WO2014061442A1 - Aluminum film, article having aluminum film formed thereon, and method for producing aluminum film - Google Patents

Abstract

An aluminum film which is a film of polycrystalline aluminum and is composed of aluminum crystal particles, wherein aluminum carbide particles exist at the interfaces among the aluminum crystal particles. The aluminum film can be produced by: carrying out electrolysis using an electrolytic solution that is produced by dissolving an organic substance in a molten salt, thereby electrodepositing an aluminum film containing the organic substance on a base; and then heating the aluminum film, thereby forming aluminum carbide particles in the aluminum film.

Description

Aluminum film, aluminum film forming body, and method for producing aluminum film

The present invention relates to an aluminum film containing aluminum carbide formed on the surface of a base material in order to improve the wear resistance of the base material, and a method for producing the same.

Aluminum is poor in wear resistance, and it is difficult to use it as a sliding member such as a gear or a shaft or a lightweight polishing tool. Various proposals have been made as methods for improving the wear resistance of aluminum.

For example, in Patent Document 1 (Japanese Patent Laid-Open No. 2009-41087), a powder mixture obtained by mechanically mixing aluminum powder and stearic acid is sintered by a discharge plasma sintering method and molded. It describes that an aluminum sintered body is produced by reacting aluminum and stearic acid to produce aluminum oxide and aluminum carbide.

In Patent Document 2 (Japanese Patent Laid-Open No. 2003-343702), a viscous material obtained by mixing an organic binder with an aluminum fine powder is applied to the surface of aluminum, and after drying, is heated to 300 ° C. or higher in a non-oxidizing or neutral atmosphere. A method in which the organic binder is carbonized by heating in the range of 600 ° C., and the activated carbon and aluminum fine powder are reacted to form a high-hardness aluminum carbide coating on the surface of the aluminum base to harden the aluminum surface. Is described.

JP 2009-41087A JP 2003-343702 A

According to the method described in Patent Document 1, aluminum and stearic acid react (solid phase reaction) at a high temperature during sintering to produce aluminum oxide (Al ₂ O ₃ ) and aluminum carbide (Al ₄ C ₃ ). In addition, since the aluminum oxide and aluminum carbide that are hard and excellent in thermal stability are finely dispersed in the sintered body of pure aluminum powder, a sintered body having high hardness can be obtained. However, this method requires a molding die and requires a sintering step, which increases costs. This method is not versatile because it does not increase the surface hardness by treating the surface of an aluminum molded product.

The method described in Patent Document 2 is versatile because it treats the surface of an aluminum molded article to increase the surface hardness. However, according to the description of Patent Document 2, what is obtained by this method is that in which an aluminum base material and an aluminum carbide layer are joined. Aluminum carbide has the property of reacting with water at room temperature to produce methane and aluminum hydroxide, and has a problem of poor stability.

In view of the above problems, an object of the present invention is to provide a high hardness aluminum film and a manufacturing method for manufacturing the high hardness aluminum film.

In the electrolysis using a molten salt electrolytic solution (sometimes abbreviated as molten salt electrolysis), the present inventors have used aluminum containing organic matter on the surface of a substrate such as aluminum by using a molten salt electrolytic solution containing organic matter. The present invention was completed by finding that an aluminum film having a structure having a structure in which fine aluminum carbide (Al ₄ C ₃ ) particles are dispersed in aluminum can be obtained by forming a plating film and then heating the plating film. .

The present invention adopts the following configuration in order to solve the above problems.
(1) A polycrystalline aluminum film composed of aluminum crystal particles,
An aluminum film in which aluminum carbide particles are present at the interface between the aluminum crystal particles.
With the configuration (1) above, the aluminum film has a high hardness, and the wear resistance can be improved.
(2) The aluminum film according to (1), wherein the volume average particle diameter of the aluminum crystal particles is 1 μm to 10 μm, and the volume average particle diameter of the aluminum carbide particles is 150 nm or less.
With the configuration (2), the aluminum film has better hardness and wear resistance.
(3) The aluminum film according to (1) or (2), wherein the content of the aluminum carbide contained in the aluminum film is 0.2% by mass to 50% by mass.
With the configuration (3), the aluminum film has good hardness without deteriorating the characteristics of the aluminum film.
(4) An aluminum film forming body in which the aluminum film according to any one of (1) to (3) is formed on a base material made of aluminum.
With the configuration (4), the surface hardness of a product based on a material containing aluminum can be increased.
(5) Electrolyzing using an electrolytic solution obtained by dissolving an organic substance in a molten salt to electrodeposit an aluminum film containing the organic substance on a substrate, and then heat-treating the aluminum film, A method for producing an aluminum film, wherein aluminum carbide particles are produced in the aluminum film.
With the configuration (5), a high hardness aluminum film can be formed on the substrate.
(6) The base material is made of aluminum, and the aluminum oxide film present on the surface of the base material is removed, and the aluminum oxide film is eluted in the molten salt by performing molten salt electrolysis using the base material as an anode. The manufacturing method of the aluminum film of Claim 5 performed by doing.
With the configuration (6), the adhesion between the substrate and the aluminum film is improved, and a homogeneous aluminum film is formed.

