Environment-friendly pickling passivation paste special for stainless steel spraying

Abstract

The invention relates to the technical field of stainless steel surface treatment, in particular to environment-friendly pickling passivation paste special for stainless steel spraying, which specifically comprises the following components in parts by weight: 15-30 parts of corrosive, 50-70 parts of passivator, 5-10 parts of nano corrosion inhibition material, 25-40 parts of filler, 1-5 parts of penetrant and 20-30 parts of water. The pickling passivation paste disclosed by the invention does not release hydrofluoric acid in the use process, has small harm to the environment, does not hurt the skin, ensures the health of constructors, effectively removes various welding seams, oxide skin and rust on the surface of stainless steel, is a green, environment-friendly and efficient product, can play a good role in protecting the surface of metal, and has a good application prospect. The corrosion of external corrosive substances to the metal surface is well isolated and inhibited, so that the speed of secondary corrosion is slowed down, the passivation effect of the metal surface is realized, and the service life of the metal is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel surface treatment, in particular to an environmentally friendly pickling passivation paste specially used for stainless steel spraying. Background Art

[0002] Stainless steel has good corrosion resistance, high temperature oxidation resistance, good low temperature performance and excellent mechanical and processing properties. Therefore, it is widely used in various fields such as petrochemical, aerospace, light industry and textile, food and medicine. In the offshore oil industry, stainless steel, as an excellent seawater corrosion-resistant metal, is increasingly widely used in various parts of offshore oil platforms. The corrosion resistance of stainless steel is mainly due to the formation of an extremely thin (about 1nm) dense passivation film on its surface in the air. This passivation film can effectively prevent the further diffusion of corrosion factors such as oxygen and moisture to the surface of stainless steel, thereby playing a role in corrosion and rust prevention. However, the passivation film formed by the natural oxidation of stainless steel materials in the air will inevitably have defects. At the same time, the oxide film on the surface of stainless steel equipment and components will be damaged during the manufacturing process such as forming, assembly, and welding, which greatly reduces the integrity of the passivation film. Due to the defects or incompleteness of this passivation film, stainless steel equipment or components will still corrode in a corrosive environment. Therefore, it is necessary to use pickling and passivation methods to further enhance the corrosion resistance of stainless steel containers before they are put into service.

[0003] For example, the invention patent with announcement number CN103225087A discloses a stainless steel pickling passivation paste and a preparation method thereof, which is mainly composed of the following components in parts by weight: 10-30 parts of a corrosive agent, 20-60 parts of a passivating agent, 10-30 parts of a gelling agent, 40-60 parts of an inorganic filler and 1-5 parts of a penetrant; the stainless steel pickling passivation paste does not release hydrofluoric acid during use, has little harm to the environment, does not hurt the skin, can effectively remove various welds, scales and rust on the surface of stainless steel, and achieves a good rust removal effect, but the protective film formed on the surface of the stainless steel after pickling is relatively fragile and is easily broken under the influence of external factors, causing the stainless steel to easily rust again during subsequent use. Summary of the invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide an environmentally friendly pickling passivation paste specially used for stainless steel spraying.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An environmentally friendly pickling passivation paste specially used for stainless steel spraying, specifically comprising the following components by weight: 15-30 parts of an etchant, 50-70 parts of a passivator, 5-10 parts of a nano corrosion inhibition material, 25-40 parts of a filler, 1-5 parts of a penetrant, and 20-30 parts of water;

[0007] The corrosive agent is selected from one or more of malic acid and citric acid;

[0008] The passivating agent is selected from one or more of nitric acid and phosphoric acid;

[0009] The filler is selected from one or more of nano-hydroxyapatite and magnesium aluminum silicate;

[0010] The penetrant is selected from one or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and coconut oil fatty acid diethanolamide.

