Surface treatment agent, aluminum or aluminum alloy material having a surface treatment film, and method for producing the same

Abstract

The technical problem of the present invention is to provide a surface treatment agent for aluminum or aluminum alloy materials that can form a surface treatment film with excellent corrosion resistance on aluminum or aluminum alloy materials and also has excellent corrosion resistance even when the film is exposed to high temperatures. The above technical problem is solved by the following surface treatment agent. A surface treatment agent for surface treatment of aluminum or aluminum alloy materials, comprising: ions (A) containing trivalent chromium, at least one kind of ions (B) selected from ions containing titanium and ions containing zirconium, ions (C) containing zinc, free fluoride ions (D), and nitrate ions (E).

Description

[0001] This application is a divisional application of the invention patent application with the application number 201980021331.4. The filing date of the original application is March 20, 2019, and the invention title is "Surface treatment agent, and aluminum or aluminum alloy material having a surface treatment film and method for producing the same". Technical Field

[0002] The present invention relates to a surface treatment agent for surface treatment of aluminum or aluminum alloy materials, an aluminum or aluminum alloy material having a surface treatment film formed by the surface treatment agent, and a method for producing the same. Background Art

[0003] In a wide range of fields such as aircraft materials, building materials, and automotive parts, surface treatment agents for aluminum or aluminum alloy materials that contain trivalent chromium have been developed at present.

[0004] For example, Patent Document 1 discloses a chemical conversion treatment liquid for metal materials, which contains: component (A) containing a water-soluble trivalent chromium compound, component (B) containing at least one selected from water-soluble titanium compounds and water-soluble zirconium compounds, component (C) containing a water-soluble nitrate compound, component (D) containing a water-soluble aluminum compound, and component (E) containing a fluorine compound, and the pH is controlled in the range of 2.3 to 5.0.

[0005] Patent Document 2 discloses a chemical conversion treatment liquid that contains a specified amount of a specific trivalent chromium compound, a specified amount of a specific zirconium compound, and a specified amount of a specific dicarboxylic acid compound.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-328501;

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2006-316334.

[0010] Problems to be Solved by the Invention

[0011] However, the films formed on aluminum or aluminum alloy materials using the surface treatment agents of Patent Documents 1 to 2 are sometimes exposed to high-temperature environments depending on the use of the aluminum or aluminum alloy, resulting in a decrease in corrosion resistance.

[0012] An object of the present invention is to provide a surface treatment agent that can form a surface treatment film with excellent corrosion resistance on aluminum or aluminum alloy materials and has excellent corrosion resistance even when the film is exposed to high temperatures, an aluminum or aluminum alloy material having a surface treatment film formed by the surface treatment agent, and a method for producing the same. Summary of the Invention

[0013] Solution to the Problem

[0014] The inventors of the present invention conducted in - depth research to solve the above - mentioned problems and found that a surface treatment agent containing: ions (A) containing trivalent chromium, at least one kind of ions (B) selected from ions containing titanium and ions containing zirconium, ions (C) containing zinc, free fluoride ions (D), and nitrate ions (E) can form a surface treatment film on an aluminum or aluminum alloy material that has excellent corrosion resistance and also has excellent corrosion resistance even when the film is exposed to high temperatures, thus completing the present invention.

[0015] The present invention for solving the above - mentioned problems is as follows:

[0016] (1) A surface treatment agent for surface - treating an aluminum or aluminum alloy material, containing: ions (A) containing trivalent chromium, at least one kind of ions (B) selected from ions containing titanium and ions containing zirconium, ions (C) containing zinc, free fluoride ions (D), and nitrate ions (E);

[0017] (2) A method for manufacturing an aluminum or aluminum alloy material having a surface treatment film, including a contacting step in which the surface treatment agent described in (1) above contacts the surface or on the surface of the aluminum or aluminum alloy material;

[0018] (3) An aluminum or aluminum alloy material having a surface treatment film, obtained by the manufacturing method described in (2) above; etc.

