A metal surface treatment agent, a method for producing the same, and a method for treating a metal surface

Abstract

This invention relates to the field of surface treatment technology, and particularly to a metal surface treatment agent and its preparation method, as well as a method for surface treatment of metals. The metal surface treatment agent provided by this invention is prepared by mixing EDTA-2Na, citric acid, malic acid, phytic acid, sodium dodecyl sulfonate, polyethylene glycol octylphenyl ether, cocoyl diethanolamide, defoamer, and water in a certain proportion. It exhibits excellent detergency and emulsification properties, effectively removing animal fats and industrial oils from workpieces, and effectively removing rust. Simultaneously, it generates a dense passivation film on the workpiece surface, effectively increasing rust prevention and coating adhesion. Furthermore, the main raw materials used in this invention are everyday chemical products, which are mild on the natural environment and harmless to the human body. Moreover, the treatment agent of this invention requires no special equipment, only a treatment tank or no treatment tank at all, the operation process is simple, there is no emission pollution, and it can effectively reduce energy consumption and save costs.

Description

Technical Field

[0001] This invention relates to the field of surface treatment technology, and in particular to a metal surface treatment agent and its preparation method, as well as a method for surface treatment of metals. Background Technology

[0002] To obtain a clean, non-active substrate surface with good adhesion and corrosion resistance, a systematic treatment process is performed on the metal surface before coating. This process generally includes the following stages:

[0003] a. Cleaning stage

[0004] Degreasing: Removes rolling oil, cutting oil, rust-preventive oil, lubricating oil, dust, fingerprints, and other organic contaminants from metal surfaces. Degreasing agents (alkaline, neutral, or acidic) are used, applied through spraying or immersion, combined with heating and mechanical force (such as spray pressure). This is the foundation for all subsequent treatments; without thorough degreasing, all subsequent treatments will be ineffective.

[0005] Rust removal / scale removal: Removes rust from steel surfaces ( (e.g., welding scale, heat treatment scale, etc.) For thick rust or heavy workpieces, sandblasting, shot blasting, and grinding are used. For light parts, rust removers (usually acidic, such as hydrochloric acid, sulfuric acid, phosphoric acid, or mixtures thereof) can be used.

[0006] b. Surface adjustment

[0007] Before phosphating, chemical methods are used to homogenize the microstructure of the metal surface, forming numerous tiny crystal nuclei, thereby promoting the formation of uniform, dense, and fine phosphating crystals in the subsequent phosphating reaction. This method is commonly used before phosphating steel, and specific surface conditioning agents are also available for stainless steel and aluminum. The method involves short-term immersion or spraying with a colloidal titanium salt surface conditioning agent.

[0008] c. Chemical conversion membrane treatment (forming an adhesion substrate)

[0009] To enhance coating adhesion and corrosion resistance, an insoluble, well-adhesive crystalline or amorphous film is formed on the metal surface. This process primarily involves phosphating, zirconium salt / zirconium-titanium treatment, and silane treatment.

[0010] As can be seen, the above surface treatment process requires multiple separate steps, and multiple reaction tanks are needed in actual treatment, such as... Figure 1 As shown, the above methods are complex and involve many steps, resulting in significant waste of space, equipment, and water. Furthermore, wastewater treatment is difficult, and many small and micro-enterprises are unable to perform coating or metal surface treatment due to inadequate equipment and facilities. Summary of the Invention

[0011] In view of this, the present invention provides a metal surface treatment agent and its preparation method, as well as a surface treatment method for metals. The metal surface treatment agent provided by the present invention has the functions of degreasing, derusting, film formation, and rust prevention, and improves the adhesion of coatings on workpieces and the corrosion resistance of workpieces. Moreover, it does not emit pollution during use, and is safe, environmentally friendly, and energy-saving.

[0012] This invention provides a metal surface treatment agent, comprising the following components by weight percentage:

[0013] EDTA-2Na: 0.1%;

[0014] Citric acid: 1%;

[0015] Malic acid: 0.5%;

[0016] Phytic acid: 20%;

[0017] Sodium dodecyl sulfonate: 1%;

[0018] Polyethylene glycol octylphenyl ether: 2%;

[0019] Cocoyl diethanolamide: 0.5%;

[0020] Defoamer: 0.1%;

[0021] Water: Balance.