[0011] As a further preferred embodiment of the present invention, the preparation method of the nano corrosion inhibition material is as follows:

[0012] 1) dissolving ruthenium chloride and ammonium chloride in deionized water, stirring thoroughly to obtain solution A, then dissolving ammonium chloride and dicyandiamide in deionized water, stirring thoroughly to obtain solution B, then adding solution A to solution B according to a certain volume, stirring at room temperature for 30-50 minutes, freeze-drying, and grinding uniformly to obtain powder particles;

[0013] 2) placing the powder particles in a muffle furnace, heating to 550-580°C, and treating at a constant temperature for 4-6 hours. After the treatment is completed, naturally cooling to room temperature, and then heating to 375-385°C in an air atmosphere, and treating at a constant temperature for 5-8 hours. Finally, placing the powder particles in a porcelain boat, heating to 300-320°C in a mixed atmosphere of equal volumes of hydrogen and argon, and treating at a constant temperature for 1-2 hours, to obtain a porous nanosheet with a two-dimensional structure;

[0014] 3) Add bismuth nitrate to deionized water, ultrasonically disperse for 1-3 minutes, transfer to a magnetic stirrer, and stir for 25-35 minutes to obtain solution C; then add sodium tungstate to deionized water, place on a magnetic stirrer, and stir for 25-35 minutes to obtain solution D;

[0015] 4) Add solution D to solution C, stir at 40-43°C for 50-70 minutes to obtain solution E, and then add the porous nanosheets to solution E according to a certain solid-liquid ratio. After ultrasonic dispersion, transfer to a high-temperature reactor and react at a constant temperature of 160-165°C for 16-20 hours. After the reaction is completed, naturally cool to room temperature, centrifuge the obtained solution, repeatedly wash with deionized water and anhydrous ethanol, and then dry to obtain the desired nano corrosion inhibition material.

[0016] Furthermore, in step 1), in the solution A, the ratio of ruthenium chloride, ammonium chloride, and deionized water is (2.4-3.2) g: (16.5-18.3) g: (100-160) mL;

[0017] In the solution B, the usage ratio of ammonium chloride, dicyandiamide and deionized water is (5-8) g: (1.0-1.5) g: (20-30) mL.

[0018] Furthermore, in step 1), the volume ratio of solution A to solution B is 1:(2.0-2.3);

[0019] The stirring speed is 150-200r / min.

[0020] Furthermore, in step 2), the heating rate of heating to 550-580°C is 3-5°C / min;

[0021] The heating rate to 375-385°C is 3-5°C / min;

[0022] The heating rate to 300-320°C is 5-8°C / min.

[0023] Furthermore, in step 3), in the solution C, the ratio of bismuth nitrate to deionized water is (1.1-1.8) g: (30-50) mL;

[0024] In the solution D, the dosage ratio of sodium tungstate and deionized water is (0.35-0.42) g: (45-60) mL.

[0025] Furthermore, in step 3), the power of the ultrasonic dispersion is 200-300W;

[0026] The stirring speed is 800-1000r / min.

[0027] Furthermore, in step 4), the volume ratio of solution D to solution C is (45-60):(30-50);

[0028] The stirring speed is 600-800r / min.

[0029] Furthermore, in step 4), the solid-liquid ratio of the porous nanosheet to solution C is 1 g: (30-50) mL.

[0030] As a further preferred embodiment of the present invention, the method for preparing the pickling passivation paste specifically comprises the following steps:

[0031] S1 Weighing: According to the weight percentage, weigh 15-30 parts of the corrosive agent, 50-70 parts of the passivating agent, 5-10 parts of the nano corrosion inhibition material, 25-40 parts of the filler, 1-5 parts of the penetrant, and 20-30 parts of water for later use;

[0032] S2 mixing: the corrosive agent, passivating agent, nano corrosion inhibitor, filler, penetrant are mixed with water in the prescribed proportion, and the whole is made into a paste after being stirred evenly. The obtained mixture is the pickling passivation paste.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] In the present invention, a porous nanosheet with a two-dimensional structure is obtained by freeze drying combined with a three-step pyrolysis method. During the three-step pyrolysis process, impurities in the substance are removed, leaving defects such as holes, forming a porous nanosheet with a porous structure. Then, the porous nanosheet is used as a substrate, and bismuth nitrate and sodium tungstate are used as raw materials without using an active agent or a polymer template. Through a hydrothermal reaction, nanoparticles with a flower-like structure are deposited on the surface of the substrate to obtain a nano corrosion inhibition material. In addition, since the surface of the porous nanosheet has obvious defects such as holes, attachment sites are provided for the deposition of nanoparticles, so that the flower-like protrusions of the nanoparticles can be embedded in the porous nanosheet. The holes in the sheet play the role of connecting the porous nanosheets, so that the porous nanosheets of the two-dimensional sheet structure are connected by the nanoparticles and stacked on each other to form a multi-layer structure; by adding the nano-corrosion inhibition material to the passivation paste, after the metal is pickled, the nano-corrosion inhibition material can adhere to the metal surface, and through the mutual intercalation between the sheets, a continuous phase nano-covering layer is constructed, which can play a good protective role on the metal surface, and well isolate and inhibit the erosion of the metal surface by external corrosive substances, thereby slowing down the speed of secondary corrosion, achieving the passivation effect of the metal surface, and thus improving the service life of the metal.

