U.S. patent application number 14/425457 was filed with the patent office on 2015-07-30 for aluminum plating apparatus and method for producing aluminum film using same.
This patent application is currently assigned to SUMITOMO ELECTRIC INDUSTRIES, LTD.. The applicant listed for this patent is SUMITOMO ELECTRIC INDUSTRIES, LTD.. Invention is credited to Kengo Goto, Akihisa Hosoe, Koutarou Kimura, Junichi Nishimura, Kazuki Okuno, Hideaki Sakaida.
Application Number | 20150211143 14/425457 |
Document ID | / |
Family ID | 50236886 |
Filed Date | 2015-07-30 |
United States Patent
Application |
20150211143 |
Kind Code |
A1 |
Nishimura; Junichi ; et
al. |
July 30, 2015 |
ALUMINUM PLATING APPARATUS AND METHOD FOR PRODUCING ALUMINUM FILM
USING SAME
Abstract
The invention offers an aluminum-plating apparatus that can
satisfactorily form an aluminum plating even on the surface of a
base body that has a surface on which an insulating or poorly
conductive metal oxide film or the like is formed. The
aluminum-plating apparatus electrodeposits aluminum onto a base
body by conveying the base body in a plating bath. The plating bath
is divided into a first electrolysis chamber and a second
electrolysis chamber by a partition plate in this order from the
upstream side in the conveying direction for the base body. In the
first electrolysis chamber, a negative electrode provided in the
chamber is electrically connected with the base body such that the
base body acts as a positive electrode. In the second electrolysis
chamber, a positive electrode provided in the chamber is
electrically connected with the base body such that the base body
acts as a negative electrode.
Inventors: |
Nishimura; Junichi;
(Osaka-shi, JP) ; Hosoe; Akihisa; (Osaka-shi,
JP) ; Okuno; Kazuki; (Osaka-shi, JP) ; Kimura;
Koutarou; (Osaka-shi, JP) ; Goto; Kengo;
(Osaka-shi, JP) ; Sakaida; Hideaki; (Osaka-shi,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SUMITOMO ELECTRIC INDUSTRIES, LTD. |
Osaka-shi, Osaka |
|
JP |
|
|
Assignee: |
SUMITOMO ELECTRIC INDUSTRIES,
LTD.
Osaka-shi
JP
|
Family ID: |
50236886 |
Appl. No.: |
14/425457 |
Filed: |
June 13, 2013 |
PCT Filed: |
June 13, 2013 |
PCT NO: |
PCT/JP2013/066294 |
371 Date: |
March 3, 2015 |
Current U.S.
Class: |
205/164 ;
204/243.1; 204/245; 205/233 |
Current CPC
Class: |
C25D 3/665 20130101;
C25D 17/06 20130101; C25D 5/003 20130101; C25D 7/0642 20130101;
C25D 5/44 20130101; C25D 5/56 20130101; C25D 7/0621 20130101; C25D
3/44 20130101; C25D 3/66 20130101 |
International
Class: |
C25D 17/06 20060101
C25D017/06; C25D 5/56 20060101 C25D005/56; C25D 3/66 20060101
C25D003/66 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 5, 2012 |
JP |
2012-194779 |
Claims
1. An aluminum-plating apparatus for electrodepositing aluminum
onto a base body by conveying the base body in a plating bath, the
apparatus having a feature in that: the plating bath is divided
into a first electrolysis chamber and a second electrolysis chamber
by a partition plate in this order from the upstream side in a
direction that the base body is conveyed; in the first electrolysis
chamber, which is provided with a negative electrode, the negative
electrode is electrically connected with the base body in such a
way that the base body acts as a positive electrode; and in the
second electrolysis chamber, which is provided with a positive
electrode, the positive electrode is electrically connected with
the base body in such a way that the base body acts as a negative
electrode.
2. The aluminum-plating apparatus as defined by claim 1, the
apparatus comprising, at the upstream side of an entrance of the
first electrolysis chamber, a first electricity supply roller that
gives an electric potential to the base body and concurrently
conveys the base body.
3. The aluminum-plating apparatus as defined by claim 1, the
apparatus comprising, at the downstream side of an exit of the
second electrolysis chamber, a second electricity supply roller
that gives an electric potential to the base body and concurrently
conveys the base body.
4. The aluminum-plating apparatus as defined by claim 1, wherein
the plating bath contains a molten-salt bath composed mainly of
aluminum chloride.
5. The aluminum-plating apparatus as defined by claim 1, wherein
the base body is a sheet composed of a resin formed body having a
three-dimensional network structure that has undergone conductive
treatment.
6. An aluminum-plating apparatus, comprising two or more
aluminum-plating apparatuses each as defined by claim 1; the
apparatuses being positioned in series in a direction that the base
body is conveyed.