[0022] Preferably, the defoamer is an organosilicone defoamer.

[0023] Preferably, the water is pure water.

[0024] The present invention also provides a method for preparing the metal surface treatment agent described in the above technical solution, comprising:

[0025] A metal surface treatment agent is obtained by mixing EDTA-2Na, citric acid, malic acid, phytic acid, sodium dodecyl sulfonate, polyethylene glycol octylphenyl ether, cocoyl diethanolamide, defoamer, and water.

[0026] Preferably, the preparation method includes:

[0027] S1. Take some water, add EDTA-2Na, and stir well;

[0028] S2. Add citric acid to the solution obtained in step S1 and stir until completely dissolved;

[0029] S3. Add malic acid to the solution obtained in step S2 and stir until completely dissolved;

[0030] S4. Add phytic acid to the solution obtained in step S3, and add the remaining water, stirring until completely dissolved;

[0031] S5. Add sodium dodecyl sulfonate, polyethylene glycol octylphenyl ether, and cocoyl diethanolamide to the solution obtained in step S4, and stir to react.

[0032] S6. Add defoamer to the solution obtained in step S5, let it stand, and obtain metal surface treatment agent.

[0033] Preferably, the stirring speed in each step is independently selected from 60 to 100 rpm.

[0034] Preferably, in step S6, the settling time is 0.5 to 1 hour.

[0035] The present invention also provides a surface treatment method for metal, comprising: immersing the metal workpiece to be treated in a surface treatment agent, and then removing and drying it;

[0036] The surface treatment agent is the metal surface treatment agent described in the above technical solution or the metal surface treatment agent prepared by the preparation method described in the above technical solution.

[0037] Preferably, the soaking time is ≤5 min.

[0038] Preferably, after drying, the process further includes wiping the workpiece with a surface treatment agent and then drying it.

[0039] The metal surface treatment agent provided by this invention is a surface treatment agent whose main component is organic acid. It is prepared by mixing EDTA-2Na, citric acid, malic acid, phytic acid, sodium dodecyl sulfonate, polyethylene glycol octylphenyl ether, cocoyl diethanolamide, defoamer, and water in a certain proportion. It has excellent detergency and emulsification properties, effectively removing animal fats and industrial machine oils from workpieces, and effectively removing rust. At the same time, it can also form a dense passivation film layer on the workpiece surface, effectively increasing the rust prevention effect and coating adhesion. In addition, the main raw materials used in this invention are organic substances, which are mild to the natural environment and harmless to the human body. Moreover, the treatment agent of this invention does not require special equipment, only a treatment tank is needed, or no treatment tank is needed at all. The operation process is simple, there is no emission pollution, and it can effectively reduce energy consumption and save costs. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the reaction tank required for surface treatment engineering in the prior art;

[0042] Figure 2 This is a schematic diagram of a workpiece treated with the metal surface treatment agent of the present invention. Detailed Implementation

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0044] In this article, the technical features described in an open-ended manner include both closed technical solutions composed of the listed features and open technical solutions that include the listed features.

[0045] The term “and / or” as used herein includes any and all combinations of one or more of the related listed items.

[0046] In this document, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when a range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0047] In this article, when referring to units of data ranges, if a unit is only followed by the right endpoint, it means that the units of the left and right endpoints are the same.

[0048] In a first aspect, the present invention provides a metal surface treatment agent comprising, by weight percentage, the following components:

[0049] EDTA-2Na: 0.1%;

[0050] Citric acid: 1%;

[0051] Malic acid: 0.5%;

[0052] Phytic acid: 20%;

[0053] Sodium dodecyl sulfonate: 1%;

[0054] Polyethylene glycol octylphenyl ether: 2%;

[0055] Cocoyl diethanolamide: 0.5%;

[0056] Defoamer: 0.1%;

[0057] Water: Balance.

