CN107557778A - A kind of composite passivant and its preparation method and application - Google Patents

Abstract

The present invention relates to a kind of composite passivant and its preparation method and application, the passivator contains following components：The 600g/L of acrylic acid 200；The 100g/L of polyurethane 40；The 0.05g/L of graphene 0.005；The 4g/L of chelating agent 2；The 15g/L of corrosion inhibiter 8；The 15g/L of surfactant 5.The composite passivant that the present invention obtains can form the passivating film of one layer of water white transparency on plating piece surface, and product has metallic luster；Chromium ion is free of in composite passivant, health and ecological environment will not be damaged.Composite passivant that the present invention obtains while the corrosion resistance of plating piece can be improved, through 5% neutral salt spray test, average salt-fog resistant time reaches 81h, and the protection good to workpiece can be realized under harsh working condition, is had a good application prospect.

Description

A kind of compound passivating agent and its preparation method and application

technical field

The invention relates to the technical field of hot-dip plating, in particular to a composite passivator and its preparation method and application.

Background technique

Galvanizing refers to a surface treatment technology that coats a layer of zinc on the surface of metals, alloys or other materials to achieve aesthetics and anti-rust effects. The main method used is hot-dip galvanizing. In dry air, the galvanized layer has good corrosion resistance and is not easily corroded. However, in a humid environment, after the condensed water adheres to the surface of the galvanized layer, it will react with oxygen, carbon dioxide and other chemical gases or substances to form a corrosive solution, which can be used as an electrolyte and chemical Electrochemical corrosion occurs on the zinc layer with poor stability to produce "white rust", which seriously affects the appearance and quality of the plated parts.

Passivation is a commonly used method to protect metal coatings. Due to the interaction between metal and oxidizing substances, a very thin, dense, good covering performance is formed on the metal surface, and it is firmly adsorbed on the metal surface. passivation film on it. This layer of film exists in an independent phase, and plays the role of completely separating the metal from the corrosive medium, preventing the metal from contacting with the corrosive medium, so that the metal basically stops dissolving and forms a passive state to achieve anti-corrosion.

For the hot-dip plating industry, the passivation process commonly used at home and abroad is chromate passivation, but this chromium-containing passivation agent is easy to cause cancer and is toxic, and it is difficult to treat the waste liquid, which will cause harm to the human body and the environment. Great harm. With the advancement of science and technology and the enhancement of human environmental protection concepts, it has become the focus of current research to study non-toxic and environmentally friendly chromium-free passivation instead of chromate passivation. For example, CN102747352A discloses a passivating agent for hot-dip galvanized steel sheets, including water and the following components: nano-SiO ₂ 30g/L-90g/L, water-soluble acrylic resin 30g/L-60g/L, plant Acid and/or phosphoric acid 40g/L-80g/L, titanium acetylacetonate 3g/L-12g/L, vanadium acetylacetonate 10g/L-30g/L and isopropanol 50g/L-100g/L. CN105839098A discloses a chromium-free passivator for hot-dip galvanized steel sheets and a preparation method thereof, comprising: 25-40 parts by mass of phytic acid, 8-15 parts of sodium silicate, 10-18 parts of sodium citrate, 5-16 parts of rosin resin, 15-25 parts of concentrated polytetrafluoroethylene dispersion, 6-14 parts of sulfonated lignin, 18-30 parts of ethanol, and 20-30 parts of water. CN105887066A discloses a rust passivator. The components are proportioned by weight: 5-10 parts of acrylic emulsion, 10-20 parts of tannic acid as a conversion accelerator, 70-80 parts of isopropanol as a penetrant, and anhydrous 150-200 parts of ethanol, 150-210 parts of film-forming agent phosphoric acid, 20-30 parts of conversion accelerator lactic acid, 25-30 parts of ethylene glycol butyl ether, and 350-425 parts of water.