7. An aluminum-plating apparatus, comprising an aluminum-plating
apparatus: that is positioned at a preceding positon of the
aluminum-plating apparatus as defined by claim 1, the preceding
positon being the most upstream position in a direction that the
base body is conveyed; that electrodeposits aluminum onto the base
body by conveying the base body in a plating bath; and that has a
feature in that in the plating bath, which is provided with a
positive electrode, the positive electrode is electrically
connected with the base body in such a way that the base body acts
as a negative electrode.
8. A method of producing an aluminum film, the method
electrodepositing aluminum onto a base body using the
aluminum-plating apparatus as defined by claim 1.
Description
TECHNICAL FIELD
[0001] The present invention relates to an aluminum-plating
apparatus for electroplating the surface of a base body with
aluminum and a method of producing an aluminum film using the
foregoing apparatus.
BACKGROUND ART
[0002] Aluminum forms a close-knit oxide film on its surface to be
passivated and thus exhibits excellent corrosion resistance. For
this reason, aluminum plating is performed on the surface of a
steel tape and the like to enhance the corrosion resistance.
[0003] To perform aluminum plating on the surface of a steel tape,
first, the steel tape is conveyed continuously into a plating bath
through a conductor roll. The tape runs in a positive electrode
immersed in a plating liquid in the plating bath. At this moment,
the steel tape is electrically connected so as to act as a negative
electrode, so that electrolysis occurs between the positive
electrode and the steel tape, which is the negative electrode. As a
result, aluminum is electrodeposited on the surface of the steel
tape to form an aluminum plating. The steel tape running in the
plating liquid undergoes a direction change by a turn roll to run
upward this time. In this case, also, plating is performed in
relation to the positive electrode. The steel tape on which the
aluminum plating is formed leaves the plating bath, passes another
conductor roll, and is taken out of the system (the published
Japanese patent application Tokukaihei 05-222599 (Patent Literature
1)).
[0004] As a metallic porous body having a three-dimensional network
structure, a porous body composed of aluminum holds promise as a
material for increasing the capacity of the positive electrode of a
lithium-ion battery. At present, exploiting conductivity, corrosion
resistance, lightweight, and other excellent features of aluminum,
a material produced by coating an active material such as lithium
cobalt oxide on the surface of an aluminum foil is used as the
positive electrode of a lithium-ion battery. When the positive
electrode is formed by using the porous body composed of aluminum,
it is possible to increase the surface area and to fill the active
material even at the interior of the aluminum. As a result, even
when the electrode is thickened, a decrease in the utilization rate
of the active material is avoided. Consequently, the utilization
rate of the active material per unit area is increased, and
therefore the capacity of the positive electrode can be
increased.
[0005] The present applicant has proposed a method of
electroplating a resin formed body having a three-dimensional
network structure with aluminum as a production method of the
above-described aluminum porous body (the published Japanese patent
application Tokukai 2012-007233 (Patent Literature 2)). The
conventional aluminum molten-salt bath is required to be heated to
high temperature. Consequently, when the surface of a resin formed
body is electroplated with aluminum, the resin cannot withstand the
high temperature and melts, which is one of the problems in this
case. However, according to the method stated in Patent Literature
2, the mixing of an organochloride salt, such as
1-ethyl-3-methylimidazolium chloride (EMIC) or 1-butylpyridinium
chloride (BPC), and aluminum chloride (AlCl.sub.3) forms an
aluminum bath that is a liquid at room temperature, thereby
enabling a resin formed body to be electroplated with aluminum. In
particular, the EMIC-AlCl.sub.3 system is good in the
characteristics of the liquid, so that it is useful as an
aluminum-plating liquid.
[0006] In the above-described aluminum-plated steel tape and
aluminum porous body having a three-dimensional network structure,
in order to obtain a surface having excellent glossiness and to
increase the thickness of the layer of the aluminum plating, it is
necessary that a base body having a surface of aluminum be further
plated with aluminum.
[0007] However, as described above, an oxide film is formed on the
surface of the aluminum. Therefore, even when it is intended to
electrodeposit aluminum onto the aluminum surface, electricity
cannot be supplied uniformly to the surface. As a result, a plating
is formed in the shape of islands, which is a problem.
CITATION LIST
Patent Literature
[0008] Patent Literature 1: the published Japanese patent
application Tokukaihei 05-222599
[0009] Patent Literature 2: the published Japanese patent
application Tokukai 2012-007233
SUMMARY OF INVENTION
Technical Problem
[0010] In view of the above-described problem, an object of the
present invention is to offer an aluminum-plating apparatus that
can satisfactorily form an aluminum plating even on the surface of
a base body that has a surface on which an insulating or poorly
conductive metal oxide film or the like is formed.
Solution to Problem
[0011] The present inventors have studied intensely to solve the
above-described problem and have found that it is effective to
perform aluminum plating after electrolytically removing, in a
plating bath, an oxide film formed on the surface of a metal. Thus,
the present invention is completed. More specifically, the present
invention has the constitution described below.
