JP2016037622A - Electrolytic polishing method for aluminum member, and aluminum member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolytic polishing method for an aluminum member, which provides high gloss and can form a thin oxide film when subjecting an aluminum member formed of aluminum or an aluminum alloy to an electrolytic polishing treatment.SOLUTION: Provided is an electrolytic polishing method for dissolving and smoothing a surface of an aluminum member 4, comprising the steps of: immersing the aluminum member 4, formed of aluminum or an aluminum alloy, in an electrolytic polishing liquid 2 stored in a container 3; and supplying a direct current by means of a direct current power supply device 7 with the aluminum member 4 as an anode and with the container 3 which stores the electrolytic polishing liquid 2 or a cathode plate 6 immersed in the electrolytic polishing liquid 2 in the container 3 as a cathode. When carrying out electrolytic polishing of the aluminum member 4, the temperature of the electrolytic polishing liquid 2 is 80°C, and the electric current density is set at a value at nearly an end point of a composite region where the aluminum member immersed in the electrolytic polishing liquid 2 is subjected to an electrolytic polishing treatment and an etching treatment.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electropolishing method for melting and smoothing the surface of an aluminum member made of aluminum or an aluminum alloy, and an aluminum member electropolished by the electropolishing method, in particular, having high gloss and a thin oxide film. The present invention relates to an aluminum member electropolishing method that can be formed, and an aluminum member that has been electropolished by the electropolishing method.

  Conventionally, as a method of polishing a metal object to be polished, physical polishing for smoothing the surface of the object to be polished by physical means or the surface of the object to be polished by an electrochemical action. Electropolishing that dissolves and smoothes is known.

  In physical polishing, the metal surface is smoothed by cutting, etc., but when cutting etc., abrasive grains, buffs, oil, compound, etc. are used, so fine scratches can be made on the surface of the object to be polished, Since abrasive grains remain on this surface, sufficient cleaning is necessary. If the abrasive grains embedded in the surface cannot be removed cleanly, they may cause corrosion, or later from the metal surface. There is a demerit that residues such as abrasive grains are released and cause impurities, and the object to be polished is subjected to physical force due to cutting or the like, resulting in a deteriorated layer accompanying processing. There are disadvantages.

  In contrast, an object to be polished made of a metal such as aluminum or stainless steel is immersed in an electrolytic polishing liquid, and the object to be polished is used as an anode, and a cathode plate immersed in an electrolytic polishing liquid in a container containing the electrolytic polishing liquid or a cathode In electropolishing, in which the surface of the metal body to be polished is smoothed by dissolving the metal surface of the object to be polished by applying a direct current, it has been popular since immediately after the Second World War as a technique for processing the surface of the metal body to be polished. In recent years, in addition to the automobile industry and electrical equipment industry, in recent years, the semiconductor industry related to aluminum alloy surface treatment, LED lighting reflectors, solar light collectors, etc. In the field of the pharmaceutical industry, such as the surface treatment of containers containing chemicals indispensable for guaranteeing the purity of semiconductors, and in the field of semiconductor manufacturing equipment, more and more attention has been paid.

  In such electropolishing, it is a disadvantage of physical polishing that the generation of residual stress on the object to be polished due to the physical polishing of the object to be polished and the occurrence of an altered layer on the object to be polished with polishing. In addition, since the polishing surface can be cleaned by electrochemically dissolving the surface, there is a situation in which the interest in the semiconductor industry and the pharmaceutical industry is increasing.

  As a technique related to the electropolishing, Patent Document 1 discloses a method for producing a metal product by an electropolishing method.

Further, in Patent Document 2 filed by the applicant of the present application, an aluminum member with a thin oxide film having a high glossiness (8 ° gloss) (1000 or more) and an absorbance of 0.1 or less is obtained by electrolytic polishing treatment. For this purpose, an aluminum member is immersed in an electrolytic polishing solution contained in a container, the aluminum member is used as an anode, and a cathode plate immersed in the container containing the electrolytic polishing solution or the electrolytic polishing solution in the container is used as a direct current. In an aluminum member electropolishing method in which the surface of an aluminum member is melted and smoothed by passing an electric current, the temperature of the aluminum member immersed in the electrolytic polishing liquid is 80 ° C. or more, and the current density is 0.128 A / It is disclosed that the electropolishing treatment is performed at cm ^{2 to} 0.211 A / cm ² .