[0019] Advantages of the Invention

[0020] According to the present invention, it is possible to provide a surface treatment agent that can form a surface treatment film on an aluminum or aluminum alloy material that has excellent corrosion resistance and also has excellent corrosion resistance even when the film is exposed to high temperatures, an aluminum or aluminum alloy material having a surface treatment film formed by this surface treatment agent, and a manufacturing method thereof. Detailed Description of the Invention

[0021] (1) Surface Treatment Agent

[0022] The surface treatment agent of this embodiment is a treatment agent for surface treatment of aluminum or aluminum alloy materials. This surface treatment agent can also be used as a chemical conversion treatment agent. This surface treatment agent contains: ions (A) containing trivalent chromium, at least one kind of ions (B) selected from ions containing titanium and ions containing zirconium, ions (C) containing zinc, free fluoride ions (D), and nitrate ions (E). The surface treatment agent can be a surface treatment agent in which only the supply sources of these ions are added to an aqueous medium, or a surface treatment agent to which other components are further added. Each component, composition (content), and acidity and alkalinity are described in detail below. In addition, as the ions containing the above metals, metal ions, metal oxide ions, metal hydroxide ions, metal complex ions, etc. can be cited.

[0023] (Ions containing trivalent chromium)

[0024] As the supply source of the ions (A) containing trivalent chromium in the surface treatment agent, there is no particular limitation as long as it can provide the ions (A) by mixing it with an aqueous medium. For example, chromium fluoride, chromium nitrate, chromium sulfate, chromium phosphate, etc. can be cited. These can be used alone or in combination of two or more. The content of the ions (A) in the surface treatment agent is not particularly limited, and is generally in the range of 5 to 1000 mg / L in terms of chromium conversion mass concentration, preferably in the range of 20 to 700 mg / L. In addition, in this embodiment, it is preferably free of hexavalent chromium ions. In addition, "free of hexavalent chromium ions" does not mean that its content is zero, and unavoidable mixing is allowed. Specifically, it can be 10 mg / L or less, 5 mg / L or less, 1 mg / L or less, 0.5 mg / L or less, 0.1 mg / L or less.

[0025] (At least one kind of ions selected from ions containing titanium and ions containing zirconium)

[0026] As a source of the ion (B) which is at least one selected from ions containing titanium and ions containing zirconium in the surface treatment agent, there is no particular limitation as long as it can provide the ion (B) by mixing with an aqueous medium. Examples include: titanium sulfate, titanium oxysulfate, ammonium titanium sulfate, titanium nitrate, titanium oxynitrate, ammonium titanium nitrate, hexafluorotitanic acid, hexafluorotitanium complex salt, zirconium sulfate, zirconium oxysulfate, ammonium zirconium sulfate, zirconium nitrate, zirconium oxynitrate, ammonium zirconium nitrate, hexafluorozirconic acid, hexafluorozirconium complex salt, titanium lactate, titanium acetylacetonate, triethanolamine titanium, octyl glycolic acid titanium, tetra isopropyl titanate, tetra n-butyl titanate, zirconium acetate, zirconium lactate, tetraacetylacetonate zirconium, tributoxyacetylacetonate zirconium, tetra n-butoxy zirconium, tetra n-propoxy zirconium, etc. These can be used alone or in combination of two or more. The content of the ion (B) in the surface treatment agent is not particularly limited, and is generally in the range of 5 to 1000 mg / L in terms of the mass concentration in terms of metal conversion (in the case of mixing two or more sources, it refers to the total mass concentration in terms of metal conversion), preferably in the range of 20 to 700 mg / L.

[0027] (Ions containing zinc)

[0028] As a source of the zinc-containing ion (C) in the surface treatment agent, there is no particular limitation as long as it can provide the ion (C) by mixing with an aqueous medium. Examples include: metallic zinc, zinc oxide, zinc carbonate, zinc nitrate, zinc chloride, zinc sulfate, zinc fluoride, zinc iodide, zinc dihydrogen phosphate, zinc acetylacetonate, etc. These can be used alone or in combination of two or more. The content of the ion (C) in the surface treatment agent is not particularly limited, and is generally in the range of 20 to 10000 mg / L in terms of the mass concentration in terms of zinc conversion, can be in the range of 50 to 10000 mg / L, preferably in the range of 300 to 8000 mg / L, and more preferably in the range of 700 to 5000 mg / L.

