JP6507652B2 - Aluminum or aluminum alloy member and method of manufacturing the same - Google Patents

Description

  The present invention relates to an aluminum or aluminum alloy member and a method of manufacturing the same, and more particularly, an aluminum or aluminum alloy member in which micropores present in an anodic oxide film formed on the surface of aluminum or aluminum alloy have a predetermined configuration. And a method of manufacturing the same.

  The anodized film formed on the surface of aluminum or aluminum alloy has a cell structure, and small holes of nm size exist in each cell. As an example of utilizing the large number of pores of the anodized film applied to such aluminum or aluminum alloy, for example, the adhesion to a coating or a resin is improved by its anchor effect, or a noble metal is supported in the pores. Or using a film as a filtration filter. In particular, when this coating is used to improve adhesion with coating or resin, if the viscosity of the coating or resin is high, it will be difficult for the coating or resin to enter into the pores of the film, so the larger the pore diameter preferable. In addition, in the case of using it as a catalyst carrier or a filtration filter, or when using it for providing a heat insulating effect to a piston, it is easy to obtain a high effect if the film has a film thickness as thick as possible.

  The following is known as a method of enlarging the pore diameter of the anodic oxide film.

  In Japanese Patent Application Laid-Open No. 2003-13801, a mixed solution of trisodium phosphate and potassium fluoride is used to form an anodic oxide film having a pore diameter of 100 nm, and then a mixed solution of 1 wt% phosphoric acid and 4 wt% sulfamic acid (30 ° C. , And the method of expanding the pore diameter to 150 nm by immersion for 5 to 15 minutes. However, this method is not preferable from the environment because it is necessary to produce an anodic oxide film using potassium fluoride having toxicity.

  In JP 2011-252192 A, aluminum phosphate is formed by treating the anodized film with phosphoric acid concentration, temperature, and immersion time satisfying a predetermined formula, and the moisture in the air and the film are used. A method is described which prevents the pores from being blocked naturally by hydration reaction. In the examples, although the results of expanding the pore diameter by this method are also described, there is a problem that the film is dissolved and the film thickness is greatly reduced under the processing conditions in which the pore diameter is expanded.

Unexamined-Japanese-Patent No. 2003-13801 JP, 2011-252192, A

  The pore diameter of the anodized film can be determined depending on the anodizing treatment solution and the electrolytic conditions, but there is a problem that it is difficult to form a thick film under the processing conditions for forming a large pore diameter. Then, although the method of post-processing the formed anodic oxide film and enlarging a pore diameter is disclosed in said literature, as above-mentioned, a reagent has toxicity and film | membrane itself melt | dissolves, There is a problem that the thickness is reduced. In particular, the latter method is not preferable when it is used in an application where a highly accurate dimension such as a piston is required.

  Therefore, the object of the present invention is to prevent the film thickness of the anodized film formed on the surface of aluminum or aluminum alloy from decreasing and to enlarge the diameter of the pores present on the surface of the anodized film. An aluminum or aluminum alloy member comprising an anodized film having a large thickness and a large pore size, and a method of manufacturing the same.

  In order to achieve the above object, the present invention is, as one aspect thereof, an aluminum or aluminum alloy member comprising aluminum or an aluminum alloy and an anodized film formed on the surface, the surface of the anodized film And a plurality of pores are present, the inner surface of the pores is covered with a hydrate compound, and the hydrate compound contains lithium-aluminum hydrate.

The hole whose inner surface is covered with the hydrated compound preferably has a hole diameter of 10 nm or more on the surface of the member. Moreover, it is preferable that the film thickness of the said anodic oxide film is 10 micrometers or more. The lithium-aluminum hydrate preferably contains LiH (AlO ₂ ) _2. 5H ₂ O.

  Moreover, this invention is another manufacturing method of aluminum or aluminum alloy member, Comprising: The aluminum or aluminum alloy in which the anodic oxidation film was formed is immersed in the pre-processing liquid containing phosphate ion, and is pre-processed. And the anodized film on the pretreated aluminum or aluminum alloy is subjected to a hydration treatment with a hydration treatment solution containing lithium ions to form a plurality of pores present on the surface of the anodized film. Expanding the pore size and covering the inner surface of the pore with a hydrated compound containing lithium-aluminum hydrate.