[0012] (1) An aluminum-plating apparatus for electrodepositing
aluminum onto a base body by conveying the base body in a plating
bath. The apparatus has the following feature: [0013] the
above-described plating bath is divided into a first electrolysis
chamber and a second electrolysis chamber by a partition plate in
this order from the upstream side in a direction that the
above-described base body is conveyed; [0014] in the
above-described first electrolysis chamber, which is provided with
a negative electrode, the negative electrode is electrically
connected with the above-described base body in such a way that the
above-described base body acts as a positive electrode; and [0015]
in the above-described second electrolysis chamber, which is
provided with a positive electrode, the positive electrode is
electrically connected with the above-described base body in such a
way that the above-described base body acts as a negative
electrode.
[0016] The aluminum-plating apparatus stated in (1) above performs
reverse electrolysis in the first electrolysis chamber. Therefore,
even when an insulating or poorly conductive metal oxide film or
the like is formed on the surface of a base body, it can be removed
electrolytically, so that aluminum can be satisfactorily
electrodeposited in the subsequent second electrolysis chamber.
[0017] (2) The aluminum-plating apparatus as stated in (1) above,
the apparatus having, at the upstream side of an entrance of the
above-described first electrolysis chamber, a first electricity
supply roller that gives an electric potential to the
above-described base body and concurrently conveys the base
body.
[0018] The invention stated in (2) above enables the giving of an
electric potential to the base body in the vicinity of the first
electrolysis chamber while the base body is being conveyed.
[0019] (3) The aluminum-plating apparatus as stated in (1) or (2)
above, the apparatus having, at the downstream side of an exit of
the above-described second electrolysis chamber, a second
electricity supply roller that gives an electric potential to the
above-described base body and concurrently conveys the base
body.
[0020] The invention stated in (3) above enables the giving of an
electric potential to the base body in the vicinity of the second
electrolysis chamber while the base body is being conveyed.
[0021] (4) The aluminum-plating apparatus as stated in any one of
(1) to (3) above, in which the above-described plating bath
contains a molten-salt bath composed mainly of aluminum
chloride.
[0022] The invention stated in (4) above enables the use of the
conventional molten-salt bath composed mainly of aluminum chloride
and consequently the obtaining of a good-quality aluminum film.
[0023] (5) The aluminum-plating apparatus as stated in any one of
(1) to (4) above, in which the above-described base body is a sheet
formed of a resin formed body having a three-dimensional network
structure that has undergone conductive treatment.
[0024] The invention stated in (5) above enables the continuous
production of a resin structure that has an aluminum film on the
surface of a resin formed body having a three-dimensional network
structure.
[0025] (6) An aluminum-plating apparatus, having two or more
aluminum-plating apparatuses each as stated in any one of (1) to
(5) above;
the apparatuses being positioned in series in a direction that the
above-described base body is conveyed.
[0026] The invention stated in (6) above enables the providing of
only one set of incidental equipment, such as a supplying facility
and a taking-up facility for the base body, so that the investment
for the equipment can be reduced significantly.
[0027] (7) An aluminum-plating apparatus, having an
aluminum-plating apparatus: [0028] that is positioned at a
preceding position of the aluminum-plating apparatus as stated in
any one of (1) to (6) above, the preceding position being the most
upstream position in a direction that the above-described base body
is conveyed; [0029] that electrodeposits aluminum onto the
above-described base body by conveying the above-described base
body in a plating bath; and [0030] that has a feature in that in
the plating bath, which is provided with a positive electrode, the
positive electrode is electrically connected with the
above-described base body in such a way that the above-described
base body acts as a negative electrode.
[0031] The invention stated in (7) above enables the use of the
conventional aluminum-plating apparatus at the most upstream
position in a direction that the base body is conveyed when the
apparatus uses a base body that has a surface on which no
insulating or poorly conductive metal oxide film or the like is
formed. In addition, only one set of incidental equipment, such as
a supplying facility and a taking-up facility for the base body, is
necessary, so that the investment for the equipment can be reduced
significantly.
[0032] (8) A method of producing an aluminum film, the method
electrodepositing aluminum onto a base body using the
aluminum-plating apparatus as stated in any one of (1) to (7)
above.
[0033] The method of producing an aluminum film stated in (8) above
enables the formation of a good-quality aluminum film on the
surface of a base body even when the base body has a surface on
which an insulating or poorly conductive metal oxide film or the
like is formed.
Advantageous Effects of Invention
[0034] The present invention can offer an aluminum-plating
apparatus that can satisfactorily form an aluminum plating even on
the surface of a base body that has a surface on which an
insulating or poorly conductive metal oxide film or the like is
formed.
BRIEF DESCRIPTION OF DRAWING
[0035] FIG. 1 is a diagram showing an example of the
aluminum-plating apparatus of the present invention.