[0029] (Free fluoride ion)

[0030] As a source of the free fluoride ion (D) in the surface treatment agent, there is no particular limitation as long as it can provide the free fluoride ion (D) by mixing with an aqueous medium. Examples include: hydrofluoric acid, ammonium fluoride, chromium fluoride, hexafluorotitanic acid, hexafluorotitanium complex salt, hexafluorozirconic acid, hexafluorozirconium complex salt, magnesium fluoride, aluminum fluoride, hexafluorosilicic acid, sodium fluoride, potassium fluoride, zinc fluoride, etc. These can be used alone or in combination of two or more. In addition, the free fluoride ion (D) can be provided by the same compound as the source of (A), (B) and / or (C) above, or can be provided by a compound different from the source of (A), (B) and / or (C) above. The fluorine conversion mass concentration of the free fluoride ion (D) in the surface treatment agent is preferably 3 to 100 mg / L, more preferably 5 to 70 mg / L.

[0031] (Nitrate ion)

[0032] As a source of nitrate ion (E) in the surface treatment agent, there is no particular limitation as long as it can provide nitrate ion (E) when mixed with an aqueous medium. Examples include: nitric acid, sodium nitrate, potassium nitrate, magnesium nitrate, ammonium nitrate, cerium nitrate, manganese nitrate, strontium nitrate, calcium nitrate, cobalt nitrate, aluminum nitrate, zinc nitrate, etc. These can be used alone or in combination of two or more. In addition, nitrate ion (E) can be provided by the same compound as the source of (A), (B) and / or (C) above, or by a compound different from the source of (A), (B) and / or (C) above. The content of nitrate ion (E) in the surface treatment agent is not particularly limited, and is usually in the range of 100 to 30000 mg / L in terms of mass concentration in terms of nitric acid conversion.

[0033] (Other components)

[0034] As long as it is within the range that does not impair the effects of the present invention, various metal components and additives can be added to the surface treatment agent of the present embodiment. Examples of metal components include: vanadium, molybdenum, tungsten, manganese, cerium, magnesium, calcium, cobalt, nickel, strontium, lithium, niobium, yttrium, bismuth, etc. Examples of additives include: compounds having a hydroxyl group, compounds having a formyl group, compounds having a benzoyl group, compounds having an amino group, compounds having an imino group, compounds having a cyano group, compounds having an azo group, compounds having a mercapto group, compounds having a sulfo group, compounds having a nitro group, compounds having a urethane bond, etc. These metal components and additives can be used alone or in combination of two or more. Considering the addition within the range that does not impair the effects of the present invention, the content of these additives is at most a few mass% relative to the total amount of the surface treatment agent.

[0035] On the other hand, the surface treatment agent of the present embodiment preferably does not contain a compound having a carboxyl group, preferably does not contain a compound having an amidino group, preferably does not contain a compound having an aromatic ring, and more preferably does not contain an organic substance. By using a surface treatment agent that does not contain an organic substance, a decrease in the corrosion resistance of the formed film can be suppressed. In addition, "does not contain an organic substance" does not mean that its content must be zero, and it is allowed to contain within the range that does not significantly impair the effects of the present invention. Specifically, it can be 10 mg / L or less, 5 mg / L or less, 1 mg / L or less, 0.5 mg / L or less, 0.1 mg / L or less, or zero. In addition, an organic substance refers to a compound mainly composed of carbon, and its derivatives can also be included in the organic substance.

[0036] (Acid-base property)

[0037] The pH of the surface treatment agent of the present embodiment is not particularly limited, preferably 2.3 to 5.0, more preferably 3.0 to 4.5. Here, the pH in this specification refers to the value at the temperature when the surface treatment agent contacts the surface of the aluminum or aluminum alloy material. The pH can be measured by, for example, a portable conductivity / pH meter [WM-32EP (manufactured by DKK-TOACORPORATION)] and the like.

