KR900002507B1 - Composite film formation method on the surface of aluminum material - Google Patents

Abstract

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Description

[Name of invention]

Composite film formation method on the surface of aluminum material

[Brief Description of Drawings]

1A to 1D are views for explaining the method according to the present invention and showing the process sequence of the method.

2A to 2C are views for explaining the change of the aluminum oxide film formed on the surface of the aluminum material as the processes of FIGS. 1A to 1D proceed.

3 is a view for explaining another example of nickel plating treatment in the method according to the present invention.

4A to 4C are graphs showing changes in film thickness with time over voltage in the process of forming the aluminum oxide film of the method according to the present invention.

5A to 5D are views for explaining the method of the second embodiment according to the present invention and showing the process sequence of the method.

6A to 6E are views for explaining the change of the aluminum oxide film formed on the surface of the aluminum material as the processes of FIGS. 5A to 5D are performed.

7A to 7E are views for explaining the method of the third embodiment according to the present invention, showing the process sequence of the method.

8A to 8F show changes in the aluminum oxide film formed on the surface of the aluminum material as the processes of FIGS. 7A to 7E proceed.

Detailed description of the invention

[Technical Field]

The present invention relates to a method for forming a high corrosion resistance and conductive film having a high hardness on the surface of the aluminum material.

[Background of invention]

Conventional cases for electronic calculators and telecommunication equipment are made of steel and the surface of the case has been subjected to surface treatment such as electroplating, nickel plating or conductive paint coating for electronic shielding and electrostatic shielding.

On the other hand, the light-weight member in which the highly corrosion-resistant aluminum oxide film was formed on the surface of the aluminum material is known under the trade name "ALUMITE". In order to make the aluminum oxide film conductive, nickel plating after the formation of the aluminum oxide film on the surface of the aluminum material has been announced (Fukuda and Fukushima, Ginjoku Zyogigi Jutsugen 뀨 -Sho, Ginjoku Hyomen Gijutsu in May 1982). "Deposition of Nickel and Zinc on Micropores in Anodized Aluminum Films"). According to the published paper, a voltage of 20 V was applied to an aluminum material immersed in 98 g / 1 sulfuric acid solution at 30 ° C. for 30 minutes, and then decreased from 20 V to 0.08 V in 4 minutes, and then to 0.08 V. It is maintained for 13 minutes and nickel electroplated at a current density of 0.5 A / dm 2 after 10 to 20 minutes after the carbon electrode and galvanic cell configuration.

When plating cases such as an electronic calculator by the conventional plating technology, there is a fear that plating failure occurs in the inner corners of the square structure such as the square pipes. The electroplated cases have a problem in that a whisker, a hairy crystal, grows with time, and the whiskers short-circuit electronic components embedded in the case. Surface treatment by coating of conductive paint cannot achieve high corrosion resistance, and also on the electronic parts embedded in the coated case because the dust or fiber fragments in the air stick or melt on the surface of the coated cases. There was a problem that could be caused by falling conductive fiber pieces.

The nickel electroplating method for plating the aluminum oxide film of air requires a long plating time, and a sporing phenomenon in which hydrogen gas is exploded in pores of the aluminum oxide film during plating treatment is likely to occur, which is practically satisfactory. A film having corrosion resistance and conductivity could not be formed.

An object of the present invention is to eliminate the above problems and to produce a corrosion-resistant, conductive lightweight member that can be practically applied to the aluminum oxide film on the surface of the aluminum material so that the member can be applied to configure the case for full calculator It also provides a method of forming and nickel-plating an aluminum oxide film in a short plating time without involving sparing.

The contacts or terminals of electronic components are made of metals such as aluminum and plated with gold to reduce the resistance to at least a small value. In the conventional gold plating treatment, the surface of the aluminum material is nickel plated by a conventional method, and then the nickel plated surface is plated with gold. During gold plating, aluminum material as cathode and soluble gold as anode are immersed in the gold cyanide bath, and the aluminum material and soluble gold are connected to the DC power source for gold plating.