[0036] FIG. 2 is a diagram showing another example of the
aluminum-plating apparatus of the present invention.
DESCRIPTION OF EMBODIMENTS
[0037] The aluminum-plating apparatus of the present invention is
an aluminum-plating apparatus for electrodepositing aluminum onto a
base body by conveying the base body in a plating bath. The
apparatus has the following feature: [0038] the above-described
plating bath is divided into a first electrolysis chamber and a
second electrolysis chamber by a partition plate in this order from
the upstream side in a direction that the above-described base body
is conveyed; [0039] in the above-described first electrolysis
chamber, which is provided with a negative electrode, the negative
electrode is electrically connected with the above-described base
body in such a way that the above-described base body acts as a
positive electrode; and [0040] in the above-described second
electrolysis chamber, which is provided with a positive electrode,
the positive electrode is electrically connected with the
above-described base body in such a way that the above-described
base body acts as a negative electrode.
[0041] The above-described base body is not particularly limited.
However, an outstanding effect is exerted in the case of a base
body onto which the conventional aluminum-plating apparatus cannot
satisfactorily electrodeposit aluminum, such as a metal having a
metal oxide film (a passive film) on its surface. The types of the
foregoing base body include a steel tape (a steel plate), an
aluminum porous body having a three-dimensional network structure,
a SUS plate, a Cu or Cu alloy plate, and a Zn or Zn alloy
plate.
[0042] The above-described plating bath contains a plating liquid.
The plating liquid is not particularly limited provided that the
liquid has a composition capable of performing electroplating with
aluminum. Aluminum has a high affinity for oxygen and has an
electric potential lower than that of hydrogen. Consequently, it is
difficult to perform electroplating in an aqueous solution-based
plating bath, so that a molten-salt bath is used. A molten-salt
bath composed mainly of aluminum chloride can be advantageously
used.
[0043] As for the molten salt, an organic molten salt in the form
of a eutectic salt of an organohalide and an aluminum halide and an
inorganic molten salt in the form of a eutectic salt of a
halogenide of an alkali metal and an aluminum halide can be used.
When an organic molten-salt bath, which melts at relatively low
temperature, is used, plating can be performed without decomposing
a resin formed body used as a base body, which is desirable. As for
the organohalide, an imidazolium salt, a pyridinium salt, and the
like can be used. More specifically, 1-ethyl-3-methylimdazolium
chloride (EMIC) and butylpyridinium chloride (BPC) are
desirable.
[0044] When moisture or oxygen intrudes into a molten salt, the
molten salt deteriorates. Therefore, it is desirable to perform
plating not only in a nitrogen, argon, or other inert gas
atmosphere but also in an enclosed environment.
[0045] As for the molten-salt bath, a molten-salt bath containing
nitrogen is desirable. When a resin formed body having a
three-dimensional network structure is used as the above-described
base body, if a salt that melts at high temperature is used as the
molten salt, the resin dissolves or decomposes in the molten salt
more quickly than the layer of plating grows. As a result, the
layer of plating cannot be formed on the surface of the resin
formed body. In this case, an imidazolium salt bath can be
advantageously used. An imidazolium salt bath can be used even at
relatively low temperature without affecting the resin.
[0046] As the imidazolium salt, a salt containing an imidazolium
cation having an alkyl group at the 1, 3 position can be
advantageously used. In particular, an aluminum
chloride-1-ethyl-3-methylimdazolium chloride
(AlCl.sub.3-EMIC)-based molten salt is most advantageously used
because it has high stability and therefore is less likely to
decompose. Plating can be performed on urethane-resin foam,
melamine-resin foam, and the like. The temperature of the
molten-salt bath is 10.degree. C. to 100.degree. C., desirably
25.degree. C. to 45.degree. C. As the temperature decreases to low
temperature, the range of electric-current density that enables
plating is narrowed, so that it becomes difficult to perform
plating on the entire surface of the resin formed body. A high
temperature exceeding 100.degree. C. tends to create a problem of
impairing the shape of the resin used as the base body.
[0047] When a base body having a high melting point, such as a
steel tape, is used, an inorganic-salt bath can also be used as the
molten salt. The inorganic-salt bath is typically a salt of a
two-constituent system or multiconstituent system of
AlCl.sub.3--XCl (X: alkali metal). The foregoing inorganic-salt
bath generally has a high melting temperature in comparison with an
organic-salt bath such as an imidazolium salt bath but has few
limitations on environmental conditions such as moisture and
oxygen, thereby enabling the practical use at a low cost as a
whole.