  It is preferable that the phosphate ion concentration of the said pre-processing liquid is the range of 0.1-2.0 mol / L. It is preferable that the temperature of the said pre-processing liquid is the range of 10-30 degreeC. The immersion time in the pretreatment solution is preferably in the range of 30 seconds to 4 minutes.

  As described above, according to the present invention, by immersing the anodized film in the pretreatment solution containing phosphate ions, it is possible to take in more phosphate ions in the film, and then hydrate the lithium ion containing solution. By hydration treatment with the treatment solution, the inside of the pores of the film is dissolved and the pore diameter is expanded, but the subsequent formation of a hydrated compound containing lithium-aluminum hydrate is incorporated in the film. Since the phosphate ion suppresses, the pore diameter can be expanded without blocking the pores of the film. Moreover, in this method, since the inside of the pores of the film is only dissolved, the film thickness of the anodized film can be maintained.

  Furthermore, the anodized film can also be protected by a hydrated compound formed on the inner surface of the pore. Such a pore can improve adhesion by coating or resin entering into the pore when painting or resin is welded. In addition, since the catalyst and the filtered matter can be stored in the pores, it can be used as a catalyst carrier or a filtration filter. Furthermore, the presence of the pores forms an air layer on the surface of the anodized film, so that the anodized film can be provided with a heat insulating effect. For example, when used for surface treatment of a piston, heat insulation of the piston The effect can be improved. In particular, because the hydrated compound contains lithium-aluminum hydrate, the corrosion resistance can be improved while maintaining the pores of the anodized film.

In the manufacturing method of the aluminum or aluminum alloy member concerning the present invention, it is a sectional view showing typically the aluminum or aluminum alloy member pre-processed. In the manufacturing method of the aluminum or aluminum alloy member concerning the present invention, it is a sectional view showing typically the hydrated aluminum or aluminum alloy member. It is an electron micrograph which shows the micropore which exists in the surface of an anodic oxide film in a control example. It is an electron micrograph which shows the micropore which exists in the surface of an anodic oxide film in a test example.

  Hereinafter, an embodiment of an aluminum or aluminum alloy member according to the present invention and a method of manufacturing the same will be described.

  First, in the method of manufacturing an aluminum or aluminum alloy member according to the present embodiment, the step of forming an anodized film on the surface of aluminum or aluminum alloy, the aluminum or aluminum alloy on which the anodized film is formed, phosphate ion Immersing in a pre-treatment solution containing the above to perform pre-treatment, and hydrating the anodized film on the surface of the pre-treated aluminum or aluminum alloy with a hydration treatment solution containing lithium ions It is included.

  The object to be treated, that is, the object forming the anodized film may be an aluminum alloy other than aluminum. The aluminum alloy is not particularly limited, and may contain components such as silicon and copper. Moreover, the manufacturing method of aluminum or an aluminum alloy is not specifically limited, either, A wrought material, a cast material, and a die-cast material can apply this method.

  In the step of forming the anodized film, in the anodizing solution, aluminum or an aluminum alloy is disposed as an anode, and a titanium or stainless steel plate is disposed as a cathode, and electrolytic treatment is performed. Thereby, an anodic oxide film containing aluminum oxide as a main component can be formed on the surface of aluminum or an aluminum alloy. The anodizing solution is not particularly limited. For example, any of an acid bath of sulfuric acid, oxalic acid, chromic acid or the like, or an alkaline bath of sodium hydroxide, sodium phosphate, sodium fluoride or the like may be used. In particular, it is preferable to use sulfuric acid because it is easy to form a film having a thick film thickness.

  The method of the electrolytic treatment is not particularly limited, and any of direct current electrolysis, alternating current electrolysis, AC / DC superimposed electrolysis, Duty electrolysis and the like may be used. After the electrolytic treatment, it is preferable to perform washing with water at least once. By washing with water, the anodizing treatment solution adhering to the aluminum or the aluminum alloy can be removed to some extent, or the concentration of the treatment solution which can not be removed can be reduced, and the amount mixed in the next step can be reduced. The water used in the water washing is preferably water having few impurities such as ion exchange water and pure water.

