Silicide

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silicide

[′sil·ə‚sīd]
(chemistry)
A binary compound in which silicon is bonded with a more electropositive element.

Silicide

 

any of the chemical compounds of silicon with metals and certain nonmetals. Suicides can be divided into three basic groups according to the type of chemical bond: ionic-co-valent, covalent, and metallic. Ionic-covalent suicides are formed from alkali metals (with the exception of sodium and potassium), alkaline-earth metals, and metals of the copper and zinc subgroups. Covalent suicides are formed from boron, carbon, nitrogen, oxygen, phosphorus, and sulfur and can be referred to as, for example, borides, carbides, and nitrides of silicon. Metallic silicides are formed from transition metals.

Suicides are obtained by fusing or sintering a powdery mixture of Si and a given metal or by heating metal oxides with Si, SiC, SiO2, and natural or synthetic silicates (sometimes mixed with carbon). Other methods include the interaction of a metal with a mixture of SiCl4 and H2 and the electrolysis of melts composed of K2SiF6 and an oxide of a given metal.

Covalent and metallic suicides, in addition to being refractory, are resistant to oxidation and the action of mineral acids and various aggressive gases. Suicides are used in heat-resistant cermet composition materials in aviation and rocket engineering. MoSi2 is used in the manufacture of heaters for furnaces heated by electrical resistance and operating under exposure to air at temperatures up to 1600°C. FeSi2, Fe3Si2, and Fe2Si are constituents of ferrosilicon, which is used in the deoxidation and alloying of steel. Silicon carbide is a semiconductor material.

REFERENCES

Nekrasov, B. V. Osnovy obshchei khimii, 3rd ed., vols. 1-2. Moscow, 1973.
Gel’d, P. V., and F. A. Sidorenko. Silitsidy perekhodnykh metallov chetvertogo perioda. Moscow, 1971. [23–1081–]
References in periodicals archive ?
Two-step annealing process during silicidation was suggested to decrease the lateral excursion of silicide into the channel region [12].
After the annealing treatment, diffraction peaks corresponding to [Cu.sub.3] x Si copper silicides were observed.
The source of these cartridges is called sodium silicide.
The remaining melt of the liquid metal is enriched with boron, silicon, chromium and is displaced into the central part of the brazed joint where further cooling results in the solidification of the low-melting brittle eutectic phases, consisting of the solid solution and silicides (borides) (3), (5).
(1.) At low temperatures, niobium silicides were preferred to form at the beginning of deposition, which blocked the further reactions between carbon and niobium to form carbides.
A host of exotic materials -- mercury-cadmium-telluride, gallium arsenide and platinum silicides, among others -- replaced the early lead sulphide and lead telluride detectors.
MMoSi.sub.2] also is the most oxidation-resistant material of all the silicides. Behrendt coats the SCS6 fibers in this CMC with BN to protect the fiber from the molten silicon.
Johnson, "Diffusionless orthorhombic to hexagonal transitions in ternary silicides and germanides," Inorganic Chemistry, vol.
The above oxidation temperature was chosen so as to be low enough to minimize the substrate oxidation in order to prevent the formation of tantalum silicides. The thickness of thus obtained [Ta.sub.2][O.sub.5] films and the refractive index were measured ellipsometrically ([lambda] = 632.8 nm).
Sinha, "Elastic stiffness and thermal expansion coefficients of various refractory silicides and silicon nitride films," Thin Solid Films, vol.
He addresses the use of sputtering targets and sputtered films in the microelectronic industry; sputtering and thin film deposition; the performance of sputtering targets and productivity; sputtering target manufacturing; sputtering targets and thin films for integrated circuits, flat panel displays, photovoltaics, silicides, and magnetic data storage; and troubleshooting.
Chemists and material scientists examine such aspects as the decomposition kinetics of MAX phase in extreme environments, the effect of transition metal silicides on microstructure and mechanical properties of ultra-high temperature ceramics, designing polymer-derived ceramics for applications at ultra-high temperatures and in extreme environments, reactive melt infiltration of carbon fiber reinforced ceramic composites, wetting and joining structural ceramic components, and tungsten composites reinforced with carbide particles in extreme hazard environments.