The above-mentioned chromium-free passivators have many advantages such as easy availability of raw materials, high scratch resistance and high rust removal performance, but their corrosion resistance is generally insufficient, and the average salt spray resistance time is about 70 hours, which is difficult to meet the harsh conditions such as high temperature and humidity. The protection of plated parts under working conditions cannot meet the requirements of factory production. Therefore, it is particularly necessary to develop a chromium-free passivator with high corrosion resistance.

Contents of the invention

In order to solve the above-mentioned technical problems, the present invention provides a composite passivator and its preparation method and application. The passivator does not contain chromium ions, which reduces the harm to the environment; after passivation, the plated parts have a metallic luster and obtain It has good surface effect and can greatly improve the corrosion resistance of plated parts. It is a new type of environmentally friendly passivator with excellent performance.

The technical scheme adopted in the present invention is: provide a kind of compound passivating agent, described passivating agent contains following components: Acrylic acid 200-600g/L; Polyurethane 40-100g/L; Graphene 0.005-0.05g/L; Mixture 2-4g/L; corrosion inhibitor 8-15g/L; surfactant 5-15g/L.

According to the present invention, the content of acrylic acid in the composite passivator is 200-600g/L, such as 200g/L, 230g/L, 250g/L, 280g/L, 300g/L, 330g/L, 350g/L L, 380g/L, 400g/L, 430g/L, 450g/L, 480g/L, 500g/L, 530g/L, 550g/L, 580g/L or 600g/L, and specific points between the above values Value, limited to space and for the sake of brevity, the present invention is no longer exhaustive enumeration.

According to the present invention, the content of polyurethane in the composite passivator is 40-100g/L, such as 40g/L, 45g/L, 50g/L, 55g/L, 60g/L, 65g/L, 70g/L L, 75g/L, 80g/L, 85g/L, 90g/L, 95g/L or 100g/L, and the specific point values between the above-mentioned values, limited by space and for the sake of simplicity, the present invention is no longer exhaustive enumerate.

According to the present invention, the content of graphene in the composite passivator is 0.005-0.05g/L, such as 0.005g/L, 0.01g/L, 0.015g/L, 0.02g/L, 0.025g/L . enumerate.

According to the present invention, the chelating agent is phytic acid and/or tannic acid; the content of the chelating agent in the passivating agent is 2-4g/L, such as 2g/L, 2.3g/L, 2.5g/L L, 2.8g/L, 3g/L, 3.3g/L, 3.5g/L, 3.8g/L or 4g/L, and specific point values between the above values, due to space limitations and for the sake of brevity, this The inventions are not exhaustively listed.

According to the present invention, the corrosion inhibitor is an organic phosphonic acid, such as hydroxyethylidene diphosphonic acid, aminotrimethylene phosphonic acid, diethylenetriaminepentamethylenephosphonic acid, etc. In consideration of the present invention, the present invention is no longer exhaustively enumerated. The content of the corrosion inhibitor is 8-15g/L, such as 8g/L, 9g/L, 10g/L, 11g/L, 12g/L, 13g/L, 14g/L or 15g/L, and The specific point values between the above numerical values are limited in space and for the sake of simplicity, the present invention will not list them exhaustively.

According to the present invention, the surfactant is an ether, such as fatty alcohol polyoxyethylene ether, alkyl polyether, nonylphenol polyoxyethylene ether, etc., and the present invention is no longer exhaustive due to space limitations and brevity. enumerate. The content of surfactant is 5-15g/L, such as 5g/L, 6g/L, 7g/L, 8g/L, 9g/L, 10g/L, 11g/L, 12g/L, 13g/L , 14g/L or 15g/L, and specific point values between the above-mentioned numerical values, the present invention is no longer exhaustively enumerated due to space limitation and for the sake of brevity.