  The film thickness of the anodized film thus obtained is preferably 10 to 500 μm. If the film thickness of the anodized film is 10 μm, a sufficient antirust effect can be obtained. A thick anodic oxide film is preferable, but a thickness of 500 μm or less is preferable because the anodic oxide film can be easily formed. Moreover, as for the film thickness of an anodic oxide film, 10-300 micrometers is more preferable, and 10-100 micrometers is still more preferable.

  In the pretreatment step, the aluminum or aluminum alloy on which the anodized film has been formed is immersed in a pretreatment solution which is an aqueous solution containing phosphate ions. Thereby, phosphate ions are taken into the anodized film. In particular, as shown in FIG. 1, a plurality of holes 24 exist in the surface of the anodized film 22 formed on the aluminum or aluminum alloy 10, and the phosphate ions 26 of the pretreatment liquid are of the anodized film 22. Not only the surface but also the bottom of the hole 24 is taken. This phosphate ion has the function of suppressing the lithium-aluminum hydration reaction. Therefore, the phosphate ion 26a taken into the anodized film 22 can suppress the formation of the hydrated compound in the next step, and thus, the pore 24 can be prevented from being blocked by the hydrated compound.

  The reagent used as a phosphate ion source is not particularly limited as long as it is a compound containing phosphate ion, but a phosphoric acid or phosphate containing water-soluble phosphate ion is preferable, and ortho phosphoric acid, hydrogen phosphate and the like Disodium, sodium dihydrogen phosphate, trisodium phosphate, potassium phosphate, calcium dihydrogen phosphate, lithium phosphate, ammonium phosphate and the like are more preferable. Among these, phosphoric acid is particularly preferable because it is easy to be dissolved in water and easy to adjust the concentration of phosphate ion, in consideration of actual production.

  The pH of the pretreatment liquid is not particularly limited, and it can be used in the range of pH 1 to 12, and it is possible to sufficiently incorporate phosphate ions into the anodized film whether acidic, neutral or alkaline. However, since the pH of the hydration process liquid of the next step is alkaline, in order to suppress the change of the pH of the hydration process liquid when it is mixed in the next process, neutral or basic, ie, a range of pH 7 to 12 It is preferable to set the pH to 10.5 or more. In addition, when compounds other than the phosphate ion source are mixed in the pretreatment solution, it may be difficult to take in phosphate ions in the anodized film, so compounds other than the reagent of the phosphate ion source are mixed in the pretreatment solution. Preferably not.

  The phosphate ion concentration of the pretreatment liquid is preferably in the range of 0.1 to 2.0 mol / L. By setting the phosphate ion concentration to 0.1 mol / L or more, a sufficient amount of phosphate ion can be taken into the anodized film, and the formation of a hydrated compound in the next step is suppressed, and the formation of a hydrated compound Can prevent the pore from being blocked. Also, by setting the phosphate ion concentration to less than 2.0 mol / L, the pre-treatment solution itself is prevented from dissolving the film and reducing the film thickness because the force to dissolve the anodic oxide film becomes too large. Can. The concentration of phosphate ion in the pretreatment liquid is more preferably in the range of 0.5 to 2.0 mol / L, and still more preferably in the range of 1.0 to 2.0 mol / L.

  The temperature of the pretreatment liquid is preferably in the range of 10 to 30 ° C. By setting the temperature to 10 ° C. or higher, the activity of phosphate ions in the pretreatment liquid can be activated, and phosphate ions can be appropriately incorporated into the anodized film. Also, by setting the temperature to 30 ° C. or less, as in the case where the phosphate ion concentration is high, the force of the pretreatment liquid itself to dissolve the anodic oxide film becomes too large to dissolve the film and the film thickness decreases. , Can prevent. The temperature of the pretreatment liquid is more preferably in the range of 20 to 30 ° C.

  The immersion time in the pretreatment solution is preferably in the range of 30 seconds to 4 minutes. By setting the immersion time to 30 seconds or more, phosphate ions in the pretreatment liquid can be sufficiently taken into the anodized film, and the hydration reaction in the next step can be appropriately suppressed. Further, by setting the film thickness to 4 minutes or less, it is possible to prevent the anodic oxide film from being dissolved and the film thickness being reduced by immersion for a long time. The immersion time is more preferably in the range of 1 to 4 minutes.