[0038] As described above, the composition of the surface treatment agent of the present embodiment has been described. Another aspect of the present invention is a surface treatment agent for surface treatment of aluminum or aluminum alloy materials, which is prepared by adding a supply source of ions (A) containing trivalent chromium, a supply source of at least one kind of ions (B) selected from ions containing titanium and ions containing zirconium, a supply source of ions (C) containing zinc, a supply source of free fluoride ions (D), and a supply source of nitrate ions (E). In addition, the supply source of free fluoride ions (D) may be the same compound as the supply source of (A), (B), and / or (C) above, or may be a compound different from the supply source of (A), (B), and / or (C) above. Furthermore, the supply source of nitrate ions (E) may be the same compound as the supply source of (A), (B), and / or (C) above, or may be a compound different from the supply source of (A), (B), and / or (C) above.

[0039] (2) Method for manufacturing the surface treatment agent

[0040] The surface treatment agent of the present embodiment can be obtained by appropriately adding the above-mentioned supply source of ions (A) containing trivalent chromium, a supply source of at least one kind of ions (B) selected from ions containing titanium and ions containing zirconium, a supply source of ions (C) containing zinc, a supply source of free fluoride ions (D), and a supply source of nitrate ions (E) to an aqueous medium and stirring. In addition, when manufacturing, a solid supply source can be added to the aqueous medium, or the solid supply source can be previously dissolved in the aqueous medium and then added as an aqueous medium solution. Furthermore, the pH range of the surface treatment agent is as described above. It is preferably adjusted using pH regulators such as nitric acid, hydrofluoric acid, ammonium bicarbonate, ammonia water, etc., but is not limited to these components. In addition, one or more than two kinds of pH regulators can be used.

[0041] As the aqueous medium, water is usually used. It may contain an organic solvent miscible with water within the range that does not impair the effects of the present invention, but water is preferred. When containing an organic solvent miscible with water, it can be 10 mg / L or less, 5 mg / L or less, 1 mg / L or less, 0.5 mg / L or less, 0.1 mg / L or less.

[0042] (3) Method for manufacturing an aluminum or aluminum alloy material having a surface treatment film

[0043] The manufacturing method of an aluminum or aluminum alloy material having a film formed by the surface treatment agent of the present embodiment includes a contacting step in which the surface treatment agent of the present embodiment contacts the surface or on the surface of the aluminum or aluminum alloy material. Thereby, a surface treatment film is formed on the surface or on the surface of the aluminum or aluminum alloy material. Pretreatment steps such as a degreasing step and a pickling step can be performed before the contacting step. In addition, a water washing step can be performed after each step, and a drying step can also be performed after the water washing step.

[0044] (Aluminum or aluminum alloy material)

[0045] The aluminum or aluminum alloy material as the object of the surface treatment agent is not particularly limited, but is particularly effective for aluminum die-cast materials with an oxide film thickness on the surface and alloy composition segregation. The use of the aluminum or aluminum alloy material is not particularly limited, and examples include marine propulsion engines and their peripheral equipment, internal combustion engine components for motorcycles, etc.

[0046] (Degreasing step)

[0047] In the manufacturing method of the present embodiment, it is preferable to perform a degreasing step before the contacting step, in which a known degreasing agent contacts the surface or on the surface of the aluminum or aluminum alloy material. The degreasing method is not particularly limited, and examples include solvent degreasing and alkali degreasing.

[0048] (Contacting step)

[0049] In the contacting step in the manufacturing method of the present embodiment, the contacting temperature and the contacting time are not particularly limited. Usually, the surface treatment agent contacts the surface or on the surface of the aluminum or aluminum alloy material at 30 to 80°C, preferably at 40 to 70°C for 10 to 600 seconds. In addition, after this step, water washing and deionized water washing can be performed as needed, and then it can be dried. The drying temperature is not particularly limited, and is preferably 50 to 140°C. In addition, as a method of contacting the surface treatment agent with the surface or on the surface of the aluminum or aluminum alloy material, there is no particular limitation, and examples include an immersion method, a spraying method, and a flow coating method.