The present invention also protects the preparation method of the above-mentioned composite passivator, which method comprises the following steps:

(1) Put the surfactant, corrosion inhibitor and chelating agent in their respective reactors according to the formula amount, and then add water to heat up and stir, the dissolution temperature is 50-70°C, stir until completely dissolved, and the amount of water added should not be Too much, just ensure that it can be completely dissolved under the above conditions; then mix the solution of the three according to the order of addition of surfactant, corrosion inhibitor, and chelating agent, and keep stirring at 50-70°C until mixed Uniform, cooled to room temperature to obtain a mixed solution;

(2) Add acrylic acid to the mixed solution of step (1) according to the formula quantity, and stir until completely dissolved;

(3) Add polyurethane to the solution obtained in step (2) according to the formula, and stir until uniformly mixed;

(4) add water to the graphene of formula quantity, stir 3-5h under ultrasonic then, to dissolving completely, obtain transparent graphene solution;

(5) The graphene solution that step (4) obtains is added in the solution of step (3), then add water again, and whole solution is allocated to 1L, obtains described composite passivator after stirring evenly.

According to the present invention, the melting temperature of the step (1) is 50-70°C, for example, it can be 50°C, 53°C, 55°C, 58°C, 60°C, 63°C, 65°C, 68°C or 70°C. The specific point values between the above numerical values are limited in space and for the sake of brevity, the present invention will not list them exhaustively.

The above is only the preferred preparation process of the compound passivator of the present invention, but it can not be used as a limitation of the present invention, and the preparation process can be properly adjusted according to actual conditions.

The composite passivator of the invention can be used for passivation of hot-dip plated parts.

Compared with the prior art, the present invention has the following beneficial effects:

1) The composite passivator of the present invention does not contain chromium ions, and will not cause harm to human health and the ecological environment. The formula uses acrylic acid as the main raw material, which has good stain resistance, weather resistance and solvent resistance. When acrylic acid is used alone, its heat resistance and water resistance are poor after film formation, and it is hot-sticky and brittle, which limits its use in hot-dip galvanizing. The development and application of chromium passivation; this application introduces polyurethane to compound acrylic acid and polyurethane to form a passivation film with good luster, heat resistance and water resistance on the surface of the plated parts; at the same time, graphite is added to the formula A small amount of graphene is added to the composite solution of acrylic acid and polyurethane to make it synergistic with the two to form a single-layer dense barrier layer to prevent the entry of aggressive media and effectively improve the performance of galvanized parts. corrosion resistance. Graphene is a two-dimensional single-layer crystal composed of a hexagonal structure of carbon atoms. The structure of graphene is very stable, and the connection between each carbon atom is very flexible. When an external mechanical force is applied, the surface of the carbon atom will bend and deform, thus making the Carbon atoms do not need to be rearranged to adapt to external forces, so the structure remains stable. Graphene has a large specific surface area and is an electron-rich hydrophobic material, which effectively makes up for the shortcomings of acrylic acid's poor water resistance.

2) Add chelating agent, corrosion inhibitor and tensio-active agent simultaneously in the passivating agent of the present application, described chelating agent can promote the combination of passivating agent and metal ion, and corrosion inhibitor can slow down material corrosion, and surfactant can improve organic matter The solubility of the passivator reduces the surface tension, which helps the whole passivator to form an organic whole and fully play its role.

3) The test of 5% neutral salt spray test (GB12335) shows that the composite passivator of the present invention can greatly improve the corrosion resistance of the plated parts, the salt spray resistance time is more than 75h, the average salt spray resistance time reaches 81h, and can be used in Good protection of the workpiece under severe working conditions such as high temperature and humidity.

4) When the composite passivating agent of the present invention is used in hot-dip galvanizing, a colorless and transparent passivation film can be formed on the surface of the plated part, which will not cover the metallic luster of the original coating, and the product has good brightness and beautiful appearance.

