Metal cemented borides

Uses. Amorphous boron is used as an addictive in pyrotechnic mixtures, solid rockets propellants, explosives, etc. Refractory metal borides are used as addic-tives to cemented carbides. High purity boron is used in electronics as a dopant to... 

Cemented borides with a metallic matrix have also been fabricated successfully from the ternary transition metal borides of so-called x-, ip- and ca-types since these composites can easily be liquid phase sintered with metallic melts. 

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). 

It follows that the oxides, nitrides, borides, carbides, and silicides (not to be confused with silicates) of all metals and NMESs are ceramics which, needless to say, leads to a vast number of compounds. This number becomes even more daunting when it is appreciated that the silicates are also, by definition, ceramics. Because of the abundance of oxygen and silicon in nature, silicates are ubiquitous rocks, dust, clay, mud, mountains, sand — in short, the vast majority of the earth s crust — are composed of silicate-based minerals. When it is also appreciated that even cement, bricks, and concrete are essentially silicates, the case could be made that we live in a ceramic world. 

Similarly, between metals and ceramics, there are materials containing metallic binders borides, nitrides, carbides, silicides. These hard metal ceramics or "cemented carbides are also termed cermets. These are produced based on a powder metallurgical route, the technological steps of the ceramic process (powder shaping => sintering) being followed. Germany was intensively involved in the fundamental research (which was forced ahead in the in-... 

Most of the developments in cemented borides aim at the high wear resistance due to the superior hardness compared to carbide-based hard metals. One of the most important applications are, therefore, the cutting tools where cemented boride have to compete with tungsten carbide, titanium carbonitride, and ceramic materials as well. 

Compares the wear, scuffing, and spalling resistance of sheet-metal dies coated by the following surface-hardening processes uncoated, nitrided, borided, nitrogen ion implanted, chrome plated, sulfiirized, uncoated cemented carbide, TiC -I- TiN by CVD, TiC by CVD, VC by TRD, and NbC by TRD... 

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