[0048] To enhance the smoothness and glossiness of a film of
aluminum plating formed on the surface of a base body, an additive
such as xylene, benzene, toluene, and 1,10-phenanthroline may be
added. In particular, 1,10-phenanthroline can be advantageously
used. It is desirable that the amount of addition of the
above-described additive be 0.25 to 7 g/L. When the amount is 0.25
g/L or more, a sufficiently smooth film of aluminum plating can be
obtained. When 7 g/L or less, a decrease in plating efficiency can
be suppressed.
[0049] In the following, a further detailed explanation of the
present invention is given by referring to the drawing as
appropriate.
[0050] FIG. 1 is a diagram showing an example of the structure of
the aluminum-plating apparatus of the present invention. As shown
in FIG. 1, in the aluminum-plating apparatus of the present
invention, a plating bath 102 containing a plating liquid is
divided into a first electrolysis chamber 104 and a second
electrolysis chamber 105 by a partition plate 103. A base body 101
is conveyed continuously from the first electrolysis chamber 104 to
the second electrolysis chamber 105.
[0051] The partition plate 103 is provided to electrically separate
the first electrolysis chamber 104 and the second electrolysis
chamber 105. An insulating partition plate can be advantageously
used. For example, Teflon (registered trademark), ceramics, glass,
a super engineering plastic such as polyether ether ketone (PEEK),
and a heat-resistant vinyl chloride resin can be used.
[0052] The partition plate 103 is provided with a passing aperture
for the base body. It is desirable that the passing aperture have
the minimum possible dimension only allowing the passing of the
base body. For example, it is desirable that the passing aperture
for the base body have the shape of a slit.
[0053] The first electrolysis chamber 104, to which the base body
101 is conveyed initially, is provided with negative electrodes
107, which are electrically connected in such a way that the base
body 101 acts as a positive electrode in the first electrolysis
chamber 104. This configuration creates electrolysis between the
negative electrodes 107 and the base body 101. As a result, a metal
oxide film formed on the surface of the base body 101 is
electrolytically removed, so that the surface of the metal forming
the base body 101 is exposed.
[0054] The negative electrodes 107 are not particularly limited.
For example, aluminum, titanium, and copper can be advantageously
used.
[0055] FIG. 1 shows, as an example, the case where two negative
electrodes 107 are provided: one above the base body 101 and the
other below. Nevertheless, the number of the negative electrodes
107 is not particularly limited. One electrode or three or more
electrodes may be employed. The location at which the negative
electrodes 107 are provided is not particularly limited. However,
it is desirable to provide them at a position closest possible to
the base body 101 so that the electrolysis can occur
effectively.
[0056] To cause the base body 101 to act as the positive electrode
in the first electrolysis chamber 104, the terminal of the positive
electrode of the power source connected to the negative electrodes
107 is connected to the base body 101. In this case, to cause the
electrolysis to occur effectively, it is desirable that the base
body 101 be connected to the positive electrode at the upstream
side in the vicinity of the entrance of the first electrolysis
chamber 104.
[0057] FIG. 1 shows the case where a first electricity supply
roller 106 is provided at the upstream side of the entrance of the
first electrolysis chamber 104 and is connected to the positive
electrode of the power source. By employing this configuration,
while the base body 101 is being continuously conveyed by the first
electricity supply roller 106 and a first conveying roller 110, an
electric potential is given to the base body 101 by the first
electricity supply roller 106, so that the base body 101 acts as
the positive electrode in the first electrolysis chamber 104. FIG.
1 shows the case where the first conveying roller 110 is provided
at the opposite side of the first electricity supply roller 106.
Nevertheless, in place of the first conveying roller 110, an
electricity supply roller connected to the positive electrode may
be provided.
[0058] The quantity of the metal oxide film to be electrolytically
removed in the first electrolysis chamber 104 can be adjusted as
appropriate according to the quantity of the oxide film formed on
the base body 101. For example, in the case where the base body is
made of aluminum, the quantity of deposition or the quantity of
dissolution of aluminum can be adjusted based on the following
equation:
the quantity of deposition of aluminum/the quantity of dissolution
of aluminum [g]=0.3352.times.I [A].times.t [Hr] (Equation).
[0059] In the above equation, "I" denotes the current value and "t"
denotes time. The constant 0.3352 is a constant specific to
aluminum, and when the base body is made of another metal, the
constant can be changed to the constant specific to that metal to
carry out the calculation.
[0060] Subsequently, the base body 101 whose metal oxide film is
removed as described above is conveyed to the second electrolysis
chamber 105 through the slit formed in the partition plate 103. The
second electrolysis chamber 105 is provided with positive
electrodes 109, which are electrically connected in such a way that
the base body 101 acts as a negative electrode in the second
electrolysis chamber 105. This configuration creates electrolysis
between the positive electrodes 109 and the base body 101. As a
result, aluminum is electrodeposited on the surface of the base
body 101.
[0061] As described above, the metal oxide film formed on the
surface of the base body 101 is removed in the first electrolysis
chamber 104. Consequently, a uniform aluminum plating can be formed
on the surface of the base body 101 in the second electrolysis
chamber 105.