  After immersing in the pretreatment solution, it is preferable to carry out water washing at least once and then carry out the hydration treatment of the next step, as in the step of forming the anodized film.

  In the step of hydration treatment, the anodized film formed on the surface of aluminum or aluminum alloy is subjected to hydration treatment with a hydration treatment solution which is an aqueous solution containing lithium ions. An aqueous solution containing such lithium ions has conventionally been used to close the pores of the anodized film. This aqueous solution dissolves the inside of the pore to enlarge the pore diameter, and then, it reacts with the aluminate ion generated by the dissolution to form a hydrated compound of lithium and aluminum, and the pore causes a pore It is something to shut up. However, in the present invention, since phosphate ions are sufficiently taken into the pore portion of the anodized film in the above-mentioned pretreatment step, the hydration reaction of lithium and aluminum is not sufficient in this hydration step. It is suppressed, and it becomes difficult to form a hydrated compound. Therefore, as shown in FIG. 2, the hydration treatment solution dissolves the inside of the holes 24 present on the surface of the anodic oxide film 22 to enlarge the pore diameter, and the hydration compound 32 is formed on the surface portion of the enlarged holes 34. Only the diameter of the final hole 34 can be greatly expanded than originally.

  As a reagent serving as a lithium ion source, lithium hydroxide, lithium carbonate, lithium sulfate, lithium chloride, or a hydrate thereof can be used. Among these, lithium hydroxide and lithium carbonate are preferable because the aqueous solution is alkaline and nontoxic.

  0.02-20 g / L is preferable and, as for the lithium ion concentration of a hydration process liquid, 0.08-10 g / L is more preferable. The pH of the hydration treatment solution is preferably 10.5 or more, more preferably 11 or more, and still more preferably 12 or more. Although the upper limit of pH is not specifically limited, 14 or less is preferable. Since the pH varies depending on the lithium ion source, the pH of the hydration treatment solution can be adjusted using an acid such as sulfuric acid, oxalic acid or chromic acid, or a base such as sodium hydroxide, sodium carbonate or sodium fluoride. .

  The method of hydration treatment is to immerse the aluminum or aluminum alloy on which the anodized film is formed in the hydration treatment solution, spray the hydration treatment solution on the surface of the anodized film, apply with a brush etc. Then, the hydration treatment solution may be attached to the anodized film. 10-65 degreeC is preferable and, as for the temperature of a hydration process liquid, 25-50 degreeC is more preferable. The hydration treatment time is preferably 30 seconds to 5 minutes. After the hydration treatment solution is applied, the anodized film is preferably washed with water or hot water, and dried with an air blow or a drier.

By such hydration treatment, as shown in FIG. 2, the inner surface of the plurality of fine holes 34 present on the surface of the anodized film 22 formed on the aluminum or aluminum alloy 10 is a layer of the hydration compound 32. The covered aluminum or aluminum alloy member 30 can be obtained. Hydrated compound 32 contains at least lithium-aluminum hydrate, and may also contain boehmite. The lithium-aluminum hydrate is, for example, LiH (AlO ₂ ) _2. 5H ₂ O, and the boehmite is, for example, AlO.OH. Since LiH (AlO ₂ ) _2. 5 H ₂ O is more resistant to moisture than boehmite, it can improve corrosion resistance.

  The enlarged hole 34 is covered on its inner surface by a layer of hydration product 32, but the hole diameter on the surface of the member 30 is 10 nm or more. If the pore diameter is 10 nm or more, for example, in order to improve the coating adhesion with the coating or resin, the coating adhesion can be improved because the anchor effect by the coating or the resin entering the hole works sufficiently . Further, the hole diameter of the holes 34 is preferably enlarged to 1.5 times or more of the hole diameter of the holes 24 of the initial anodic oxide film, and more preferably to 2 times or more.

