Aqueous composition, method for producing surface-treated metal, and metal

Abstract

The purpose is to provide an aqueous composition or the like for treating the surface of an aluminum-containing metal so that a material other than a metal can satisfactorily adhere to the surface of the metal. The present disclosure relates to an aqueous composition for treating the surface of an aluminum-containing metal, the aqueous composition containing 0.01-15.00 mass% of hydrogen peroxide, 0.10-15.00 mass% of fluoride ions, 0.10-30.00 mass% of phosphoric acid, and 0.10-15.00 mass% of chloride ions with respect to the total amount of the aqueous composition.

Description

Aqueous composition, method for producing surface-treated metal, and metal

[0001] This invention relates to aqueous compositions, methods for producing surface-treated metals, and metals.

[0002] Aluminum is used in a variety of products, including positive electrode current collectors in batteries such as lithium-ion secondary batteries, transportation equipment such as automobiles, and electronic devices such as smartphones and computers. When using aluminum in such applications, non-metallic materials dispersed in an aqueous solvent are sometimes attached to the aluminum. For example, in the positive electrode of a battery, positive electrode materials used in the positive electrode, such as positive electrode active material, may be attached to a positive electrode current collector containing aluminum. In addition, in transportation equipment and electronic devices, resin may be attached to metals containing aluminum to reinforce strength and ensure insulation. In such cases, various studies have been conducted on how to ensure good adhesion of non-metallic materials to aluminum. For example, Patent Document 1 discloses a current collector material that modifies the surface of the aluminum current collector material to improve adhesion with the active material, thereby reducing the electrical resistance generated between the current collector and the coating containing the active material.

[0003] Japanese Patent Publication No. 2014-211960

[0004] Patent Document 1 mentions surface roughening as a method for modifying the surface of aluminum, and chemical etching is given as an example of a method for roughening the surface. In the chemical etching disclosed in Patent Document 1, sodium hydroxide and hydrochloric acid are used. On the other hand, even if the surface is roughened by this chemical etching, there are cases in which non-metallic materials do not adhere well to the aluminum.

[0005] The present invention has been made in view of the above-mentioned problems, and aims to provide an aqueous composition, etc., for treating the surface of a metal containing aluminum, so that a non-metallic material dispersed in an aqueous solvent (hereinafter also simply referred to as "non-metallic material") can adhere well to the surface of the metal.

[0006] The inventors diligently studied to solve the above problems. As a result, they found that an aqueous composition for treating the surface of a metal containing aluminum, comprising, in proportion to the total amount of the aqueous composition, 0.01% to 15.00% by mass of hydrogen peroxide, 0.10% to 15.00% by mass of fluoride ions, 0.10% to 30.00% by mass of phosphoric acid, and 0.10% to 15.00% by mass of chloride ions, can solve the above problems, and thus completed the present invention.

[0007] In other words, the present invention includes the following embodiments: [1] An aqueous composition for treating the surface of a metal containing aluminum, comprising, in proportion to the total amount of the aqueous composition, 0.01% by mass or more and 15.00% by mass or less of hydrogen peroxide, 0.10% by mass or more and 15.00% by mass or less of fluoride ions, 0.10% by mass or more and 30.00% by mass or less of phosphoric acid, and 0.10% by mass or more and 15.00% by mass or less of chloride ions. [2] A method for producing a surface-treated metal, comprising the step of contacting the aluminum-containing metal with the aqueous composition described in [1] to treat the surface of the metal. [3] The method for producing the surface-treated metal according to [2], wherein the surface roughness Ra of the surface of the surface-treated metal is 0.05 μm or more and 1.50 μm or less, the maximum height Rz of the surface of the surface-treated metal is 0.50 μm or more and 10.00 μm or less, and the contact angle of the surface of the surface-treated metal with water is 80° or less. [4] The manufacturing method according to [2] or [3], wherein the thickness of the metal before being subjected to the above process is 1 μm or more and 100 μm or less. [5] A metal having a surface and containing aluminum, wherein the surface roughness Ra of the surface is 0.05 μm or more and 1.50 μm or less, the maximum height Rz of the surface is 0.50 μm or more and 10.00 μm or less, and the contact angle of the surface with water is 80° or less. [6] The metal according to [5], wherein the thickness is 1 μm or more and 100 μm or less.

