Normal-temperature nickel-free conductive confining liquid for aluminum alloy anode oxide film, preparation method and confining method

Abstract

The invention discloses normal-temperature nickel-free conductive confining liquid for an aluminum alloy anode oxide film, a preparation method and a confining method. The sealing liquid comprises a sealing agent and a pH regulator; the sealing agent is prepared from the following components according to volume mass: 700 to 800 ml / L of solvent, 0.2 to 1.5 mol / L of main salt, 2.0 to 40.0 g / L of film-forming agent, 0.2 to 30.0 g / L of film-forming accelerant and 50 to 100 ml / L of deionized water, the pH value of the sealing agent is regulated to 0.1-1.2 by adopting a pH regulator; the main salt is any one or a mixture of two of anhydrous stannous chloride and stannous chloride dehydrate. The confining liquid is free of nickel and fluorine, free of other harmful heavy metals, energy-saving, free of sewage discharge, resistant to corrosion and conductive, and suitable for protection treatment of aluminum components with surface conduction requirements. The aluminum alloy anode oxide film is subjected to sealing treatment, and a nickel-free sealing film which is excellent in corrosion resistance and has electrical conductivity can be obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of surface treatment of metal materials, and particularly relates to a room-temperature nickel-free conductive sealing solution for an aluminum alloy anodic oxidation film, a preparation method and a sealing method. Background Art

[0002] Due to its excellent electrical conductivity, thermal conductivity, high specific strength and other characteristics, aluminum alloy is widely used in building profiles, aerospace, rail transit, electronics 3C and other fields. However, the standard electrode potential of aluminum is relatively negative (-1.66V), and its chemical properties are relatively active. Although a certain protective oxide film can be formed under natural conditions, its corrosion resistance is limited. In actual applications, necessary surface treatment is usually required to improve the corrosion resistance of aluminum alloy. Among them, anodic oxidation is one of the most widely used surface treatment technologies. After anodic oxidation treatment of aluminum alloy, a porous alumina film is formed on its surface. This film layer is divided into two layers in the microstructure. The outer layer is a porous structure, and the bottom layer is a continuous alumina thin film with extremely limited thickness. Usually, a sealing treatment is required. Through sealing, the outer porous layer is sealed by the sealing material, and the corrosion resistance of the oxide film is significantly improved. In addition to effectively improving the corrosion resistance of the film layer, some sealing processes also have a dyeing function, obtaining beautiful colors on the surface of the device and playing a good decorative role.

[0003] There are many traditional sealing processes for anodic oxidation films. The early nickel-containing and fluorine-containing sealing processes can obtain a sealing film with excellent corrosion resistance and are widely used in the industrial field. However, Ni and F elements are harmful to the human body and pollute the environment. Since then, with the enhancement of environmental awareness and the national energy conservation and emission reduction policies, nickel-free sealing processes have emerged one after another, such as boiling water sealing, organic matter sealing and other technologies. However, high-temperature water (or steam) sealing has high energy consumption. Currently, most in the field are organic systems or organic-inorganic composite sealing systems. For example, Patent 201810971060.6 applies for the protection of a sealing agent, a preparation method and a sealing method for an aluminum alloy anodic oxidation film. By the combined use of molybdate, phosphate, iodine compound, lanthanum compound and silane coupling agent, this invention can effectively prevent or reduce the fading of dyes after dyeing of the aluminum alloy anodic oxidation film and improve the corrosion resistance of the aluminum alloy anodic oxidation film. The patent application with the application number 202111561016.6 applies for the protection of a composite sealing method for an aluminum alloy anodic oxidation film. Coating an organic coating on the surface of the aluminum alloy anodic oxidation film and timely performing ultraviolet light curing treatment within a predetermined time, irradiating for 60 - 80s, the sealing treatment can be completed. This process is simple, energy-saving, environmentally friendly, has high sealing quality, and the sealing film has alkali resistance. Patent 202311250608.5 applies for the protection of a non-toxic and highly corrosion-resistant sealing method for an aluminum alloy anodic oxidation film. This invention uses cerium salt and cysteine to perform a sealing treatment on the aluminum alloy anodic oxidation film, and on this basis, uses fluorosilane for hydrophobic modification. The final sealing film has a water contact angle of 137.5°, and has good corrosion resistance.