[0062] The positive electrodes 109 are not particularly limited.
For example, aluminum, titanium, and copper can be advantageously
used.
[0063] As in the case of the negative electrodes 107, FIG. 1 shows,
as an example, the case where two positive electrodes 109 are
provided: one above the base body 101 and the other below.
Nevertheless, the number of the positive electrodes 109 is not
particularly limited. One electrode or three or more electrodes may
be employed. The location at which the positive electrodes 109 are
provided is not particularly limited. However, it is desirable to
provide them at a position closest possible to the base body 101 so
that the electrolysis can occur effectively.
[0064] To cause the base body 101 to act as the negative electrode
in the second electrolysis chamber 105, the terminal of the
negative electrode of the power source connected to the positive
electrodes 109 is connected to the base body 101. In this case, to
cause the electrolysis to occur effectively, it is desirable that
the base body 101 be connected to the negative electrode at the
downstream side in the vicinity of the exit of the second
electrolysis chamber 105.
[0065] FIG. 1 shows the case where a second electricity supply
roller 108 is provided at the downstream side of the exit of the
second electrolysis chamber 105 and is connected to the negative
electrode of the power source. By employing this configuration,
while the base body 101 is being continuously conveyed by the
second electricity supply roller 108 and a second conveying roller
111, an electric potential is given to the base body 101 by the
second electricity supply roller 108, so that the base body 101
acts as the negative electrode in the second electrolysis chamber
105. FIG. 1 shows the case where the second conveying roller 111 is
provided at the opposite side of the second electricity supply
roller 108. Nevertheless, in place of the second conveying roller
111, an electricity supply roller connected to the negative
electrode may be provided.
[0066] The quantity of the aluminum to be deposited in the second
electrolysis chamber 105 can be calculated by using the
above-described equation. Consequently, the current value and time
can be adjusted in such a way that a desired quantity of aluminum
is electrodeposited on the surface of the base body 101. The time
can be adjusted by changing the conveying speed for the base body
101.
[0067] As described above, by using the aluminum-plating apparatus
of the present invention, an aluminum plating can be satisfactorily
formed even on the surface of a base body that has a surface on
which an insulating or poorly conductive metal oxide film or the
like is formed.
[0068] In the case where aluminum plating is performed on a long
base body such as a steel tape and a sheet composed of a resin
formed body having a three-dimensional network structure, the use
of the aluminum-plating apparatus of the present invention can
effectively produce a product by increasing the line speed.
[0069] In the case of the conventional aluminum-plating apparatus
equipped with one plating bath, when it is intended to increase the
production capacity by increasing the line speed, it can be
conceived to increase the length of the positive electrode. For
example, when the plating is performed vertically, the plating bath
is deepened, and when the plating is performed horizontally, the
plating bath is lengthened. Actually, however, the length of the
positive electrode effective for the plating has a limitation. More
specifically, although the plating is performed at a high current
density at the position close to the conductor roll, the plating is
not performed at the position far from the conductor roll.
Consequently, in an apparatus equipped with one plating bath, the
increase in line speed has a limitation, so that the production
capacity cannot be increased.
[0070] For that reason, it can be conceived to increase the line
speed by constituting the plating bath with two or more baths.
However, even when two or more conventional plating apparatuses are
installed in tandem to carry out continuous operation, in the case
of a metal that is likely to form an oxide film on its surface,
such as aluminum, the film formed in the plating bath in the
preceding position cannot be satisfactorily plated with aluminum,
which is a problem. More specifically, an oxide film is formed on
the surface of aluminum at the space between the plating baths.
When an oxide film is formed, aluminum is deposited in the form of
islands. In other words, plating cannot be performed
satisfactorily. Even when the space between the plating baths is
filled with an N.sub.2 or other inert atmosphere, oxygen cannot be
removed completely and remains at an amount on the order of ppm.
Even when aluminum is exposed to such a minute amount of oxygen as
described above, an oxide film (a passive film) is formed on the
surface of aluminum.
[0071] To evade the above-described problem, the aluminum-plating
apparatus of the present invention can remove, in the first
electrolysis chamber, an oxide film formed on the surface of
aluminum. Consequently, when two or more aluminum-plating
apparatuses are provided in series in the conveying direction for
the base body, the second and subsequent baths, also, can form a
smooth and good-quality aluminum plating. By using an
aluminum-plating apparatus in which two or more aluminum-plating
apparatuses described above are provided in series in the conveying
direction for the base body, the line speed of the base body can be
increased and hence the production efficiency of the product can be
increased. Because the foregoing aluminum-plating apparatus
performs aluminum plating continuously using multiple
aluminum-plating apparatuses, only one set of incidental equipment,
such as a supplying facility and a taking-up facility for the base
body, is necessary, so that the investment for the equipment can be
reduced significantly.