[0035] The pickling passivation paste of the present invention does not release hydrofluoric acid during use, has little harm to the environment, does not hurt the skin, ensures the health of construction workers and effectively removes various welds, oxide scales and rust on the surface of stainless steel. It is a green, environmentally friendly and efficient product, and can well protect the metal surface, well isolate and inhibit the erosion of the metal surface by external corrosive substances, thereby slowing down the speed of secondary corrosion, achieving the passivation effect of the metal surface, and thus improving the service life of the metal. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In the embodiment of the present invention, malic acid is selected as the corrosive agent; nitric acid is selected as the passivating agent; nano-hydroxyapatite is selected as the filler; and fatty alcohol polyoxyethylene ether is selected as the penetrant.

[0038] Example 1

[0039] An environmentally friendly pickling passivation paste specially used for stainless steel spraying, specifically comprising the following components by weight: 15 parts of corrosive agent, 50 parts of passivating agent, 5 parts of nano corrosion inhibition material, 25 parts of filler, 1 part of penetrant, and 20 parts of water;

[0040] The preparation method of the pickling passivation paste specifically comprises the following steps:

[0041] S1 Weighing: According to the weight, weigh 15 parts of corrosive agent, 50 parts of passivating agent, 5 parts of nano corrosion inhibition material, 25 parts of filler, 1 part of penetrant, and 20 parts of water for later use;

[0042] S2 mixing: the corrosive agent, passivating agent, nano corrosion inhibitor, filler, penetrant are mixed with water in the prescribed proportion, and the whole is made into a paste after being stirred evenly. The obtained mixture is the pickling passivation paste.

[0043] Wherein, the preparation method of the nano corrosion inhibition material is as follows:

[0044] 1) Dissolve 2.4 g of ruthenium chloride and 16.5 g of ammonium chloride in 100 mL of deionized water, stir thoroughly to obtain solution A, then dissolve 5 g of ammonium chloride and 1 g of dicyandiamide in 20 mL of deionized water, stir thoroughly to obtain solution B, then add solution A to solution B at a volume ratio of 1:2, stir at 150 r / min for 30 min at room temperature, freeze-dry, and grind uniformly to obtain powder particles;

[0045] 2) The powder particles are placed in a muffle furnace, heated to 550°C at a rate of 3°C / min, and treated at a constant temperature for 4 hours. After the treatment is completed, the powder particles are naturally cooled to room temperature, and then heated to 375°C at a rate of 3°C / min in an air atmosphere, and treated at a constant temperature for 5 hours. Finally, the powder particles are placed in a porcelain boat, and heated to 300°C at a rate of 5°C / min in a mixed atmosphere composed of equal volumes of hydrogen and argon, and treated at a constant temperature for 1 hour to obtain a porous nanosheet with a two-dimensional structure;

[0046] 3) 1.1 g of bismuth nitrate was added to 30 mL of deionized water, and after 200 W ultrasonic dispersion for 1 min, the mixture was transferred to a magnetic stirrer and stirred at 800 r / min for 25 min to obtain solution C; 0.35 g of sodium tungstate was added to 45 mL of deionized water, and the mixture was placed on a magnetic stirrer and stirred at 800 r / min for 25 min to obtain solution D;

[0047] 4) Add 45 mL of solution D to 30 mL of solution C, stir at 600 r / min for 50 min at 40 ° C to obtain solution E, and then add the porous nanosheets to solution E at a solid-liquid ratio of 1 g: 30 mL. After ultrasonic dispersion, transfer to a high-temperature reactor and react at a constant temperature of 160 ° C for 16 hours. After the reaction is completed, cool naturally to room temperature, centrifuge the obtained solution, repeatedly wash with deionized water and anhydrous ethanol, and then dry to obtain the desired nano corrosion inhibition material.