(Evaluation test of anodic oxide film)
The surface of the anodized film formed according to the present invention was observed using an electron microscope, and a test was conducted to measure the pore diameter of the micropores present in the film surface. The pore diameter was taken as the average value of the pore diameters of the micropore openings (average value of five micropores). Before and after the series of treatments, the evaluation result is ○ for the anodized film whose pore diameter is enlarged by 1.5 to 2 times, and ◎ that which is expanded by more than 2 times. Others, for example, those with a change of less than 1.5 times, those with closed pores, and those with broken pores (cell structure) due to dissolution of the film were regarded as x. In addition, the film thickness of the anodized film is measured with a film thickness meter (manufactured by Fisher Instruments), and when the film thickness is reduced by 20% or more before and after the anodic oxidation treatment, the evaluation results are displayed. × and other than that ○. The film thickness is also the average film thickness (average value of five parts) of the anodized film. The result of the comprehensive evaluation was evaluated as x when either one of the evaluation result of the pore diameter and the evaluation result of the film thickness was x, and in other cases, it was ○ or 合 わ せ according to the evaluation result of the pore diameter.

  As a test piece used for formation of an anodic oxide film, aluminum alloy A1100 material was used. This is to avoid the distribution of the current density in the test piece being dispersed due to the influence of the alloying component when the alloy component is contained in a large amount, and the pore diameter may differ depending on the measurement position of the test piece. .

(Control 1)
An anodic oxide film is formed on the surface of the test piece by immersing a test piece of aluminum alloy A1100 material as a positive electrode in a 200 g / L concentration sulfuric acid bath and applying a direct current for 10 minutes at a current density of 2 A / dm ² did. The anodic oxide film was observed using an electron microscope and found to have a pore diameter of 15 nm and a film thickness of 20 μm. FIG. 3 shows an electron micrograph of the surface of the anodized film. The black part in the photograph is the pore. This anodic oxide film was used as Comparative Example 1 as a reference for judging changes in pore diameter and film thickness before and after treatment in Test Examples 1 to 4 below.

Test Example 1: Influence of phosphate ion concentration in pretreatment
A test piece of aluminum alloy A1100 material is immersed as an anode in a 200 g / L concentration sulfuric acid bath and a direct current of ² A / dm ² current density is applied for 10 minutes to obtain a pore diameter of 15 nm and a film thickness of 20 μm. An anodic oxide film was formed. Next, as pretreatment, as shown in Table 1 below, phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate, trisodium phosphate, using a reagent of a phosphoric acid compound different in pH, phosphoric acid The test piece which formed the anodic oxide film was immersed for 2 minutes in the aqueous solution (20 degreeC) prepared so that ion concentration might be 0.01-6 mol / L. Thereafter, as a hydration treatment, a test piece pretreated with a pH 13 aqueous solution (25 ° C.) prepared to have a lithium ion concentration of 0.2 g / L using lithium hydroxide monohydrate, for 1 minute Soaked. The surface of the test piece after the hydration treatment was observed with an electron microscope to measure the diameter of pores present on the surface, and the film thickness of the anodic oxide film was measured with a film thickness meter. Each value measured in Test Example 1 is compared with the reference value of Control Example 1 described above, and the evaluation result is shown in Table 1.

  As shown in Table 1, when the phosphate ion concentration is in the range of 0.1 to 2 mol / L (sample numbers 2 to 4, 8, 11, 12, 14, 15), the film thickness of the anodic oxide film is maintained It was possible to enlarge the pore diameter sufficiently. The electron micrograph of the surface of the anodic oxide film of the sample number 4 is shown in FIG. 4 as an example of the mode. It is presumed that a large amount of phosphate ions are incorporated into the film. On the other hand, when the phosphate ion concentration was less than 0.1 mol / L (Sample Nos. 1, 7, 10, 13), the pores were clogged. This is presumed to be one in which the formation of a hydrated compound of lithium and aluminum in the hydration process could not be suppressed because the phosphate ion is less likely to be incorporated into the film. Moreover, when the phosphate ion concentration exceeded 2 mol / L (sample numbers 5, 6, 9), the film thickness decreased and the pores (cell structure) were broken. It is presumed that this is because the anodic oxide film dissolves and the film itself becomes brittle because the solvency of the treatment liquid in the pretreatment increases. In addition, the reagent as a phosphate ion source shows the same effect in any of phosphoric acid, sodium dihydrogen phosphate, disodium hydrogen phosphate and trisodium phosphate, and the type and treatment of the phosphate ion source It was found that the pH of the solution had no effect.