JP 2006-348336 A JP 2013-133507 A

  When applying conventional electropolishing methods and electropolishing aluminum or aluminum alloys, there is a situation that the oxide film formed on the surface of the object to be polished becomes thicker due to the electropolishing process. In a thick state, many relatively deep microscopic holes are formed on the surface (so-called porous state), and chemical components and moisture contained in the electrolyte may remain in these holes. Therefore, for example, when an aluminum member manufactured by electropolishing treatment is placed in a vacuum atmosphere, chemicals that have been contained in the holes may be released to the outside due to the vacuum action, particularly in a vacuum atmosphere. However, there is a problem that it is not suitable to use an object to be polished that has been subjected to electrolytic polishing.

Moreover, in the electrolytic polishing method of the aluminum member of patent document 2, when performing the electrolytic polishing of the aluminum member, the temperature of the aluminum member immersed in the electrolytic polishing liquid is 80 ° C. or more, and the current density is 0.128 A / By carrying out at cm ^{2 to} 0.211 A / cm ² , an aluminum member having a thin oxide film with a glossiness of 1000 or more and an absorbance of 0.1 or less can be formed, but contained in a container. If the electropolishing is performed multiple times with the same electropolishing liquid without replacing the electropolishing liquid, the aluminum member dissolves in the electropolishing liquid, so that the glossiness of the electropolished aluminum member and the thickness of the oxide film are increased. There remains a problem of affecting this.

  The present invention has been made in view of the above problems. When an aluminum member made of aluminum or an aluminum alloy is subjected to an electropolishing treatment, the electropolishing of the aluminum member can be formed with a high glossiness and a thin oxide film. The object is to provide an aluminum member electropolished by the method and the electropolishing method.

The invention relating to the electrolytic polishing method of the aluminum member,
An aluminum member made of aluminum or an aluminum alloy is immersed in an electropolishing liquid contained in a container,
Using the aluminum member as an anode and a cathode plate immersed in the electrolytic polishing liquid in the container or the electrolytic polishing liquid in the container as a cathode, the surface of the aluminum member is dissolved and smoothed by applying a direct current. In the electrolytic polishing method of an aluminum member,
When performing the electrolytic polishing of the aluminum member,
The temperature of the electropolishing liquid is 80 ° C.,
The current density is determined by a numerical value in the vicinity of the end point of the composite region where the aluminum member immersed in the electrolytic polishing liquid is subjected to the electrolytic polishing process and the etching process.

The invention relating to the electrolytic polishing method of the aluminum member,
The electrolytic polishing liquid is a mixed acid electrolytic solution in which phosphoric acid and sulfuric acid are mixed at a predetermined ratio.

  The aluminum member is electropolished by the electropolishing method, so that the glossiness is 1500 or more and the absorbance is 0.1 or less.

  According to the present invention, when electropolishing an aluminum member, the temperature of the electropolishing liquid is 80 ° C., and the current density is near the end point of the composite region where the aluminum member is subjected to electropolishing and etching. By executing the numerical value, the glossiness of the aluminum member can be increased regardless of the dissolution concentration of the aluminum member in the electrolytic polishing liquid, and an oxide film formed on the surface of the aluminum member by electrolytic polishing is formed into a thin film. can do. In the present invention, the glossiness is close to the thickness of the oxide film formed when the aluminum member is naturally oxidized (oxidized at room temperature) while the glossiness is 1000 or more (more preferably 1500 or more). In addition, since the absorbance can be formed to be 0.1 or less, it is possible to reduce the depth of the micropores formed on the surface of the aluminum member subjected to the electropolishing treatment. Even in a vacuum atmosphere, it is possible to prevent the electrolytic polishing liquid and the like from being released from the fine holes on the surface of the aluminum member. Therefore, the use of the aluminum member can be expanded in various fields, and its value is enormous.

It is a schematic block diagram which shows the electrolytic polishing apparatus as embodiment which implements the electrolytic polishing method of this invention. It is a graph of the experimental result which shows the melt | dissolution density | concentration (mg / l) of the aluminum member melt | dissolved in the electrolytic polishing liquid with the electrolytic polishing of the aluminum member. In addition, the broken line marked with ○ is the experimental result of “9 times for the first time”, the broken line marked with △ is the experimental result of “for 9 times of the second time”, and the broken line marked with □ is the result of the “third time” 9 ”shows the experimental results. It is a graph of the experimental result which shows the relationship between the current density when electropolishing an aluminum member, and glossiness. In addition, the broken line marked with ○ is the experimental result of “9 times for the first time”, the broken line marked with △ is the experimental result of “for 9 times of the second time”, and the broken line marked with □ is the result of the “third time” 9 ”shows the experimental results. It is a graph of the experimental result which shows the relationship between the current density when the aluminum member is electropolished, and a light absorbency. In addition, the broken line marked with ○ is the experimental result of “9 times for the first time”, the broken line marked with △ is the experimental result of “for 9 times of the second time”, and the broken line marked with □ is the result of the “third time” 9 ”shows the experimental results.