[0050] (4) Aluminum or aluminum alloy material having a surface treatment film

[0051] The aluminum or aluminum alloy material having a surface treatment film manufactured by the above manufacturing method is another embodiment of the present invention. The adhesion amount of the surface treatment film on the aluminum or aluminum alloy material is not particularly limited, and preferably the total mass of Cr, Ti and / or Zr, Zn contained in the surface treatment film is 1 to 200 mg / m per unit area 2 .

[0052] The aluminum or aluminum alloy material with a surface treatment film according to this embodiment has excellent corrosion resistance even without performing a painting process of painting on the surface treatment film, and also has excellent corrosion resistance even when the film is exposed to high temperatures, but a painting process can also be performed.

[0053] The above painting process is not particularly limited. For example, it can be performed by a painting method such as aqueous painting, solvent painting, powder painting, anionic electrodeposition painting, or cationic electrodeposition painting using a known coating composition.

[0054] Examples

[0055] Examples and comparative examples of the present invention will be described below. In addition, the present invention is not limited to these examples.

[0056] <Aluminum material>

[0057] Aluminum die-casting material (JIS-ADC12)

[0058] <Surface treatment agent>

[0059] The surface treatment agents of Examples 1 to 20 and Comparative Examples 1 to 3 having ion concentrations shown in Table 6 were obtained by mixing the sources shown in Tables 1 to 5 in water. In addition, ammonia water was used as a pH adjuster. In addition, the free fluoride ion concentration was measured using a commercially available fluoride ion meter [ion electrode: fluoride ion composite electrode F-2021 (manufactured by DKK-TOA CORPORATION)].

[0060] [Table 1]

[0061] Label Name Manufacturer A1 Chromium(III) fluoride trihydrate Manufactured by Showa Chemical A2 Chromium(III) nitrate nonahydrate Manufactured by Wako Pure Chemical Industries A3 Chromium(III) sulfate Manufactured by Junsei Chemical

[0062] [Table 2]

[0063] Label Name Manufacturer B1 Hexafluorozirconic acid Manufactured by Morita Chemical Industries B2 Hexafluorotitanic acid Manufactured by Morita Chemical Industries

[0064] [Table 3]

[0065] Label Name Manufacturer C1 Zinc nitrate hexahydrate Manufactured by Wako Pure Chemical Industries C2 Zinc sulfate heptahydrate Manufactured by Wako Pure Chemical Industries C3 Zinc chloride Manufactured by Tokyo Chemical Industry

[0066] [Table 4]

[0067] Label Name Manufacturer D1 Hydrofluoric acid Manufactured by Wako Pure Chemical Industries

[0068] [Table 5]

[0069] Label Name Manufacturer E1 Nitric acid Manufactured by Sumitomo Chemical E2 Aluminum sulfate nonahydrate Manufactured by Wako Pure Chemical Industries

[0070] [Table 6]

[0071]

[0072] <<Manufacture of aluminum die-casting material with surface treatment film>>

[0073] Aluminum die-cast materials having surface treatment films were produced using the surface treatment agents of Examples 1 to 20 and Comparative Examples 1 to 3, and these were designated as Test Specimens 1 to 23.

[0074] Specifically, the aluminum die-casting material is immersed in an alkaline degreasing agent [a 20 g / L aqueous solution of Fine Cleaner 315E (manufactured by Parkersei Co., Ltd., Japan)] at 60°C for 2 minutes, and then the surface is rinsed with tap water to clean it. Then, the surface treatment agent is sprayed on the surface or surface of the aluminum die-casting material at the contact temperature described in Table 6, thereby performing the contact process. Then, it is washed with running tap water (normal temperature, 30 seconds) and washed with deionized water (normal temperature, 30 seconds). Then, it is dried in an electric oven (80°C, 5 minutes) to produce aluminum die-casting materials with surface treatment films (test pieces 1 to 23). For the adhesion amount of the surface treatment films of test pieces 1 to 23, the total mass of Cr, Ti and / or Zr, and Zn contained in the surface treatment films is measured using a scanning fluorescent X-ray analyzer [ZSXprimus II (manufactured by Rigaku Corporation)]. The measurement results are shown in Table 7.

