Composite material and processing method using the material

Abstract

An abrasive composite material containing a matrix, abrasive grains, and carbon fiber having a multi-layer structure, each fiber filament of the carbon fiber having an outer diameter of about 2 to about 500 nm and an aspect ratio of about 5 to about 15,000, and including a hollow space extending along its center axis. Preferably, the carbon fiber has a BET specific surface area of about 4 m 2 /g or more; the carbon fiber has, at a carbon (002) plane, an interlayer distance (d 002 ) of about 0.345 nm or less as measured by means of X-ray diffractometry; and the ratio of the peak height (Id) of the band at 1,341 to 1,349 cm −1 in a Raman scattering spectrum of the carbon fiber to the peak height (Ig) of the band at 1,570 to 1,578 cm −1 in the spectrum; i.e., Id/Ig, is about 1.5 or less. More preferably, the carbon fiber contains branched vapor grown carbon fiber; boron is contained, in an amount of about 0.01 to about 5 mass %, in the interior of crystals constituting the carbon fiber; and the amount of the carbon fiber contained in the abrasive composite material is about 2 to about 40 vol. %. When the abrasive composite material is employed, high-precision grinding or polishing can be attained. When the composite material is employed in a cutting tool material, the resultant cutting tool material realizes high-speed, high-efficiency cutting, and enables wire-cut electrical discharge machining.

What is claimed is:  
     
         1 . An abrasive composite material comprising a matrix, abrasive grains, and carbon fiber having a multi-layer structure, each fiber filament of the carbon fiber having an outer diameter of about 2 to about 500 nm and an aspect ratio of about 5 to about 15,000, and including a hollow space extending along its center axis.  
     
     
         2 . An abrasive composite material according to  claim 1 , wherein the carbon fiber has a BET specific surface area of at least about 4 m 2 /g.  
     
     
         3 . An abrasive composite material according to  claim 1 , wherein the carbon fiber has, at a carbon (002) plane, an interlayer distance (d 002 ) of about 0.345 nm or less as measured by means of X-ray diffractometry.  
     
     
         4 . An abrasive composite material according to  claim 1 , wherein the ratio of the peak height (Id) of the band at 1,341 to 1,349 cm −1  in a Raman scattering spectrum of the carbon fiber to the peak height (Ig) of the band at 1,570 to 1,578 cm −1  in the spectrum; i.e., Id/Ig, is about 1.5 or less.  
     
     
         5 . An abrasive composite material according to  claim 1 , wherein the carbon fiber contains branched vapor grown carbon fiber.  
     
     
         6 . An abrasive composite material according to  claim 1 , wherein boron is contained, in an amount of about 0.01 to about 5 mass %, in the interior of crystals constituting the carbon fiber.  
     
     
         7 . An abrasive composite material according to  claim 1 , wherein the amount of the carbon fiber is about 2 to about 40 vol. % with respect to the abrasive composite material.  
     
     
         8 . An abrasive composite material according to  claim 1 , wherein the abrasive grains are formed of at least one material selected from among cerium oxide, silicon oxide, silicon carbide, boron carbide, boron nitride, zirconium oxide, diamond, and sapphire.  
     
     
         9 . An abrasive composite material according to  claim 1 , wherein the matrix is formed of at least one material selected from among a resin, a metal, and a ceramic material.  
     
     
         10 . An abrasive composite material according to  claim 9 , wherein the resin contains at least one species selected from among a phenolic resin, a melamine resin, a polyurethane resin, an epoxy resin, a urea resin, an unsaturated polyester resin, a silicone resin, a polyimide resin, an epoxy resin, a cyanate ester resin, and a benzoxazine resin.  
     
     
         11 . A grinding wheel formed through molding of an abrasive composite material as recited in  claim 1 .  
     
     
         12 . A grinding material comprising an abrasive composite material as recited in  claim 1 .  
     
     
         13 . A polishing material comprising an abrasive composite material as recited in  claim 1 .  
     
     
         14 . A cutting tool material comprising an abrasive composite material as recited in  claim 1 .  
     
     
         15 . A cutting tool material according to  claim 14 , wherein the matrix contains the carbon fiber in an amount of about 20 to about 45 vol. %.  
     
     
         16 . A wire-cut electrical discharge machining material comprising a cutting tool material as recited in  claim 14 .  
     
     
         17 . A wire-cut electrical discharge machining method employing a cutting tool material as recited in  claim 14 .  
     
     
         18 . A method for producing a cutting tool, which employs a wire-cut electrical discharge machining method as recited in  claim 17 .  
     
     
         19 . A method for producing an electronic part, which method comprises a step of grinding at least one species selected from among a semiconductor, an interlayer insulating film, and a wiring material by use of an abrasive composite material as recited in  claim 1 .  
     
     
         20 . A method for producing an electronic part, which method comprises a step of polishing at least one species selected from among a semiconductor, an interlayer insulating film, and a wiring material by use of an abrasive composite material as recited in  claim 1 .  
     
     
         21 . A method for producing an electronic part according to  claim 19  or  20 , wherein the semiconductor is at least one species selected from among polycrystalline silicon, single-crystal silicon, and amorphous silicon.