5) In the preparation method of the present invention, the feeding sequence of each raw material is strictly controlled to ensure that each step can be fully dissolved, which is conducive to the full synergistic effect of each component, and the corrosion resistance of the prepared passivator is significantly enhanced.

detailed description

In order to facilitate understanding of the present invention, the present invention enumerates the following examples. It should be clear to those skilled in the art that the embodiments are only for helping to understand the present invention, and should not be regarded as specific limitations on the present invention.

The composite passivator of the present invention, the passivator contains the following components: acrylic acid 200-600g/L; polyurethane 40-100g/L; graphene 0.005-0.05g/L; chelating agent 2-4g/L; corrosion inhibitor Agent 8-15g/L; Surfactant 5-15g/L.

The preparation method of above-mentioned composite passivator, this method may further comprise the steps:

(1) Put the surfactant, corrosion inhibitor and chelating agent in their respective reactors according to the formula amount, and then add water to heat up and stir, the dissolution temperature is 50-70°C, stir until completely dissolved, and the amount of water added should not be Too much, just ensure that it can be completely dissolved under the above conditions; then mix the solution of the three according to the order of addition of surfactant, corrosion inhibitor, and chelating agent, and keep stirring at 50-70°C until mixed Uniform, cooled to room temperature to obtain a mixed solution;

(2) Add acrylic acid to the mixed solution of step (1) according to the formula quantity, and stir until completely dissolved;

(3) Add polyurethane to the solution obtained in step (2) according to the formula, and stir until uniformly mixed;

(4) add water to the graphene of formula quantity, stir 3-5h under ultrasonic then, to dissolving completely, obtain transparent graphene solution;

(5) The graphene solution that step (4) obtains is added in the solution of step (3), then add water again, and whole solution is allocated to 1L, obtains described composite passivator after stirring evenly.

Example 1

Each component and its mass concentration are as shown in Table 1 in the composite passivator provided by the present embodiment:

Table 1

name molecular formula Mass concentration (g/L) acrylic acid C ₃ H ₄ O ₂ 300 Polyurethane -[-O-CONH-]n- 50 Graphene C 0.01 Fatty alcohol polyoxyethylene ether RO-( _{CH2CH2O )} nH 10 hydroxyethylidene diphosphonic acid C ₂ H ₈ O ₇ P ₂ 10 Phytic acid C ₆ H ₁₈ 0 ₂₄ P ₆ 4

Prepare above-mentioned composite passivator according to the following methods:

(1) Put 10g of fatty alcohol polyoxyethylene ether, 10g of hydroxyethylidene diphosphoric acid and 4g of phytic acid into their respective reactors, then add water to raise the temperature, and keep stirring until the dissolution temperature is 60°C. Dissolve all of them, then mix the three solutions according to the order of addition of surfactant, corrosion inhibitor and chelating agent, stir continuously at 50-70°C until uniformly mixed, and cool to room temperature to obtain a mixed solution;

(2) Add 300g of acrylic acid into the mixed solution obtained in step (1), and stir until completely dissolved;

(3) Add 50 g of polyurethane to the solution obtained in step (2), stir magnetically for 2 h, until completely mixed;

(4) add water to 0.01g graphene powder, then stir 4h under ultrasonic, to dissolve completely, obtain transparent graphene solution;

(5) The graphene solution that step (4) obtains is added in the solution that step (3) obtains, then add water again, whole solution is allocated to 1L, obtains described composite passivator after stirring evenly.

Example 2

Each component and its mass concentration are as shown in Table 2 in the composite passivator provided by the present embodiment:

Table 2

name molecular formula Mass concentration (g/L) acrylic acid C ₃ H ₄ O ₂ 400 Polyurethane -[-O-CONH-]n- 50 Graphene C 0.01 Fatty alcohol polyoxyethylene ether RO-( _{CH2CH2O )} nH 10 hydroxyethylidene diphosphonic acid C ₂ H ₈ O ₇ P ₂ 10 Phytic acid C ₆ H ₁₈ 0 ₂₄ P ₆ 4

The preparation method is the same as in Example 1.