[0004] Looking at the current research status in the field of sealing aluminum alloy anodic oxidation films, the main purpose of the sealing treatment is still to improve corrosion resistance, and some are also to prevent color fading after dyeing. There is no research considering anodic oxidation and subsequent sealing treatment. Although the corrosion resistance of the device is improved, the surface of the device completely loses its conductive function, greatly limiting the application of anodized workpieces in the field of electronics and microelectronics. Summary of the Invention

[0005] Based on this, in view of the above technical problems: the current defects that both aluminum alloy anodic oxidation films and sealing films are non-conductive, the present invention provides an anodic oxidation film sealing solution for aluminum alloy at room temperature, nickel-free and with a conductive sealing film, taking into account energy conservation, environmental protection, good corrosion resistance and conductivity, which is a green and environmentally friendly functional sealing technology for aluminum alloy anodic oxidation. The present invention uses a stannous chloride salt system soluble in conventional solvents to seal the aluminum alloy anodic oxidation film, significantly improving the corrosion resistance of the sealed surface and having good conductivity of the film layer.

[0006] In the first aspect, the present invention provides a room-temperature nickel-free conductive sealing solution for aluminum alloy anodic oxidation films, which includes: a sealing agent and a pH regulator; The composition of the sealing agent and the dosage of each component are by volume mass: Solvent 700 - 800 ml / L Main salt 0.2 - 1.5 mol / L Film-forming agent 2.0 - 40.0 g / L Film-forming accelerator 0.2 - 30.0 g / L Deionized water 50 - 100 ml / L; The sealing agent is adjusted to pH = 0.1 - 1.2 with a pH regulator; The main salt is any one or a mixture of two of anhydrous stannous chloride and stannous chloride dihydrate.

[0007] Further, the composition of the sealing agent and the dosage of each component are by volume mass: Solvent 720 - 780 ml / L; Main salt 0.3 - 1.2 mol / L; Film-forming agent 5.0 - 35.0 g / L; Film-forming accelerator 2.0 - 25.0 g / L; Deionized water 60 - 90 ml / L.

[0008] Further, the film-forming agent is one or more of polybisphenol A diglycidyl ether, diglycidyl terephthalate, diglycidyl isophthalate, diglycidyl hexahydrophthalate, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, bis((3,4-epoxycyclohexyl)methyl) adipate, and isophorone diisocyanate.

[0009] Further, the film-forming accelerator is at least one of m-phenylenediamine, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, dicyandiamide, 2-ethyl-4-methylimidazole, and 2-phenylimidazole.

[0010] Further, the pH regulator is a 15% hydrochloric acid solution or 25% ammonia water.

[0011] Further, the solvent is one or more of ethanol, n-propanol, isopropanol, n-butanol, isobutanol, glycerol, and ethyl acetate.

[0012] In a second aspect, the present invention provides a method for preparing a room-temperature nickel-free conductive sealing solution for an aluminum alloy anodic oxidation film, which includes the following steps: (1) Add 700-800 ml of solvent, 50-100 ml of deionized water, and 0.2-1.5 mol of the main salt to a round-bottom flask in sequence, and stir until completely dissolved; (2) Reflux the above solution at 80-140 °C for 1-2 hours, cool to room temperature, add 2.0-40.0 g of the film-forming agent and 0.20-30.0 g of the film-forming accelerator in sequence, stir evenly, and adjust the pH to 0.1-1.2 with a pH regulator; (3) Transfer the above solution to a volumetric flask, and make up the solvent to 1000 mL to complete the preparation of the sealing solution; The main salt is any one or a mixture of two of anhydrous stannous chloride and stannous chloride dihydrate.

[0013] In a third aspect, the present invention further provides a room-temperature nickel-free conductive sealing method for an aluminum alloy anodic oxidation film, which includes the following steps: S1. Pretreatment of degreasing and pickling of aluminum alloy; S2. Anodic oxidation treatment of aluminum alloy; S3. Sealing treatment of the anodic oxidation film: After the aluminum alloy workpiece after anodic oxidation treatment is cleaned and dried, it is immediately immersed in the sealing solution as described in claim 1 for sealing treatment at room temperature for 3-6 minutes. After the sealing is completed, it is placed in a vacuum drying oven for treatment at 50-60 °C for 2-5 minutes, and then heated to 120-180 °C for treatment for 5-40 minutes to complete the sealing treatment.

