U.S. patent application number 10/645333 was filed with the patent office on 2004-04-08 for method for producing composite metal product.
Invention is credited to Koide, Atsushi, Miyagawa, Mamoru, Suganuma, Masashi, Takizawa, Kiyoto, Yamagiwa, Yoshitoshi.
Application Number | 20040067153 10/645333 |
Document ID | / |
Family ID | 32040354 |
Filed Date | 2004-04-08 |
United States Patent
Application |
20040067153 |
Kind Code |
A1 |
Koide, Atsushi ; et
al. |
April 8, 2004 |
Method for producing composite metal product
Abstract
A carbon nano material is mixed with a metal material in a
powder state. A resultant mixed material is compressed by a hot
press and molded to granules. The metal in the granules are melted,
blended and thus obtained composite material is injected into and
fill a mold to form a composite metal product comprising the carbon
nano material and the metal material. With the above process, it is
possible to injection mold said granules to obtain the composite
metal product to which the characteristics of the carbon nano
material are applied.
Inventors: |
Koide, Atsushi; (Nagano-ken,
JP) ; Takizawa, Kiyoto; (Nagano-ken, JP) ;
Yamagiwa, Yoshitoshi; (Nagano-ken, JP) ; Suganuma,
Masashi; (Nagano-ken, JP) ; Miyagawa, Mamoru;
(Nagano-ken, JP) |
Correspondence
Address: |
WEINGARTEN, SCHURGIN, GAGNEBIN & LEBOVICI LLP
TEN POST OFFICE SQUARE
BOSTON
MA
02109
US
|
Family ID: |
32040354 |
Appl. No.: |
10/645333 |
Filed: |
August 21, 2003 |
Current U.S.
Class: |
419/8 ;
419/14 |
Current CPC
Class: |
C22C 49/14 20130101;
C22C 1/1036 20130101; B22D 17/28 20130101; C22C 2001/1047 20130101;
C22C 26/00 20130101; B22D 17/2061 20130101; B82Y 30/00 20130101;
C22C 2026/002 20130101 |
Class at
Publication: |
419/008 ;
419/014 |
International
Class: |
B22F 007/04 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 22, 2002 |
JP |
2002-242292 |
Claims
What is claimed is:
1. A method for producing a composite metal product containing a
carbon nano material and a metal material, comprising the steps of:
mixing the carbon nano material with the metal material in a powder
state; compressing a resultant mixed material to a solid material
by a hot press and forming said solid mixed material to granules
such as chips, pellets, and the like; melting the metal and keading
the granules to form a composite material and injecting the
composite material into a mold to form the composite metal product;
and obtaining the composite metal product.
2. The method according to claim 1, wherein the melting and
kneading step and the injecting step are performed by using an
inline screw type injection machine or a screw type
preplasticization injection machine.
3. The method according to claim 1 or 2, wherein the metal material
comprises a low melting point metal material.
4. A composite metal product containing a carbon nano material and
a metal material, wherein said composit metal product is obtained
by any of the methods according to claims 1 to 3.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a method for producing a
composite metal product comprising a carbon nano material and a
metal material by injection molding.
[0003] 2. Description of the Related Art
[0004] A carbon nano material, which is a kind of crystalline
carbon materials, has such characteristics that its heat
conductivity is five times or more as high as that of aluminum
(Al), magnesium (Mg) and the like, it is excellent in electric
conductivity, and it is also excellent in slidability because it
has a low friction factor. Since the carbon nano material is very
minute, however, it is said that the material is preferably used by
being composited with other material.
[0005] In a conventional method, a composite material is obtained
by mixing the carbon nano material and metal powder, pressing and
pulverizing said mixture so that the the particle size is from 5
.mu.m to 1 nm, and a composite product is obtained by hot pressing
said pulverized mixture. The aboveconventional method has a problem
in that metal products of electronic equipment such as heat sinks,
shields and bearings, and the like are difficult to be molded by a
hot press from a composite material containing the crystalline
carbon material.
SUMMARY OF THE INVENTION
[0006] An object of the present invention, which has been devised
to solve the above problems of the prior art, is to provide a novel
compositing and molding method for enabling a carbon nano material
to be composited with a metal material by injection molding and
applying the characteristics of the carbon nano material to a metal
product without being limited by the size and shape of the metal
product so that functions required to the parts of electronic
equipment such as high heat conductivity, excellent electric
conductivity, excellent slidability, and the like can be improved,
and to provide a composite metal product.
[0007] A method for producing a composite metal product containing
a carbon nano material and a metal material of the present
invention for achieving the above object comprises the steps of;
mixing a carbon nano material with a metal material in a powder
state; compressing a resultant mixed material to a solid material
by a hot press and forming said solid mixed material into granules
such as chips, pelletes, and the like; melting the metal thereof
and kneading the granules to form a composite material and
injecting and the composite material into a mold to form the
composite metal product; and obtaining a composite metal product
containing the carbon nano material and the metal material. The
metal material is preferably a low melting point metal. The above
melting and kneading step and the injecting step may be performed
by using an inline screw type injection machine or a screw type
preplasticization injection machine. Further, the object of the
present invention is achieved by a composite metal product obtained
by any one of the above methods.
[0008] According to the above arrangement, since the carbon nano
material and the metal material are formed to the granules which
are used as a molding material, a material used in a compositing
and molding process can be easily supplied. Further, since the
metal material can be effectively melted and the carbon nano
material and the metal material can be blended in a short time, a
composite metal product having uniform quality can be obtained.