In the conventional method of gold-plating the surface of an aluminum material, plating defects, such as a swelling of a plating, are likely to occur due to pinched or other defects in the surface of the aluminum material. In addition, the cost of plating the aluminum material increases because a large amount of gold must be deposited on the surface of the aluminum material to provide a surface with satisfactory conductivity.

In addition, the above-mentioned known method of electroplating an aluminum oxide film with nickel is difficult to put to practical use due to the tendency of the plating time to be taken for a long time and also to cause the sporing phenomenon of hydrogen gas exploding in pores in the aluminum oxide oxide film.

It is another object of the present invention to solve the above-mentioned problems. The corrosion resistant and conductive composite films of aluminum oxide and nickel are formed on the surface of the aluminum material within a short plating time without causing sporing, and then the composite film is made of gold. After plating, a small amount of gold is used to seal the pores in the aluminum oxide film to provide a gold plating method of aluminum material which can form a gold plating film without defects.

The aluminum material coated with chromium hard anodized film or chromium hardened anodized film is used as a case component in order to construct the case for electronic equipment with a light weight structure and to harden the surface of such a case.

Conventional aluminum members coated with a hard anodized film cannot be coated with a hard paint film. Thus, the plating surface appears only in its own color of plated chromium or rhodium, ie black or chromium or rhodium color of chromium. Therefore, the surface of the hard member cannot be finished with a desired color.

In addition, the above known method of electronickel plating an aluminum oxide film not only requires a very long plating time but also may cause a spatter phenomenon in which hydrogen gas explodes in pores in the aluminum oxide film during plating treatment. It was difficult to put the old method into practical use.

It is another object of the present invention to solve the above problems and to form a corrosion resistant conductive film composed of aluminum oxide and nickel in a short plating time without causing sporing, and to form a hard anode on the aluminum material forming the composite film. The present invention provides a hard anodized dyeing method for forming an oxide film and then immersing it in a dye solution to dye the plated surface of an aluminum material in a desired color.

[Initiation of invention]

In order to achieve the object of the present invention, the present invention is to form an aluminum oxide film having pores on the surface of the aluminum material by applying a voltage of 20V to the aluminum material in the sulfuric acid solution, and the aluminum oxide forming the bottom of the pores After the voltage is dropped to almost 0V to dissolve the film, apply a voltage of about 0.1V or less, nickel-plating the surface of the aluminum material by electroplating and nickel-plated aluminum material. Forming an aluminum oxide film on the surface of the aluminum material, including the step of inhibiting gold and nickel-plating the aluminum material coated with the aluminum oxide film to precipitate nickel in the pores of the aluminum oxide film. The present invention provides a method of forming a composite film on the surface of aluminum materials to form an electrically connected metal precipitate.

When the nickel oxide film having a good shape that does not cause spattering during nickel plating is formed on the surface of the aluminum material, the barrier layer in the pore portion of the aluminum oxide film can be dissolved uniformly and reliably, and the above-described treatment When the voltage is applied to the aluminum material in the sulfuric acid solution under the condition, the nickel deposited in the pores is electrically connected to the aluminum material.

In order to achieve the first and second objects of the present invention, the present invention provides a method for forming an aluminum oxide film on the surface of an aluminum material and a gold plating on the aluminum oxide film. Applying a voltage to the aluminum material in the interior, dropping the voltage to almost zero voltage, applying a voltage of less than about 0.1 V to the aluminum material, and sealing pores in the aluminum oxide film with a nickel acetate solution. It includes.

In the nickel plating treatment, an aluminum oxide film having an optimum shape which does not cause sporing is formed on the surface of the aluminum material by applying a voltage to the aluminum material under the above-mentioned conditions in a sulfuric acid solution under a predetermined condition. When deposited by electroplating in the pores at a suitable surface settling rate, the precipitated nickel is connected to the aluminum material. A gold film is formed by gold plating on nickel precipitates formed in pores of the aluminum oxide film formed on the surface of the aluminum material.

In order to achieve the first and third objects of the present invention, the present invention is to provide a method for dyeing an aluminum material coated with a hard anodized film formed on the surface of the aluminum, the method according to a preferred embodiment of the present invention Applying a voltage to the aluminum material in the sulfuric acid solution, dropping the voltage to almost 0 volts, then applying a voltage of about 0.1V or less to the aluminum material, and saturating the pores in the film coating the aluminum material. Immersing the aluminum material in the dye solution, and sealing the pores by dyeing and coating the aluminum material with a nickel acetate solution.