According to the present invention, a high hardness aluminum film can be formed on the surface of a substrate.

It is a figure which shows an example of the manufacturing apparatus of the aluminum film of this invention. It is a figure which shows the transmission electron microscope (Transmission Electron Microscope; TEM) photograph of the aluminum film of this invention. It is a figure which shows the relationship between the overvoltage and the density | concentration of organic substance (smoothing agent). It is a figure which shows the relationship between organic substance (smoothing agent) density | concentration and content of aluminum carbide. It is a figure which shows an example of the aluminum plating apparatus of this invention.

The aluminum plating film of the present invention is obtained by electrolyzing a molten salt obtained by dissolving an organic substance on a substrate as an electrolytic solution and electrodepositing aluminum on the cathode.
An organic molten salt or an inorganic molten salt can be used as the molten salt, and an organic molten salt that is a eutectic salt of an organic halide and an aluminum halide can be used as the organic molten salt. Examples of organic halides include imidazolium salts and pyridinium salts (such as butylpyridinium chloride (BPC)), and specific examples of molten salts include aluminum chloride and alkylimidazolium chloride, or aluminum chloride and Molten salts containing alkylpyridinium chloride are preferred.

Of these, an imidazolium salt is preferable, and a salt containing an imidazolium cation having an alkyl group (having 1 to 5 carbon atoms) at the 1,3-position is preferably used. In particular, aluminum chloride-1-ethyl-3-methylimidazolium chloride (AlCl ₃ -EMIC) type molten salt is most preferably used because of its high stability and resistance to decomposition and high electrical conductivity. The temperature of the molten salt bath is 10 ° C to 100 ° C, preferably 25 ° C to 45 ° C. The higher the temperature, the wider the current density range that can be plated, and by setting it to 100 ° C. or lower, the heating cost is reduced and the decomposition of the molten salt can be suppressed.
As the pyridinium salt, butylpyridinium chloride (BPC) or the like can be used.

As the inorganic molten salt, an eutectic salt of an alkali metal halide and an aluminum halide (AlCl ₃ -XCl (X: alkali metal)) can be used. Such an inorganic molten salt generally has a higher melting temperature than an organic salt bath such as an imidazolium salt bath, but is less restricted by environmental conditions such as moisture and oxygen, and can be put into practical use at a low cost overall. .
However, in the present invention, an organic substance is added to the molten salt as described later. However, since the inorganic molten salt has a high melting point, it is necessary to increase the temperature of the plating solution, and the organic substance may volatilize and decompose at a high temperature. It is preferable to use an organic molten salt that melts at a low temperature.

An organic material added to the electrolytic solution is taken into the aluminum plating film obtained by electrolysis.
The aluminum plating film formed on the substrate is heat-treated in the next step.
By performing the heat treatment, the organic matter taken into the aluminum plating film is decomposed and reacted with aluminum constituting the aluminum plating film to form fine aluminum carbide particles.
Since the organic substance is dissolved in the molten salt and is uniformly taken in as a molecule into the plating film, the aluminum carbide particles generated by the above reaction are uniformly dispersed in the aluminum. The aluminum carbide particles are present in the interstices between the aluminum crystal particles.

FIG. 2 is a TEM photograph of the aluminum film of the present invention (aluminum carbide particles are present in a portion surrounded by a square), and a grain size of about 100 nm is formed at a grain boundary portion of aluminum particles having a diameter of about 1 μm to 10 μm. It can be seen that fine particles of aluminum carbide having a diameter are uniformly dispersed.
The aluminum film may be an aluminum alloy film containing iron, copper, manganese, chromium, titanium, and magnesium in addition to aluminum as a metal component. The aluminum alloy coating can be obtained by performing electrolysis by adding iron, copper, manganese, chromium, titanium, and magnesium as metal components to the electrolytic solution.

