Chromium-free electroplating passivator with high salt spray resistance and high oxidation resistance and preparation method thereof

Abstract

The invention discloses a chromium-free electroplating passivator with high salt spray resistance and high oxidation resistance and a preparation method thereof. Relates to the technical field of passivators. The electroplating passivator provided by the invention comprises molybdate, vanadate, phosphate, silicate, an azole compound and attapulgite. The preparation method of the electroplating passivator comprises the following steps: adding molybdate, vanadate, phosphate and silicate into deionized water to prepare a salt solution; mixing the salt solutions, adding the attapulgite and the imidazole compound into the mixed salt solution, and adding water to adjust the concentration of each component; and adding a pH regulator to regulate the pH to obtain the electroplating passivator. The electroplating passivator is applied to the field of stainless steel surface passivation. According to the invention, molybdate and vanadate are compounded, and attapulgite is added and interacts with other components, so that a more stable passivation film is formed; the attapulgite has a special porous high-adsorption structure; the attapulgite fills pores and scratches on the surface of the workpiece, salt spray corrosion and contact with oxygen are reduced, and salt spray resistance and oxidation resistance are improved.

Description

Technical Field

[0001] The present application relates to the technical field of passivators, and in particular to a chromium-free, highly salt-spray-resistant and highly-oxidation-resistant electroplating passivator and a preparation method thereof. Background Art

[0002] Stainless steel, as a material widely used in modern industry, has a history of more than 100 years. Stainless steel has many advantages such as high strength, weldability, corrosion resistance and convenient machining. It has extremely important applications in industries such as aerospace, chemical industry, instrument materials, medicine and energy, as well as architectural decoration. However, when there are corrosive anions (such as Cl-) in the system where stainless steel is located, stainless steel will undergo pitting corrosion, which will lead to other very serious forms of corrosion. Accidental corrosion failure of stainless steel will cause serious economic losses, environmental pollution, personal injury and other disasters. The corrosion resistance of stainless steel is determined by the stability of its surface passivation film, so it is necessary to properly treat its surface to improve its corrosion resistance.

[0003] At present, some passivators used for stainless steel contain chromium ions, which have a great impact on the environment. Therefore, it is necessary to develop a passivating liquid that does not contain chromium and has high salt spray resistance and high antioxidant properties. Summary of the invention

[0004] In order to solve at least one of the above technical problems, a passivation solution with high salt spray resistance and high oxidation resistance is developed. The present application provides a chromium-free, highly salt spray-resistant and highly antioxidant electroplating passivator and a preparation method thereof.

[0005] On the one hand, the present application provides a chromium-free, highly salt spray-resistant, and highly antioxidant electroplating passivating agent, comprising the following components in parts by weight:

[0006] 8-12 parts of molybdate;

[0007] 4-8 parts of vanadate;

[0008] 1-2 parts of phosphate;

[0009] 1-2 parts of silicate;

[0010] 0.2-1 part of azole compound;

[0011] 0.5 to 1.5 parts of attapulgite.

[0012] Optionally, the attapulgite is modified by the following method:

[0013] Attapulgite and graphene oxide are added into deionized water at a weight ratio of 100:1-3, the water temperature is heated to 80-95° C. for stirring and mixing, and then the mixture of the attapulgite and graphene oxide is dried to obtain modified attapulgite.

[0014] Optionally, the weight ratio of the total weight of the molybdate and the vanadate to the attapulgite is 1:(0.050-0.075).

[0015] Optionally, the particle size of the attapulgite is 0.02 to 2 μm.

[0016] Optionally, the molybdate is sodium molybdate;

[0017] And / or, the vanadate is sodium metavanadate;

[0018] And / or, the phosphate is sodium dihydrogen phosphate;

[0019] And / or, the silicate is sodium silicate;

[0020] And / or, the azole compound is benzotriazole.

[0021] In a second aspect, the present application provides a method for preparing the above-mentioned electroplating passivating agent, comprising the following steps:

[0022] S1. Preparation of salt solution

[0023] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0024] S2. Preparation of electroplating passivating agent

[0025] The salt solutions prepared in S1 are mixed, and attapulgite and the imidazole compound are added to the mixed salt solution, and water is added to adjust the concentration of each component;

[0026] S3. Adjust pH

[0027] A pH adjuster is added to adjust the pH to obtain an electroplating passivating agent.