In the nickel plating process, an aluminum oxide film having a suitable shape without causing sporing is formed on the surface of the aluminum material, and then a voltage is applied to the aluminum material under the above-mentioned conditions in a sulfuric acid solution of a predetermined condition to form pores in the aluminum oxide film. The barrier layer forming the bottoms of the pores is uniformly and reliably dissolved, and then a hard anodization film is formed on the nickel precipitates exposed on the surface of the aluminum oxide film through hard anodization. After hard anodization, the coated aluminum material is immersed in a dye solution of the desired color to saturate the pores of the aluminum oxide film with a dye solution so that the coated surface of the aluminum material is not covered with the hard anodization film. Find the color you want.

[Examples of the Invention]

1A to 1D are views for explaining a method according to the present invention and showing the process sequence of the method. As shown in FIG. 1A, the aluminum material 2 and the carbon electrode 3 are immersed in a sulfuric acid solution having a concentration in the range of 50 to 80 g / 1. Then, the aluminum material 2 is used as the anode and the carbon electrode 3 is used as the cathode. Walk on both ends.

The temperature of sulfuric acid solution is maintained at 30 ± 2 ℃.

)막 8이 제 2a 도에 나타낸 바와같이 알미늄소재 2의 표면위에 형성된다. 상부로부터 관측할 때 산화알미늄막 8은 세공 9을 각각 갖는 도시안된 벌집배열식으로 배영되는 다수의 6각형 셀(cell)8b들로 구성된다. 각 셀8b의 바닥을 형성하는 장벽층 8a는 알미늄소재 2의 표면을 완전히 덮는다. 각 셀8b는 외경이 약 1,600Å, 내경이 500Å, 그리고 높이가 약 10㎛이다.Within 10 minutes

A film 8 is formed on the surface of the aluminum material 2 as shown in FIG. 2A. When viewed from the top, the aluminum oxide film 8 is composed of a plurality of hexagonal cells 8b, which are backstroked in an unillustrated honeycomb array each having pores 9. The barrier layer 8a forming the bottom of each cell 8b completely covers the surface of the aluminum material 2. Each cell 8b has an outer diameter of about 1,600 microns, an inner diameter of 500 microns, and a height of about 10 microns.

The thickness of the aluminum oxide film 8, that is, the height of the cell 8b, depends on the period in which the voltage is applied. 4A, 4B and 4C show variations in the thickness of the aluminum oxide film 8 as time passes for voltages of 20V, 17.5V and 15V, respectively. In this embodiment, the thickness of the aluminum oxide film is formed to about 10 μm. When the thickness is 10 탆 or more, it becomes difficult to satisfactorily penetrate the plating solution into the cells during the nickel plating process, which causes the poor plating. An excessively small thickness, for example, an aluminum oxide film having 5 탆 or less does not have sufficient strength and such a thin aluminum oxide film is not preferable in practical terms.

The appropriate thickness should be determined according to the purpose. The period for applying voltage and pressure is appropriately selected to obtain an aluminum oxide film having a desired thickness. According to the present invention, the thickness is about 10 占 퐉 so as to give sufficient strength to the aluminum oxide film while achieving satisfactory plating during the self plating process. The voltage can be selected from 15 to 20 volts and the period is selected within the range of 10 to 30 minutes (preferably 10 to 20 minutes). Too low a voltage, for example, 13 volts or less cannot form an aluminum oxide film at all, and a voltage of 20 V or more cannot form a satisfactory aluminum oxide film. In this embodiment, a voltage of about 10 mu m (shown in dotted lines in FIG. 4a) is formed by applying a voltage of 20 V for 10 minutes.

As a result, after the aluminum oxide film 8 is formed, the voltage is dropped from 20 volts to zero or almost zero, and then a low voltage of 0.1 V or less is applied for 10 to 15 minutes. In this way, the barrier layer 8A of the cells 8B of the aluminum oxide film 8 is dissolved to communicate with the pore valent aluminum material 2. In fact, due to the low voltage, a very thin barrier layer is formed, but the very thin barrier layer is electrolyzed and completely removed during the next nickel plating process. Therefore, the lower the low voltage, the better the result.

