A chromium-free passivating agent for aluminum parts and a chromium-free passivating treatment process for aluminum parts

Abstract

The present invention relates to the technical field of aluminum passivation, and specifically to a chromium-free passivation agent for aluminum and a chromium-free passivation treatment process for aluminum. The passivation agent comprises, by mass percentage, 1-2% of fluorozirconic acid, 1-5% of fluorotitanic acid, 0.1-1% of resin, and the remainder of water. The treatment process comprises: performing passivation treatment on aluminum material using the above-mentioned chromium-free passivation agent for aluminum. It is not only harmless to the environment and operators, but also the effect after treatment is not inferior to the traditional hexavalent chromium process or trivalent chromium process, and the composition is simple, and it is easy to produce and apply.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum part passivation, and in particular to a chromium-free passivation agent for aluminum parts and a chromium-free passivation treatment process for aluminum parts. Background Art

[0002] The traditional hexavalent chromium or trivalent chromium passivation of aluminum parts before painting has excellent performance after painting, but the agent will cause serious harm to the environment and operators during use. Therefore, the country should strictly prohibit its use, so it is necessary to develop an agent that is harmless to the environment and operators.

[0003] In view of this, this application is hereby filed. Summary of the invention

[0004] The first object of the present invention is to provide a chromium-free passivating agent for aluminum parts, which is not only harmless to the environment and operators, but also has a treatment effect that is not inferior to that of traditional hexavalent chromium process or trivalent chromium process, and has a simple composition and is easy to produce and use.

[0005] The second object of the present invention is to provide a chromium-free passivation treatment process for aluminum parts, which can further improve the passivation effect of aluminum materials while achieving environmental protection and safety, and is simple and practical.

[0006] The embodiment of the present invention is achieved as follows:

[0007] A chromium-free passivating agent for aluminum parts comprises the following components by mass percentage: 1-2% of fluorozirconic acid, 1-5% of fluorotitanic acid, 0.1-1% of resin, and the balance of water.

[0008] Furthermore, the chromium-free passivation agent for aluminum parts includes the following components by mass percentage: 1.5-1.8% of fluorozirconic acid, 3-4% of fluorotitanic acid, 0.4-0.7% of resin, and the balance of water.

[0009] Furthermore, the resin includes at least one of a water-soluble acrylic resin and a bisphenol A epoxy resin.

[0010] Furthermore, the chromium-free passivation agent for aluminum parts also includes a pH regulator. The amount of the pH regulator is determined according to the required pH value, wherein the required pH value ranges from 2.5 to 3.8.

[0011] A chromium-free passivation treatment process for aluminum parts comprises: using the above-mentioned chromium-free passivation agent for aluminum parts to perform passivation treatment on aluminum materials.

[0012] Furthermore, after the aluminum parts are passivated with the chromium-free passivating agent for aluminum parts, the residual agent on the surface of the aluminum parts is washed and dried, and then hydrogen peroxide is sprayed on the surface of the aluminum parts and left to stand for 30 seconds, and then dried.

[0013] The beneficial effects of the technical solution of the embodiment of the present invention include:

[0014] After the aluminum material is passivated by the chromium-free passivator provided in the embodiment of the present invention, the passivation layer obtained is stable and reliable. In addition, by treating the passivator with hydrogen peroxide after treatment, the tolerance of the passivation layer to humidity and boiling water can be effectively improved.

[0015] In general, the chromium-free passivation agent for aluminum parts provided in the embodiment of the present invention is not only harmless to the environment and operators, but also has a treatment effect that is not inferior to that of the traditional hexavalent chromium process or trivalent chromium process, and has simple ingredients and is easy to produce and use. The chromium-free passivation treatment process for aluminum parts provided in the embodiment of the present invention can further improve the passivation effect of aluminum materials while achieving environmental protection and safety, and is simple and practical. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0017] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0019] The embodiment of the present invention provides a chromium-free passivating agent for aluminum parts, which comprises the following components by mass percentage: 1-2% of fluorozirconic acid, 1-5% of fluorotitanic acid, 0.1-1% of resin, and the balance of water.

[0020] Optionally, the chromium-free passivation agent for aluminum parts includes the following components by mass percentage: 1.5-1.8% of fluorozirconic acid, 3-4% of fluorotitanic acid, 0.4-0.7% of resin, and the balance of water.

[0021] The resin includes at least one of a water-soluble acrylic resin and a bisphenol A epoxy resin.

[0022] The chromium-free passivation agent for aluminum parts also includes: pH regulator.