[0008] The following describes in detail embodiments of the present invention (hereinafter referred to as "this embodiment"), but the present invention is not limited thereto, and various modifications are possible without departing from its spirit.

[0009] 1. Aqueous Composition The aqueous composition of this embodiment (hereinafter also simply referred to as "aqueous composition") is an aqueous composition for treating the surface of an aluminum-containing metal (hereinafter also referred to as "aluminum-containing metal"), and contains, in proportion to the total amount of the aqueous composition, 0.01% by mass to 15.00% by mass of hydrogen peroxide, 0.10% by mass to 15.00% by mass of fluoride ions, 0.10% by mass to 30.00% by mass of phosphoric acid, and 0.10% by mass to 15.00% by mass of chloride ions. The surface of the aluminum-containing metal to which the aqueous composition of this embodiment is applied becomes highly hydrophilic, and as a result, the adhesion between the aluminum-containing metal and non-metallic materials dispersed in an aqueous solvent is improved. Furthermore, due to the high hydrophilicity, it tends to be easier to uniformly coat the non-metallic material onto the surface, i.e., the coatability is improved.

[0010] Furthermore, the surface of an aluminum-containing metal treated with such an aqueous composition tends to be roughened to have a fine roughness. Therefore, when the roughened surface of the aluminum-containing metal comes into contact with a non-metallic material dispersed in an aqueous solvent, the non-metallic material easily penetrates into the depressions in the surface. As a result, the material engages with the surface through an anchoring effect, which tends to increase the bonding strength between the roughened aluminum-containing metal and the material. Non-metallic materials dispersed in an aqueous solvent include substances that are fluid and easily penetrate into depressions. More specifically, examples include cathode materials such as cathode active material compositions containing cathode active material dispersed in an aqueous solvent, and resins dispersed in an aqueous solvent.

[0011] The exact reason why the surface of the aluminum-containing metal becomes roughened to have minute roughness when using the aqueous composition of this embodiment is unclear, but the inventors believe the reason is as follows. However, the reason is not limited to the following. That is, a predetermined amount of phosphoric acid and a predetermined amount of fluoride ions dissolve the surface of the aluminum-containing metal, and a predetermined amount of hydrogen peroxide promotes this dissolution. Furthermore, a predetermined amount of chloride ions causes the dissolution to proceed unevenly on the surface. In this way, the surface of the aluminum-containing metal becomes minutely rough.

[0012] The aqueous composition of this embodiment will be described in detail below.

[0013] 1.1. Hydrogen Peroxide The aqueous composition of this embodiment contains 0.01% by mass or more and 15.00% by mass or less of hydrogen peroxide based on the total amount of the aqueous composition. The hydrogen peroxide content is preferably 0.1% by mass or more and 12.5% ​​by mass or less, more preferably 0.2% by mass or more and 10.0% by mass or less, even more preferably 0.5% by mass or more and 7.5% by mass or less, and even more preferably 1.0% by mass or more and 5.0% by mass or less, based on the total amount of the aqueous composition. When the hydrogen peroxide content is within the above range, the dissolution of the surface of the aluminum-containing metal by the phosphoric acid and fluoride ions described later is more easily promoted, and the adhesion of non-metallic materials tends to be further improved. In addition, the hydrophilicity of the surface tends to be further improved, and the adhesion and coating properties of non-metallic materials tend to be further improved.

[0014] 1.2. Fluoride Ions The aqueous composition of this embodiment contains 0.10% by mass or more and 15.00% by mass or less of fluoride ions based on the total amount of the aqueous composition. Examples of fluorides that provide fluoride ions include alkali metal fluorides such as sodium fluoride and potassium fluoride, alkaline earth metal fluorides such as calcium fluoride, ammonium fluoride, ammonium hydrogen fluoride, and copper fluoride. Among these, ammonium hydrogen fluoride is preferred from the viewpoint of more effectively and reliably achieving the effects of the present invention. The fluoride may be used alone or two or more may be used in combination.

