Copper alloy composite and method for manufacturing same

Abstract

An integrated product whose joint strength between a copper alloy and a carbon fiber prepreg is extremely high. A copper alloy given a certain special surface shape yields tremendous bonding strength through compatibility with an epoxy resin adhesive. With a composite part in which this technology is utilized to integrate a copper alloy member as a cover material with a CFRP, it is possible to take advantage of the characteristics of both the copper alloy and the FRP due to the tremendous bonding strength. In a step in which an FRP prepreg is put into a mold and heated and cured, usually the mold is first coated with a release agent to facilitate release from the mold, but with high-technology CFRP, bleeding of the release agent often diminishes the properties. A copper alloy sheet 21 is used as a cover material, and a CFRP 22 is cured.

1 . A copper alloy composite, comprising:
 a copper alloy part having micron-order roughness produced by chemical etching, whose surface, when observed by electron microscope, has ultrafine texturing in which holes or depressions that are circular in shape with a diameter of 10 to 150 nm or elliptical in shape with an average of major and minor diameters of 10 to 150 nm are present over substantially the entire surface at an irregular spacing of 30 to 300 nm, the surface being mainly a thin layer of cupric oxide; and   an adherend that is bonded using, as an adhesive, an epoxy adhesive that has permeated the ultrafine texturing.   
     
     
         2 . A copper alloy composite, comprising:
 a copper alloy part having micron-order roughness produced by chemical etching, whose surface, when observed by electron microscope, has ultrafine texturing in which bumps that are circular in shape with a diameter of 10 to 200 nm or elliptical in shape with an average of major and minor diameters of 10 to 200 nm are present over substantially the entire surface, the surface being mainly a thin layer of cupric oxide; and   an adherend that is bonded using, as an adhesive, an epoxy adhesive that has permeated the ultrafine texturing.   
     
     
         3 . A copper alloy composite, comprising:
 a copper alloy part having micron-order roughness produced by chemical etching, substantially the entire surface of which is covered with, when observed by electron microscope, ultrafine texturing in which granules or amorphous polygons with a diameter of 10 to 150 nm are lined up and partially melted together in a stacked shape, the surface being mainly a thin layer of cupric oxide; and   an adherend that is bonded using, as an adhesive, an epoxy adhesive that has permeated the ultrafine texturing.   
     
     
         4 . A copper alloy composite, comprising:
 a copper alloy part having micron-order roughness produced by chemical etching, substantially the entire surface of which is covered with, when observed by electron microscope, ultrafine texturing in the form of gullies on the slope of a lava plateau, in which granules with a diameter of 10 to 20 nm and amorphous polygons with a diameter of 50 to 150 nm are mixed together in a stacked shape, the surface being mainly a thin layer of cupric oxide; and   an adherend that is bonded using, as an adhesive, an epoxy adhesive that has permeated the ultrafine texturing.   
     
     
         5 . The copper alloy composite according to any of  claims 1  to  4 ,
 wherein the adherend is a copper alloy part which is made of a copper alloy and on which the ultrafine texturing has been formed.   
     
     
         6 . The copper alloy composite according to any of  claims 1  to  4 ,
 wherein the adherend is a fiber-reinforced plastic that contains the epoxy adhesive and has been reinforced by filling and layering at least one type selected from long fibers, short fibers and fiber cloth.   
     
     
         7 . The copper alloy composite according to any of  claims 1  to  4 ,
 wherein the micron-order surface roughness is such that the mean length of a roughness curve (RSm) is 0.8 to 10 μm and the maximum height of roughness (Rz) is 0.2 to 5 μm.   
     
     
         8 . The copper alloy composite according to any of  claims 1  to  4 ,
 wherein the resin component of the cured epoxy resin contains no more than 30 weight parts elastomer component per 100 weight parts of total resin component.   
     
     
         9 . The copper alloy composite according to any of  claims 1  to  4 ,
 wherein the cured epoxy resin contains a total of no more than 50 weight parts filler per 100 weight parts of total resin component.   
     
     
         10 . The copper alloy composite according to  claim 9 ,
 wherein the filler is one type selected from reinforcing fibers of glass fiber, carbon fiber, and aramid fiber, and   at least one type selected from powder fillers of calcium carbonate, magnesium carbonate, silica, talc, clay, and glass.   
     
     
         11 . The copper alloy composite according to  claim 8 ,
 wherein the elastomer component is at least one type selected from vulcanized rubber powders with a particle size of 1 to 30 μm, semi-crosslinked rubber, unvulcanized rubber, terminal-modified thermoplastic resins in which the melt softening point of a hydroxyl group terminated polyether sulfone is at least 300° C., and polyolefin resins.   
     
     
         12 . A method for manufacturing a copper alloy composite, comprising:
 a step of shaping a copper alloy part by machining or the like from a casting or an intermediate material;   a chemical etching step of immersing the shaped copper alloy part in an acidic aqueous solution containing an oxidant;   a surface hardening step of immersing the chemically etched copper alloy part in a strongly basic aqueous solution containing an oxidant;   a step of coating the necessary portions of the copper alloy part with an uncured epoxy resin;   a step of adjusting a prepreg of a fiber-reinforced plastic to the required size;   a step of applying the prepreg to the coated side of the copper alloy part; and   a step of positioning the prepreg and the copper alloy part, and heating the prepreg and the copper alloy part while holding them down, to cure the epoxy resin component.   
     
     
         13 . A method for manufacturing a copper alloy composite, comprising:
 a step of shaping a copper alloy part by machining or the like from a casting or an intermediate material;   a chemical etching step of immersing the shaped copper alloy part in an acidic aqueous solution containing an oxidant, to form ultrafine texturing on the surface thereof;   a surface hardening step of immersing the chemically etched copper alloy part in a strongly basic aqueous solution containing an oxidant;   a step of coating the necessary portions of the copper alloy part with an uncured epoxy resin;   a hardening pretreatment step of putting the copper alloy part that has been coated with the uncured epoxy resin in a sealed vessel, depressurizing, and then pressurizing to force the uncured epoxy resin into the ultrafine texturing on the copper alloy surface;   a step of adjusting a prepreg of a fiber-reinforced plastic to the required size;   a step of applying the prepreg of a fiber-reinforced plastic to the coated side of the copper alloy part; and   
       a step of positioning the prepreg and the copper alloy part, and heating the prepreg and the copper alloy part while holding them down, to cure the epoxy resin component.