[0028] Optionally, in said S2, in preparing the electroplating passivating agent, the concentration of molybdate is 8 to 12 g / L;

[0029] and / or, the concentration of vanadate is 8 to 12 g / L;

[0030] and / or, the concentration of phosphate is 4 to 8 g / L;

[0031] and / or, the concentration of silicate is 1 to 2 g / L;

[0032] and / or, the concentration of the azole compound is 1 to 2 g / L;

[0033] And / or, the concentration of attapulgite is 0.5 to 1.5 g / L.

[0034] Optionally, in S3, adjusting the pH, the pH is adjusted to 3-6.

[0035] In a third aspect, the present application provides the application of the above-mentioned electroplating passivator in the field of stainless steel surface passivation.

[0036] In summary, the present invention includes at least one of the following beneficial technical effects:

[0037] 1. The salt spray resistance and oxidation resistance of the passivator can be improved by compounding molybdate and vanadate;

[0038] 2. By adding attapulgite, it interacts with other components to form a more stable passivation film, improving salt spray resistance and antioxidant properties;

[0039] 3. The special porous high adsorption structure of attapulgite improves the adhesion between the passivation film and the workpiece surface, thereby improving the salt spray resistance and oxidation resistance;

[0040] 4. The use of submicron attapulgite can fill the pores and scratches on the surface of the workpiece, reduce salt spray corrosion and contact with oxygen, thereby improving salt spray resistance and antioxidant properties. DETAILED DESCRIPTION

[0041] The present application is further described in detail below with reference to the embodiments.

[0042] In the following examples of the present application, the main components involved, unless otherwise specified, were purchased from commercially available products.

[0043] As the molybdate, sodium molybdate is exemplified.

[0044] As the vanadate, sodium metavanadate is exemplified.

[0045] As the phosphate, sodium dihydrogen phosphate is exemplified.

[0046] As the silicate, sodium silicate is exemplified.

[0047] The azole compound is exemplified by benzotriazole.

[0048] Attapulgite: particle size is 0.02~2μm.

[0049] Graphene oxide, diameter 0.01 μm-15 μm, thickness 0.55 nm-3.85 nm, number of layers <10, >99% wt; purchased from Shenzhen Turing Evolution Technology Co., Ltd. Specific embodiments

[0051] Examples 1 to 5 are used to prepare a chromium-free, highly salt spray-resistant and highly antioxidant electroplating passivating agent, as described below.

[0052] Example 1

[0053] The electroplating passivating agent in this embodiment includes the following components by weight: 8 parts of molybdate, 8 parts of vanadate, 1 part of phosphate, 1 part of silicate, 0.2 parts of azole compound, and 0.5 parts of attapulgite. The preparation method is as follows.

[0054] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0055] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 8g / L; the concentration of vanadate is 8g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 1g / L; the concentration of azole compounds is 0.2g / L; the concentration of attapulgite is 0.5g / L. A pH regulator is added to adjust the pH to 4 to obtain an electroplating passivation agent.

[0056] Example 2

[0057] The electroplating passivating agent in this embodiment includes the following components by weight: 9 parts of molybdate, 8 parts of vanadate, 3 parts of phosphate, 1 part of silicate, 0.4 parts of azole compound, and 0.8 parts of attapulgite. The preparation method is as follows.

[0058] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0059] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 9 g / L; the concentration of vanadate is 7 g / L; the concentration of phosphate is 2 g / L; the concentration of silicate is 1 g / L; the concentration of azole compounds is 0.4 g / L; the concentration of attapulgite is 0.8 g / L. A pH regulator is added to adjust the pH to 4.5 to obtain an electroplating passivation agent.

[0060] Example 3

[0061] The electroplating passivating agent in this embodiment includes the following components by weight: 10 parts of molybdate, 6 parts of vanadate, 1 part of phosphate, 2 parts of silicate, 0.6 parts of azole compound, and 1 part of attapulgite. The preparation method is as follows.

[0062] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0063] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 10g / L; the concentration of vanadate is 6g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 2g / L; the concentration of azole compounds is 0.6g / L; the concentration of attapulgite is 1g / L. A pH regulator is added to adjust the pH to 3.5 to obtain an electroplating passivation agent.

[0064] Example 4

[0065] The electroplating passivating agent in this embodiment includes the following components by weight: 11 parts of molybdate, 5 parts of vanadate, 2 parts of phosphate, 2 parts of silicate, 0.8 parts of azole compound, and 1.2 parts of attapulgite. The preparation method is as follows.