The atmosphere for the heat treatment may be an air atmosphere.
The heating temperature and the heating time may be appropriately set depending on the concentration of the organic substance in the aluminum plating film, and are usually 570 ° C. to 640 ° C. and 5 minutes to 30 minutes.

Since a part of the organic matter is taken into the plating film during the plating process, the concentration of the organic matter in the electrolytic solution decreases as the plating proceeds. Therefore, in order to allow a predetermined amount of organic matter to be taken into the plating film, it is necessary to maintain the concentration of the organic matter in the electrolytic solution within a predetermined setting range.
For this reason, it is necessary to monitor the concentration of the organic substance in the electrolytic solution. The concentration of the organic substance in the electrolytic solution measures the overvoltage, and based on this measured value, the organic substance can be obtained in a predetermined range. Can be adjusted by adding to the electrolyte. Monitoring may be performed continuously or at intervals.

The overvoltage is the absolute value of the potential difference between the theoretical potential (equilibrium electrode potential) at which the aluminum electrodeposition reaction occurs and the electrode potential when the aluminum electrodeposition reaction actually starts. Since the absolute value of the potential difference reflects the concentration of the organic substance, the concentration of the organic substance in the electrolytic solution can be controlled by adjusting the amount of the organic substance added so that the overvoltage is within a predetermined range.

Any organic substance can be used as long as it is soluble in the molten salt.
If the concentration of the organic substance in the electrolytic solution is high, the concentration of the organic substance taken into the aluminum plating film also increases, the content of aluminum carbide in the aluminum film increases, and the hardness of the aluminum film also increases. The hardness of the aluminum film can be appropriately set by adjusting the content of aluminum carbide according to the application.
The concentration of the organic substance is set so that the content of aluminum carbide in the aluminum film is 0.2 mass% to 50 mass%, preferably 2 mass% to 10 mass%.

For applications such as sliding materials, the aluminum film preferably has a smooth surface.
In order to make the aluminum plating film have a smooth surface, it is preferable to add an organic substance (smoothing agent) having a function of smoothing the surface of the plating film to the molten salt electrolyte.

Examples of the organic substance that serves as a smoothing agent (hereinafter also referred to as a smoothing agent) include benzene, xylene, pyridinebenzotriazole, polystyrene, 1,10-phenanthroline, and the like, which can be appropriately selected depending on the type of the molten salt.
When using AlCl ₃ -EMIC as the molten salt, 1,10-phenanthroline is particularly preferably used.

FIG. 3 shows the relationship between the overvoltage and the concentration of the smoothing agent when AlCl ₃ -EMIC is used as the molten salt and 1,10-phenanthroline (denoted as “phen” in the figure) is used as the smoothing agent. Show. The concentration of 1,10-phenanthroline is indicated by the mass with respect to the plating solution.
FIG. 4 shows the relationship between the concentration of the leveling agent and the content of aluminum carbide when AlCl ₃ -EMIC is used as the molten salt and 1,10-phenanthroline is used as the leveling agent.
The content of aluminum carbide in the aluminum film can be controlled by measuring the overvoltage and adjusting the concentration of the organic matter (smoothing agent) in the electrolyte based on this signal.

As the base material for forming the aluminum film, an appropriate one can be selected. However, the main object of the present invention is to improve the wear resistance of the aluminum base material among the base materials. Is preferably used.
However, when the substrate is made of aluminum, an aluminum oxide film is usually present on the surface of the aluminum, so the adhesion between the aluminum plating film and the aluminum substrate is not good, and the aluminum film is easy to peel off. . Therefore, in order to improve the adhesion of the aluminum film to the base material, the oxide film present on the surface of the aluminum base material is removed by reverse electrolytic treatment or the like, and then the base material is subjected to molten salt electrolytic treatment to form the aluminum film. It is preferable to form.
In the reverse electrolysis treatment, the oxide film on the surface of the aluminum substrate is eluted in the molten salt by performing an electrolytic treatment using the aluminum substrate having an oxide film as an anode in a molten salt electrolytic bath.
On the other hand, when an aluminum film is isolated, it is preferable that an aluminum oxide film is present.