[0023] The amount of pH adjuster used is determined according to the desired pH value. Optionally, the desired pH value ranges from 2.5 to 3.8.

[0024] The chromium-free passivation agent for aluminum parts provided in the embodiment of the present invention realizes chromium-free treatment and significantly simplifies the components of the passivation agent, thereby making the production and use of the chromium-free passivation agent for aluminum parts simpler.

[0025] The embodiment of the present invention further provides a chromium-free passivation treatment process for aluminum parts, which comprises: performing passivation treatment on aluminum materials using the above-mentioned chromium-free passivation agent for aluminum parts.

[0026] Furthermore, after the aluminum parts are passivated with the chromium-free passivating agent for aluminum parts, the residual agent on the surface of the aluminum parts is washed and dried, and then hydrogen peroxide is sprayed on the surface of the aluminum parts and left to stand for 30 seconds, and then dried.

[0027] Through this design, after the aluminum material is passivated with the aluminum chromium-free passivator, it is then treated once with hydrogen peroxide, which helps to further improve the stability of the passivation layer of the aluminum part.

[0028] The method for preparing nanocellulose in the present invention comprises the following steps:

[0029] S1. Crush corn stalks into 50-mesh powder, take 10 g of corn stalk powder and disperse it in 200 ml of 9 wt.% sodium hydroxide solution, stir at 60° C. for 1 h, and then perform vacuum filtration;

[0030] S2, placing the material obtained in step S1 into 200 ml of a mixed solution of sodium chlorite and acetic acid, stirring at 70° C. for 1 h, and then filtering and drying to obtain cellulose;

[0031] S3, put 5 g of cellulose into 100 ml of 64% sulfuric acid, react at 50°C for 1 h, and then add 1000 ml of deionized water;

[0032] S4. The solution obtained in step S3 was allowed to stand for stratification, and then the lower suspension was taken and the pH was adjusted to neutral; a clear solution was obtained by centrifugation, and then the volume was made up to 1000 ml with water to obtain a 5 mg / mL nanocellulose solution.

[0033] The method for preparing nitrogen-fluorine-doped graphene oxide in the present invention comprises the following steps:

[0034] 50 mL of 10 mg / mL graphene oxide solution was stirred for 0.5 h; then 70 mg of ammonium fluoride was added, stirred and ultrasonicated for 0.5 h, and then reacted at 180° C. for 10 h, and naturally cooled to obtain nitrogen-fluorine-doped graphene oxide.

[0035] The preparation method of the nitrogen-fluorine doped graphene oxide nanocellulose composite of the present invention comprises the following steps:

[0036] 50 mL of 10 mg / mL graphene oxide solution and 2 ml of 5 mg / ml nanocellulose solution were mixed together and stirred for 0.5 h; then 70 mg of ammonium fluoride was added, stirred and ultrasonicated for 0.5 h, and then reacted at 180°C for 10 h and naturally cooled to obtain a nitrogen-fluorine-doped graphene oxide nanocellulose composite.

[0037] The chromium-free passivation agent for aluminum parts and the chromium-free passivation treatment process for aluminum parts provided in the embodiments of the present invention are described in detail below in conjunction with specific embodiments.

[0038] Example 1

[0039] This embodiment provides a chromium-free passivation agent for aluminum parts, which includes the following components by mass percentage: 1.5% of fluorozirconic acid, 4% of fluorotitanic acid, 0.6% of water-soluble acrylic resin, and the balance of deionized water. The pH value is 3.

[0040] Example 2

[0041] This embodiment provides a chromium-free passivation agent for aluminum parts, which includes the following components by mass percentage: 1.8% of fluorozirconic acid, 3.5% of fluorotitanic acid, 0.7% of water-soluble acrylic resin, and the balance of deionized water. The pH value is 3.5.

[0042] Example 3

[0043] This embodiment provides a chromium-free passivation agent for aluminum parts, which includes the following components by mass percentage: 1.6% of fluorozirconic acid, 3% of fluorotitanic acid, 0.4% of bisphenol A epoxy resin, and the balance of deionized water. The pH value is 3.8.

[0044] Example 4

[0045] This embodiment provides a chromium-free passivation agent for aluminum parts, which includes the following components by mass percentage: 1.5% of fluorozirconic acid, 3.8% of fluorotitanic acid, 0.5% of bisphenol A epoxy resin, and the balance of deionized water. The pH value is 2.5.