[0015] The content of fluoride ions is preferably 1.00% by mass or more and 12.50% by mass or less, more preferably 2.00% by mass or more and 10.00% by mass or less, still more preferably 2.50% by mass or more and 10.00% by mass or less, and even more preferably 3.00% by mass or more and 9.00% by mass or less, based on the total amount of the aqueous composition. When the content of fluoride ions is within the above range, the dissolution of the surface of the aluminum-containing metal by the aqueous composition progresses more, resulting in a rougher surface and a tendency for the adhesion of materials other than the metal to be further improved. Also, the hydrophilicity of the surface is further improved, and the adhesion and coating properties of materials other than the metal tend to be further improved.

[0016] 1.3. Phosphoric acid The aqueous composition of the present embodiment contains 0.10% by mass or more and 30.00% by mass or less of phosphoric acid based on the total amount of the aqueous composition. In the present embodiment, phosphoric acid means phosphoric acid (H ３ PO ４ ), and phosphate ions (H ２ PO ４ － , HPO ４ ２－ , and PO ４ ３－ ), and the mass of phosphoric acid means the total amount of phosphoric acid (H ３ PO ４ ) and phosphate ions (H ２ PO ４ － , HPO ４ ２－ , and PO ４ ３－ ).

[0017] The phosphoric acid content is preferably 1.00% by mass or more and 28.00% by mass or less, more preferably 5.00% by mass or more and 26.00% by mass or less, even more preferably 6.00% by mass or more and 24.00% by mass or less, and even more preferably 7.50% by mass or more and 22.00% by mass or less, based on the total amount of the aqueous composition. When the phosphoric acid content is within the above range, the dissolution of the surface of the aluminum-containing metal by the aqueous composition proceeds more, resulting in a rougher surface and a tendency for the adhesion of non-metallic materials to improve. In addition, the hydrophilicity of the surface tends to improve, and the adhesion and coating properties of non-metallic materials tend to improve.

[0018] 1.4. Chloride Ions The aqueous composition of this embodiment contains 0.10% by mass or more and 15.00% by mass or less of chloride ions based on the total amount of the aqueous composition. Examples of chlorides that provide chloride ions include alkali metal chlorides such as sodium chloride and potassium chloride, alkaline earth metal chlorides such as calcium chloride, ammonium chloride, hydrochloric acid, and copper chloride. Among these, hydrochloric acid is preferred from the viewpoint of more effectively and reliably achieving the effects of the present invention. Chlorides may be used individually or in combination of two or more.

[0019] The chloride ion content is preferably 0.50% to 12.50% by mass, more preferably 1.00% to 10.00% by mass, even more preferably 1.30% to 7.50% by mass, even more preferably 2.00% to 7.25% by mass, and particularly preferably 2.50% to 7.00% by mass, based on the total amount of the aqueous composition. When the chloride ion content is within the above range, the dissolution of the aluminum-containing metal surface by the aqueous composition becomes more uneven, resulting in a rougher surface and a tendency for improved adhesion of non-metallic materials. Furthermore, the hydrophilicity of the surface tends to improve, leading to improved adhesion and coating properties of non-metallic materials.

[0020] 1.5. Water The aqueous composition of this embodiment contains water. The water is not particularly limited, but may be, for example, pure water or deionized water. The water content is not particularly limited, but is, for example, 55% by mass or more and 90% by mass or less of the total amount of the aqueous composition.

[0021] 1.6. Other Additives The aqueous composition of this embodiment may contain various additives commonly used for surface treatment of aluminum-containing metals, to the extent that they do not impair the effects of the present invention. These additives may be used individually or in combination of two or more.

[0022] 1.7. Method for Producing the Aqueous Composition The method for producing the aqueous composition of this embodiment is not particularly limited, but for example, the above components may be mixed together. The order of mixing is not particularly limited, but for example, the above components may be added to water all at once and mixed, or some of the above components may be added to water and mixed, and then the remaining components may be added and mixed.