  Embodiments of the present invention will be described below. Of course, it goes without saying that the present invention can be easily applied to configurations other than those described in the embodiments without departing from the spirit of the invention.

  As shown in FIG. 1, an electropolishing apparatus 1 for electropolishing an aluminum member in an embodiment for carrying out the electropolishing method of the present invention is accommodated in a container 3 containing an electropolishing liquid 2 and in the container 3. A heating means 5 for heating the electrolytic polishing liquid 2 and the object 4 to be polished, which is an aluminum member, to a predetermined temperature is provided, and the object 4 to be polished immersed in the container is used as an anode, and a cathode plate 6 provided in the container is provided. As a cathode (a container may be used as a cathode when the cathode plate 6 is not provided), a surface of the object to be polished 4 is melted and smoothed by applying a direct current from a direct current power source device 7. In addition, as the to-be-polished body 4 in this embodiment, pure aluminum (material symbol: A1050-H24) having a height of 25 mm, a width of 50 mm, and a thickness of 1.0 mm is applied as an aluminum member. Aluminum members such as aluminum and aluminum alloys may be applied.

  Next, an experimental method and experimental results when an aluminum member made of pure aluminum (material symbol: A1050-H24) is electrolytically polished by the electrolytic polishing apparatus 1 will be described below. The present invention relates to an invention empirically derived based on the experimental results using such an electropolishing apparatus 1.

<Experiment method>
As shown in FIG. 1, the electrolytic polishing treatment method for the aluminum member is performed by a two-electrode method. As the electrolytic polishing liquid, a volume ratio of 85% phosphoric acid, 98% sulfuric acid, and water is set to 6.5. : A 0.5: 2 ratio was established in the container, and the electrolytic polishing liquid as a mixed acid electrolytic polishing liquid was heated by the heating means 5 to a temperature of 80 ° C.

As an aluminum member to be immersed in an electrolytic polishing solution at 80 ° C. for electrolytic polishing, a plurality (3 times × 9 = 27) of the same conditions are prepared in advance, and the current density is (1) 0 mA / cm ² (no energization), (2) 38 mA / cm ² , (3) 75 mA / cm ² , (4) 113 mA / cm ² , (5) 151 mA / cm ² , (6) 189 mA / cm ² , ( 7) 226 mA / cm ² , (8) 264 mA / cm ² , (9) When the operation of increasing the current in the order of 302 mA / cm ² is repeated three times at nine from (1) to (9), these currents For each numerical value of density, one aluminum member prepared in advance was immersed in an electrolytic polishing solution at 80 ° C. for 180 seconds to perform electrolytic polishing of the aluminum member. Incidentally, each of the current density as described above ^{((1) 0mA / cm 2} ( without ^{energization), (2) 38mA / cm} 2, (3) 75mA / cm 2, (4) 113mA / cm 2, (5) 151 mA / cm ² , (6) 189 mA / cm ² , (7) 226 mA / cm ² , (8) 264 mA / cm ² , (9) 302 mA / cm ² ) Nine aluminum members are used in each of the first, second, and third times, and a total of 27 aluminum members are electropolished in the first to third times. When electrolytic polishing of the aluminum member was performed, the same electrolytic polishing liquid 2 contained in the container 3 was used without being replaced.

In addition, the cathode plate 6 is made of stainless steel SUS304, two plates having a height of 200 mm, a width of 50 mm, and a thickness of 0.5 m placed in a container at an interval of 130 mm, and about 150 mm of the lower part of the cathode is a liquid of an electrolytic polishing liquid. The aluminum member that is the object to be polished is used for the anode. More specifically, a pure titanium round bar having a diameter of 6 mm is bent into a U shape, and the upper part of the aluminum member is sandwiched from the width direction. The aluminum member was installed at an intermediate position between the two cathode plates 6. In addition, as a DC power supply device (specifically, PAD110-20L manufactured by Kikusui Electronics Co., Ltd.) 1, a DC power supply can be used. When electrolytic polishing is performed, the aluminum member is moved up and down at a cycle of 1 second. I went while exercising. Moreover, about the glossiness of the aluminum member surface mentioned later, a spectrocolorimeter (CM-700d by Konica Minolta Sensing Co., Ltd.) is used, and measurement conditions are an aperture diameter of 6 mm, a measurement diameter of 3 mm, a viewing angle of 2 degrees, and a light source D65. , Measured at 8 degrees of light projection / light reception, and the absorbance (ABS) was measured with an absorbance measurement device (Perkin Elmer Japan Co., Ltd., Fourier Transform Infrared Spectroscopy Spectrometer One). (incident angle 80 °, P-polarized light), measuring wavenumber range: 4000 to 400 ^-1, resolution: ^{8 cm -1,} the number of integrations: was measured at 32 times.