FIG. 1 is a diagram showing the configuration of an apparatus for maintaining the concentration of organic matter in a molten salt electrolyte at a set value.
As shown in FIG. 1, the electrolytic solution in which the organic matter has been reduced by electrodeposition overflows from the electrolytic cell 1, is continuously returned to the recovered electrolytic solution tank 21, and then sent to the replenisher storage tank 22. An organic substance storage tank 23 is connected to the recovered electrolyte tank 21, and a supply valve 24 is controlled by a control signal from a control device 25 that sends a control signal based on an overvoltage signal, whereby a predetermined amount of organic substance is recovered from the organic substance storage tank 23. The organic substance concentration in the electrolytic solution is adjusted by being supplied to the electrolytic solution tank 21. Next, the electrolytic solution is supplied from the replenisher storage tank 22 to the electrolytic tank 1 after removing solids in the liquid by the filter 26. Further, since the liquid temperature rises due to electrolysis, a cooling device may be provided to cool the electrolytic solution.

The overvoltage is measured by taking out the potential difference between the voltage between the aluminum substrate (cathode) and the anode in the electrolytic cell 1 and the theoretical potential (equilibrium electrode potential), that is, the overvoltage as an electric signal, and controlling the overvoltage and the set voltage. The amount of supply of the smoothing agent to the replenishing liquid storage tank 22 is controlled by adjusting the opening of the organic substance supply valve so that the overvoltage becomes a set value.

If moisture or oxygen is mixed in the molten salt, the molten salt will deteriorate or plating will not be performed properly. Therefore, electrolysis is performed in an inert gas atmosphere such as nitrogen or argon, and in a sealed environment. It is preferable.
Specifically, the surface of the plating bath of the electrolytic cell 1 is covered and an inert gas is bubbled from below the electrolytic cell 1 to stir the electrolytic solution and expel moisture and oxygen contained in the electrolytic solution, The space on the electrolyte surface is a nitrogen gas atmosphere. Further, instead of the lid, a shielding plate may be suspended on the surface of the electrolytic solution to shut out the outside air, or an inert gas may be supplied from above the electrolytic cell 1.

In the aluminum plating in the present invention, it is preferable to perform electroplating while adjusting the temperature of the plating bath to be 60 ° C to 120 ° C. By setting the temperature of the plating bath to 60 ° C. or higher, the viscosity of the plating bath can be sufficiently lowered, and the plating efficiency can be improved. Moreover, volatilization of aluminum chloride can be suppressed by setting it to 120 degrees C or less. The temperature of the plating bath is more preferably 60 ° C. to 100 ° C., and further preferably 60 ° C. to 80 ° C.

In addition, when aluminum is used as the base material, since a metal oxide film or the like having a low insulating or low electrical conductivity is usually formed on the surface, the surface should be uniformly energized even if it is to be electrodeposited. In some cases, a uniform aluminum film cannot be formed. The apparatus shown in FIG. 5 is a view showing an example of an apparatus in which a metal oxide film on an aluminum surface of a base material is removed in advance and aluminum plating is performed so that a homogeneous aluminum film can be formed.

As shown in FIG. 5, in the aluminum plating apparatus of the present invention, a plating tank (102) in which a plating solution is accommodated is divided into a first electrolytic chamber (104) and a second electrolytic chamber (105) by a partition plate (103). It is divided into. The substrate (101) is continuously conveyed from the first electrolysis chamber (104) to the second electrolysis chamber (105).

The partition plate (103) is provided for the purpose of electrically separating the first electrolysis chamber (104) and the second electrolysis chamber (105), and an insulating material can be preferably used. For example, Teflon (registered trademark), ceramics, glass, super engineering plastic such as PEEK (polyetheretherketone), heat-resistant vinyl chloride resin, or the like can be used.
In addition, the partition plate (103) is provided with a passage through the base, but the passage is preferably the minimum through which the base can pass. For example, it is preferable that the passage of the substrate has a slit shape.

A cathode (107) is provided in the first electrolysis chamber (104) in which the substrate (101) is first transported, and the substrate (101) acts as an anode in the first electrolysis chamber (104). So that it is electrically connected. As a result, electrolysis occurs between the cathode (107) and the substrate (101), and the metal oxide film formed on the surface of the substrate (101) is removed by electrolysis, so that the metal surface constituting the substrate (101) is removed. Exposed.
The cathode (107) is not particularly limited, and for example, aluminum, titanium, copper or the like can be preferably used.