[0023] 2. Method for Manufacturing Surface-Treated Metal The method for manufacturing surface-treated metal according to this embodiment includes a step of contacting the above-mentioned aqueous composition with an aluminum-containing metal to treat the surface of the metal (hereinafter also referred to as the "surface treatment step"). By manufacturing surface-treated metal using the method of this embodiment, the surface of the surface-treated metal tends to be sufficiently roughened. The steps that may be included in the method of this embodiment will be described in detail below.

[0024] 2.1. Surface treatment process In the surface treatment process, the above-mentioned aqueous composition is brought into contact with an aluminum-containing metal to treat the surface of the metal.

[0025] The means for bringing the aqueous composition into contact with the aluminum-containing metal are not particularly limited and include, for example, a method of spraying (jet coating) or atomizing (spray coating) the aqueous composition toward the surface of the aluminum-containing metal, a method of applying the aqueous composition to the surface of the aluminum-containing metal using a brush or blade, a method of rotating the metal while dropping the aqueous composition onto the surface of the aluminum-containing metal and using centrifugal force to spread the aqueous composition over the entire surface of the metal (spin coating), and a method of immersing the aluminum-containing metal in a bath of aqueous composition (dip coating).

[0026] The contact time between the aqueous composition and the aluminum-containing metal is preferably 5 seconds to 120 seconds, more preferably 10 seconds to 60 seconds, and even more preferably 15 seconds to 50 seconds. Contacting the aqueous composition with the aluminum-containing metal for 5 seconds or more tends to make the surface of the aluminum-containing metal rougher and improve its hydrophilicity. Furthermore, the degree of surface roughening and hydrophilicity are further increased by contacting the aqueous composition with the aluminum-containing metal for about 120 seconds. In other words, from the viewpoint of improving the degree of surface roughening and hydrophilicity while shortening the time required for surface treatment, it is preferable that the contact time between the aqueous composition and the aluminum-containing metal is 120 seconds or less.

[0027] The temperature of the aqueous composition when it is brought into contact with the aluminum-containing metal is not particularly limited, but is, for example, 20°C to 70°C.

[0028] 2.2 Other Processes The method for manufacturing surface-treated aluminum-containing metal according to this embodiment may include other processes besides the surface treatment process. Other processes are not particularly limited, but examples include an unwinding process for unwinding the aluminum-containing metal, which has been prepared in a roll shape before surface treatment, and a winding process for winding the aluminum-containing metal, after surface treatment, into a roll shape.

[0029] 3. The aluminum-containing metals to which the aluminum-containing metal aqueous composition is used include aluminum and aluminum alloys. The aluminum content in the aluminum alloy before surface treatment is preferably 50.0% by mass or more and 99.9% by mass or less, more preferably 70.0% by mass or more and 99.9% by mass or less, and even more preferably 90.0% by mass or more and 99.9% by mass or less. When the aluminum content is within the above range, the surface of the aluminum alloy is more easily roughened by the aqueous composition, and the adhesion of non-metallic materials tends to improve further. In addition, the hydrophilicity of the surface is more easily improved by the aqueous composition, and the adhesion and coating properties of non-metallic materials tend to improve further.

[0030] Other metals included in aluminum alloys are not particularly limited, but examples include iron, copper, manganese, magnesium, chromium, zinc, gallium, vanadium, nickel, zirconium, and titanium. Nonmetals included in aluminum alloys are not particularly limited, but examples include carbon, silicon, and boron. The content of components other than aluminum in aluminum alloys is not particularly limited, but examples include 0.1 to 10.0% by mass, 0.1 to 5.0% by mass, and 0.1 to 1.0% by mass.

[0031] Aluminum alloys are not particularly limited, but examples include pure aluminum alloys with an aluminum content of 99% by mass or more, aluminum-copper alloys containing mainly copper in addition to aluminum, aluminum-manganese alloys containing mainly manganese in addition to aluminum, and aluminum-magnesium alloys containing mainly magnesium in addition to aluminum. More specifically, examples include all alloys in the A1000 to A8000 series (corrosion-resistant aluminum alloys, high-strength aluminum alloys, heat-resistant aluminum alloys, etc.) as defined in the Japanese Industrial Standards (JIS), such as the pure aluminum alloys A1100, A1085, and A1050, the aluminum-copper alloy A2024, the aluminum-manganese alloy A3003, and the aluminum-magnesium alloy A5052, as well as casting aluminum alloys such as ADC1 to ADC12 (aluminum alloys for die casting). More specifically, examples include A1N30H alloy and A1100H alloy.

