Formation of silicon carbide

The formation of silicon carbide, SiC (carborundum), is prevented by the addition of a little iron as much of the silicon is added to steel to increase its resistance to attack by acids, the presence of a trace of iron does not matter. (Addition of silicon to bronze is found to increase both the strength and the hardness of the bronze.) Silicon is also manufactured by the reaction between silicon tetrachloride and zinc at 1300 K and by the reduction of trichlorosilane with hydrogen. 

Soluble polysilane polymers can also be used as precursors to silicon carbide. The first such application, using (PhMeSi)n-(Me2Si)m copolymers ("Polysilastyrene"), was to strengthen silicon nitride ceramics. The Si3N4 ceramic body was soaked in polysilane and refired, leading to the formation of silicon carbide whiskers in the pore spaces and a consequent increase in strength. (U)... 

In the following sections some examples are given of the ways in which these principles have been utilized. The first example is the use of these techniques for the low temperature preparation of oxide ceramics such as silica. This process can also be used to produce alumina, titanium oxide, or other metal oxides. The second example describes the conversion of organic polymers to carbon fiber, a process that was probably the inspiration for the later development of routes to a range of non-oxide ceramics. Following this are brief reviews of processes that lead to the formation of silicon carbide, silicon nitride, boron nitride, and aluminum nitride, plus an introduction to the synthesis of other ceramics such as phosphorus nitride, nitrogen-phosphorus-boron materials, and an example of a transition metal-containing ceramic material. 

Scheme 4 Formation of silicon carbide from poly (dimethyl-silylene)...

The formation of silicon carbide from silicon and carbon is a well-known reaction and can occur at temperatures well below the melting point of... 

The formation of silicon carbide whiskers can occur through one of three general methods vapor-solid (VS), chemical vapor deposition (CVD), vapor-liquid-solid (VLS). The processes vary widely in the raw... 

Elemental silicon is usually prepared by the high-temperature reduction of silica (sand) with coke. Excess Si02 prevents the formation of silicon carbide. 

The in situ formation of silicon carbide according to the reaction... 

Wach, R. A., Sugimoto, M., Yoshikawa, M., Formation of silicone carbide membrane by radiation curing of polycarbosilane and polyvinylsilane and its gas separation up to 250°C. Journal of the American Ceramic Society 2007, 90(1), 275-278. 

Berzelius [1] first reported the formation of silicon carbide in 1810 and 1821, but it was later rediscovered during various electrochemical experiments, notably by Despretz [2], Schiitzenberger [3], and Moissan [4]. However, it was Acheson [5] who first realized the technical importance of silicon carbide as a hard material and, believing it to be a compound of carbon and corundum, he named the new substance carborundum . By 1891, Acheson had managed to prepare silicon carbide on a large scale such that, today, it has become by far the most widely used nonoxide ceramic material. 

The triaminosilane 2 is somewhat air- and moisture-sensitive but can be stored indefinitely in an inert atmosphere. Minor deviations in the elemental analysis data are due to the formation of silicon carbide and silicon nitride. It is highly soluble in common organic solvents. The solid-state structure of 2 has been determined by single-crystal X-ray analysis and shows nitrogen-hydrogen bridges. ... 

ABSTRACT. lon/molecule reactions initiated by ground-state atomic silicon ions are described which lead to Sl-C and Sl-0 bond formation. They are viewed as the first steps In the chemical pathways leading from atomic silicon to the formation of silicon carbide and oxide molecules of the type which may be precursors for the formation of silicon carbide and silicate grain particles in carbon-rich and oxygen-rich astrophysical environments. 

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