[0048] Example 2

[0049] An environmentally friendly pickling passivation paste specially used for stainless steel spraying, specifically comprising the following components by weight: 25 parts of an etchant, 60 parts of a passivator, 7 parts of a nano corrosion inhibition material, 35 parts of a filler, 3 parts of a penetrant, and 25 parts of water;

[0050] The preparation method of the pickling passivation paste specifically comprises the following steps:

[0051] S1 Weighing: According to the weight, weigh 25 parts of corrosive agent, 60 parts of passivating agent, 7 parts of nano corrosion inhibition material, 35 parts of filler, 3 parts of penetrant, and 25 parts of water for later use;

[0052] S2 mixing: the corrosive agent, passivating agent, nano corrosion inhibitor, filler, penetrant are mixed with water in the prescribed proportion, and the whole is made into a paste after being stirred evenly. The obtained mixture is the pickling passivation paste.

[0053] Wherein, the preparation method of the nano corrosion inhibition material is as follows:

[0054] 1) 2.8 g of ruthenium chloride and 17.2 g of ammonium chloride were dissolved in 130 mL of deionized water, and the mixture was stirred thoroughly to obtain solution A. 7 g of ammonium chloride and 1.3 g of dicyandiamide were dissolved in 25 mL of deionized water, and the mixture was stirred thoroughly to obtain solution B. Solution A was then added to solution B at a volume ratio of 1:2.1, and the mixture was stirred at 180 r / min for 40 min at room temperature, and then freeze-dried. After grinding, powder particles were obtained.

[0055] 2) The powder particles are placed in a muffle furnace, heated to 570°C at a rate of 4°C / min, and treated at a constant temperature for 5 hours. After the treatment is completed, the powder particles are naturally cooled to room temperature, and then heated to 380°C at a rate of 4°C / min in an air atmosphere, and treated at a constant temperature for 7 hours. Finally, the powder particles are placed in a porcelain boat, heated to 310°C at a rate of 7°C / min in a mixed atmosphere composed of equal volumes of hydrogen and argon, and treated at a constant temperature for 1.5 hours to obtain a porous nanosheet with a two-dimensional structure;

[0056] 3) 1.5 g of bismuth nitrate was added to 40 mL of deionized water, and after 250 W ultrasonic dispersion for 2 min, the mixture was transferred to a magnetic stirrer and stirred at 900 r / min for 30 min to obtain solution C; 0.38 g of sodium tungstate was added to 52 mL of deionized water, and the mixture was placed on a magnetic stirrer and stirred at 900 r / min for 30 min to obtain solution D;

[0057] 4) Add 55 mL of solution D to 40 mL of solution C, stir at 700 r / min for 60 min at 42 °C to obtain solution E, and then add the porous nanosheets to solution E at a solid-liquid ratio of 1 g:40 mL. After ultrasonic dispersion, transfer to a high-temperature reactor and react at a constant temperature of 163 °C for 18 h. After the reaction is completed, cool naturally to room temperature, centrifuge the obtained solution, repeatedly wash with deionized water and anhydrous ethanol, and then dry to obtain the desired nano corrosion inhibition material.

[0058] Example 3

[0059] An environmentally friendly pickling passivation paste specially used for stainless steel spraying, specifically comprising the following components by weight: 30 parts of corrosive agent, 70 parts of passivating agent, 10 parts of nano corrosion inhibition material, 40 parts of filler, 5 parts of penetrant, and 30 parts of water;

[0060] The preparation method of the pickling passivation paste specifically comprises the following steps:

[0061] S1 Weighing: According to the weight, weigh 30 parts of corrosive agent, 70 parts of passivating agent, 10 parts of nano corrosion inhibition material, 40 parts of filler, 5 parts of penetrant, and 30 parts of water for later use;

[0062] S2 mixing: the corrosive agent, passivating agent, nano corrosion inhibitor, filler, penetrant are mixed with water in the prescribed proportion, and the whole is made into a paste after being stirred evenly. The obtained mixture is the pickling passivation paste.

[0063] Wherein, the preparation method of the nano corrosion inhibition material is as follows:

[0064] 1) 3.2 g of ruthenium chloride and 18.3 g of ammonium chloride were dissolved in 160 mL of deionized water, and the mixture was stirred thoroughly to obtain solution A. 8 g of ammonium chloride and 1.5 g of dicyandiamide were dissolved in 30 mL of deionized water, and the mixture was stirred thoroughly to obtain solution B. Solution A was then added to solution B at a volume ratio of 1:2.3, and the mixture was stirred at 200 r / min for 50 min at room temperature, and then freeze-dried. After grinding, powder particles were obtained.