Stepping down the voltage to nearly zero can be eliminated by uniformly dissolving the barrier layer of the cells as compared to the gradual drop in voltage.

Aluminum material 2 coated as an aluminum oxide film 8 having bottomless pores 9 formed by dissolving the barrier layer was nickel plated as shown in FIG. 1B for nickel plating using nickel electrode 5 as a cathode and as an anode. Immerse in solution 4.

Nickel plating 10 is formed in the pores 9 of the cells of the aluminum oxide film 8 during the nickel plating process (Fig. 2C).

The plating voltage is in the range of 0.4 to 1 V, while the current density is in the range of 0.15 to 0.3 A / dm 2. No plating occurs during nickel plating. In the latter part of the nickel plating process, nickel plating 10 which is connected to aluminum material 2 is formed on the surface of about 50% of the cells 8b in the aluminum oxide film 8 of nickel plated aluminum material 2b. Nickel is not deposited at all in the remaining 50% of cells 8b or at a thickness below the height of the cells. It is possible for the precipitate of nickel to electrically connect the internal aluminum material coated as the insulated aluminum oxide film 8 to the outside in a satisfactory state so that the nickel plating 10 protrudes from the surfaces of about 50% of the cells.

After the nickel plating treatment, the nickel plated aluminum material 2b is immersed in the dye solution 6 as shown in FIG. 1C to color the desired color. When the nickel-plated aluminum material 2b is immersed in the dye solution 6, the dye solution 6 penetrates the pores 9 in the aluminum oxide 8 and the surface of the aluminum oxide film 8 is colored with a desired color (Fig. 2d). This dyeing step may be omitted.

Then, as shown in FIG. 1d, the dyed aluminum material 2c was immersed in the sealing solution 7 to obtain an aluminum material coated with a nickel-plated aluminum oxide film having pores sealed by the sealed aluminum material 2d, that is, the sealing solution. . Sealing solution 7 is a mixed solution of 5 g / 1 boric acid. The sealing process is carried out at a temperature in the range of 60 to 80 ° C. for about 20 minutes.

)는 산화알미늄막 8의 셀들8b에 침투되며, 그에 의해 알미늄소재의 표면부식이 알미늄과 니켈의 이온화경향간에 큰차가 있음에도 불구하고 방지 된다. 제 2e 도에 나타낸 바와같이, 염료와 니켈하이드록사이드를 내장하는 셀들 8b의 표면부분들은 팽창하게 되어 니켈 10이 석출된 세공들을 밀봉하고 또한 니켈 10이 석출되지 않는 세공들의 입구를 좁힌다.Nickel hydroxide produced by the hydrolysis of nickel acetate during the sealing process (Ni

) Is penetrated into the cells 8b of the aluminum oxide film 8, whereby the surface corrosion of the aluminum material is prevented despite the large difference between the ionization tendencies of aluminum and nickel. As shown in FIG. 2E, the surface portions of the cells 8b containing the dye and nickel hydroxide expand to seal the pores in which nickel 10 is deposited and also narrow the entrance of the pores in which nickel 10 is not deposited.

After the sealing step using nickel acetate, the sealing step is preferably performed using boiling water at 98 ° C. to complete the sealing.

The door of the computer case needs to be colored on its outer surface, while its inner surface needs to be electrically conductive for electronic shielding and grounding. When nickel plated aluminum material 2b after dissolving the bottom barrier layer of pores in the aluminum oxide film to obtain such a door plate, only one side of the plate material (aluminum material) 2b to be plated as shown in FIG. Electroplating is performed by facing the Ni electrode 5. In this electroplating process, nickel precipitates only in pores in the aluminum oxide film coated on one surface of plate 2b. As a result, when the nickel plated sheet is immersed in the dye solution, the aluminum oxide film having the nickel precipitate is efficiently colored with the dye solution of a predetermined color. On the other hand, since the nickel precipitate is exposed on the surface of the nickel plated aluminum oxide film, the surface of the plate coated with the nickel plated aluminum oxide film is conductive even after being colored, so a separate treatment is required to make the surface conductive. none.