(Test Example 2: Effect of temperature in pretreatment)
An anodic oxide film was formed by immersing a test piece of an aluminum alloy A1100 material as a positive electrode in a sulfuric acid bath having a concentration of 200 g / L and applying a direct current having a current density of 2 A / dm ² for 10 minutes. Next, a test piece in which an anodic oxide film was formed at each temperature between 5 and 50 ° C. in an aqueous solution prepared to have a phosphate ion concentration of 1 mol / L using phosphoric acid as a reagent as pretreatment Soak for 2 minutes. Then, the test piece which pre-processed was immersed for 1 minute in the aqueous solution (25 degreeC) of pH13 prepared so that lithium ion concentration might be 0.2 g / L similarly to Experiment 1 as hydration processing. The pore diameter of the surface of the test piece after this hydration treatment was measured with an electron microscope as in Test Example 1, and the film thickness was measured with a film thickness meter. Each value measured in Test Example 2 was compared with the reference value of Control Example 1 described above, and the evaluation results are shown in Table 2.

  As shown in Table 2, when the temperature of the phosphate ion aqueous solution is in the range of 10 to 30 ° C. (Sample Nos. 3 and 17 to 19), the pore diameter can be enlarged while maintaining the film thickness of the anodic oxide film did it. On the other hand, when the temperature of the aqueous solution was lower than 10 ° C. (sample No. 16), the pores were blocked. This is presumed to be that if the temperature is low, the movement of phosphate ions becomes dull and it is difficult to be taken into the anodized film, so that the formation of the hydrated compound of lithium and aluminum in the hydration treatment can not be suppressed. Moreover, when the temperature of the aqueous solution exceeded 30 ° C. (Sample Nos. 20 and 21), the film thickness decreased and the pores (cell structure) were broken. It is presumed that this is because the anodic oxide film dissolves and the film itself becomes brittle because the solvency of the treatment liquid in the pretreatment increases.

(Test Example 3: Influence of immersion time in pretreatment)
An anodic oxide film was formed by immersing a test piece of an aluminum alloy A1100 material as a positive electrode in a sulfuric acid bath having a concentration of 200 g / L and applying a direct current having a current density of 2 A / dm ² for 10 minutes. Next, as pretreatment, a test piece having an anodic oxide film formed on an aqueous solution (20 ° C.) prepared to have a phosphate ion concentration of 1 mol / L using phosphoric acid as a reagent for 15 seconds to 10 minutes It was immersed in various times. Then, the test piece which pre-processed was immersed for 1 minute in the aqueous solution (25 degreeC) of pH13 prepared so that lithium ion concentration might be 0.2 g / L similarly to Experiment 1 as hydration processing. The pore diameter of the surface of the test piece after this hydration treatment was measured with an electron microscope as in Test Example 1, and the film thickness was measured with a film thickness meter. Each value measured in Test Example 3 was compared with the reference value of Control Example 1 described above, and the evaluation results are shown in Table 3.

  As shown in Table 3, when the immersion time in the phosphate ion aqueous solution is in the range of 30 seconds to 4 minutes (sample numbers 3 and 23 to 25), the pore diameter is maintained while maintaining the film thickness of the anodic oxide film. It was possible to expand. On the other hand, when the immersion time was shorter than 30 seconds (Sample No. 22), the pores were blocked. This is presumed to be that if the immersion time is short, the amount of phosphate ions taken into the anodized film is small, so that the formation of the hydrated compound of lithium and aluminum in the hydration process can not be suppressed. Moreover, when immersion time exceeded 4 minutes (sample numbers 26 and 27), while a film thickness reduced, the pore (cell structure) was disorganized. It is presumed that this causes the anodic oxide film to be dissolved by immersion for a long time and the film itself becomes brittle.