[0058] In this invention, the source of EDTA-2Na (disodium ethylenediaminetetraacetate) is not particularly limited; it can be a commercially available product or prepared according to methods known in the art.

[0059] In this invention, the source of the citric acid (also known as citric acid) is not particularly limited; it can be a commercially available product or prepared according to methods known in the art.

[0060] In this invention, the source of the malic acid is not particularly limited; it can be a commercially available product or prepared according to methods known in the art.

[0061] In this invention, the source of phytic acid is not particularly limited; it can be a commercially available product or prepared according to methods known in the art.

[0062] In this invention, the source of the sodium dodecyl sulfonate is not particularly limited; it can be a commercially available product or prepared according to methods known in the art.

[0063] In this invention, the source of the polyethylene glycol octylphenyl ether is not particularly limited; it can be a commercially available product or prepared according to methods known in the art.

[0064] In this invention, the source of the cocoyl diethanolamide is not particularly limited; it can be a commercially available product or prepared according to methods known in the art.

[0065] In this invention, the defoamer is preferably an organosilicone defoamer. This invention does not impose any special restrictions on the source of the defoamer; any commercially available product is acceptable.

[0066] In this invention, the water is preferably pure water. The water content is a margin, that is, to make up to 100%.

[0067] In this invention, the pH value of the metal surface treatment agent is 2.

[0068] Secondly, the present invention provides a method for preparing the metal surface treatment agent described in the above technical solution, comprising: mixing EDTA-2Na, citric acid, malic acid, phytic acid, sodium dodecyl sulfonate, polyethylene glycol octylphenyl ether, cocoyl diethanolamide, defoamer and water to obtain the metal surface treatment agent.

[0069] In this invention, preferably, the above preparation method specifically includes:

[0070] S1. Take some water, add EDTA-2Na, and stir well;

[0071] S2. Add citric acid to the solution obtained in step S1 and stir until completely dissolved;

[0072] S3. Add malic acid to the solution obtained in step S2 and stir until completely dissolved;

[0073] S4. Add phytic acid to the solution obtained in step S3, and add the remaining water, stirring until completely dissolved;

[0074] S5. Add sodium dodecyl sulfonate, polyethylene glycol octylphenyl ether, and cocoyl diethanolamide to the solution obtained in step S4, and stir to react.

[0075] S6. Add defoamer to the solution obtained in step S5, let it stand, and obtain metal surface treatment agent.

[0076] The types and amounts of EDTA-2Na, citric acid, malic acid, phytic acid, sodium dodecyl sulfonate, polyethylene glycol octylphenyl ether, cocoyl diethanolamide, defoamer, and water are consistent with those described in the previous technical solution and will not be repeated here.

[0077] In this invention, the stirring speed in each of the above steps is independently selected from 60 to 100 rpm, specifically 60 rpm, 70 rpm, 80 rpm, 90 rpm, and 100 rpm; the stirring time is preferably sufficient to completely dissolve the components and make the solution clear and transparent without impurities. In step S6, the settling time is 0.5 to 1 hour, preferably 1 hour.

[0078] Thirdly, the present invention provides a method for surface treatment of metal, comprising: immersing a metal workpiece to be treated in a surface treatment agent, and then removing and drying it; wherein the surface treatment agent is the metal surface treatment agent described in the above technical solution or the metal surface treatment agent prepared by the above preparation method.

[0079] In this invention, the soaking can be carried out at low or normal temperature; the temperature can be 1~30℃. The soaking time is ≤5min, specifically 1min, 2min, 3min, 4min, or 5min. The drying can be natural air drying. After the metal workpiece is placed in the surface treatment agent, small bubbles are generated on the surface of the workpiece, and the oil and rust on it gradually fall off. After soaking for a certain period of time, the workpiece is removed, and a light gray protective film will be seen on the surface of the workpiece. After the workpiece is allowed to dry naturally, the protective film on the surface is very obvious. The resulting workpiece can be kept rust-proof indoors for more than half a year.