[0046] Example 5

[0047] This embodiment provides a chromium-free passivation agent for aluminum parts, which includes the following components by mass percentage: 2% of fluorozirconic acid, 5% of fluorotitanic acid, 0.1% of bisphenol A epoxy resin, and the balance of deionized water. The pH value is 3.

[0048] Example 6

[0049] This embodiment provides a chromium-free passivation agent for aluminum parts, which includes the following components by mass percentage: 1% of fluorozirconic acid, 2% of fluorotitanic acid, 1% of bisphenol A epoxy resin, and the balance of deionized water. The pH value is 3.5.

[0050] Example 7

[0051] This embodiment provides a chromium-free passivation agent for aluminum parts, which includes the following components by mass percentage: 1.2% of fluorozirconic acid, 1% of fluorotitanic acid, 0.2% of water-soluble acrylic resin, and the balance of deionized water. The pH value is 2.8.

[0052] Example 8

[0053] This embodiment provides a chromium-free passivation agent for aluminum parts, which includes the following components by mass percentage: 1.8% of fluorozirconic acid, 2.5% of fluorotitanic acid, 0.8% of water-soluble acrylic resin, and the balance of deionized water. The pH value is 2.5.

[0054] Example 9

[0055] This embodiment provides a chromium-free passivation agent for aluminum parts, which is based on Example 8 and adds 1.0% nitrogen-fluorine-doped graphene oxide. Specifically, it includes the following components by mass percentage: 1.8% fluorozirconic acid, 2.5% fluorotitanic acid, 0.8% water-soluble acrylic resin, 1.0% nitrogen-fluorine-doped graphene oxide and the balance deionized water. The pH value is 2.5.

[0056] Example 10

[0057] This embodiment provides a chromium-free passivation agent for aluminum parts. On the basis of Embodiment 8, 1.0% of nitrogen-fluorine-doped graphene oxide nanocellulose composite is added. Specifically, it includes the following components by mass percentage: 1.8% of fluorozirconic acid, 2.5% of fluorotitanic acid, 0.8% of water-soluble acrylic resin, 1.0% of nitrogen-fluorine-doped graphene oxide nanocellulose composite and the balance of deionized water. The pH value is 2.5.

[0058] Experimental example

[0059] The chromium-free passivation agents for aluminum parts in Examples 1 to 10 were used to passivate the aluminum materials and then conduct acetic acid salt spray resistance tests. The test results are shown in the following table.

[0060] Acetic acid salt spray resistance 1500h Acetic acid salt spray resistance 2000h Acetic acid salt spray resistance 2500h Example 1 pass Not passed Not passed Example 2 pass Not passed Not passed Example 3 pass Not passed Not passed Example 4 pass Not passed Not passed Example 5 pass Not passed Not passed Example 6 pass Not passed Not passed Example 7 pass Not passed Not passed Example 8 pass pass Not passed Example 9 pass pass pass

[0061] By comparing the test results of the passivator provided in the embodiment of the present invention with the test results of the comparative example, it can be seen that after the aluminum material is passivated by the chromium-free passivator provided in the embodiment of the present invention, the passivation layer obtained is stable and reliable. The addition of nitrogen-fluorine doped graphene oxide is speculated to increase the bonding ability between the passivation film and the surface metal of the aluminum part. In addition, the composite composed of graphene oxide and cellulose can enhance the mechanical properties of the passivation film.

[0062] In summary, the chromium-free passivation agent for aluminum parts provided in the embodiment of the present invention is not only harmless to the environment and operators, but also has a treatment effect that is not inferior to the traditional hexavalent chromium process or trivalent chromium process, and has simple ingredients and is easy to produce and use. The chromium-free passivation treatment process for aluminum parts provided in the embodiment of the present invention can further improve the passivation effect of aluminum materials while achieving environmental protection and safety, and is simple and practical.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A chromium-free passivating agent for aluminum parts, characterized in that: The composition includes the following components by mass percentage: 1.8% of fluorozirconic acid, 2.5% of fluorotitanic acid, 0.8% of water-soluble acrylic resin, 1.0% of nitrogen-fluorine-doped graphene oxide and the balance of deionized water, and the pH value is 2.5; The preparation method of nitrogen-fluorine-doped graphene oxide comprises the following steps: Stir 50 mL of 10 mg / mL graphene oxide solution for 0.5 h; then add 70 mg of ammonium fluoride, stir and sonicate. 0.5h, then react at 180°C for 10h, and cool naturally to obtain nitrogen-fluorine-doped graphene oxide; The chromium-free passivation agent for aluminum parts has an acetic acid salt spray resistance test of ≥2500h.