Oxidation resistant carbon fiber reinforced carbon composite material and process for producing the same

1. An oxidation resistant carbon fiber reinforced carbon composite material comprising two or more layers of cloth-form or sheet-form carbon fibers adhered with a matrix, wherein the matrix comprises a ceramic powder and is uniformly distributed on the cloth-form or sheet-form carbon fibers,

wherein

the ceramic powder comprises a boron carbide powder having an average particle diameter of 5 μm or less; and

an amount of the ceramic powder is 32 volume % or more based on volume of the carbon fibers, and

wherein the composite material comprises 20 volume % or more of said cloth-form or sheet-form carbon fibers.

2. The oxidation resistant carbon fiber reinforced carbon composite material according to claim 1 , wherein the carbon fibers comprise at least one selected from the group consisting of a fine-woven spun-yarn cloth; a two-dimensional-woven cloth of continuous threads of long carbon fibers; a one-dimensional long carbon fiber sheet; short carbon fibers and a fine-woven spun-yarn cloth; short carbon fibers and a two-dimensional-woven cloth of continuous threads of long carbon fibers; and short carbon fibers and a one-dimensional long carbon fiber sheet.

3. The oxidation resistant carbon fiber reinforced carbon composite material according to claim 1 , wherein the ceramic powder consists of said boron carbide powder.

4. The oxidation resistant carbon fiber reinforced carbon composite material according to claim 1 , wherein the ceramic powder comprises the boron carbide powder and a silicon carbide powder.

5. The oxidation resistant carbon fiber reinforced carbon composite material according to claim 1 , wherein the matrix comprises a liquid synthetic resin or a liquid synthetic resin and a powdery synthetic resin uniformly mixed with the ceramic powder.

6. The oxidation resistant carbon fiber reinforced carbon composite material according to claim 5 , wherein the matrix comprises mesocarbon microbeads and/or a carbon powder having 5 to 15 weight % of a residual volatile matter.

7. The oxidation resistant carbon fiber reinforced carbon composite material according to claim 1 , wherein the cloth-form or sheet-form carbon fibers are further impregnated with a pitch or a synthetic resin to be carbonized.

8. A process for producing an oxidation resistant carbon fiber reinforced carbon composite material comprising two or more layers of cloth-form or sheet-form carbon fibers adhered with a matrix, wherein the matrix comprises a ceramic powder and is uniformly distributed on the cloth-form or sheet-form carbon fibers, wherein the composite material comprises 20 volume % or more of said cloth-form or sheet-form carbon fibers, the method comprising:

uniformly applying a slurried matrix precursor formed by mixing a liquid synthetic resin with the ceramic powder that comprises, based on volume of the carbon fibers, 32 volume % or more of a boron carbide powder having an average particle diameter of 5 μm or less to the cloth-form or sheet-form carbon fibers, and

putting in layers and baking the cloth-form or sheet-form carbon fibers.

9. The process for producing an oxidation resistant carbon fiber reinforced carbon composite material according to claim 8 , comprising uniformly infiltrating the matrix precursor into cloth-form or sheet-form carbon fibers, further, uniformly applying to surfaces of the carbon fibers, and subsequently putting in layers and baking the cloth-form or sheet-form carbon fibers put in layers and baked.

10. The process for producing an oxidation resistant carbon fiber reinforced carbon composite material according to claim 8 , comprising uniformly applying the matrix precursor to the cloth-form or sheet-form carbon fibers, putting in layers and baking the cloth-form or sheet-form carbon fibers, and further impregnating the cloth-form or sheet-form carbon fibers with pitch or synthetic resin to be carbonized.

11. The process for producing an oxidation resistant carbon fiber reinforced carbon composite material according to claim 8 , wherein the matrix precursor has a viscosity of 5 to 40 mPa-s.

12. The process for producing an oxidation resistant carbon fiber reinforced carbon composite material according to claim 8 , comprising adding to the matrix precursor any one or more among mesocarbon microbeads, carbon powder including 5 to 15 weight % of residual volatile matter, and short carbon fibers.

13. The oxidation resistant carbon fiber reinforced carbon composite material according to claim 1 , wherein the uniformly distributed matrix impregnates the cloth-form or sheet-form carbon fibers.