<Experimental result>

  When electrolytic polishing of an aluminum member is performed a total of 27 times with the same electrolytic polishing liquid without replacing the electrolytic polishing liquid 2 contained in the container 3, as shown in FIG. It can be seen that the dissolution concentration of the member 4 increases.

(First time)
Further, as shown in FIG. 3, in the first, the current density is from (1) 0 mA / cm ² (without energization) (4) In the range of 113 mA / cm ^2, glossiness (8 ° gloss) is , And is substantially constant (change in glossiness is within 300) between 500 and 1000, this is defined as the first constant transition region, and the current density is from (5) 151 mA / cm ^2. (9) In the range of 302 mA / cm ² , the glossiness (8 ° gloss) changes from 1500 to 2000 and is substantially constant (the change in glossiness is within 300). The transition area is defined as follows.

  In the first constant transition region, since the current density is low, the aluminum member is not subjected to sufficient electrolytic polishing treatment, and the etching treatment associated with being immersed in the electrolytic polishing liquid is dominant. On the other hand, in the second constant transition region, since the current density is high, the electropolishing process is dominant over the etching process, and the electropolishing process of the aluminum member is sufficiently performed without performing the etching process. The glossiness of the aluminum member in the second constant transition region is larger than that in the transition region.

In addition, the electropolishing process and the etching process antagonize between the first constant transition region where the etching process is dominant and the second constant transition region where the electropolishing process is dominant. (The current density ranges from (4) 113 mA / cm ² to (5) 151 mA / cm ² ). In the composite region that transitions from the first constant transition region to the second constant transition region, as shown in FIG. 3, the glossiness of the aluminum member rapidly increases by 1000 or more at the first time. Then, in the second constant transition region that is the end point of the composite region and changes substantially constant starting from this, the glossiness of the aluminum member is substantially constant between 1500 and 2000 (the glossiness change is within 300). Transition.

Further, as shown in FIG. 4, at the first time, the end point of the composite region (current density is (5) 151 mA / cm ² ) and the absorbance in the vicinity thereof are 0.1 or less. As the numerical value of the absorbance when the aluminum member is naturally oxidized, it is known to be about 0.03, and based on the fact that the numerical value of the absorbance of the aluminum member approaches 0.03 such as 0.1 or less, It can be determined that the thickness of the oxide film when the aluminum member is electropolished is thin. In the first shown in FIG. 4, the extent current density from (1) 0 mA / cm ² (without energization) of (5) 151mA / cm ^2, but the absorbance indicates a 0.1 or less, (5 ) If it is less than 151 mA / cm ² , the glossiness of the aluminum member tends to be low, as shown in FIG.

Considering the results of the first experiment described above, as is clear from the results of FIGS. 3 and 4, the gloss (8 ° gloss) is extremely high (1500 or more) and the absorbance can be 0.1 or less. When an aluminum member having a thin film is obtained by electropolishing, the current density is (5) 151 mA / cm ² in a state where the temperature of the electropolishing liquid in which the aluminum member is immersed is 80 ° C. In this way, the electrical control is performed, in other words, the electropolishing of the aluminum member by the current density at the end point (near the end point) of the composite region between the first constant transition region and the second constant transition region. It came to the conclusion that it is suitable to process.

(Second time)
As shown in FIG. 3, the second time, in the range current density from (1) 0mA / cm ² (without energization) of (4) 113 mA / cm ^2, glossiness (8 ° gloss) is 0 Since it is substantially constant (change in glossiness is within 300) at 500 or less, it is defined as the first constant transition region, and the current density is from (6) 189 mA / cm ² to (9 ) In the range of 302 mA / cm ² , the glossiness (8 ° gloss) changes from 1500 to 2000 and is substantially constant (change in glossiness is within 300). And will be described below.