[0080] In this invention, after the aforementioned drying, it is preferable to further perform the following steps: wiping the workpiece with a surface treatment agent, followed by drying. Specifically, a cloth is soaked in the surface treatment agent and used to wipe the oily or rusty areas of the workpiece surface. After wiping, it is dried again; the drying can be natural drying. That is, after wiping, the workpiece is left to air dry naturally. The oil and rust will form a light gray color, like white ash, while some heavy rust will react with the agent to produce a black substance. After it is completely dry, the surface is wiped again with a dry cloth before spraying to remove any dust residue, and then the coating operation can be carried out. When using in batches, if the bath solution becomes too dirty, it can be left to stand to remove excess impurities, and new solution can be added for repeated use. In this invention, there are no special restrictions on the type of metal workpiece; any conventional metal workpiece is acceptable, such as steel, aluminum, galvanized steel, etc.

[0081] As can be seen, the metal surface treatment agent of the present invention is applied to the pretreatment of metal products before coating. It replaces the traditional pretreatment by simple soaking or wiping. Subsequent coating operations can be carried out with only one process of the present invention, without the need for multiple pretreatment processes as in the prior art.

[0082] Compared with the prior art, the present invention has the following advantages:

[0083] (1) The main raw material of this invention is organic matter, which is mild to the natural environment. The finished product has a pH value of 2, is harmless to the human body, and is safe to use (it can be directly exposed to bare skin without any harm). It has good water solubility and can be diluted according to usage requirements.

[0084] (2) This invention requires no special equipment, has a simple operation process, no emissions pollution, and is highly efficient in production and use.

[0085] (3) In this invention, a variety of surfactants are combined in a certain proportion, which has good decontamination and emulsification properties and has a significant effect on removing animal fats and industrial oils from workpieces.

[0086] (4) In this invention, the combination of several organic acids achieves ideal rust removal from the workpiece, while simultaneously generating a fine passivation film on the workpiece surface. The rust prevention effect and coating adhesion are significantly improved.

[0087] (5) All raw materials used are conventional products available on the market. The purchase and production of hazardous chemicals are relatively easy, which greatly helps to save energy, reduce consumption and lower production costs.

[0088] (6) Due to the fewer procedures involved, the cost is more than 80% lower than that of traditional methods. One kilogram of product can process more than 100 square meters.

[0089] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0090] Example 1

[0091] 1. Formulation of surface treatment agent:

[0092] EDTA-2Na: 0.1%;

[0093] Citric acid: 1%;

[0094] Malic acid: 0.5%;

[0095] Phytic acid: 20%;

[0096] Sodium dodecyl sulfonate: 1%;

[0097] Polyethylene glycol octylphenyl ether: 2%;

[0098] Cocoyl diethanolamide: 0.5%;

[0099] Organosilicon defoamer: 0.1%;

[0100] Pure water: Balance.

[0101] 2. Preparation of surface treatment agent:

[0102] S1. Add some water (50% of the total water) to the reactor, then add EDTA-2Na, and start the stirring device to stir at 60 rpm for 10 minutes until the water is clear and transparent.

[0103] S2. Add citric acid to the solution obtained in step S1 and stir at the above speed until completely dissolved;

[0104] S3. Add malic acid to the solution obtained in step S2 and stir at the above speed until completely dissolved;

[0105] S4. Slowly add phytic acid to the solution obtained in step S3, and add the remaining water, stirring at the above speed until completely dissolved;

[0106] S5. Add sodium dodecyl sulfonate, polyethylene glycol octylphenyl ether, and coconut oil diethanolamide to the solution obtained in step S4, and stir the reaction at the above speed for 20 minutes to ensure that the solution is clear and free of impurities.

[0107] S6. Add defoamer to the solution obtained in step S5, let stand for 1 hour, and obtain metal surface treatment agent.

[0108] 3. Surface treatment of metal workpieces

[0109] Slowly immerse the metal workpiece in the metal surface treatment agent, soak for 5 minutes, then remove and allow to air dry completely. Take a pure cotton cloth, apply the metal surface treatment agent, and wipe the oily or rusty areas of the workpiece. After wiping, allow the workpiece to air dry naturally.