[0014] Further, the pretreatment of degreasing and pickling of the aluminum alloy is specifically carried out as follows: (1) Degreasing by alkaline washing: Place the aluminum alloy products in an alkaline washing solution containing 8 g / L of NaOH and 20 g / L of Na2SiO3, and carry out alkaline washing at room temperature for 1 - 2 minutes; (2) Wash twice with flowing tap water and once with deionized water; (3) Pickling and brightening: Place the aluminum alloy products after the above cleaning in a pickling solution containing 30 g / L of concentrated H2SO4, 300 ml / L of HNO3 (analytical pure 65 - 68%), and 0.2 g / L of OP - 10, and carry out pickling at room temperature for 1 - 3 minutes; (4) Wash twice with flowing tap water and once with deionized water.

[0015] Further, for the anodic oxidation treatment of the aluminum alloy, the specific treatment steps are as follows: Immerse the pre - treated aluminum alloy into the anodic oxidation tank for anodic oxidation treatment; The composition of the anodic oxidation bath is 185 g / L - 195 g / L of H2SO4, the treatment temperature is 18 ± 1 °C, direct current anodic oxidation for 28 - 32 min, and the current density is 1.8 A / dm 2 。

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The sealing treatment temperature of the sealing liquid of the present invention is at room temperature, without a heating device, saving equipment costs and also being beneficial for energy conservation; (2) The sealing agent of the present invention does not contain Ni, F, and other harmful heavy metal ions, and is a safe and environmentally friendly sealing treatment process.

[0017] (3) By the sealing method of the present invention, a sealing layer with excellent corrosion resistance can be obtained. The sealing film has good conductivity, and the key conductive components are SnO2 and elemental Sn, providing a feasible option for the requirements of lightweight, corrosion resistance, and conductivity of electronic and microelectronic devices.

[0018] (4) The composition of the sealing liquid of the present invention is simple, the system is stable, and it can be directly dried after sealing without water washing and no sewage discharge. Description of the Drawings

[0019] In order to more clearly illustrate the solutions in the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a flow chart of the room - temperature nickel - free conductive sealing method for aluminum alloy anodic oxidation; Figure 2Tafel polarization curves of different surfaces in 3.5 wt.% NaCl solution; Figure 3 It is the XPS analysis spectrum of Sn element on the surface of the room-temperature nickel-free conductive sealing film for anodic oxidation of aluminum alloy. Specific implementation manners

[0021] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] The present invention will be described in detail below in conjunction with the embodiments. The following embodiments are only the preferred implementation manners of the present invention and do not limit the present invention. It should be emphasized that 6063 aluminum alloy plates are selected in the specific implementation process, which does not mean that the present invention is only applicable to 6063 aluminum alloy, nor does it mean that the present invention is only applicable to plates. The anodic oxidation film is not dyed during the implementation process, but directly sealed, but this sealing method is also applicable to the process of sealing after dyeing. It should be understood that the selected substrate material, form, and whether to dye in the specific embodiments described herein are only used to explain the present invention and do not limit the present invention.

