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 high strength, high creep resistance, silicon carbide fiber having no boron nitride coating, a density of at least approximately 3.0 g/cm.sup.3, a tensile strength of at least 2.0 GPa and a creep resistance M value of greater than about 0.75 as derived from a Morscher-DiCarlo BSR

[ I claim:] [1.] A high strength, high creep resistance, silicon carbide fiber having no boron nitride coating, a density of at least approximately 3.0 g/cm.sup.3, a tensile strength of at least 2.0 GPa and a creep resistance M value of greater than about 0.75 as derived from a Morscher-DiCarlo BSR test procedure carried out at 1400 degrees C for one hour in argon, produced by the process 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.