[0032] The shape of the aluminum-containing metal is not particularly limited, but may be, for example, plate-shaped, columnar, or any other shape suitable for its application. For example, the shape of the aluminum-containing metal may be foil.

[0033] The thickness of the aluminum-containing metal before surface treatment is preferably 1 μm to 100 μm, more preferably 5 μm to 75 μm, and even more preferably 10 μm to 50 μm. Having a thickness within the above range before surface treatment tends to make it easier to perform processes such as bending on the aluminum-containing metal.

[0034] The thickness of the aluminum-containing metal after surface treatment is preferably 1 μm to 100 μm, more preferably 5 μm to 75 μm, and even more preferably 10 μm to 50 μm. Having a thickness within the above range after surface treatment tends to facilitate processing such as bending of the aluminum-containing metal.

[0035] The surface roughness Ra on the surface of the aluminum-containing metal after surface treatment is preferably 0.05 μm or more and 1.50 μm or less, more preferably 0.07 μm or more and 1.20 μm or less, still more preferably 0.10 μm or more and 1.00 μm or less, even more preferably 0.20 μm or more and 1.00 μm or less, and particularly preferably 0.25 μm or more and 1.00 μm or less. Alternatively, the lower limit value of the surface roughness Ra is preferably 0.05 μm, 0.06 μm, 0.07 μm, 0.08 μm, 0.09 μm, 0.10 μm, 0.12 μm, 0.14 μm, 0.16 μm, 0.18 μm, 0.20 μm, 0.22 μm, 0.24 μm, 0.25 μm, 0.26 μm, 0.28 μm, 0.30 μm. Also, the upper limit value of the surface roughness Ra is preferably 1.50 μm, 1.40 μm, 1.30 μm, 1.20 μm, 1.10 μm, 1.00 μm, 0.98 μm, 0.96 μm, 0.94 μm, 0.92 μm, 0.90 μm. As a suitable numerical range of the surface roughness Ra, the above-mentioned lower limit value and upper limit value may be arbitrarily combined and set. When the surface roughness Ra is within the above range, materials other than metals tend to adhere more easily to the aluminum-containing metal.

[0036] The maximum height Rz on the surface of the aluminum-containing metal after surface treatment is preferably 0.50 μm or more and 10.00 μm or less, more preferably 1.00 μm or more and 10.00 μm or less, even more preferably 1.50 μm or more and 10.00 μm or less, and even more preferably 2.00 μm or more and 10.00 μm or less. Alternatively, the lower limit of the maximum height Rz is preferably 0.50 μm, 0.60 μm, 0.70 μm, 0.80 μm, 0.90 μm, 1.00 μm, 1.25 μm, 1.50 μm, 1.75 μm, 2.00 μm, 2.25 μm, 2.50 μm, 2.75 μm, 3.00 μm, 3.25 μm, 3.50 μm, 3.75 μm, and 4.00 μm. Furthermore, the upper limit of the maximum height Rz is preferably 10.00 μm, 9.80 μm, 9.60 μm, 9.40 μm, 9.20 μm, 9.00 μm, 8.80 μm, 8.60 μm, 8.40 μm, 8.20 μm, 8.00 μm, 7.50 μm, and 7.00 μm. The preferred numerical range for the maximum height Rz may be set by arbitrarily combining the lower and upper limits mentioned above. When the maximum height Rz is within the above range, non-metallic materials tend to adhere more easily to the aluminum-containing metal.

[0037] The surface roughness Ra and maximum height Rz were measured in accordance with JIS B0601:2013.

[0038] The water contact angle on the surface of the aluminum-containing metal after surface treatment is 80° or less, preferably 70° or less, more preferably 65° or less, even more preferably 60° or less, even more preferably 40° or less, particularly preferably 30° or less, and even more preferably 20° or less. When the water contact angle is within the above range, non-metallic materials tend to adhere more easily to the aluminum-containing metal. Also, it tends to be easier to coat the surface of the aluminum-containing metal with non-metallic materials. The lower limit of the water contact angle on the surface of the aluminum-containing metal after surface treatment is not particularly limited, but for example, it is 0° or more.

