초록 ▼

A high strength, high creep resistant, boron-doped, silicon carbon fiber having no boron nitride coating, originally formed by sintering, is produced by exposing the fiber to a nitrogen atmosphere at a temperature equal to or preferably elevated above the sintering temperature and also exposing the

A high strength, high creep resistant, boron-doped, silicon carbon fiber having no boron nitride coating, originally formed by sintering, is produced by exposing the fiber to a nitrogen atmosphere at a temperature equal to or preferably elevated above the sintering temperature and also exposing the fiber to a carbon monoxide-containing atmosphere at a temperature sufficient to remove boron and boron nitride. The nitrogen atmosphere step may be performed before or after the carbon monoxide-containing atmosphere step. The resulting, uncoated SiC fibers have tensile strengths greater than approximately 2.0 GPa and Morscher-DiCarlo BSR test creep resistance M values greater than approximately 0.75 at 1400 degrees C. for one hour in argon. The method is applicable to non-sintered fibers as well, in which case the nitrogen exposure is carried out at between approximately 1750 to 2250 degrees C. and the carbon monoxide exposure is carried out at between approximately 1600 to 2200 degrees C.

대표청구항 ▼

[ I claim:] [1.] A method of forming a high strength, high creep resistance, silicon carbide fiber having no boron nitride coating, comprising the steps of:(A) providing a boron-doped, silicon carbide fiber which has been sintered at a sintering temperature to densify the fiber;(B) exposing the fibe

[ I claim:] [1.] A method of forming a high strength, high creep resistance, silicon carbide fiber having no boron nitride coating, comprising the steps of:(A) providing a boron-doped, silicon carbide fiber which has been sintered at a sintering temperature to densify the fiber;(B) exposing the fiber to a nitrogen-containing atmosphere at a temperature at least equal to the sintering temperature;(C) exposing the fiber to an atmosphere containing carbon monoxide at a temperature sufficient to remove boron and boron nitride from the fiber.