(Test Example 4: Influence of treatment conditions in hydration treatment)
An anodic oxide film was formed by immersing a test piece of an aluminum alloy A1100 material as a positive electrode in a sulfuric acid bath having a concentration of 200 g / L and applying a direct current having a current density of 2 A / dm ² for 10 minutes. Next, the test piece which formed the anodic oxide film was immersed for 2 minutes in the aqueous solution (20 degreeC) prepared so that phosphate ion concentration might be 1 mol / L, using phosphoric acid as a reagent as pre-processing. Then, as shown in Table 4 as hydration treatment, it is preferable to use an aqueous solution of pH 13 prepared so that the lithium ion concentration is in the range of 0.01 to 25 g / L using lithium hydroxide monohydrate. The pretreated test specimens were immersed at a temperature of between 80 ° C. for a time of between 5 seconds and 10 minutes. The pore diameter of the surface of the test piece after this hydration treatment was measured with an electron microscope as in Test Example 1, and the film thickness was measured with a film thickness meter. Each value measured in this test example 4 was compared with the reference value of the above-mentioned control example 1, and the result of having evaluated is shown in Table 4.

  As shown in Table 4, in the case where the lithium ion concentration is in the range of 0.05 to 10 g / L, the temperature is in the range of 10 to 40 ° C., and the immersion time is in the range of 30 seconds to 5 minutes (sample number 3, 29 And 32), the pore diameter could be sufficiently enlarged while maintaining the film thickness of the anodized film. On the other hand, when the lithium ion concentration was as low as 0.01 g / L or when the temperature was as low as 5 ° C. (Sample Nos. 28 and 30), the pore size could not be expanded. It is presumed that this is because the power to dissolve the anodized film of the processing solution is too weak. Conversely, when the lithium ion concentration was as high as 25 g / L, or when the temperature was as high as 80 ° C. (sample numbers 35 and 33), the pores were clogged. This is because the high concentration and temperature make it easy to cause a chemical reaction to form a hydrated compound of lithium and aluminum, and the effect of phosphate ion makes it difficult to suppress the formation of this hydrated compound. Infer. Moreover, when the immersion time was as short as 5 seconds (sample number 34), the pore diameter could not be expanded. It is presumed that this is because the time to dissolve the anodized film is also shortened. On the other hand, when the immersion time was as long as 10 minutes (sample number 31), part of the pores was blocked. It is presumed that this is because the formation reaction of the hydrated compound continues to progress.

DESCRIPTION OF SYMBOLS 10 Aluminum or aluminum alloy 20 Pretreated aluminum or aluminum alloy member 22 Anodized film 24, 34 Hole 26 Phosphate ion 30 Hydrated aluminum or aluminum alloy member 32 Hydrated compound

Claims (8)

An aluminum or aluminum alloy member comprising aluminum or an aluminum alloy and an anodized film formed on the surface thereof, wherein a plurality of holes are present on the surface of the anodized film, and the holes are blocked. not, the inner surface of that is covered with hydrated compound, wherein the hydrated compound is a lithium - aluminum or aluminum alloy member is intended to include hydrated aluminum.   The aluminum or aluminum alloy member according to claim 1, wherein the hole whose inner surface is covered with the hydrated compound has a pore diameter of 10 nm or more on the member surface.   The aluminum or aluminum alloy member according to claim 1, wherein a film thickness of the anodized film is 10 μm or more. The lithium - aluminum or aluminum alloy member according to any one of claims 1 to 3 aluminum hydrate is intended to include _{LiH (AlO 2) 2 · 5H} 2 O. Immersing the aluminum or aluminum alloy on which the anodized film is formed in a pretreatment solution containing phosphate ions to carry out pretreatment;
The anodic oxide film on the aluminum or aluminum alloy subjected to the pretreatment is subjected to hydration treatment with a hydration treatment solution containing lithium ions to enlarge the pore diameter of the plurality of pores present on the surface of the anodic oxide film; And a step of covering the inner surface of the hole with a hydrated compound containing lithium-aluminum hydrate.   The method according to claim 5, wherein the phosphate ion concentration of the pretreatment solution is in the range of 0.1 to 2.0 mol / L.   The method according to claim 5 or 6, wherein the temperature of the pretreatment liquid is in the range of 10 to 30 ° C.   The manufacturing method according to any one of claims 5 to 7, wherein a time of immersion in the pretreatment liquid is in a range of 30 seconds to 4 minutes.