초록 ▼

A process for production of high purity, sub-micron size, silicon carbide by reacting a mixture of silica powder and carbon powder in a mixing reactor. The reactor, initially pressurized with a non-reactive gas, is indirectly heated and when the charge reaches reaction temperature a vacuum is applie

A process for production of high purity, sub-micron size, silicon carbide by reacting a mixture of silica powder and carbon powder in a mixing reactor. The reactor, initially pressurized with a non-reactive gas, is indirectly heated and when the charge reaches reaction temperature a vacuum is applied. The charge is kept under a high vacuum until the reaction is complete, and is agitated to encourage release of carbon monoxide. After removal of excess carbon by low temperature oxidation, the product typically contains in excess of 99.5% silicon carbide of the beta-phase, has a surface area greater than 10m2/gm, is free of carbon and contains no detectable unreacted silica. The product requires no post production treatment such as grinding and acid leaching.

대표청구항 ▼

A method of making beta-silicon carbide powder, comprising mixing carbon powder with silica powder, as reactants, the method comprising the steps of: ,(i) heating the reactants in a reaction chamber under a non-reactive gas pressure which is equal to or greater than atmospheric pressure, which maint

A method of making beta-silicon carbide powder, comprising mixing carbon powder with silica powder, as reactants, the method comprising the steps of: ,(i) heating the reactants in a reaction chamber under a non-reactive gas pressure which is equal to or greater than atmospheric pressure, which maintains a carbon monoxide partial pressure sufficient to prevent significant loss of silicon monoxide until the reactants reach a temperature of between 1200 and 2000 degrees C; and (ii) subsequently maintaining the temperature of the reactants between 1200 and 2000 degrees C. to cause the reactants to react to form silicon carbide and carbon monoxide, and simultaneously applying a subatmospheric pressure to the reactants which is from about 50 millitorrs to about 500 millitorrs (i), which pressure is sufficient to remove carbon monoxide gas from the reaction chamber, while agitating the reactants to allow for passage of carbon monoxide therefrom, whereby the removal of the carbon monoxide drives the reaction to substantial completion.