Diboride

	Diboride Diboride may refer to: Aluminium diboride, compound of aluminium and boron Hafnium diboride, ultra-high temperature ceramic composed of hafnium and boron Magnesium diboride, inexpensive and simple superconductor Rhenium diboride, synthetic superhard material Titanium diboride, extremely hard ceramic compound composed of titanium and boron Zirconium diboride Zirconium diboride (ZrB2) is a highly covalent refractory ceramic material with a hexagonal crystal structure. ZrB2 is an ultra-high temperature ceramic (UHTC) with a melting point of 3246 °C. This along with its relatively low density of ..., highly covalent refractory ceramic material with a hexagonal crystal structure Due to their technological importance, refractory and electrically conductive diborides (TMB2) formed by Group 4–6 transition metals (TM): Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W are attracting increasing research interest as thin film coatings in many potential applications.Review of Transition-M ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Rhenium Diboride Rhenium diboride (ReB2) is a synthetic high-hardness material that was first synthesized in 1962. The compound is formed from a mixture of rhenium, noted for its resistance to high pressure, and boron, which forms short, strong covalent bonds with rhenium. It has regained popularity in recent times in hopes of finding a material that possesses hardness comparable to that of diamond. Unlike other high-hardness synthetic materials, such as the c-BN, rhenium diboride can be synthesized at ambient pressure, potentially simplifying a mass production. However, the high cost of rhenium and commercial availability of alternatives such as polycrystalline c-BN, make a prospect of large-scale applications less likely. Synthesis ReB2 can be synthesized by at least three different methods at standard atmospheric pressure: solid-state metathesis, melting in an electric arc, and direct heating of the elements. In the metathesis reaction, rhenium trichloride and magnesium diboride ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Magnesium Diboride Magnesium diboride is the inorganic compound of magnesium and boron with the formula MgB2. It is a dark gray, water-insoluble solid. The compound becomes superconducting at 39 K (−234 °C), which has attracted attention. In terms of its composition, MgB2 differs strikingly from most low-temperature superconductors, which feature mainly transition metals. Its superconducting mechanism is primarily described by BCS theory. Superconductivity Magnesium diboride's superconducting properties were discovered in 2001. Its critical temperature (''T''c) of is the highest amongst conventional superconductors. Among conventional ( phonon-mediated) superconductors, it is unusual. Its electronic structure is such that there exist two types of electrons at the Fermi level with widely differing behaviours, one of them ( sigma-bonding) being much more strongly superconducting than the other ( pi-bonding). This is at odds with usual theories of phonon-mediated superconductivity which ass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Aluminium Diboride Aluminium diboride (AlB2) is a chemical compound made from the metal aluminium and the metalloid boron. It is one of two compounds of aluminium and boron, the other being AlB12, which are both commonly referred to as aluminium boride. Structurally the B atoms form graphite-like sheets with Al atoms between them, and this is very similar to the structure of magnesium diboride. Single crystals of AlB2 exhibit metallic conductivity along the axis parallel to the basal hexagonal plane. Aluminium boride is considered a hazardous substance as it reacts with acids and hydrogen gas to produce toxic gases. For example, it reacts with hydrochloric acid to release borane and aluminium chloride Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula . It forms a hexahydrate with the formula , containing six water molecules of hydration. Both the anhydrous form and the hexahydrate are col .... The crystal structure of AlB2 is often used a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Hafnium Diboride Hafnium diboride is a type of ceramic composed of hafnium and boron that belongs to the class of ultra-high temperature ceramics. It has a melting temperature of about 3250 °C. It is an unusual ceramic, having relatively high thermal and electrical conductivities, properties it shares with isostructural titanium diboride and zirconium diboride. It is a grey, metallic looking material. Hafnium diboride has a hexagonal crystal structure, a molar mass of 200.11 grams per mole, and a density of 11.2 g/cm3. Hafnium diboride is often combined with carbon, boron, silicon, silicon carbide, and/or nickel to improve the consolidation of the hafnium diboride powder (sintering). It is commonly formed into a solid by a process called hot pressing, where the powders are pressed together using both heat and pressure. The material has potential for use in hypervelocity reentry vehicles such as ICBM heat shields or aerodynamic leading-edges, due to its strength and thermal properties. Unlike ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Titanium Diboride Titanium diboride (TiB2) is an extremely hard ceramic which has excellent heat conductivity, oxidation stability and wear resistance. TiB2 is also a reasonable electrical conductor,J. Schmidt et al. "Preparation of titanium diboride TiB2 by spark plasma sintering at slow heating rate" Sci. Technol. Adv. Mater. 8 (2007) 37free download/ref> so it can be used as a cathode material in aluminium smelting and can be shaped by electrical discharge machining. Physical properties TiB2 shares some properties with boron carbide and titanium carbide, but many of its properties are superior to those of B4C & TiC: Exceptional hardness at extreme temperature 2nd hardest material at 3000°C (diamond) 3rd hardest material at 2800°C (cBN) 4th hardest material at 2100°C ( B4C) 5th hardest material at 1000°C ( B6O) Advantages over other borides Highest boride elastic modulus Highest boride fracture toughness Highest boride compressive strength 3rd highest boride melting point (3230 °C) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]