[0110] Workpieces after surface treatment, such as Figure 2 As shown, the workpiece surface is free of oil and rust, and has a distinct light gray protective film.

[0111] 4. Testing

[0112] Test 1: After the third surface treatment process, the workpiece was wiped with a dry cloth to remove any dust residue before proceeding directly with the coating operation. Specifically, powder coating was applied to the metal workpiece surface using YG2L65 high-gloss powder manufactured by Chongqing Zhibang Powder Coating Co., Ltd. The adhesion of the coating to the metal workpiece surface was then tested using the cross-cut adhesion test (adhesion grades range from 0 to 5, with the effect decreasing sequentially from 0 to 5). The test results showed an adhesion grade of 0, indicating excellent adhesion.

[0113] Test 2: Salt spray resistance test: After the third surface treatment process, the workpiece was subjected to a neutral salt spray (NSS) test, referring to the national standard GB / T10125-2021. The results showed that the workpieces withstood salt spray for more than 500 hours showed no corrosion.

[0114] In summary, the metal surface treatment agent of the present invention can effectively remove oil, rust, and form a film, thereby improving the adhesion and corrosion resistance of metal coatings.

[0115] Comparative Example 1

[0116] The procedure was carried out as in Example 1, except that citric acid was not added and its deficiency was supplemented by two other organic acids, namely malic acid and phytic acid, and the ratio between malic acid and phytic acid was kept the same as in Example 1 (i.e., only malic acid and phytic acid were used as organic acids, and the total amount of organic acids was kept the same as in Example 1).

[0117] The test was conducted according to the test method described above. The results showed that the adhesion level was 1, the salt spray resistance was over 200 hours, and corrosion began after 300 hours.

[0118] Comparative Example 2

[0119] The implementation follows Example 1, except that malic acid is not added, and the deficiency is supplemented by two other organic acids, namely citric acid and phytic acid, and the ratio between citric acid and phytic acid is kept the same as in Example 1 (i.e., only citric acid and phytic acid are used as organic acids, and the total amount of organic acids is kept the same as in Example 1).

[0120] The test was conducted according to the test method described above. The results showed that the adhesion level was 2, the salt spray resistance was over 200 hours, and corrosion began after 250 hours.

[0121] Comparative Example 3

[0122] The procedure was carried out as in Example 1, except that phytic acid was not added and its deficiency was supplemented by two other organic acids, namely citric acid and malic acid, and the ratio between citric acid and malic acid was kept the same as in Example 1 (i.e., only citric acid and malic acid were used as organic acids, and the total amount of organic acids was kept the same as in Example 1).

[0123] The test was conducted according to the test method described above. The results showed that the adhesion level was 2, the salt spray resistance was over 200 hours, and corrosion began after 250 hours.

[0124] It can be seen that the adhesion of Comparative Examples 1-3 decreased and the salt spray resistance deteriorated, proving that the present invention uses a specific organic acid compound, which is beneficial to improving the adhesion and corrosion resistance of the workpiece.

[0125] Comparative Example 4

[0126] The procedure was carried out as in Example 1, except that sodium dodecyl sulfonate was not added, and the missing amount was supplemented by two other surfactants, namely polyethylene glycol octylphenyl ether and cocoyl diethanolamide, and the ratio between polyethylene glycol octylphenyl ether and cocoyl diethanolamide was kept the same as in Example 1 (i.e., only polyethylene glycol octylphenyl ether and cocoyl diethanolamide were used as surfactants, and the total amount of surfactant was kept the same as in Example 1).

[0127] The test was conducted according to the test method described above. The results showed that the salt spray resistance was over 300 hours, and corrosion began to occur after about 350 hours.

[0128] Comparative Example 5

[0129] The procedure was carried out as in Example 1, except that polyethylene glycol octylphenyl ether was not added, and the missing amount was supplemented by two other surfactants, sodium dodecyl sulfonate and cocoyl diethanolamide, and the ratio between sodium dodecyl sulfonate and cocoyl diethanolamide was kept the same as in Example 1 (i.e., only sodium dodecyl sulfonate and cocoyl diethanolamide were used as surfactants, and the total amount of surfactant was kept the same as in Example 1).