Example 3

Each component and its mass concentration are as shown in Table 3 in the composite passivator provided by the present embodiment:

table 3

name molecular formula Mass concentration (g/L) acrylic acid C ₃ H ₄ O ₂ 500 Polyurethane -[-O-CONH-]n- 50 Graphene C 0.01 Fatty alcohol polyoxyethylene ether RO-( _{CH2CH2O )} nH 10 hydroxyethylidene diphosphonic acid C ₂ H ₈ O ₇ P ₂ 10 Phytic acid C ₆ H ₁₈ 0 ₂₄ P ₆ 4

The preparation method is the same as in Example 1.

Example 4

Each component and its mass concentration are as shown in Table 4 in the composite passivator provided by the present embodiment:

Table 4

name molecular formula Mass concentration (g/L) acrylic acid C ₃ H ₄ O ₂ 400 Polyurethane -[-O-CONH-]n- 60 Graphene C 0.01 Fatty alcohol polyoxyethylene ether RO-( _{CH2CH2O )} nH 10 hydroxyethylidene diphosphonic acid C ₂ H ₈ O ₇ P ₂ 10 Phytic acid C ₆ H ₁₈ 0 ₂₄ P ₆ 4

The preparation method is the same as in Example 1.

Example 5

Each component and its mass concentration are as shown in Table 5 in the composite passivator provided by the present embodiment:

table 5

The preparation method is the same as in Example 1.

Example 6

Each component and its mass concentration in the composite passivator provided by the present embodiment are as shown in Table 6:

Table 6

name molecular formula Mass concentration (g/L) acrylic acid C ₃ H ₄ O ₂ 400 Polyurethane -[-O-CONH-]n- 60 Graphene C 0.03 Fatty alcohol polyoxyethylene ether RO-( _{CH2CH2O )} nH 10 hydroxyethylidene diphosphonic acid C ₂ H ₈ O ₇ P ₂ 10 Tannic acid C ₇₆ H ₅₂ O ₄₆ 4

The preparation method is the same as in Example 1.

Example 7

Each component and its mass concentration are as shown in Table 7 in the composite passivator provided by the present embodiment:

Table 7

name molecular formula Mass concentration (g/L) acrylic acid C ₃ H ₄ O ₂ 400 Polyurethane -[-O-CONH-]n- 70 Graphene C 0.02 Fatty alcohol polyoxyethylene ether RO-( _{CH2CH2O )} nH 10 hydroxyethylidene diphosphonic acid C ₂ H ₈ O ₇ P ₂ 10 Tannic acid C ₇₆ H ₅₂ O ₄₆ 4

The preparation method is the same as in Example 1.

Example 8

Each component and its mass concentration are as shown in Table 8 in the composite passivator provided by the present embodiment:

Table 8

name molecular formula Mass concentration (g/L) acrylic acid C ₃ H ₄ O ₂ 400 Polyurethane -[-O-CONH-]n- 80 Graphene C 0.02 Fatty alcohol polyoxyethylene ether RO-( _{CH2CH2O )} nH 10 hydroxyethylidene diphosphonic acid C ₂ H ₈ O ₇ P ₂ 10 Tannic acid C ₇₆ H ₅₂ O ₄₆ 4

The preparation method is the same as in Example 1.

Comparative example 1

Compared with Example 1, except that acrylic acid is not added in the composite passivator, other components, concentrations and preparation methods are the same as in Example 1.

Comparative example 2

Compared with Example 1, except that acrylic acid is not added to the composite passivator, and the concentration of polyurethane is adjusted to 30g/L, other components, concentrations and preparation methods are the same as in Example 1.

Comparative example 3

Compared with Example 1, except that polyurethane is not added in the composite passivator, other components and concentration and preparation method are all the same as Example 1.