Further, since molding the composite metal product is achieved by
injection molding, the composite metal product has a high molded
accuracy and the product is not limited in its shape and size
different from a product formed by a press. Therefore, it is
possible to easily produce a composite metal product having
functions of high heat conductivity, excellent electric
conductivity, low friction factor, and the like.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a process view of a method of producing a
composite metal product cpmprising a carbon nano material and a low
melting point metal according to the present invention; and
[0010] FIG. 2 is a schematic sectional view of a screw type
preplasticization injection machine for use in the method of the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0011] First, powder of a carbon nano material 1, which is known as
a carbon nano tube and the like, and powder of a low melting point
metal material 2, which is composed of at least one selected from
the group consisting of metals, alloys of magnesium (Mg), tin (Sn),
aluminum (Al), copper (Cu), lead (Pb), and zinc (Zn), are charged
into a mixer 3 and stirred and mixed therein as shown in FIG. 1. A
conventional mixer for a powder may be used for the mixer 3 and an
example of the metals used herein is a magnesium-base alloy of a
low melting point metal. It is preferable that they be mixed in an
inert gas astmosphere. There is a carbon nano tube having a
diameter of 10 nm (0.01 .mu.m) and a length of 1 to 10 .mu.m as a
commercially available carbon nano tube.
[0012] Next, the mixed material 4 is transferred to a hot press 5
and heated and compressed so that it is molded to a sheet-shaped
solid material 6. An example of the compession molding conditions
is such that a carbon nano tube is added in an amount less than 30
vol % without an addition of a binder, a compression temperature is
about 500.degree. C. and a compression pressure is about 30 MPa.
The solid material 6 molded by the compression molding is processed
to granules 7 such as pellets, chips, and the like by known means
such as cutting, pulverizing, grinding or crushing, and the
granules 7 are as a molding material supplied to an injection
machine, which has an injection device 8 having heating means
around the outer periphery thereof and a mold 9 for a product.
[0013] The injection machine 8 has an injection screw 83 with a
check valve disposed in a heating cylinder 82 having a nozzle 81 at
the head thereof, the injection screw 83 rotating and moving
forward and rearward in the heating cylinder 82. Further, a hopper
84 is mounted on a supply port formed on the heating cylinder 82 at
a rear portion thereof. The granules 7 are supplied from the hopper
84 into the heating cylinder 82 , where the low melting point metal
is melted, are blended by the rotation of the injection screw 83
and formed a composite material and this composite material is fed
to the head of the screw 83 under pressure. Then, after the
composite material is weighed (stored) in the head portion of the
heating cylinder 82 in a molten state of the metal when the screw
is moved rearward by internal pressure, they are injected into and
fill the mold 9 for a product as a molding material as the screw
moves forward. Note that it is preferable that the inside space of
the heating cylinder 82 be filled with an inert gas atmosphere to
prevent oxidation.
[0014] The mold 9 is composed of a pair of open/close divided molds
93 attached to a stationary platen 91 and a movable platen 92 of a
mold clamping unit (not shown) and has cavities 94 for forming two
sets of products in the interior thereof and a sprue 95 which is
located at the center of both the cavities 94 and against which a
nozzle 81 is abutted. The composite material injected from the
nozzle 81 fills both the cavities 94 from the sprue 95, thereby
composite metal products 10, in which the carbon nano material 1 is
uniformly composited with the metal material 2, are formed.
[0015] Although the above embodiment employs the inline screw type
injection machine 8 and the metal material in the granules 7 is
melted and blended with the carbon nano material by the injection
screw 83 and thus obtained composite material is injected into and
fill the mold 9, the above operation can be effectively executed by
employing a screw type preplasticization injection machine that is
used to mold a resin.
[0016] As shown in FIG. 2, a screw type preplasticization injection
machine ordinarily constructed includes a melting/kneading device
14 and an injection device 17 disposed in parallel with each other,
and a flow path 18 having an open/close valve 19 is disposed
between the head of the melting/kneading device 14 and the
injection device 17 so that the melting/kneading device 14
communicates with the injection device 17 through the flow path 18.
The melting/kneading device 14 has a melting/kneading cylinder 11
having a melting/kneading screw 12 disposed therein and a hopper 13
disposed on the cylinder 11 at a rear portion thereof, and the
injection device 17 has an injection cylinder 15 including an
injection plunger 16 forward and rearward movably disposed
therein.
[0017] Accordingly, in the molding process, the granules are
melted, wherein the metal is melted, and blended by the
melting/kneading device 14, thereby a composite material is formed,
then thus obtained composite material is fed to the front portion
of the injection cylinder 15 under pressure and weighed therein.
After the composite material is weighed, the open/close valve 19 of
the flow path 18 is closed. In the injection device 17, the
composite material is injected from a nozzle 20 into and fill the
mold 9 as the injection cylinder 16 moves forward. In the
melting/kneading device 14, the metal of the granules 7 supplied
thereto begin to be melted and blended while the injection and
filling operation is executed in the injection device 17.
Accordingly, the screw type preplasticization injection machine can
more effectively mold the composite metal products 10, in which the
carbon nano material 1 is uniformly composited with the metal
material 2, than the inline screw type injection machine that
executes both the melting/kneading operation and the injecting
operation in the same machine.
* * * * *