[0023] Example 1 This embodiment provides a room-temperature nickel-free conductive sealing method for anodic oxidation of aluminum alloy, including the following steps: S1. Pretreatment of degreasing and pickling of aluminum alloy, and the specific treatment steps are as follows: (1) Alkaline cleaning and degreasing: Place the aluminum alloy product in an alkaline cleaning solution containing 8 g / L of NaOH and 20 g / L of Na2SiO3, and perform alkaline cleaning at room temperature for 1 - 2 minutes; (2) Wash twice with flowing tap water and once with deionized water; (3) Pickling and brightening: Place the above-mentioned cleaned aluminum alloy product in a pickling solution containing 30 g / L of concentrated H2SO4, 300 ml / L of HNO3 (analytical pure 65 - 68%), and 0.2 g / L of OP-10, and perform pickling at room temperature for 1 - 3 minutes; (4) Wash twice with flowing tap water and once with deionized water; S2. Anodic oxidation treatment of aluminum alloy: Immerse the pre-treated aluminum alloy into the anodic oxidation tank for anodic oxidation treatment; the composition of the anodic oxidation tank solution is 185 g / L of H2SO4, the treatment temperature is 18 ± 1 °C, direct current anodic oxidation for 28 min, and the current density is 1.8 A / dm2 ; S3. Anodic oxidation film sealing treatment: After the anodized aluminum alloy workpieces are cleaned and dried by blowing, they are immediately immersed in the above-mentioned sealing agent for sealing treatment. Sealing is carried out at room temperature for 3 min. After sealing is completed, they are treated in a vacuum drying oven at 50 °C for 2 min, and then heated to 140 °C for 25 min to complete the sealing treatment. The composition of the used sealing agent is: absolute ethanol 800 ml / L; stannous chloride anhydrous 0.5 mol / L; diglycidyl terephthalate 8 g / L; hexahydrophthalic anhydride 1.5 g / L; deionized water 100 ml / L. Preparation process of the sealing agent: Add 800 mL of ethanol and 100 mL of deionized water to a round-bottom flask, add 0.5 mol of stannous chloride anhydrous, and stir to dissolve; reflux at 90 °C for 2.0 hours and cool to room temperature; sequentially add 8 g of diglycidyl terephthalate and 1.5 g of hexahydrophthalic anhydride, stir until uniform, and add 5 ml of hydrochloric acid (15%) to adjust the pH value; transfer the solution to a 1000 mL volumetric flask and make up the absolute ethanol to 1000 mL.

[0024] Example 2 This example provides a room-temperature nickel-free conductive sealing method for anodizing aluminum alloy, including the following steps: S1. Pretreatment of degreasing and pickling of aluminum alloy, and the specific treatment steps are as follows: (1) Alkaline cleaning and degreasing: Place the aluminum alloy products in an alkaline cleaning solution containing 8 g / L of NaOH and 20 g / L of Na2SiO3, and carry out alkaline cleaning at room temperature for 1 - 2 minutes; (2) Wash twice with running tap water and once with deionized water; (3) Pickling and brightening: Place the above-mentioned cleaned aluminum alloy products in a pickling solution containing 30 g / L of concentrated H2SO4, 300 ml / L of HNO3 (analytical pure 65 - 68%), and 0.2 g / L of OP-10, and carry out pickling at room temperature for 1 - 3 minutes; (4) Wash twice with running tap water and once with deionized water; S2. Anodic oxidation treatment of aluminum alloy: Immerse the pre-treated aluminum alloy into the anodic oxidation tank for anodic oxidation treatment; The composition of the anodic oxidation tank solution is 190 g / L of H2SO4, the treatment temperature is 18 ± 1 °C, direct current anodic oxidation for 30 min, and the current density is 1.8 A / dm 2 ; S3. Anodic Oxide Film Sealing Treatment: After the anodized aluminum alloy workpieces are cleaned and dried by blowing, they are immediately immersed in the above-mentioned sealing agent for sealing treatment. Sealing is carried out at room temperature for 5 minutes. After sealing is completed, they are treated in a vacuum drying oven at 60 °C for 3 minutes, and then heated to 180 °C for 20 minutes to complete the sealing treatment. The composition of the used sealing agent is: absolute ethanol 650 ml / L, glycerol 100 ml / L; stannous chloride dihydrate 0.7 mol / L; diglycidyl hexahydrophthalate 10 g / L; dicyandiamide 1.0 g / L, 2-ethyl-4-methylimidazole 0.2 g / L; deionized water 95 ml / L. Preparation process of the sealing agent: Add 650 mL of absolute ethanol, 100 mL of glycerol, and 95 mL of deionized water to a round-bottom flask, add 0.7 mol of stannous chloride dihydrate, and stir to dissolve; reflux at 105 °C for 1.5 hours and cool to room temperature; sequentially add 10 g of diglycidyl hexahydrophthalate; 1.0 g of dicyandiamide and 0.2 g of 2-ethyl-4-methylimidazole, and stir until uniform without adjusting the pH value; transfer the solution to a 1000 mL volumetric flask and make up the absolute ethanol to 1000 mL.