Comparative example 4

Compared with Example 1, except that polyurethane is not added to the composite passivator, and the concentration of acrylic acid is adjusted to 150g/L, other components, concentrations and preparation methods are the same as in Example 1.

Comparative example 5

Compared with Example 1, except that graphene is not added in the composite passivator, other components, concentrations and preparation methods are the same as in Example 1.

Comparative example 6

Compared with Example 1, except that no graphene is added, and the concentration of acrylic acid is adjusted to 150g/L, other components, concentrations and preparation methods are the same as in Example 1.

Comparative example 7

Each component and mass concentration thereof are as shown in table 9 in this comparative example passivating agent:

Table 9

name molecular formula Mass concentration (g/L) acrylic acid C ₃ H ₄ O ₂ 400 Polyurethane -[-O-CONH-]n- 80 Graphene C 0.02

Preparation method: add water to dissolve acrylic acid and polyurethane respectively according to the formula quantity, then add the solution of acrylic acid to polyurethane, stir until mixed evenly, and obtain a mixed solution; add water to the formula quantity of graphene, and then stir for 4 hours under ultrasonic , until completely dissolved to obtain a transparent graphene solution; the graphene solution obtained above was added to the above mixed solution, and then water was added to prepare the whole solution to 1L, and the passivator was obtained after stirring evenly.

Comparative example 8

Each component and its mass concentration are as shown in table 10 in the passivating agent that this comparative example provides:

Table 10

name molecular formula Mass concentration (g/L) acrylic acid C ₃ H ₄ O ₂ 400 Polyurethane -[-O-CONH-]n- 80 Graphene C 0.02 Fatty alcohol polyoxyethylene ether RO-( _{CH2CH2O )} nH 10

The preparation method is the same as in Example 1.

Comparative example 9

Each component and its mass concentration are as shown in table 11 in the composite passivator that this comparative example provides:

Table 11

name molecular formula Mass concentration (g/L) acrylic acid C ₃ H ₄ O ₂ 400 Polyurethane -[-O-CONH-]n- 80 Graphene C 0.02 hydroxyethylidene diphosphonic acid C ₂ H ₈ O ₇ P ₂ 10

The preparation method is the same as in Example 1.

Comparative example 10

Each component and its mass concentration are as shown in table 11 in the composite passivator that this comparative example provides:

Table 12

name molecular formula Mass concentration (g/L) acrylic acid C ₃ H ₄ O ₂ 400 Polyurethane -[-O-CONH-]n- 80 Graphene C 0.02 Tannic acid C ₇₆ H ₅₂ O ₄₆ 4

The preparation method is the same as in Example 1.

Corrosion resistance test:

The composite passivators prepared in Examples 1-8 and Comparative Examples 1-10 were applied to the passivation of hot-dip galvanized sheets. Except for the different passivating agents, the size and other conditions of the hot-dip galvanized sheets used are exactly the same. The specific operations are: hot-dip galvanizing→sodium hydroxide alkali cleaning→absolute ethanol alcohol cleaning→lighting→passivation (chemical immersion)→ drying. The passivation time is 10s, and the passivation temperature is 30°C. Place the passivated hot-dip galvanized steel sheet in a salt spray test chamber for a neutral salt spray test (according to GB-6458-86). The specific experimental conditions are as follows: the concentration of the sodium chloride solution is 5%, the pH of the solution is 6-7, the test temperature is 35°C, and the sedimentation rate of the salt mist is between 1-2ml/80cm·h. The results of the neutral salt spray test are shown in Table 13.