FIG. 5 illustrates the case where two cathodes (107) are provided in the vertical direction of the base body (101). However, the number of cathodes (107) is not particularly limited, and one or three or more are provided. It doesn't matter. Further, the position where the cathode (107) is provided is not particularly limited, but it is preferable that the cathode (107) is provided as close as possible to the base (101) because electrolysis occurs efficiently.

In order for the substrate (101) to act as an anode in the first electrolysis chamber (104), the anode terminal of the power source connected to the cathode (107) and the substrate (101) are connected. That's fine. At this time, it is preferable that the substrate (101) is connected to the anode on the upstream side in the vicinity of the inlet of the first electrolysis chamber (104) because electrolysis occurs efficiently.

FIG. 5 shows a case where a first power supply roller (106) is provided upstream of the inlet of the first electrolysis chamber (104), and the first power supply roller (106) is connected to the anode of the power source. ing. As a result, the substrate (101) is applied with a potential from the first power supply roller (106) while being continuously transported by the first power supply roller (106) and the first transport roller (110). It will act as an anode in the electrolysis chamber (104). FIG. 5 shows the case where the first conveying roller (110) is provided on the opposite side of the first power supply roller (106), but it is connected to the anode instead of the first conveying roller (110). A power feeding roller may be provided.

What is necessary is just to adjust suitably the quantity of the metal oxide film electrolytically removed in a 1st electrolysis chamber (104) according to the quantity of the oxide film currently formed on the base | substrate (101). For example, when the substrate is aluminum, the precipitation amount or dissolution amount of aluminum can be prepared based on the following formula.
Aluminum precipitation / electrolysis [g]
= 0.3352 × I [A] × t [Hr] (formula)
In the above formula, I represents a current value, t represents time, a constant 0.3352 is a constant peculiar to aluminum, and when the substrate is another metal, it is calculated by changing to a constant peculiar to that metal. Good.

The substrate (101) from which the metal oxide film has been removed as described above is subsequently conveyed to the second electrolysis chamber (105) through a slit provided in the partition plate (103). An anode (109) is provided in the second electrolysis chamber (105), and the base (101) is electrically connected so as to act as a cathode in the second electrolysis chamber (105). As a result, electrolysis occurs between the anode (109) and the substrate (101), and aluminum is electrodeposited on the surface of the substrate (101).

Since the metal oxide film formed on the surface of the base (101) as described above is removed in the first electrolysis chamber (104), the second electrolysis chamber (105) is formed on the surface of the base (101). It is possible to form a uniform aluminum plating.
The anode (109) is not particularly limited, and for example, aluminum, titanium, copper or the like can be preferably used.

As in the case of the cathode (107), FIG. 5 illustrates the case where two anodes (109) are provided in the vertical direction of the substrate (101), but the number of anodes (109) is not particularly limited. One or three or more may be used. Further, the position where the anode (109) is provided is not particularly limited, but it is preferable to provide the anode (109) as close to the substrate (101) as possible because electrolysis occurs efficiently.

In order for the substrate (101) to act as a cathode in the second electrolysis chamber (105), the cathode terminal of the power source connected to the anode (109) and the substrate (101) are connected. That's fine. At this time, it is preferable that the substrate (101) is connected to the cathode on the downstream side in the vicinity of the outlet of the second electrolysis chamber (105) because electrolysis occurs efficiently.

FIG. 5 shows a case where a second power supply roller (108) is provided downstream of the outlet of the second electrolysis chamber (105) and the second power supply roller (108) is connected to the cathode of the power source. ing. As a result, the substrate (101) is applied with a potential from the second power supply roller (108) while being continuously transported by the second power supply roller (108) and the second transport roller (111). It comes to act as a cathode in the electrolysis chamber (105). FIG. 5 shows the case where the second transport roller (111) is provided on the opposite side of the second power supply roller (108), but it is connected to the cathode instead of the second transport roller (111). A power feeding roller may be provided.

The amount of aluminum deposited in the second electrolysis chamber (105) can be calculated by the above formula. Therefore, the current value and time may be adjusted so that desired aluminum is electrodeposited on the surface of the substrate (101). The time can be adjusted by changing the conveyance speed of the substrate (101).

Hereinafter, the present invention will be described in more detail based on examples. However, these examples are merely examples, and the metal porous body of the present invention is not limited to these examples. The scope of the present invention is defined by the scope of the claims, and includes meanings equivalent to the scope of the claims and all modifications within the scope.

