Preparation of boron-doped silicon carbide fibers
AssigneeUniversity of Florida
InventorsMichael D. Sacks, William Toreki, Christopher D. Batich, Guang J. Choi
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Abstract
A method of preparing polymer derived silicon fibers comprising the steps of providing a spin dope solution comprising a silicon carbide forming organosilicon polymer, preferably polycarbosilane, a solvent, a soluble boron precursor, preferably solid boron hydride, and a nitrogen containing precursor, preferably polyvinylsilazane; spinning the solution to form high strength green fibers; and heat treating the green fibers to produce high strength, homogeneously doped, boron containing fibers. The fibers produced are high strength, homogeneously boron doped silicon carbide fibers with average tensile strength in the range of from about 2.0 to 4.0 GPa at room temperature.
Claims14
A, homogeneously boron doped, polymer derived, silicon carbide fiber produced by the process comprising the steps of providing a spin dope solution comprising a silicon carbide forming organosilicon polymer, a solvent, a soluble boron precursor and a nitrogen containing precursor which reacts with said soluble boron precursor to form a boron compound such that boron remains in said fiber after heat treating;
- forming green fibers from said spin dope solution by spinning;
- and heat treating to sinter said green fibers to produce, homogeneously doped, boron containing fibers having a tensile strength of at least 2.0 GPa, wherein the fiber retains at least 90% of the original tensile strength after being heated treated at a temperature of up to 1800.degree. C.
A sintered, boron doped, polymer derived, silicon carbide fiber where said boron is homogeneously dispersed within said fiber, wherein the fiber retains at least 90% of the original tensile strength after being heated treated at a temperature of up to 1800.degree. C.
Dependencies are inferred from the claim text.