[0066] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0067] The salt solutions were mixed, and attapulgite and imidazole compounds were added to the mixed salt solution. Water was added to adjust the concentrations of the components, and the concentrations of molybdate were 11 g / L, vanadate were 5 g / L, phosphate were 2 g / L, silicate were 2 g / L, azole compounds were 0.8 g / L, and attapulgite were 1.2 g / L. A pH regulator was added to adjust the pH to 5.5 to obtain an electroplating passivation agent.

[0068] Example 5

[0069] The electroplating passivating agent in this embodiment includes the following components by weight: 12 parts of molybdate, 4 parts of vanadate, 1 part of phosphate, 2 parts of silicate, 1 part of azole compound, and 1.5 parts of attapulgite. The preparation method is as follows.

[0070] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0071] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 12g / L; the concentration of vanadate is 4g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 2g / L; the concentration of azole compounds is 1g / L; the concentration of attapulgite is 1.5g / L. A pH regulator is added to adjust the pH to 5 to obtain an electroplating passivation agent.

[0072] The above-mentioned embodiments 1 to 5 are applied to the surface passivation of stainless steel workpieces 1 to 5, with the stainless steel workpieces 1 to 5 as anodes and lead or stainless steel as cathodes. The passivating agents prepared in the above-mentioned embodiments 1 to 5 are added respectively and a voltage of 1.8V is passed for passivation treatment for 5 minutes, and then the workpieces are treated with water, rinsed and blown dry. The salt water immersion is 80°C and 20% salt water immersion. The oxidation weight gain is 170°C. After oxidation for 10 hours, the workpiece is per cm 3 of weight gain.

[0073] The salt spray test was carried out on the stainless steel workpiece, and the test results are shown in Table 1.

[0074] Table 1

[0075]

[0076] It can be seen from Examples 1 to 5 and Table 1 that the passivator prepared by the technical scheme in Examples 1 to 5 of the present application, after being applied to the surface passivation of a stainless steel workpiece, the stainless steel workpiece can last for more than 60 hours in a salt spray test, and can be immersed in salt water for more than 70 hours, and the oxidation weight gain is less than 4.5 mg, indicating that the passivator prepared in the present application can have good salt spray resistance and antioxidant properties when applied to the passivation of a stainless steel workpiece.

[0077] The inventors found that the performance of the passivator prepared in Examples 2 to 4 was significantly better than that of other examples. Therefore, the following Examples 6 to 17 were made to further verify the influence of the weight ratio of the total weight of molybdate and vanadate to attapulgite in the technical scheme of the present application on the salt spray resistance and antioxidant properties of the passivator; the details are as follows.

[0078] Examples 6 to 9 are based on Example 1, except that only the amount of attapulgite added is changed, as shown below.

[0079] Example 6

[0080] The electroplating passivating agent in this embodiment includes the following components by weight: 8 parts of molybdate, 8 parts of vanadate, 1 part of phosphate, 1 part of silicate, 0.2 parts of azole compound, and 0.8 parts of attapulgite. The preparation method is as follows.

[0081] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0082] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 8g / L; the concentration of vanadate is 8g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 1g / L; the concentration of azole compounds is 0.2g / L; the concentration of attapulgite is 0.8g / L. A pH regulator is added to adjust the pH to 4 to obtain an electroplating passivation agent.

[0083] Example 7

[0084] The electroplating passivating agent in this embodiment includes the following components by weight: 8 parts of molybdate, 8 parts of vanadate, 1 part of phosphate, 1 part of silicate, 0.2 parts of azole compound, and 1.0 part of attapulgite. The preparation method is as follows.

[0085] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0086] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 8g / L; the concentration of vanadate is 8g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 1g / L; the concentration of azole compounds is 0.2g / L; the concentration of attapulgite is 1.0g / L. A pH regulator is added to adjust the pH to 4 to obtain an electroplating passivation agent.

[0087] Example 8

[0088] The electroplating passivating agent in this embodiment includes the following components by weight: 8 parts of molybdate, 8 parts of vanadate, 1 part of phosphate, 1 part of silicate, 0.2 parts of azole compound, and 1.2 parts of attapulgite. The preparation method is as follows.

[0089] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0090] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 8g / L; the concentration of vanadate is 8g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 1g / L; the concentration of azole compounds is 0.2g / L; the concentration of attapulgite is 1.2g / L. A pH regulator is added to adjust the pH to 4 to obtain an electroplating passivation agent.

[0091] Example 9

[0092] The electroplating passivating agent in this embodiment includes the following components by weight: 8 parts of molybdate, 8 parts of vanadate, 1 part of phosphate, 1 part of silicate, 0.2 parts of azole compound, and 1.5 parts of attapulgite. The preparation method is as follows.