[Example 1]
(Plating process)
After removing the aluminum oxide film on the surface of the aluminum substrate (80 mm × 50 mm × 1 mmt) by reverse electrolysis, this was connected to the cathode side in the electrolytic cell, and the aluminum plate (purity 99.99%) of the counter electrode was connected to the anode side Then, plating was performed under the following electrolysis conditions while bubbling nitrogen from the bottom of the electrolytic cell at a flow rate of 0.2 L / min to form an aluminum plating film on the surface of the aluminum base plate. In the measurement of overvoltage, aluminum was used for the reference electrode and the counter electrode, and platinum was used for the working electrode.
The electrolysis conditions were as follows.
Molten salt composition: 33 mol% EMIC-66 mol% AlCl ₃
Organic matter: 1,10-phenanthroline Liquid temperature: 45 ° C
Current density: 2 A / dm ² (DC current)
Setting overvoltage: -120 mV to -140 mV
(Heat treatment process)
The obtained sample was heat-treated in the atmosphere at 600 ° C. for 20 minutes.
The film thickness of the obtained aluminum film, the aluminum carbide content in the aluminum film by X-ray diffraction (XRD), and the Vickers hardness of the aluminum film were evaluated. The evaluation results are shown in Table 1.

[Example 2]
An aluminum plating film was formed on the substrate in the same manner as in Example 1 except that the electrolysis conditions were as follows, and then the obtained sample was heat-treated in the atmosphere at 600 ° C. for 20 minutes.
For the sample obtained by the heat treatment, the film thickness of the aluminum film, the aluminum carbide content in the aluminum film by X-ray diffraction (XRD), and the Vickers hardness of the aluminum film were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.
(Electrolysis conditions)
Electrolyte composition: 33 mol% EMIC-66 mol% AlCl ₃
Organic matter (smoothing agent): Xylene liquid temperature: 45 ° C
Current density: 2 A / dm ² (DC current)
Setting overvoltage: -120 mV to -140 mV

[Example 3]
An aluminum plating film was formed on the substrate in the same manner as in Example 1 except that the electrolysis conditions were as follows, and then the obtained sample was heat-treated in the atmosphere at 600 ° C. for 20 minutes.
For the sample obtained by heat treatment, the film thickness of the aluminum film, the aluminum carbide content in the aluminum film by X-ray diffraction (XRD), and the Vickers hardness of the aluminum film were measured in the same manner as in Example 1. The evaluation results are shown in Table 1.
(Electrolysis conditions)
Electrolyte composition: 33 mol% EMIC-66 mol% AlCl ₃
Organic matter (smoothing agent): Toluene liquid temperature: 45 ° C
Current density: 2 A / dm ² (DC current)
Setting overvoltage: -120 mV to -140 mV

[Comparative Example 1]
In Example 1, an aluminum film was obtained in the same manner as in Example 1 except that no organic substance was added to the electrolytic solution, and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

DESCRIPTION OF SYMBOLS 1 Electrolysis tank 21 Recovery electrolyte tank 22 Replenishment liquid storage tank 23 Organic substance storage tank 24 Supply valve 25 Control device 26 Filter 101 Base 102 Plating tank 103 Partition plate 104 First electrolysis chamber 105 Second electrolysis chamber 106 First feeding roller 107 Cathode 108 Second power supply roller 109 Anode 110 Second transport roller 111 Second transport roller

Claims (6)

1. A polycrystalline aluminum film composed of aluminum crystal particles,
   An aluminum film in which aluminum carbide particles are present at the interface between the aluminum crystal particles.
2. 2. The aluminum film according to claim 1, wherein the volume average particle diameter of the aluminum crystal particles is 1 μm to 10 μm, and the volume average particle diameter of the aluminum carbide particles is 150 nm or less.
3. 3. The aluminum film according to claim 1, wherein a content of the aluminum carbide contained in the aluminum film is 0.2% by mass to 50% by mass.
4. An aluminum film forming body in which the aluminum film according to any one of claims 1 to 3 is formed on a base material made of aluminum.
5. By electrolysis using an electrolytic solution obtained by dissolving an organic substance in a molten salt, an aluminum film containing the organic substance is electrodeposited on a substrate,
   Next, a method for producing an aluminum film, wherein the aluminum film is heat-treated to produce aluminum carbide particles in the aluminum film.
6. The base material is made of aluminum, and the aluminum oxide film present on the surface of the base material is removed by eluting the aluminum oxide film into the molten salt by subjecting the base material to an anode and molten salt electrolysis. The manufacturing method of the aluminum film of Claim 5 to perform.

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