[0039] The surface roughness Ra and the maximum height Rz on the surface of the aluminum-containing metal can be adjusted by treating the surface of the aluminum-containing metal with the above-described aqueous composition. For example, by increasing the treatment time of the aqueous composition, the surface roughness Ra and the maximum height Rz tend to increase. Also, by adjusting the composition of the aqueous composition, the surface roughness Ra and the maximum height Rz can be adjusted. For example, by setting the hydrogen peroxide content within the above range, the surface roughness Ra and the maximum height Rz tend to increase. Alternatively, by setting the fluoride ion content within the above range, the surface roughness Ra and the maximum height Rz tend to increase. Alternatively, by setting the phosphoric acid content within the above range, the surface roughness Ra and the maximum height Rz tend to increase. Alternatively, by setting the chloride ion content within the above range, the surface roughness Ra and the maximum height Rz tend to increase. By combining and adjusting the contents of these respective components, the surface roughness Ra and the maximum height Rz tend to be controllable within the above range.

[0040] The contact angle of water on the surface of the aluminum-containing metal can be adjusted by treating the surface of the aluminum-containing metal with the above-described aqueous composition. For example, by increasing the treatment time of the aqueous composition, the contact angle of water can be decreased. Also, by adjusting the composition of the aqueous composition, the contact angle of water can be adjusted. Specifically, by increasing the hydrogen peroxide content, the contact angle of water can be decreased. Also, by increasing the fluoride ion content, the contact angle of water can be decreased. Also, by increasing the phosphoric acid content, the contact angle of water can be decreased. Also, by increasing the chloride ion content, the contact angle of water can be decreased.

[0041] Hereinafter, the present invention will be described more specifically using examples and comparative examples. The present invention is not limited in any way by the following examples. Unless otherwise specified, each operation in the examples was performed under the conditions of room temperature (25 ° C) and 1 atmosphere.

[0042] 1. Preparation of aqueous composition [Example 1] 2.5% by mass of hydrogen peroxide, 10% by mass of ammonium hydrogen fluoride, 15% by mass of phosphoric acid, and 5% by mass of hydrochloric acid were added to deionized water and mixed to obtain 100% by mass of the aqueous composition of Example 1. The content of hydrogen peroxide, fluoride ions, phosphoric acid, and chloride ions in the aqueous composition of Example 1 are shown in Table 1, respectively.

[0043] [Examples 2-25] Aqueous compositions of Examples 2-25 were obtained in the same manner as in Example 1, except that the content of hydrogen peroxide, ammonium hydrogen fluoride, phosphoric acid, and hydrochloric acid added to the deionized water was changed as shown in Table 2. The content of hydrogen peroxide, fluoride ions, phosphoric acid, and chloride ions in Examples 2-25 are as shown in Table 1.

[0044] [Comparative Examples 1-4] Aqueous compositions of Comparative Examples 1-4 were obtained in the same manner as in Example 1, except that the content of hydrogen peroxide, ammonium hydrogen fluoride, phosphoric acid, and hydrochloric acid added to the deionized water was changed as shown in Table 2. The content of hydrogen peroxide, fluoride ions, phosphoric acid, and chloride ions in Comparative Examples 1-4 are as shown in Table 1.

[0045] 2. Surface treatment of aluminum-containing metal [Example 1] An entire aluminum alloy (A1N30H) with a thickness of 15 μm was immersed in the aqueous composition of Example 1 for surface treatment, and then washed with water and dried to obtain the surface-treated aluminum-containing metal of Example 1. The treatment conditions were that the temperature of the aqueous composition was 30°C and the immersion time was 10 seconds.

[0046] [Examples 2-25] Except for changing the type and thickness of the aluminum-containing metal used, and the treatment conditions (temperature of the aqueous composition and immersion time) as shown in Table 1, surface-treated aluminum-containing metals of Examples 2-25 were obtained in the same manner as in Example 1.