  In the first constant transition region, since the current density is low, the aluminum member is not subjected to sufficient electrolytic polishing treatment, and the etching treatment associated with being immersed in the electrolytic polishing liquid is dominant. On the other hand, in the second constant transition region, since the current density is high, the electropolishing process is dominant over the etching process, and the electropolishing process of the aluminum member is sufficiently performed without performing the etching process. The glossiness of the aluminum member in the second constant transition region is larger than that in the transition region.

In addition, the electropolishing process and the etching process antagonize between the first constant transition region where the etching process is dominant and the second constant transition region where the electropolishing process is dominant. (The current density ranges from (4) 113 mA / cm ² to (6) 189 mA / cm ² ). In the composite region that transitions from the first constant transition region to the second constant transition region, as shown in FIG. 3, the glossiness of the aluminum member rapidly increases by 1000 or more in the second time. Then, in the second constant transition region that is the end point of the composite region and changes substantially constant starting from this, the glossiness of the aluminum member is substantially constant between 1500 and 2000 (the glossiness change is within 300). Transition.

Further, as shown in FIG. 4, at the second time, the end point of the composite region (current density is (6) 189 mA / cm ² ) and the absorbance in the vicinity thereof are 0.1 or less. As the numerical value of the absorbance when the aluminum member is naturally oxidized, it is known to be about 0.03, and based on the fact that the numerical value of the absorbance of the aluminum member approaches 0.03 such as 0.1 or less, It can be determined that the thickness of the oxide film when the aluminum member is electropolished is thin. In the second time shown in FIG. 4, the extent current density from (1) 0 mA / cm ² (without energization) of (6) 189mA / cm ^2, but the absorbance indicates a 0.1 or less, (6 ) If it is less than 189 mA / cm ² , the glossiness of the aluminum member tends to be low, as shown in the second time in FIG.

Considering the results of the second experiment described above, as is apparent from the results of FIGS. 3 and 4, the gloss (8 ° gloss) is extremely high (1500 or more) and the absorbance can be 0.1 or less. When an aluminum member having a thin film is obtained by electropolishing, the current density is (6) 189 mA / cm ² in a state where the temperature of the electropolishing liquid in which the aluminum member is immersed is 80 ° C. In this way, the electrical control is performed, in other words, the electropolishing of the aluminum member by the current density at the end point (near the end point) of the composite region between the first constant transition region and the second constant transition region. It came to the conclusion that it is suitable to process.

(3rd)
As shown in FIG. 3, in the third, in the range current density from (1) 0mA / cm ² (without energization) of (4) 113mA / cm ^2, glossiness (8 ° gloss) is 0 Since it is substantially constant (change in glossiness is within 300) at 500 or less, this is defined as the first constant transition region, and the current density is from (7) 226 mA / cm ² to (9 ) In the range of 302 mA / cm ² , the glossiness (8 ° gloss) changes from 1500 to 2000 and is substantially constant (change in glossiness is within 300). And will be described below.

  In the first constant transition region, since the current density is low, the aluminum member is not subjected to sufficient electrolytic polishing treatment, and the etching treatment associated with being immersed in the electrolytic polishing liquid is dominant. On the other hand, in the second constant transition region, since the current density is high, the electropolishing process is dominant over the etching process, and the electropolishing process of the aluminum member is sufficiently performed without performing the etching process. The glossiness of the aluminum member in the second constant transition region is larger than that in the transition region.

In addition, the electropolishing process and the etching process antagonize between the first constant transition region where the etching process is dominant and the second constant transition region where the electropolishing process is dominant. (The current density ranges from (4) 113 mA / cm ² to (7) 226 mA / cm ² ). In the composite region that transitions from the first constant transition region to the second constant transition region, as shown in FIG. 3, the glossiness of the aluminum member rapidly increases by 1000 or more at the third time. Then, in the second constant transition region that is the end point of the composite region and changes substantially constant starting from this, the glossiness of the aluminum member is substantially constant between 1500 and 2000 (the glossiness change is within 300). Transition.

In addition, as shown in FIG. 4, at the third time, the end point of the composite region (current density is (7) 226 mA / cm ² ) and the absorbance in the vicinity thereof are 0.1 or less. As the numerical value of the absorbance when the aluminum member is naturally oxidized, it is known to be about 0.03, and based on the fact that the numerical value of the absorbance of the aluminum member approaches 0.03 such as 0.1 or less, It can be determined that the thickness of the oxide film when the aluminum member is electropolished is thin. In the third shown in FIG. 4, the extent current density from (1) 0 mA / cm ² (without energization) of (7) 226mA / cm ^2, but the absorbance indicates a 0.1 or less, (7 ) If it is less than 226 mA / cm ² , the glossiness of the aluminum member tends to be low, as shown in the third time in FIG.