[0093] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0094] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 8g / L; the concentration of vanadate is 8g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 1g / L; the concentration of azole compounds is 0.2g / L; the concentration of attapulgite is 1.5g / L. A pH regulator is added to adjust the pH to 4 to obtain an electroplating passivation agent.

[0095] The passivating agents prepared in the above Examples 6 to 9 were applied to stainless steel workpieces 7 to 10, and the test performance results are shown in Table 2.

[0096] Table 2

[0097]

[0098]

[0099] Examples 10 to 13 are based on Example 3, except that only the amount of attapulgite added is changed, as shown below.

[0100] Example 10

[0101] The electroplating passivating agent in this embodiment includes the following components by weight: 10 parts of molybdate, 6 parts of vanadate, 1 part of phosphate, 2 parts of silicate, 0.6 parts of azole compound, and 0.5 parts of attapulgite. The preparation method is as follows.

[0102] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0103] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 10g / L; the concentration of vanadate is 6g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 2g / L; the concentration of azole compounds is 0.6g / L; the concentration of attapulgite is 0.5g / L. A pH regulator is added to adjust the pH to 3.5 to obtain an electroplating passivation agent.

[0104] Embodiment 11

[0105] The electroplating passivating agent in this embodiment includes the following components by weight: 10 parts of molybdate, 6 parts of vanadate, 1 part of phosphate, 2 parts of silicate, 0.6 parts of azole compound, and 0.8 parts of attapulgite. The preparation method is as follows.

[0106] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0107] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 10g / L; the concentration of vanadate is 6g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 2g / L; the concentration of azole compounds is 0.6g / L; the concentration of attapulgite is 0.8g / L. A pH regulator is added to adjust the pH to 3.5 to obtain an electroplating passivation agent.

[0108] Example 12

[0109] The electroplating passivating agent in this embodiment includes the following components by weight: 10 parts of molybdate, 6 parts of vanadate, 1 part of phosphate, 2 parts of silicate, 0.6 parts of azole compound, and 1.2 parts of attapulgite. The preparation method is as follows.

[0110] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0111] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 10g / L; the concentration of vanadate is 6g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 2g / L; the concentration of azole compounds is 0.6g / L; the concentration of attapulgite is 1.2g / L. A pH regulator is added to adjust the pH to 3.5 to obtain an electroplating passivation agent.

[0112] Embodiment 13

[0113] The electroplating passivating agent in this embodiment includes the following components by weight: 10 parts of molybdate, 6 parts of vanadate, 1 part of phosphate, 2 parts of silicate, 0.6 parts of azole compound, and 1.5 parts of attapulgite. The preparation method is as follows.

[0114] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0115] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 10g / L; the concentration of vanadate is 6g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 2g / L; the concentration of azole compounds is 0.6g / L; the concentration of attapulgite is 1.5g / L. A pH regulator is added to adjust the pH to 3.5 to obtain an electroplating passivation agent.

[0116] The passivating agents prepared in the above Examples 10 to 13 were applied to the stainless steel workpieces 11 to 14, and the test performance results are shown in Table 3.

[0117] Table 3

[0118]

[0119] Examples 14 to 17 are based on Example 5, except that only the amount of attapulgite added is changed, as shown below.

[0120] Embodiment 14

[0121] The electroplating passivating agent in this embodiment includes the following components by weight: 12 parts of molybdate, 4 parts of vanadate, 1 part of phosphate, 2 parts of silicate, 1 part of azole compound, and 0.5 parts of attapulgite. The preparation method is as follows.

[0122] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0123] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 12g / L; the concentration of vanadate is 4g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 2g / L; the concentration of azole compounds is 1g / L; the concentration of attapulgite is 0.5g / L. A pH regulator is added to adjust the pH to 5 to obtain an electroplating passivation agent.

[0124] Embodiment 15

[0125] The electroplating passivating agent in this embodiment includes the following components by weight: 12 parts of molybdate, 4 parts of vanadate, 1 part of phosphate, 2 parts of silicate, 1 part of azole compound, and 0.8 parts of attapulgite. The preparation method is as follows.

[0126] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0127] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 12g / L; the concentration of vanadate is 4g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 2g / L; the concentration of azole compounds is 1g / L; the concentration of attapulgite is 0.8g / L. A pH regulator is added to adjust the pH to 5 to obtain an electroplating passivation agent.

[0128] Example 16

[0129] The electroplating passivating agent in this embodiment includes the following components by weight: 12 parts of molybdate, 4 parts of vanadate, 1 part of phosphate, 2 parts of silicate, 1 part of azole compound, and 1.0 part of attapulgite. The preparation method is as follows.