In the above-mentioned embodiment, sulfuric acid is used as an sulphating agent for forming an aluminum tetrachloride film. Because sulfuric acid is stable and cheap. The concentration of sulfuric acid is in the range of 50 to 80 g / 1. This is because selective anodization occurs when the sulfuric acid concentration is less than 50 g / 1, especially when spots or stains are formed on the surface of the material when the material is an alloy. On the other hand, when the sulfuric acid concentration is more than 80g / 1, the CR ratio (weight of produced film / weight of dissolved aluminum) does not vary even when the current density is in the range of 1 to 4A / dm 2, and the conductivity of the electrolyte solution is Decreases with increasing concentration. The preferred temperature of the sulfuric acid solution for forming the aluminum oxide film is in the range of 30 ± 2 ° C. to form a hard film at a normal temperature without cooling.

This is because a temperature above the range softens the coating too much. The electrolytic voltage and time for forming the aluminum oxide film are 20 volts and 10 minutes to limit the thickness of the film (height of the cells) to a maximum of about 10 mu m. Upon removing the barriers that form the bottom of the pores in the aluminum oxide film, the voltage drops from 20 volts to zero and then a voltage of 0.1 V is applied to the aluminum material for 10 to 15 minutes for the following reason. The thickness of the barrier layer is determined by the anodic oxidation voltage, which is about 14 kV per 1 V of the electrolytic bath voltage. In the present invention, since the electrolysis is performed at 20 volts, a barrier layer having a thickness of about 280 kPa is formed. In order to stop the growth of the barrier layer grown to 280 kHz, the voltage is dropped to almost 0 V and then electrolyzed for a sufficient time at a very low voltage to reach 3 kHz or less. The barrier layer is still not removed when the voltage drops to zero at the moment. The voltage in the range of 0.4 to 1 V for nickel plating is the lowest voltage condition for nickel plating an aluminum material coated with an aluminum oxide film having pores from which the barrier layer is removed. Nickel does not precipitate when the voltage is below 0.4 volts, and sparing occurs when the voltage is about 1 volt.

As apparent from the foregoing description, this method of forming a composite film on the surface of the aluminum material according to the present invention can form a highly corrosion resistant and conductive composite film on the surface of the aluminum material in a short time without causing sporing, The aluminum material coated with such a composite film can be used as a high corrosion resistance, conductive and lightweight material, and has a high conductive surface for electronic equipment and computers without difficulty of performing conventional surface treatment such as electroplating, nickel plating or conductive coating. It can be used to form a corrosion resistant and lightweight case. In addition, according to the present invention, since the amount of nickel deposited during the nickel plating process is about 1/15 of the amount of nickel required for the conventional nickel plating process, the present invention reduces the cost of nickel plating.

막 110이 제 6 a도에 보인바와같이 알미늄소재 102의 표면상에 형성된다. 상부에서 보면 산화알미늄막 110은 벌집모양으로 배열된 세공들 111로 되어 있다. 각 세공 110b의 바닥을 형성하는 장벽층 110a는 알미늄소재 102의 표면을 완전히 덮는다. 각 셀 110b는 외경이 약 1600Å, 내경이 500Å 그리고 높이가 약 10㎛이다.5A to 5D are views for explaining the method of the second embodiment according to the present invention, and show the process sequence of the method. As shown in FIG. 5A, the aluminum material 102 and the carbon electrode 103 are immersed in a sulfuric acid solution having a concentration in the range of 50 to 80 g / 1, and the aluminum material 102 is used as the anode and the carbon electrode 103 as the cathode. Apply voltage. The temperature of sulfuric acid solution is maintained at 30 ± 2 ℃. Aluminum oxide in 10 minutes

A film 110 is formed on the surface of the aluminum material 102 as shown in FIG. 6A. When viewed from the top, the aluminum oxide film 110 has pores 111 arranged in a honeycomb shape. The barrier layer 110a forming the bottom of each pore 110b completely covers the surface of the aluminum material 102. Each cell 110b has an outer diameter of about 1600 mm, an inner diameter of 500 mm and a height of about 10 m.