[0072] The number of aluminum apparatuses provided in series is not
particularly limited. The number can be selected as appropriate
according to the purpose, such as the thickness of a layer of
aluminum plating to be formed. For example, when a resin formed
body having a three-dimensional network structure is used as the
base body, the providing of 2 to 20 or so aluminum-plating
apparatuses can effectively produce an aluminum porous body.
[0073] When a resin formed body having a three-dimensional network
structure having undergone conductive treatment by coating carbon,
for example, is used as the base body, a conventional
aluminum-plating apparatus may be provided at a preceding positon
of the above-described aluminum-plating apparatus of the present
invention, the preceding positon being the most upstream position
in the conveying direction for the base body. As for the
conventional aluminum-plating apparatus, an aluminum-plating
apparatus described below can be advantageously used. The
aluminum-plating apparatus electrodeposits aluminum onto the base
body by passing the base body 101 through the plating bath 202 as
shown in FIG. 2 and has a feature in that in the plating bath 202,
positive electrodes 209 provided in the plating bath 202 are
electrically connected with the above-described base body 101 in
such a way that the above-described base body 101 acts as a
negative electrode.
[0074] In other words, the aluminum-plating apparatus of the
present invention has an aluminum-plating apparatus: [0075] that is
positioned at a preceding positon of the above-described
aluminum-plating apparatus, the preceding positon being the most
upstream position in a direction that the above-described base body
is conveyed; [0076] that electrodeposits aluminum onto the
above-described base body by conveying the above-described base
body in a plating bath; and [0077] that has a feature in that in
the plating bath, which is provided with a positive electrode, the
positive electrode is electrically connected with the
above-described base body in such a way that the above-described
base body acts as a negative electrode. By performing aluminum
plating by placing the above-described aluminum-plating apparatus
of the present invention, which is provided with the first
electrolysis chamber that performs reverse electrolysis, in series
with the second or subsequent aluminum-plating apparatus in the
aluminum-plating apparatuses arranged in series as described above,
a uniform and good-quality aluminum plating can be formed on the
base body effectively. In addition, as described above, the
aluminum-plating apparatus of the present invention enables the
providing of only one set of incidental equipment, such as a
supplying facility and a taking-up facility for the base body, so
that the investment for the equipment can be reduced
significantly.
EXAMPLES
[0078] In the following, a further detailed explanation of the
present invention is given based on examples. These examples are
illustrative and not limit the aluminum-plating apparatus and the
like of the present invention. The scope of the present invention
is shown by the scope of the claims and covers all revisions and
modifications included within the meaning and scope equivalent to
the scope of the claims.
Example 1
[0079] Ten aluminum apparatuses of the present invention shown in
FIG. 1 were placed in series to form a film of aluminum plating on
a base body.
Base Body
[0080] As the base body, a resin formed body was used that had a
three-dimensional network structure having a surface on which an
aluminum film was formed by the sputtering process.
[0081] As the resin formed body having a three-dimensional network
structure, a foamed-urethane resin formed body having a porosity of
95%, the number of pores (the number of cells) per inch of about
50, a pore diameter of about 550 .mu.m, a width of 500 mm, and a
thickness of 1 mm was used. Conductive treatment was performed by
forming an aluminum film having a coating weight of 10 g/m.sup.2 on
the foamed-urethane resin formed body by the sputtering
process.
[0082] It was confirmed that an aluminum oxide film of 30 nm was
formed in the aluminum film on the surface of the resin formed
body.
Aluminum-Plating Apparatus
[0083] Ten aluminum apparatuses of the present invention shown in
FIG. 1 were prepared to be placed in series. The space between the
aluminum-plating apparatuses was filled with nitrogen to form an
inert atmosphere. The rotation speed of the roller was adjusted in
such a way that the line speed of the base body to be conveyed
became 0.1 to 1.0 m/min. The structure of the individual aluminum
apparatus is described below.
Molten-Salt Bath
[0084] A molten-salt bath having a composition of 33-mol % EMIC and
67-mol % AlCl.sub.3 was produced by mixing them in a nitrogen
atmosphere. In addition, 1,10-phenanthroline was added such that it
had a concentration of 0.5 g/L.
[0085] Furthermore, nitrogen was introduced into the plating liquid
to prevent the formation of an oxide film during the
electrodepositing of aluminum.
Partition Plate
[0086] A partition plate made of Teflon (registered trademark) was
placed in the plating bath to partition the plating bath into a
first electrolysis chamber and a second electrolysis chamber. A
partition plate was provided with a slit, which had a width of 560
mm and a height of 5 mm, to be used as a passing aperture for the
base body.
First Electricity Supply Roller
[0087] A first electricity supply roller made of aluminum was used,
the center of the roller being connected to the terminal of the
positive electrode of a power source.