[0130] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0131] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 12g / L; the concentration of vanadate is 4g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 2g / L; the concentration of azole compounds is 1g / L; the concentration of attapulgite is 1.0g / L. A pH regulator is added to adjust the pH to 5 to obtain an electroplating passivation agent.

[0132] Embodiment 17

[0133] The electroplating passivating agent in this embodiment includes the following components by weight: 12 parts of molybdate, 4 parts of vanadate, 1 part of phosphate, 2 parts of silicate, 1 part of azole compound, and 1.2 parts of attapulgite. The preparation method is as follows.

[0134] Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions;

[0135] The salt solutions are mixed, and attapulgite and imidazole compounds are added to the mixed salt solution, and water is added to adjust the concentration of each component, the concentration of molybdate is 12g / L; the concentration of vanadate is 4g / L; the concentration of phosphate is 1g / L; the concentration of silicate is 2g / L; the concentration of azole compounds is 1g / L; the concentration of attapulgite is 1.2g / L. A pH regulator is added to adjust the pH to 5 to obtain an electroplating passivation agent.

[0136] The passivating agents prepared in the above Examples 14 to 17 were applied to stainless steel workpieces 15 to 18, and the test performance results are shown in Table 4.

[0137] Table 4

[0138]

[0139] It can be seen from Examples 6 to 17 and Tables 2 to 4 that the passivation solution is prepared by the technical solution of the present application, and the weight ratio of the total weight of molybdate and vanadate to attapulgite is controlled between 1: (0.05 to 0.075). The passivator prepared can be used for surface passivation of stainless steel workpieces. The stainless steel workpiece can last for more than 65 hours in the salt spray test and more than 80 hours in the salt water immersion test, and the oxidation weight gain is less than 4.0 mg. This indicates that the passivator prepared in the present application can have good salt spray resistance and antioxidant properties when used in the passivation of stainless steel workpieces.

[0140] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A chromium-free, highly salt-spray-resistant and highly anti-oxidative electroplating passivating agent, characterized in that: The composition comprises the following components by weight: 8-12 parts of molybdate; 4-8 parts of vanadate; 1-2 parts of phosphate; 1-2 parts of silicate; 0.2-1 part of azole compound; 0.5 to 1.5 parts of attapulgite.

2. The electroplating passivating agent according to claim 1, characterized in that: The attapulgite is modified by the following method: Attapulgite and graphene oxide are added into deionized water at a weight ratio of 100:1-3, the water temperature is heated to 80-95° C. for stirring and mixing, and then the mixture of the attapulgite and graphene oxide is dried to obtain modified attapulgite.

3. The electroplating passivating agent according to claim 2, characterized in that: The weight ratio of the total weight of the molybdate and the vanadate to the attapulgite is 1:(0.050-0.075).

4. The electroplating passivating agent according to claim 1 or 2, characterized in that: The particle size of the attapulgite is 0.02 to 2 μm.

5. The electroplating passivating agent according to claim 1, characterized in that: The molybdate is sodium molybdate; And / or, the vanadate is sodium metavanadate; And / or, the phosphate is sodium dihydrogen phosphate; And / or, the silicate is sodium silicate; And / or, the azole compound is benzotriazole.

6. A method for preparing the electroplating passivating agent according to claim 1, characterized in that: The following steps are involved: S1. Preparation of salt solution Molybdate, vanadate, phosphate and silicate are added into deionized water to prepare corresponding salt solutions; S2. Preparation of electroplating passivating agent The salt solutions prepared in S1 are mixed, and attapulgite and the imidazole compound are added to the mixed salt solution, and water is added to adjust the concentration of each component; S3. Adjust pH A pH adjuster is added to adjust the pH to obtain an electroplating passivating agent.

7. The preparation method according to claim 6, characterized in that: In said S2, in preparing the electroplating passivating agent, the concentration of molybdate is 8-12 g / L; and / or, the concentration of vanadate is 8 to 12 g / L; and / or, the concentration of phosphate is 4 to 8 g / L; and / or, the concentration of silicate is 1 to 2 g / L; and / or, the concentration of the azole compound is 1 to 2 g / L; And / or, the concentration of attapulgite is 0.5 to 1.5 g / L.

8. The preparation method according to claim 6, characterized in that: S3. In the pH adjustment process, adjust the pH to 3-6.

9. Use of the electroplating passivator according to claim 1 in the field of stainless steel surface passivation.

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