After the aluminum oxide film 110 was formed, the voltage was dropped from 20V to 0V. Then apply a voltage of 0.1V for 10-15 minutes. This dissolves the barrier layer 110a forming the bottom of the cells 110b so that the pores 111 are connected to the aluminum material 102 as shown in FIG. 6B.

An aluminum material 102 coated with an aluminum oxide film 110 having bottomless pores 111 was immersed in a nickel plating solution 104 for nickel plating using aluminum 102 as a cathode and nickel electrodes 105 as an anode as shown in FIG. 5B. do. Nickel precipitates 112 are formed in the pores in the aluminum oxide film 110 (Fig. 6C) during the nickel plating process. The plating voltage is in the range of 0.4 to 1 V, and the current density is in the range of 0.15 to 0.8 A / dm 2. No plating occurs during nickel plating. After the nickel plating treatment, the aluminum material 102 is deposited with nickel plating 12 electrically connected to the internal aluminum material on the surface of about 50% of the cells 110b in the aluminum oxide film 110. Nickel is not deposited at all in the remaining 50% of the cells 110b or at a thickness below the height of the cells. As such, the nickel precipitates 112 protrude from the surface of about 50% of the cells 110b, so that the internal aluminum material 102 coated with the insulated aluminum oxide film 110 is electrically connected to the outside in a satisfactory state.

를 함유한다. 금도금용액 107은 염화금에 암모니아를 첨가하여 생긴 침전물을 시안화카륨으로 용해시켜 제조한다. 금도금 처리시에 금석출물들 113은 제 6d 도에 보인 바와같은 산화알미늄막 110의 표면상에 노출된 니켈석출물들 112의 상부표면위에 형성된다.After nickel plating, the nickel plated aluminum material 102b and the anodes 106 (gold, platinum or light carbon) were subjected to nickel plating aluminum material 102b to obtain a gold plated aluminum material 102c as shown in FIG. 5c. Immerse in 107 gold plating solution. Gold plating solution 107 is a basic solute

It contains. The gold plating solution 107 is prepared by dissolving the precipitate formed by adding ammonia to gold chloride with potassium cyanide. In the gold plating process, gold precipitates 113 are formed on the upper surface of the nickel precipitates 112 exposed on the surface of the aluminum oxide film 110 as shown in FIG. 6D.

)이 산화알미늄막 110의 셀들 110b를 침투하며, 그에의해 알미늄과 니켈의 이온화경향들가의 큰차로 인해 전지를 형성하기 쉬움에도 불구하고 알미늄소재의 표면부식이 방지된다. 제 6 e도에 나타낸 바와같이 밀봉처리후의 각 셀 110b는 세공내의 수산화니켈을 수용한 상태로 표면부분들이 팽창하여 니켈석출물들 112가 석출된 세공들을 밀봉시키고 또한 니켈석출물 112가 석출되지 않는 세공들의 입구를 좁혀주게 된다.Then, as shown in FIG. 5D, the gold-plated aluminum material 102c is immersed in the sealing solution 109 for sealing treatment to obtain a sealed aluminum material 102d. That is, an aluminum material coated with an aluminum oxide film having a sealed pore coated with nickel plating and gold plating is obtained. The sealing solution is a mixture containing 5 g / 1 nickel acetate and 5 g / 1 boric acid. The sealing treatment is performed at a temperature in the range of 60 to 80 ° C. for about 20 minutes. Nickel hydroxide produced by hydrolysis of nickel acetate during sealing

) Penetrates the cells 110b of the aluminum oxide film 110, thereby preventing the surface corrosion of the aluminum material even though the battery is easily formed due to the large difference in the ionization tendencies of aluminum and nickel. As shown in FIG. 6E, each cell 110b after the sealing treatment expands the surface portions with the nickel hydroxide in the pores to seal the pores in which the nickel precipitates 112 are deposited, and also the pores in which the nickel precipitates 112 are not precipitated. Narrowed the entrance.

Nickel acetate is preferably sealed by using 98 ° C water after sealing.