[0025] Example 3 This example provides a room-temperature nickel-free conductive sealing method for anodizing aluminum alloys, including the following steps: S1. Pretreatment of Degreasing and Pickling of Aluminum Alloy, and the specific treatment steps are as follows: (1) Alkaline Cleaning and Degreasing: Place the aluminum alloy products in an alkaline cleaning solution containing 8 g / L of NaOH and 20 g / L of Na2SiO3, and carry out alkaline cleaning at room temperature for 1 - 2 minutes; (2) Wash twice with running tap water and once with deionized water; (3) Pickling and Brightening: Place the above-mentioned cleaned aluminum alloy products in a pickling solution containing 30 g / L of concentrated H2SO4, 300 ml / L of HNO3 (analytical pure 65 - 68%), and 0.2 g / L of OP-10, and carry out pickling at room temperature for 1 - 3 minutes; (4) Wash twice with running tap water and once with deionized water; S2. Anodic Oxidation Treatment of Aluminum Alloy: Immerse the pre-treated aluminum alloy into the anodic oxidation tank for anodic oxidation treatment; The composition of the anodic oxidation tank solution is 195 g / L of H2SO4, the treatment temperature is 18 ± 1 °C, direct current anodic oxidation for 32 minutes, and the current density is 1.8 A / dm 2 ; S3. Anodic Oxide Film Sealing Treatment: After the anodized aluminum alloy workpiece is cleaned and dried, it is immediately immersed in the above-mentioned sealing agent for sealing treatment. Sealing is carried out at room temperature for 4 minutes. After sealing is completed, it is treated in a vacuum drying oven at 55 °C for 5 minutes, and then heated to 150 °C for 30 minutes to complete the sealing treatment. The composition of the used sealing agent is: 800 ml / L of n-butanol; 1.2 mol / L of stannous chloride dihydrate; 30 g / L of diglycidyl isophthalate; 10.0 g / L of tetrahydrophthalic anhydride; 85 ml / L of deionized water. Preparation process of the sealing agent: Add 800 mL of n-butanol and 85 mL of deionized water to a round-bottom flask, add 1.2 mol of stannous chloride dihydrate, and stir to dissolve; reflux at 120 °C for 1.0 hour and cool to room temperature; add 30 g of diglycidyl isophthalate and 10.0 g of tetrahydrophthalic anhydride in sequence, stir until uniform, and there is no need to adjust the pH value; transfer the solution to a 1000 mL volumetric flask and make up to 1000 mL with n-butanol.

[0026] Example 4 This example provides a room-temperature nickel-free conductive sealing method for anodizing aluminum alloy, which includes the following steps: S1. Pretreatment of Aluminum Alloy Degreasing and Pickling, and the specific treatment steps are as follows: (1) Alkaline Cleaning and Degreasing: Place the aluminum alloy product in an alkaline cleaning solution containing 8 g / L of NaOH and 20 g / L of Na2SiO3, and carry out alkaline cleaning at room temperature for 1 - 2 minutes; (2) Wash twice with running tap water and once with deionized water; (3) Pickling and Brightening: Place the above-mentioned cleaned aluminum alloy product in a pickling solution containing 30 g / L of concentrated H2SO4, 300 ml / L of HNO3 (analytical pure 65 - 68%), and 0.2 g / L of OP-10, and carry out pickling at room temperature for 1 - 3 minutes; (4) Wash twice with running tap water and once with deionized water; S2. Anodic Oxidation Treatment of Aluminum Alloy: Immerse the pre-treated aluminum alloy into the anodic oxidation tank for anodic oxidation treatment; the composition of the anodic oxidation tank solution is 185 g / L of H2SO4, the treatment temperature is 18 ± 1 °C, direct current anodic oxidation for 28 minutes, and the current density is 1.8 A / dm 2 ; S3. Anodic oxidation film sealing treatment: The aluminum alloy workpiece after anodic oxidation treatment is immediately immersed in the above-mentioned sealing agent for sealing treatment after cleaning and air drying. Sealing is carried out at room temperature for 6 minutes. After sealing is completed, it is treated in a vacuum drying oven at 52°C for 4 minutes, and then heated to 120°C for 40 minutes to complete the sealing treatment. The composition of the used sealing agent is as follows: ethyl acetate 200 ml / L, n-propanol 600 ml / L; stannous chloride anhydrous 0.4 mol / L, stannous chloride dihydrate 0.6 mol / L; 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate 12 g / L; hexahydrophthalic anhydride 2.0 g / L, tetrahydrophthalic anhydride 2.0 g / L; deionized water 80 ml / L. Sealing agent preparation process: Add 200 ml of ethyl acetate, 600 ml of n-propanol, and 80 mL of deionized water to a round-bottom flask, add 0.4 mol of stannous chloride anhydrous and 0.6 mol of stannous chloride dihydrate, stir and dissolve; reflux at 100°C for 2.0 hours, and cool to room temperature; sequentially add 12 g of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate; 2.0 g of hexahydrophthalic anhydride and 2.0 g of tetrahydrophthalic anhydride, stir until uniform, and there is no need to adjust the pH value; transfer the solution to a 1000 mL volumetric flask and make up to 1000 mL with n-propanol added.