Table 13

Passivator No. Salt spray resistance time (h) Example 1 78 Example 2 78 Example 3 79 Example 4 80 Example 5 82 Example 6 79 Example 7 84 Example 8 88 Comparative example 1 69 Comparative example 2 66 Comparative example 3 71 Comparative example 4 66 Comparative example 5 69 Comparative example 6 64 Comparative example 7 58 Comparative example 8 63 Comparative example 9 62 Comparative example 10 64

The products passivated by the passivating agent obtained in the present invention have good corrosion resistance. The salt spray resistance time of the samples after the passivating agent passivation provided by the first eight groups of embodiments is not less than 78 hours, and the average salt spray resistance time is 81 hours. It can be used under severe conditions such as high temperature and humidity, and can meet the requirements of industrial production. Far greater than the standard of salt spray resistance for 72 hours after passivation by hexavalent chromium color passivator, 24 hours after passivation by hexavalent chromium blue and white passivator, and salt spray resistance after passivation by trivalent chromium passivator Standard 75h. Compared with the prior art, the composite passivator provided by the invention can greatly improve the corrosion resistance of the plated parts.

It can be seen from Comparative Examples 1-10 that, for the present invention, acrylic acid, polyurethane and graphene, surfactants, chelating agents and corrosion inhibitors are all essential components, and synergistic effects are produced between them. When any component is lacking, its corrosion resistance decreases significantly, and a very small amount of graphene can greatly improve the corrosion resistance of the composite passivator. Compared with Example 1 in Comparative Example 5, when there is no graphene, its corrosion resistance decreases significantly. Combined with the experimental data, it is shown that the acrylic acid and polyurethane of the present application have a synergistic promoting effect.

As can be seen from the above data, the preferred formulation of the compound passivator of the present application is 400g/L of acrylic acid; 80g/L of polyurethane; 0.02g/L of graphene; 4g/L of chelating agent; 10g/L of corrosion inhibitor; Dose 10g/L, namely the formula among the embodiment 8.

The applicant declares that the present invention illustrates the detailed process equipment and process flow of the present invention through the above-mentioned examples, but the present invention is not limited to the above-mentioned detailed process equipment and process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process equipment and process flow process can be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the claims of the present invention Inside.

Claims (7)

1. A composite passivator, said passivator contains the following components: acrylic acid 200-600g/L; polyurethane 40-100g/L; graphene 0.005-0.05g/L; chelating agent 2-4g/L; Corrosion inhibitor 8-15g/L; Surfactant 5-15g/L. 2. A composite passivator, said passivator contains the following components: acrylic acid 300-500g/L; polyurethane 50-80g/L; graphene 0.01-0.03g/L; chelating agent 2-4g/L; Corrosion inhibitor 8-15g/L; Surfactant 5-15g/L. 3. passivating agent as claimed in claim 1 or 2, is characterized in that, described chelating agent is phytic acid and/or tannic acid. 4. passivating agent as claimed in claim 1 or 2, is characterized in that, described corrosion inhibitor is organic phosphonic acid. 5. passivating agent as claimed in claim 1 or 2, is characterized in that, described tensio-active agent is ether. 6. a preparation method of the arbitrary described composite passivating agent of claim 1-5, the method may further comprise the steps: (1) Put the surfactant, corrosion inhibitor and chelating agent in their respective reactors according to the formula amount, then add water to raise the temperature and stir, the dissolution temperature is 50-70°C, stir until completely dissolved; then put the three The solution is mixed according to the order of addition of surfactant, corrosion inhibitor, and chelating agent, stirred continuously at 50-70°C until uniformly mixed, and cooled to room temperature to obtain a mixed solution; (2) Add acrylic acid to the mixed solution in step (1) according to the formula amount, and stir until completely dissolved; (3) Add polyurethane to the solution obtained in step (2) according to the formula, and stir until evenly mixed; (4) Add water to the formulated amount of graphene, then stir under ultrasonic for 3-5h until completely dissolved to obtain a transparent graphene solution; (5) Add the graphene solution obtained in step (4) to the solution in step (3), and then add water to make the whole solution up to 1L, and stir evenly to obtain the composite passivator. 7. an application of the arbitrary described composite passivating agent of claim 1-6, is characterized in that, described composite passivating agent can be used for the passivation of the plated part of hot-dip plating.