As is apparent from the foregoing description, this method of forming a composite film on the surface of the aluminum material in the second embodiment of the present invention has a high corrosion resistance composed of aluminum oxide and nickel on the aluminum material in a short time without causing sporing. After forming a conductive composite film, gold plating is performed, and the pores in the aluminum oxide film are sealed by immersing the aluminum material coated in the nickel acetate solution. Therefore, the amount of gold required to impart a predetermined conductivity and corrosion resistance to the aluminum material coated with the composite film is about 1/15 of the amount of gold required for the same purpose, which is advantageous in terms of cost. In addition, the method of the present invention can obtain a stable gold plating excellent in quality without poor plating.

막 210이 제 8a 도에 나타낸 바와 같이 알미늄 소재 202의 표면상에 형성된다.7A to 7E show processes of a method of forming a composite film on the surface of aluminum materials in a third embodiment according to the present invention. As shown in FIG. 7a, the aluminum material 202 and the carbon electrodes 203 are immersed in a sulfuric acid solution 201 having a sulfuric acid concentration in the range of 50 to 80 g / 1, and then the aluminum material 202 is used as the anode and the carbon electrodes 203 as the cathode. Apply a voltage of 20V across both ends. The temperature of sulfuric acid solution 201 is maintained at 30 ± 2 ℃. If you continue for 10 minutes like this

A film 210 is formed on the surface of the aluminum material 202 as shown in FIG. 8A.

The aluminum oxide film 210 is formed of a plurality of hexagonal cells 210b arranged in a honeycomb shape, not shown, as seen from above having pores 211. The barrier layer 210a forming the bottom of each cell 210b completely covers the surface of the aluminum material 202. Each cell 210b has an outer diameter of about 160 microns, an inner diameter of about 500 microns, and a height of about 10 microns.

After the aluminum oxide film 210 was formed, the voltage was dropped from 21V to 0, and a voltage of 0.1V was applied for 10 to 15 minutes. Then, the barrier layer 210a forming the bottom of the cells 210b of the aluminum oxide film 210 is dissolved as shown in FIG. 8B so that the pores 211 communicate with the aluminum material 202.

The aluminum material 202 coated with the aluminum oxide film 210 having the bottom-dissolved pores 211 was immersed in the nickel liquid 204 as shown in FIG. 7B, and nickel plated using the aluminum material 202 as the cathode as the anode. do. During the nickel plating process, nickel plating 212 is formed in pores 211 in the aluminum oxide film 210 (Fig. 8C).

The plating voltage is in the range of 0.15 to 0.8 A / dm 2. No plating occurs during the nickel plating process. As described above, in the aluminum material 202 after the nickel plating treatment, nickel plating 12 is formed on the surface of the cell 210b of about 50% of the aluminum oxide film 210 to conduct with the internal aluminum material 202. Nickel is not deposited at all in the remaining 50% cell 210b or at a thickness below the height of the cells. If nickel is deposited on the surface of about 50% of the cells 210b, the nickele precipitation may allow the internal aluminum material coated with the insulated aluminum oxide film 210 to be electrically connected to the outside under satisfactory conditions.

After the nickel plating process, hard plating of chromium or rhodium is performed on the nickel plated aluminum material 202b. In FIG. 7C and 206 in FIG. 7C, anodes such as lead electrodes are used, and 207 is a hard anode oxidation solution. For example, when hard chromium plating is used, the hard anodization solution 207 is a mixture of chromic acid and a small amount of sulfuric acid. Aluminum material 202c of the hard anode is produced at the cathode in the hard anode oxidation solution 207. In the hard anode oxidation process, hard plating 213 is formed on the upper surface of the nickel precipitates 212 exposed on the surface of the aluminum oxide film 210 as shown in FIG.

Then, as shown in FIG. 7D, the hard anodized aluminum material 202c is immersed in the dye solution 208 to produce a colored aluminum material 202d colored in a desired color. The dye solution 208 penetrates into pores of the aluminum oxide film 210 to color the surface of the aluminum oxide film with a desired color.

