Silicon carbide powder synthesis

V. Venkateswaran, J. M. Halstead, and B. Mehosky, "Synthesis of High-Purity Sinterable Silicon Carbide Powders," in Proceedings of the 23rd... 

HP Martin, R Ecke, and E Muller, Synthesis of nanocrystalline silicon carbide powder by carbothermal reduction, J. Ear Ceram. Soc.,18,1737-1742(1998). 

We here describe the synthesis of the polycarbosilane (H2SiCH2CH2) and its use as a preceramic compound for the preparation of silicon carbide in form of a powder or fibers. 

Milonjic, S.K., Cerovic, L., and Uskokovic, D.P., Sol-gel synthesis of silicon carbide and silicon nitride powders and their surface properties, in Materials Science of Carbides, Gogotsi, Y.G. and Andrievski, R.A., eds., Kluwer, Dordrecht, 1999, p. 343. 

As already mentioned, synthesis of multinary silicon boron nitrides or carbon nitrides cannot be achieved via the well-known powder route, including mixing, milling, and sintering of binary nitride/carbide powders, because the interdiffiision of the covalent nitrides, and carbides, proceeds... 

Carbides of metals and other elements have been produced by this approach, including carbides of boron, silicon, titanium, zirconium, hafnium, vanadium, niobium, molybdenum, tungsten, tantalnm, and thorium (Funke, Klementiev, Kosukhin, 1969 Sheppard Wilson, 1972 MacKinnon Wickens, 1973 Chase, 1974 Steiger Wilson, 1974 Swaney, 1974 MacKinnon Renben, 1975). The produced caibide particles are very small their diameter is usually about 20-200 mu. Halides are mixed with hydrocarbons, usually in a ratio H2 Me = 2-30. The gas mixture is heated up in plasma to temperatures of 1300-4000 K time of synthesis exceeds 50 ms. As an example, production of submicron boron carbide powder from gaseous boron trichloride and methane occurs in the strongly endothermic process ... 

At the present time, most of the work is centered on the development of silicon carbide and silicon-nitride powders. Polysilanes are the basic precursor for the synthesis of silicon carbide from sol-gel. This was first achieved by the conversion of polydimethyl silane through a carbosilane intermediate. However this silane has poor solubility and low char yield and considerable shrinkage occurs during conversion to the final product. Precursors are being developed with a much larger SiC yield notably those based on trifiinctional alkoxides and chlorosilanes. These materials are being evaluated for the production of powders.P JP l... 

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