P-Silicon Carbide Powder

Carbothermal Reduction of Silica The primary method to synthesize [i-SiC is by carbothermal reduction reaction below 1900 °C that is, carbon reacts with silica (Si02) to produce SiC and CO gas. The chemical equation for this reaction is commonly written as  

According to the reaction mechanism proposed by Weimer [49], the reaction takes place in several steps [Eqs. (5) to (8)]  

Various processing methods are available for obtaining carbon/sUica mixtures with different scales of mixing. Depending on the nature of the reactants, these methods can usually be grouped into four categories  

However, when the mixtures are prepared from raw materials with fine particle sizes, significant deviations from ideal narrow particle size distributions do occur. The scale of mixing may still be large due to agglomerates, even though fine particles are used. Additionally, the resultant powder may have a mixed morphology of equiaxed and acicular particles [60, 61]. The product may also contain a significant 

As an example, the particulate component may be colloidal silica, while the soluble component may be sugar or a carbon-bearing polymer (or oligomer). Wei et al. [75] prepared SiC by mixing a colloidal Si02 suspension (mean crystallite size 14 nm) and either a sucrose or a phenolic resin solution. The SiC product had a primary crystallite size of approximately 10-20 nm. 

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