[0047] [Comparative Examples 1-4] Surface-treated aluminum-containing metals for Comparative Examples 1-4 were obtained in the same manner as in Example 1, except that the type and thickness of the aluminum-containing metal used, and the treatment conditions (temperature of the aqueous composition and immersion time) were changed as shown in Table 1.

[0048] Table 3 shows the composition of the aluminum-containing metals used in each example and comparative example. A1N30H and A1100H are names according to JIS H4160:1994. The values ​​in Table 3 represent the mass percentage of the total amount of aluminum-containing metal. The values ​​shown under "Other (each)" indicate the content of each element if elements other than those shown in Table 3 are present. "Other (total)" indicates the total content of elements other than those shown in Table 3 if they are present.

[0049] 3. Measurement Results 3.1. Surface Roughness Ra and Maximum Height Rz For each example of surface-treated aluminum-containing metal, the surface roughness Ra and maximum height Rz were measured using a VK-X250 laser microscope manufactured by Keyence Corporation. The measurement results are shown in Table 1.

[0050] 3.2. Thickness For each example of surface-treated aluminum-containing metal, the thickness was measured at three locations using a Mitutoyo high-precision digital micrometer MDH-25MB, and the average value was calculated. The calculation results are shown in the "Thickness after Treatment" column of Table 1. The three measurement locations were near the center, one end, and the other end opposite to the first end of each example of surface-treated aluminum-containing metal.

[0051] The reason why the thickness of aluminum-containing metal may increase due to surface treatment is presumed to be as follows: Since the thickness of aluminum-containing metal is the average of the thicknesses measured at three points using a micrometer, if there are irregularities on the surface of the metal, the value obtained from the measurement will be the average of the heights of the peaks of the protrusions. Here, although the surface of the aluminum-containing metal partially dissolves due to surface treatment, the molten aluminum may precipitate on the surface of the metal, forming protrusions. In that case, it is presumed that the thickness of the aluminum-containing metal may increase in the measurement results due to surface treatment.

[0052] 3.3. Water Contact Angle For each example of surface-treated aluminum-containing metal, the contact angle with water on the metal surface was measured using a contact angle meter (θ / 2 method, manufactured by Kyowa Interface Science Co., Ltd., CA-X (product name)). The measurement results are shown in Table 1. Note that <10 indicates that the water contact angle was less than 10°.

[0053] Furthermore, Table 4 shows the surface roughness Ra, maximum height Rz, and water contact angle for A1N30H and A1100H when the surface was not treated with an aqueous composition.

[0054]

[0055]

[0056]

[0057]

[0058] The adhesion and coating properties of the water-dispersed cathode material to the surface-treated aluminum-containing metal in each embodiment are higher than those of the same cathode material to the surface-treated aluminum-containing metal in each comparative example.

Claims

1. An aqueous composition for treating the surface of a metal containing aluminum, comprising, in proportion to the total amount of the aqueous composition, 0.01% by mass or more and 15.00% by mass or less of hydrogen peroxide, 0.10% by mass or more and 15.00% by mass or less of fluoride ions, 0.10% by mass or more and 30.00% by mass or less of phosphoric acid, and 0.10% by mass or more and 15.00% by mass or less of chloride ions.

2. A method for producing a surface-treated metal, comprising the step of contacting an aluminum-containing metal with the aqueous composition described in claim 1 to treat the surface of the metal.

3. The manufacturing method according to claim 2, wherein the surface roughness Ra of the surface of the surface-treated metal is 0.05 μm or more and 1.50 μm or less, the maximum height Rz of the surface of the surface-treated metal is 0.50 μm or more and 10.00 μm or less, and the contact angle of the surface of the surface-treated metal with water is 80° or less.

4. The manufacturing method according to claim 2, wherein the thickness of the metal before being subjected to the above step is 1 μm or more and 100 μm or less.

5. A metal having a surface and containing aluminum, wherein the surface roughness Ra of the surface is 0.05 μm or more and 1.50 μm or less, the maximum height Rz of the surface is 0.50 μm or more and 10.00 μm or less, and the contact angle of the surface with water is 80° or less.

6. The metal according to claim 5, wherein the thickness is 1 μm or more and 100 μm or less.

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