Considering the results of the third experiment described above, as is apparent from the results of FIGS. 3 and 4, the gloss (8 ° gloss) is extremely high (1500 or more) and the absorbance can be 0.1 or less. When an aluminum member having a thin film is obtained by electropolishing, the current density is (7) 226 mA / cm ² in a state where the temperature of the electropolishing liquid in which the aluminum member is immersed is 80 ° C. In this way, the electrical control is performed, in other words, the electropolishing of the aluminum member by the current density at the end point (near the end point) of the composite region between the first constant transition region and the second constant transition region. It came to the conclusion that it is suitable to process.

  In addition, as shown in FIG. 2, when electrolytic polishing of a plurality of aluminum members is performed with the same electrolytic polishing liquid without replacing the electrolytic polishing liquid 2 accommodated in the container 3, aluminum is used depending on the number of times. Although the dissolution concentration of the member increases, it has been found that in such a case, suitable conditions for electrolytic polishing of the aluminum member change. That is, when an aluminum member having an extremely high gloss (8 ° gloss) and a thin oxide film is obtained by electrolytic polishing, the current density is increased according to the increase in the dissolution concentration of the aluminum member in the electrolytic polishing liquid 2. It turns out that it has to increase.

  As described above, according to the electrolytic polishing method for an aluminum member of the present embodiment, an aluminum member made of aluminum or an aluminum alloy is immersed in the electrolytic polishing liquid 2 accommodated in the container 3, the aluminum member is used as an anode, and the electrolytic polishing liquid is used. In the electrolytic polishing method for an aluminum member, the surface of the aluminum member is melted and smoothed by applying a direct current with a cathode plate immersed in the container 3 containing 2 or the electrolytic polishing liquid 2 in the container as a cathode. When performing electropolishing of the member, the temperature of the electropolishing liquid 2 is 80 ° C., and the current density is that of the composite region where the electropolishing and etching processes are performed on the aluminum member immersed in the electropolishing liquid 2. Regardless of the dissolution concentration of the aluminum member in the electropolishing liquid 2 by performing the value at or near the end point The oxide film formed on the surface of the aluminum member by and electrolytic polishing can increase the gloss of the aluminum member can be formed into a thin film. Further, in the present invention, while the glossiness is 1000 or more (more specifically 1500 or more), the oxide film is close to the thickness of the oxide film formed when the aluminum member is naturally oxidized (oxidized at room temperature). Since the absorbance can be close to 0.03 and 0.1 or less, the depth of the fine holes formed on the surface of the aluminum member subjected to the electrolytic polishing treatment is reduced. Accordingly, even in a vacuum atmosphere, it is possible to suppress the discharge of the electrolytic polishing liquid or the like from the fine holes on the surface of the aluminum member. Therefore, the use of the aluminum member can be expanded in various fields, and its value is enormous.

DESCRIPTION OF SYMBOLS 1 Electropolishing apparatus 2 Electrolytic polishing liquid 3 Container 4 Polishing body (aluminum member)
5 Heating means 6 Cathode plate 7 DC power supply

Claims (3)

An aluminum member made of aluminum or an aluminum alloy is immersed in an electropolishing liquid contained in a container,
Using the aluminum member as an anode and a cathode plate immersed in the electrolytic polishing liquid in the container or the electrolytic polishing liquid in the container as a cathode, the surface of the aluminum member is dissolved and smoothed by applying a direct current. In the electrolytic polishing method of an aluminum member,
When performing the electrolytic polishing of the aluminum member,
The temperature of the electropolishing liquid is 80 ° C.,
The method for electrolytic polishing an aluminum member, wherein the current density is determined by a numerical value near an end point of a composite region where the electrolytic polishing process and the etching process are performed on the aluminum member immersed in the electrolytic polishing liquid.   2. The method of electrolytic polishing an aluminum member according to claim 1, wherein the electrolytic polishing liquid is a mixed acid electrolytic solution in which phosphoric acid and sulfuric acid are mixed at a predetermined ratio.   An aluminum member characterized by having a glossiness of 1500 or more and an absorbance of 0.1 or less by being electropolished by the electropolishing method according to claim 1 or 2.

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