[0027] The test pieces for the following electrochemical analysis are the test pieces prepared in Examples 1-4, and the corrosion resistance of the samples was analyzed by an electrochemical method. The test equipment used is a CHI-604e electrochemical workstation. A three-electrode system is adopted. The working electrode is the sample prepared in Examples 1-4, the auxiliary electrode is a platinum sheet of 1 cm×1 cm, and the reference electrode is a saturated calomel electrode. The electrolyte solution is 3.5 wt% (pH 6.8) NaCl solution. The test voltage range is ±300 mV (relative to the open circuit voltage), and the scanning speed is 2 mV / s. The corrosion resistance of the 6063 aluminum alloy matrix, the unsealed anodic oxidation surface, and the sealed samples (Examples 1-4) was compared during the detection. The test results are as Figure 2 shown. The curve data fitting results are shown in Table 1 below.

[0028] The electrical contact resistance (ECR) of the sealed surface is determined by a comprehensive test system designed according to the SJ 20813-2002 standard. The ECR value is collected at room temperature by a DC low-resistance tester (RK2512N+), and the data accuracy is 0.05%. A constant load pressure of 140 (±0.5) N is applied to the copper electrode with a press. After the indicated pressure value is stable, the resistance value is read. The results are shown in Table 1: Table 1. Comparison of corrosion resistance and surface resistance of different samples It can be seen from the test results that the self-corrosion current density of the anodized surface in a 3.5 wt.% NaCl solution is approximately 1.0 μA / cm². -2 After being sealed by this sealing method, the overall change in the self-corrosion current density is not significant, remaining at the same order of magnitude as the surface without sealing in anodization, indicating excellent corrosion resistance. Regarding the surface contact resistance, the surface without sealing is an insulator without conductive function, while for the surface sealed by the technology of the present invention, the surface contact resistance drops sharply, and the test results of the examples do not exceed 30 mΩ·cm². 2 It has good conductivity. From the XPS spectrum analysis of the tin element in the film layer (sample of Example 3), it can be seen that the tin element mainly exists in the forms of SnO₂ and elemental Sn, which are the key conductive components of the film layer.

[0029] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device.

[0030] The above is only the preferred specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered within the protection scope of the present invention.

[0031] Obviously, the above-described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The preferred embodiments of the present application are given in the drawings, but do not limit the patent scope of the present application. The present application can be implemented in many different forms. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure content of the present application more thorough and comprehensive. Although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions described in the foregoing specific embodiments, or perform equivalent substitutions for some of the technical features. Any equivalent structure directly or indirectly using the content of the specification and drawings of the present application in other related technical fields shall be within the scope of the patent protection of the present application by the same token.

Claims

1. A room-temperature nickel-free conductive sealing solution for anodized aluminum alloy films, characterized in that, It includes: a sealing agent and a pH regulator; The composition of the sealing agent and the dosage of each component are as follows by volume and mass: Solvent 700 - 800 ml / L Main salt 0.2 - 1.5 mol / L Film-forming agent 2.0 - 40.0 g / L Film-forming accelerator 0.2 - 30.0 g / L Deionized water 50 - 100 ml / L; The sealing agent is adjusted to pH = 0.1 - 1.2 with a pH regulator; The main salt is any one or a mixture of two of stannous chloride anhydrous and stannous chloride dihydrate.