[0130] The test was conducted according to the test method described above. The results showed that the salt spray resistance was over 300 hours, and corrosion began to occur after about 350 hours.

[0131] Comparative Example 6

[0132] The procedure was carried out as in Example 1, except that no cocoyl diethanolamide was added. The missing amount of cocoyl diethanolamide was supplemented by two other surfactants, namely sodium dodecyl sulfonate and polyethylene glycol octyl phenyl ether, and the ratio between sodium dodecyl sulfonate and polyethylene glycol octyl phenyl ether was kept the same as in Example 1 (i.e., only sodium dodecyl sulfonate and polyethylene glycol octyl phenyl ether were used as surfactants, and the total amount of surfactant was kept the same as in Example 1).

[0133] The test was conducted according to the test method described above. The results showed that the salt spray resistance was over 300 hours, and corrosion began to occur after about 350 hours.

[0134] It can be seen that the corrosion resistance of comparative examples 4-6 deteriorated, proving that the specific active agent compounding used in this invention is beneficial to improving the corrosion resistance of the workpiece.

[0135] A comparison of existing treatment agents and the organic acid treatment agent of this invention is shown in Table 1 below:

[0136] Table 1: Comparison of different treatment agents

[0137]

[0138] As can be seen, compared with existing treatment agents, the treatment agent of the present invention has mild operating conditions, short processing time, strong operation convenience, can effectively form film, enhance coating adhesion, enhance workpiece corrosion resistance, high environmental protection, and low energy consumption.

[0139] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A metal surface treatment agent, characterized by comprising: It comprises the following components by weight percentage: EDTA-2Na: 0.1%; Citric acid: 1%; Malic acid: 0.5%; Phytic acid: 20%; Sodium dodecyl sulfonate: 1%; Polyethylene glycol octylphenyl ether: 2%; Cocoyl diethanolamide: 0.5%; Defoamer: 0.1%; Water: Balance.

2. The metal surface treatment agent according to claim 1, characterized in that, The defoamer is an organosilicone defoamer.

3. The metal surface treatment agent according to claim 1, characterized in that, The water is pure water.

4. A method for preparing a metal surface treatment agent according to any one of claims 1 to 3, characterized in that, include: A metal surface treatment agent is obtained by mixing EDTA-2Na, citric acid, malic acid, phytic acid, sodium dodecyl sulfonate, polyethylene glycol octylphenyl ether, cocoyl diethanolamide, defoamer, and water.

5. The preparation method according to claim 4, characterized in that, include: S1. Take some water, add EDTA-2Na, and stir well; S2. Add citric acid to the solution obtained in step S1 and stir until completely dissolved; S3. Add malic acid to the solution obtained in step S2 and stir until completely dissolved; S4. Add phytic acid to the solution obtained in step S3, and add the remaining water, stirring until completely dissolved; S5. Add sodium dodecyl sulfonate, polyethylene glycol octylphenyl ether, and cocoyl diethanolamide to the solution obtained in step S4, and stir to react. S6. Add defoamer to the solution obtained in step S5, let it stand, and obtain metal surface treatment agent.

6. The preparation method according to claim 5, characterized in that, The stirring speed in each step is independently selected from 60 to 100 rpm.

7. The preparation method according to claim 5, characterized in that, In step S6, the settling time is 0.5 to 1 hour.

8. A surface treatment method for metal, characterized in that, include: The metal workpiece to be treated is immersed in the surface treatment agent, then removed and dried; The surface treatment agent is a metal surface treatment agent according to any one of claims 1 to 3 or a metal surface treatment agent prepared by any one of claims 4 to 7.

9. The surface treatment method according to claim 8, characterized in that, The soaking time is ≤5 minutes.

10. The surface treatment method according to claim 8, characterized in that, After drying, the process also includes wiping the workpiece with a surface treatment agent and then drying it.

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