[0065] 2) The powder particles are placed in a muffle furnace, heated to 580°C at a rate of 5°C / min, and treated at a constant temperature for 6 hours. After the treatment is completed, the powder particles are naturally cooled to room temperature, and then heated to 385°C at a rate of 5°C / min in an air atmosphere, and treated at a constant temperature for 8 hours. Finally, the powder particles are placed in a porcelain boat, and heated to 320°C at a rate of 8°C / min in a mixed atmosphere composed of equal volumes of hydrogen and argon, and treated at a constant temperature for 2 hours to obtain a porous nanosheet with a two-dimensional structure;

[0066] 3) 1.8 g of bismuth nitrate was added to 50 mL of deionized water, and after 300 W ultrasonic dispersion for 3 min, the mixture was transferred to a magnetic stirrer and stirred at 1000 r / min for 35 min to obtain solution C; 0.42 g of sodium tungstate was added to 60 mL of deionized water, and the mixture was placed on a magnetic stirrer and stirred at 1000 r / min for 35 min to obtain solution D;

[0067] 4) Add 60 mL of solution D to 50 mL of solution C, stir at 800 r / min for 70 min at 43 ° C to obtain solution E, and then add the porous nanosheets to solution E at a solid-liquid ratio of 1 g: 50 mL. After ultrasonic dispersion, transfer to a high-temperature reactor and react at a constant temperature of 165 ° C for 20 h. After the reaction is completed, cool naturally to room temperature, centrifuge the obtained solution, repeatedly wash with deionized water and anhydrous ethanol, and then dry to obtain the desired nano corrosion inhibition material.

[0068] Comparative Example 1: This comparative example is basically the same as Example 1, except that it does not contain nano corrosion inhibition material.

[0069] Comparative Example 2: This comparative example is basically the same as Example 1, except that benzotriazole is used instead of the nano corrosion inhibition material.

[0070] Comparative Example 3: This comparative example is basically the same as Example 1, except that, in the preparation of the nano corrosion inhibition material, the heating treatment in a mixed atmosphere composed of equal volumes of hydrogen and argon in 2) is omitted.

[0071] Comparative Example 4: This comparative example is basically the same as Example 1, except that in the preparation of the nano corrosion inhibition material, steps 1)-2) are omitted.

[0072] Comparative Example 5: This comparative example is basically the same as Example 1, except that in the preparation of the nano corrosion inhibition material, steps 3)-4) are omitted.

[0073] Test experiment:

[0074] The methods provided in Examples 1-3 and Comparative Examples 1-5 were respectively used to prepare pickling passivation paste samples, and then the oil stains on the surface of the stainless steel were first cleaned, and the pickling passivation paste samples were applied to the surface of the parts to be cleaned, so that the product thickness was more than 2 mm, and maintained for 15-30 minutes, and then the surface of the workpiece was cleaned with a dilute sodium carbonate solution, and finally the workpiece was rinsed with clean water until the pH value of the cleaning solution was close to neutral; then 3mL nitric acid + 1g potassium ferrocyanide + 50mL clean water was prepared into a solution, and then diluted to 100mL with clean water to prepare a test reagent, and the filter paper soaked in the reagent was attached to the workpiece to observe whether blue spots appear within 1 minute. The results are shown in Table 1.

[0075] Table 1

[0076]

[0077] It can be seen from Table 1 that the pickling passivation paste in the present invention can play a good protective role on the metal surface, and can well isolate and inhibit the corrosion of the metal surface by external corrosive substances, thereby slowing down the speed of secondary corrosion, achieving the passivation effect of the metal surface, and thus improving the service life of the metal.

[0078] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An environmentally friendly pickling passivation paste for stainless steel spraying, characterized in that: Specifically, it includes the following components by weight: 15-30 parts of corrosive agent, 50-70 parts of passivating agent, 5-10 parts of nano corrosion inhibition material, 25-40 parts of filler, 1-5 parts of penetrant, and 20-30 parts of water; The corrosive agent is selected from one or more of malic acid and citric acid; The passivating agent is selected from one or more of nitric acid and phosphoric acid; The filler is selected from one or more of nano-hydroxyapatite and magnesium aluminum silicate; The penetrant is selected from one or more of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and coconut oil fatty acid diethanolamide.