)는 산화알미늄막 210의 셀들 210b에 침투되며 그에 의해 산화알미늄과 니켈의 이온화 경향간의 큰 차로 인해 전지를 형성함에도 불구하고 알미늄소재의 표면 부식은 방지된다. 제 8 f도에 나타낸 바와같이, 밀봉처리는 수산화니켈을 함유하는 셀들 210b의 표면부분들을 팽창시키는 원인이 되므로, 니켈석출물들 212가 석출되는 세공들이 밀봉되고, 니켈석출물이 석출되지 않는 세공들의 입구가 좁아진다.Then, as shown in FIG. 7E, the color aluminum material 202d is immersed in the sealing solution 209 to obtain a sealed aluminum material 202e. The sealing solution is a mixture containing 5 g / 1 nickel acetate and 5 g / 1 boric acid. The sealing treatment is carried out at a temperature in the range of 60 to 80 ° C. for about 20 minutes. Nickel hydroxide (Ni during sealing)

) Penetrates the cells 210b of the aluminum oxide film 210, thereby preventing the surface corrosion of the aluminum material even though the battery is formed due to the large difference between the tendency of the aluminum oxide and the ionization of nickel. As shown in Fig. 8F, the sealing treatment causes the surface portions of the cells 210b containing nickel hydroxide to expand, so that the pores in which the nickel precipitates 212 are deposited are sealed, and the entrances of the pores in which the nickel precipitates are not precipitated are sealed. Becomes narrower.

The sealing is preferably completed by another sealing treatment using water at 98 ° C. after the sealing treatment using nickel acetate.

As is apparent from the foregoing description, this method including the hard anodization process and the coloring process according to the present invention forms a highly corrosion-resistant, conductive composite film composed of aluminum oxide and nickel on an aluminum material in a short time without causing sporing. . By immersing the aluminum material coated with the hard anodization coating, the composite film can be colored in a desired color without the hard anodization coating.

Claims (9)

Forming an aluminum oxide film having pores on the surface of the aluminum material by applying a voltage of 20V to the aluminum material for several tens of minutes in a sulfuric acid solution having a concentration of 50 ± 80 g / 1 at 30 ± 2 ° C., and setting the voltage from 20V to zero. Applying a voltage of 0.1 V to the aluminum material for 10 to 15 minutes to dissolve the aluminum oxide film forming the bottoms of the pores after the descent, and the pores of the aluminum oxide film to electrically connect the nickel precipitates with the aluminum material. Oxidation and precipitation of metals electrically connected to the aluminum material, the method comprising nickel plating an aluminum material coated with an aluminum oxide film at 1 to 0.8 V (0.15 to 0.2 A / dm 2) to form nickel precipitates therein. Method for forming a composite film on the surface of an aluminum material for forming an aluminum film. The method of forming a composite film on the surface of an aluminum material as claimed in claim 1, wherein the nickel plating process is carried out with gold plating on the nickel precipitates formed by nickel plating. According to claim 1, the nickel material formed by nickel plating after the plating process of the hard metal plated with a hard metal, and then coated with an aluminum oxide film having an aluminum oxide film having nickel precipitates coated with a crystalline metal coating dye solution aluminum oxide A method of forming a composite film on the surface of an aluminum material which is immersed in a dye solution to penetrate the pores of the film. The method of forming a composite film on the surface of an aluminum material according to claim 1, wherein the pores of the aluminum oxide film are sealed by a sealing treatment using a sealing solution containing nickel acetate. The method of claim 1, wherein the concentration of the sulfuric acid solution is in the range of 50 to 80 g / 1 and the temperature is maintained at 30 ± 2 ° C. 5. 4. The method of forming a composite film on the surface of an aluminum material according to claim 1, wherein a voltage in the range of 15 to 20 V is applied to the aluminum material for 10 to 20 minutes to form the aluminum oxide film. The method of forming a composite film on the surface of an aluminum material according to claim 1, wherein a voltage of about 01 V or less is applied for 10 to 15 minutes so as to require an aluminum oxide film forming a bottom of pores. The method of forming a composite film on the surface of an aluminum material according to claim 1, wherein the voltage for the nickel plating process is in the range of 0.4 to 1V. 4. The composite of claim 1, wherein the aluminum material is an aluminum plate material, and the aluminum plate material is disposed in the nickel plating solution during nickel plating so that only one side thereof faces the nickel electrode so as to form a nickel precipitate on only one side thereof. Film formation method.

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