[0075] [Table 7]

[0076]

[0077] Furthermore, the following tests were performed on the test pieces 1 to 23 to evaluate the corrosion resistance and post-heat corrosion resistance of the surface treatment films.

[0078] <<Evaluation Method>>

[0079] <Corrosion resistance>

[0080] Test pieces 1 to 23 were subjected to a 240-hour neutral salt water spray test (JIS-Z2371:2015). After drying, the proportion of white rust formed on the surface of the test pieces was visually measured. The white rust ratio is the ratio of the area of white rust to the area of the observed area. The evaluation criteria are as follows. The evaluation results are shown in Table 8.

[0081] <Evaluation Criteria>

[0082] 5. The proportion of white rust is less than 10%

[0083] 4. The proportion of white rust is more than 10% to less than 30%

[0084] 3. The proportion of white rust is more than 30% to less than 50%

[0085] 2. The proportion of white rust is more than 50% to less than 70%

[0086] The proportion of white rust exceeds 70%.

[0087] <Corrosion resistance after heating>

[0088] After heating each test piece in an electric oven (180 °C, 20 minutes), a neutral salt spray test (JIS-Z2371:2015) was conducted for 240 hours. After drying, the proportion of white rust generated on the surface of the metal material was measured visually. The proportion of white rust is the proportion of the area where white rust has occurred to the area of the observation site. The evaluation criteria are as described below. The evaluation results are shown in Table 8.

[0089] <Evaluation criteria>

[0090] 5 The proportion of white rust is 10% or less

[0091] 4 The proportion of white rust exceeds 10% to 30% or less

[0092] 3 The proportion of white rust exceeds 30% to 50% or less

[0093] 2 The proportion of white rust exceeds 50% to 70% or less

[0094] 1 The proportion of white rust exceeds 70%.

[0095] [Table 8]

[0096] .

Claims

1. A manufacturing method of an aluminum or aluminum alloy material with a surface treatment film, The manufacturing method includes a contacting step in which a surface treatment agent contacts the surface or on the surface of the aluminum or aluminum alloy material, The surface treatment agent contains: ionic A containing trivalent chromium, at least one ionic B selected from an ionic containing titanium and an ionic containing zirconium, ionic C containing zinc, free fluoride ion D, and nitrate ion E, The surface treatment agent does not contain a compound having an aromatic ring, The pH of the surface treatment agent is 4 to 5.0, In the surface treatment agent, the content of ionic A containing trivalent chromium is 20 to 150 mg / L, the content of at least one ionic B selected from an ionic containing titanium and an ionic containing zirconium is 20 to 100 mg / L, the content of ionic C containing zinc is 300 to 1700 mg / L, and the mass concentration of free fluoride ion D in terms of fluorine is 3 to 15 mg / L, In the contacting step, the contacting temperature of the surface treatment agent with the aluminum or aluminum alloy material is 50 to 75 °C.

2. The manufacturing method of an aluminum or aluminum alloy material with a surface treatment film according to claim 1, wherein, The ionic A is from at least one selected from chromium(III) fluoride trihydrate, chromium(III) nitrate nonahydrate, and chromium(III) sulfate, The ionic B is from at least one selected from zirconium hexafluoride and titanium hexafluoride, The ionic C is from at least one selected from zinc nitrate hexahydrate, zinc sulfate heptahydrate, and zinc chloride, The ionic D is from hydrofluoric acid, The ionic E is from at least one selected from nitric acid and aluminum nitrate nonahydrate.

3. An aluminum or aluminum alloy material with a surface treatment film obtained by the manufacturing method of an aluminum or aluminum alloy material with a surface treatment film according to claim 1 or 2.

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