2. The environmentally friendly pickling passivation paste for stainless steel spraying according to claim 1 is characterized in that: The preparation method of the nano corrosion inhibition material is as follows: 1) dissolving ruthenium chloride and ammonium chloride in deionized water, stirring thoroughly to obtain solution A, then dissolving ammonium chloride and dicyandiamide in deionized water, stirring thoroughly to obtain solution B, then adding solution A to solution B according to a certain volume, stirring at room temperature for 30-50 minutes, freeze-drying, and grinding uniformly to obtain powder particles; 2) placing the powder particles in a muffle furnace, heating to 550-580°C, and treating at a constant temperature for 4-6 hours. After the treatment is completed, naturally cooling to room temperature, and then heating to 375-385°C in an air atmosphere, and treating at a constant temperature for 5-8 hours. Finally, placing the powder particles in a porcelain boat, heating to 300-320°C in a mixed atmosphere of equal volumes of hydrogen and argon, and treating at a constant temperature for 1-2 hours, to obtain a porous nanosheet with a two-dimensional structure; 3) Add bismuth nitrate to deionized water, ultrasonically disperse for 1-3 minutes, transfer to a magnetic stirrer, and stir for 25-35 minutes to obtain solution C; then add sodium tungstate to deionized water, place on a magnetic stirrer, and stir for 25-35 minutes to obtain solution D; 4) Add solution D to solution C, stir at 40-43°C for 50-70 minutes to obtain solution E, and then add the porous nanosheets to solution E according to a certain solid-liquid ratio. After ultrasonic dispersion, transfer to a high-temperature reactor and react at a constant temperature of 160-165°C for 16-20 hours. After the reaction is completed, naturally cool to room temperature, centrifuge the obtained solution, repeatedly wash with deionized water and anhydrous ethanol, and then dry to obtain the desired nano corrosion inhibition material.

3. The environmentally friendly pickling passivation paste for stainless steel spraying according to claim 2 is characterized in that: In step 1), in the solution A, the ratio of ruthenium chloride, ammonium chloride and deionized water is (2.4-3.2) g: (16.5-18.3) g: (100-160) mL; In the solution B, the usage ratio of ammonium chloride, dicyandiamide and deionized water is (5-8) g: (1.0-1.5) g: (20-30) mL.

4. The environmentally friendly pickling passivation paste for stainless steel spraying according to claim 2 is characterized in that: In step 1), the volume ratio of solution A to solution B is 1:(2.0-2.3); The stirring speed is 150-200r / min.

5. The environmentally friendly pickling passivation paste for stainless steel spraying according to claim 2 is characterized in that: In step 2), the heating rate of heating to 550-580°C is 3-5°C / min; The heating rate to 375-385°C is 3-5°C / min; The heating rate to 300-320°C is 5-8°C / min.

6. The environmentally friendly pickling passivation paste for stainless steel spraying according to claim 2 is characterized in that: In step 3), in the solution C, the ratio of bismuth nitrate to deionized water is (1.1-1.8) g: (30-50) mL; In the solution D, the dosage ratio of sodium tungstate and deionized water is (0.35-0.42) g: (45-60) mL.

7. The environmentally friendly pickling passivation paste for stainless steel spraying according to claim 2 is characterized in that: In step 3), the power of the ultrasonic dispersion is 200-300W; The stirring speed is 800-1000r / min.

8. The environmentally friendly pickling passivation paste for stainless steel spraying according to claim 2 is characterized in that: In step 4), the volume ratio of solution D to solution C is (45-60): (30-50); The stirring speed is 600-800r / min.

9. The environmentally friendly pickling passivation paste for stainless steel spraying according to claim 2, characterized in that: In step 4), the solid-liquid ratio of the porous nanosheet to solution C is 1 g: (30-50) mL.

10. The environmentally friendly pickling passivation paste for stainless steel spraying according to claim 1, characterized in that: The preparation method of the pickling passivation paste specifically comprises the following steps: S1 Weighing: According to the weight percentage, weigh 15-30 parts of the corrosive agent, 50-70 parts of the passivating agent, 5-10 parts of the nano corrosion inhibition material, 25-40 parts of the filler, 1-5 parts of the penetrant, and 20-30 parts of water for later use; S2 mixing: the corrosive agent, passivating agent, nano corrosion inhibitor, filler, penetrant are mixed with water in the prescribed proportion, and the whole is made into a paste after being stirred evenly. The obtained mixture is the pickling passivation paste.

Images