forms. Boron forms borides with metals that are less electronegative than itself including titanium, zirconium, and hafnium. 

BORONCOMPOUNDS - REFRACTORY BORON COMPOUNDS] (Vol 4) Magnesium bromide [7789-48-2]... 

Boron Carbide. Boron carbide [12069-32-87, B4C, is produced by the reaction of boron oxide and coke in an electric arc furnace (70% B4C) or by that of carbon and boric anhydride in a carbon resistance furnace (80% B4C) (see Boron compounds, refractory BORON compounds). It is primarily used as a loose abrasive for grinding and lapping hard metals, gems, and optics (18).. Although B4C is oxidation-prone, the slow speed of lapping does not generate enough heat to oxidize the abrasive. 

T. Lundstrom, and H. Bokngren, On Refractory Boron Compounds Crystallizing in B4C-type Structures, in Proceeding of the 11th International Symposium on Boron, Borides and Related Compounds Jap. J. Appl. Physics, Series No. 10, eds. R. Uno and I. Higashi, Tokyo, 1994, 1. 

Elemental boron is a refractory material that is usually isolated either as a shiny black crystalline solid or a softer, browner, more impure amorphous solid. Reduction of readily available boron compounds containing boron oxygen bonds to elemental boron is energy intensive and costly. This has limited the extent of conunercial use of this material. Many related refractory boron compounds have been prepared and characterized including metal borides, boron carbides, boron nitrides, and various boron metal alloys. These refractory materials and elemental boron are also discussed in some detail in the article Borides Solid-state Chemistry. Other general references are available on elemental boron and other refractory boron compounds. " ... 

Sodium borates are the most important industrial boron compounds. They are mainly utilized as such, but are also used as starting materials (in addition to calcium borates) for the manufacture of industrially interesting boron compounds (boric acid, di-boron trioxide, inorganic borates, refractory boron-derivatives, boron carbide, boron... 

Wentorf, R. H., Jr., Refractory Boron Compounds, in Kirk Othmer, Encyclopedia of Chemical Technology, John Wiley Sons, New York... 

Unlike the interstitial nitrides, the covalent nitrides are not metallic compounds. The differences in electronegativity and atomic size between the nitrogen and the other element are small and their electronic bonding is essentially covalent. In this respect, they are similar to the covalent carbides. They include the nitrides of Group mb (B, Al, Ga, In, Tl) and those of silicon and phosphorus. Of these, only three are considered refractory boron nitride, silicon nitride, and aluminum nitride. These are reviewed in Chs. 12 and 13. 

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