2. The room-temperature nickel-free conductive sealing solution for anodized aluminum alloy film according to claim 1, characterized in that, The film-forming agent is one or more of polybisphenol A diglycidyl ether, terephthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, bis((3,4-epoxycyclohexyl)methyl) adipate, and isophorone diisocyanate.

3. The room-temperature nickel-free conductive sealing solution for anodized aluminum alloy film according to claim 1, characterized in that, The film-forming accelerator is at least one of m-phenylenediamine, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, dicyandiamide, 2-ethyl-4-methylimidazole, and 2-phenylimidazole.

4. The room-temperature nickel-free conductive sealing solution for anodic oxidation film of aluminum alloy according to claim 1, characterized in that The pH regulator is a 15% hydrochloric acid solution or 25% ammonia water.

5. The room-temperature nickel-free conductive sealing solution for anodic oxidation film of aluminum alloy according to claim 1, characterized in that, The solvent is one or more of ethanol, n-propanol, isopropanol, n-butanol, isobutanol, glycerol, and ethyl acetate.

6. A preparation method of a nickel-free conductive sealing solution for anodic oxidation film of aluminum alloy at room temperature, characterized in that, It includes the following steps: (1) Add 700 - 800 ml of solvent, 50 - 100 ml of deionized water, and 0.2 - 1.5 mol of main salt to a round-bottom flask in sequence, and stir until completely dissolved; (2) Reflux the above solution at 80 - 140 °C for 1 - 2 hours, cool to room temperature, add 2.0 - 40.0 g of film-forming agent and 0.20 - 30.0 g of film-forming accelerator in sequence, stir evenly, and adjust to pH = 0.1 - 1.2 with a pH regulator; (3) Transfer the above solution to a volumetric flask and make up the solvent to 1000 mL to complete the preparation of the sealing solution; The main salt is any one or a mixture of two of stannous chloride anhydrous and stannous chloride dihydrate.

7. A room-temperature nickel-free conductive sealing method for anodic oxidation film of aluminum alloy as described in claim 1, characterized in that, It includes the following steps: S1. Pretreatment of degreasing and pickling of aluminum alloy; S2. Anodic oxidation treatment of aluminum alloy; S3. Sealing treatment of anodic oxidation film: After the aluminum alloy workpiece after anodic oxidation treatment is cleaned and blown dry, it is immediately immersed in the sealing solution as described in claim 1 for sealing treatment at room temperature for 3 - 6 minutes. After the sealing is completed, it is placed in a vacuum drying oven for treatment at 50 - 60 °C for 2 - 5 minutes, and then heated to 120 - 180 °C for treatment for 5 - 40 minutes to complete the sealing treatment.

8. The room-temperature nickel-free conductive sealing method for anodized aluminum alloy film according to claim 7, characterized in that For the pretreatment of degreasing and pickling of the aluminum alloy, the specific treatment steps are as follows: (1) Degreasing with alkali: Place the aluminum alloy product in an alkali cleaning solution containing 8 g / L of NaOH and 20 g / L of Na2SiO3, and perform alkali cleaning at room temperature for 1 - 2 minutes; (2) Wash twice with running tap water and once with deionized water; (3) Pickling and brightening: The above-mentioned cleaned aluminum alloy products are placed in a pickling solution containing 30 g / L of concentrated H2SO4, 300 ml / L of HNO3 (analytical pure, 65 - 68%), and 0.2 g / L of OP-10, and pickled at room temperature for 1 - 3 minutes; (4) Wash twice with running tap water and once with deionized water.

9. The room-temperature nickel-free conductive sealing method for anodized aluminum alloy film according to claim 8, characterized in that, The anodic oxidation treatment of the aluminum alloy is carried out as follows: Immerse the pre-treated aluminum alloy into the anodic oxidation tank for anodic oxidation treatment; the composition of the anodic oxidation bath is 185 g / L - 195 g / L of H2SO4, the treatment temperature is 18 ± 1 °C, direct current anodic oxidation for 28 - 32 min, and the current density is 1.8 A / dm 2 .

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