Negative Electrode
[0088] Negative electrodes made of aluminum were placed in the
first electrolysis chamber. As shown in FIG. 1, the negative
electrodes were placed at two positions: one above the base body
and the other below.
First Electrolysis Chamber
[0089] To create electrolysis between the base body and the
negative electrodes in the first electrolysis chamber, a current
density was set at 10 A/dm.sup.2.
Second Electricity Supply Roller
[0090] A second electricity supply roller made of aluminum was
used, the center of the roller being connected to the terminal of
the negative electrode of a power source.
Positive Electrode
[0091] Positive electrodes made of aluminum were placed in the
second electrolysis chamber. As shown in FIG. 1, the positive
electrodes were placed at two positions: one above the base body
and the other below.
Second Electrolysis Chamber
[0092] To create electrolysis between the base body and the
positive electrodes in the second electrolysis chamber, a current
density was set at 5 A/dm.sup.2.
[0093] The base body having undergone conductive treatment as
described above was conveyed continuously into the ten aluminum
apparatuses each having the above-described structure to form a
film of aluminum plating on the surface of the base body. This
operation formed an aluminum film of 10 .mu.m on the surface of the
base body. The formed film of plating was a uniform and
good-quality film.
[0094] As described above, it was confirmed that even when the
operation uses a base body that has a surface on which an aluminum
oxide film is formed, the use of the aluminum-plating apparatus of
the present invention can further form a good-quality film of
aluminum plating.
Example 2
[0095] As shown in FIG. 2, a conventional aluminum-plating
apparatus was placed at the most upstream side in the conveying
direction for the base body. Nine aluminum apparatuses of the
present invention used in Example 1 were placed in series at the
downstream side of the above-described conventional
aluminum-plating apparatus to form a film of aluminum plating on a
base body.
Base Body
[0096] A resin formed body having the same three-dimensional
network structure as that employed in Example 1 was used.
[0097] Conductive treatment of the resin formed body was carried
out by coating a carbon paint as a conductive paint on the surface
of a resinous porous body. The carbon paint contained 25% carbon
particles, a resin binder, an introfier, and an antifoaming agent.
The carbon black had a particle diameter of 0.5 .mu.m.
Aluminum-Plating Apparatus
[0098] The conventional aluminum-plating apparatus placed at the
most upstream side in the conveying direction for the base body had
the same structure as that of the second electrolysis chamber in
the aluminum-plating apparatus used in Example 1. More
specifically, the plating liquid, the electricity supply roller,
and the positive electrodes respectively had the same structure as
that of the plating liquid, the second electricity supply roller,
and the positive electrodes all used in Example 1.
[0099] The second and subsequent aluminum-plating apparatuses had
the same structure as that of the aluminum-plating apparatuses used
in Example 1. Nine apparatuses as described above were placed in
series.
[0100] Observation of the base body having a surface on which a
film of aluminum plating was formed revealed that an aluminum film
of 10 .mu.m was formed on the surface of the base body and that the
formed film of plating was a uniform and good-quality film.
Comparative Example 1
[0101] A film of aluminum plating was formed on the surface of a
base body through the same procedure as that used in Example 1,
except that as the aluminum-plating apparatus, 10 conventional
aluminum-plating apparatuses were used by placing them in series.
As for the conventional aluminum-plating apparatuses, the
aluminum-plating apparatus placed at the most upstream side in
Example 2 were used. As with Example 1, the space between the
aluminum-plating apparatuses was filled with nitrogen to form an
inert atmosphere.
[0102] Observation of the film of aluminum plating formed on the
surface of the base body revealed that the deposition created the
shape of islands and that the film was inferior in quality to the
film formed by using the apparatus of Example 1.
Comparative Example 2
[0103] A film of aluminum plating was formed on the surface of a
base body through the same procedure as that used in Example 2,
except that as the aluminum-plating apparatus, 10 conventional
aluminum-plating apparatuses were used by placing them in series.
As for the conventional aluminum-plating apparatuses, the
aluminum-plating apparatus placed at the most upstream side in
Example 2 were used. As with Example 2, the space between the
aluminum-plating apparatuses was filled with nitrogen to form an
inert atmosphere.
[0104] Observation of the film of aluminum plating formed on the
surface of the base body revealed that the deposition created the
shape of islands and that the film was inferior in quality to the
film formed by using the apparatus of Example 2.
REFERENCE SIGNS LIST
[0105] 101: Base body [0106] 102: Plating bath [0107] 103:
Partition plate [0108] 104: First electrolysis chamber [0109] 105:
Second electrolysis chamber [0110] 106: First electricity supply
roller [0111] 107: Negative electrode [0112] 108: Second
electricity supply roller [0113] 109: Positive electrode [0114]
110: Second conveying roller [0115] 111: Second conveying roller
[0116] 202: Plating bath [0117] 208: Electricity supply roller
[0118] 209: Positive electrode
* * * * *