초록 ▼

Organic fibers are oxidized, ground and blended with a source of silica. Heat treatment of the blend in the range of 1400°to 1700°C. results in the formation of SiC whiskers. Various fibers including PAN, pitch and rayon which can be processed to form carbon and/or graphite fibers can be used as the

Organic fibers are oxidized, ground and blended with a source of silica. Heat treatment of the blend in the range of 1400°to 1700°C. results in the formation of SiC whiskers. Various fibers including PAN, pitch and rayon which can be processed to form carbon and/or graphite fibers can be used as the carbon source. Ashed rice hulls as the source of silica are blended with the chopped fiber to form the SiC whiskers.

대표청구항 ▼

A process for the manufacture of SiC whiskers comprising the steps of: (1) Selecting an organic fiber from the group consisting of polymers, copolymers, and terpolymers of acrylonitrile oxidized in air at a temperature from 200°to 400°C.; (2) Grinding or chopping the fiber obtained in step 1 to form

A process for the manufacture of SiC whiskers comprising the steps of: (1) Selecting an organic fiber from the group consisting of polymers, copolymers, and terpolymers of acrylonitrile oxidized in air at a temperature from 200°to 400°C.; (2) Grinding or chopping the fiber obtained in step 1 to form a short fiber of approximately 10 to 100mlength; (3) Mixing the ground fiber obtained above with amorphous SiO2; (4) Placing the mixture obtained above in a furnace and increasing the temperature to a carbide-forming temperature within the range of of 1400°to 1800°C. in a non-oxidizing atmosphere; (5) When the temperature reaches said carbide-forming temperature, maintaining the mixture at that temperature in an atmosphere of inert gas for a period of 1 to 4 hours; and (6) Removing the product from the furnace. A process for the manufacture of SiC whiskers comprised of: (1) Ashing rice hulls at a temperature from about 400°to 700°C. to form amorphous SiO2; (2) Mixing the ash with ground fibers from 10 to 100min length selected from the group consisting of polyacrylonitrile fibers oxidized in air at 200°to 400°C., carbonized polyacrylonitrile fibers, graphitized polyacrylonitrile fibers, graphitized viscose rayon, carbonized mesophase petroleum pitch fibers, and fibrous alpha-cellulose carbonized in a nonoxidizing atmosphere; (3) Placing the mixture obtained in an inert atmosphere of argon; (4) Increasing the temperature at a rate of from 100°C. to 200°C. per minute from ambient to a carbide-forming temperature between 1400°C. and 1800°C., holding the mixture at that temperature in argon for a period of approximately one hour to form SiC whiskers; and (5) Removing the product from the heating chamber.