Corrosion-resistant stud bolt and preparation method and application thereof

Abstract

The application discloses a kind of corrosion-resistant stud bolts and preparation method and application, belong to alloy technical field, anticorrosive coating is coated on the surface of stud bolt embryo, coating thickness is 30-50 μm, solidifies 3-4h at 55-60 DEG C, anticorrosive coating is coated again, coating thickness is 30-50 μm, solidifies 96-120h at 40-45 DEG C, obtains corrosion-resistant stud bolt;The application is broken in the self-repairing microsphere in anticorrosive coating after being extruded by nut, and self-repairing is generated at the broken place, forms new anticorrosive coating, reduces the influence of anticorrosive performance due to the extrusion of nut coating rupture, and the synergistic effect of corrosion inhibitor benzotriazole and corrosion-resistant composite layered powder is used to improve the anticorrosive performance of corrosion-resistant stud bolt.

Description

Technical Field

[0001] This invention belongs to the field of alloy technology, and relates to double-ended studs, specifically to a corrosion-resistant double-ended stud, its preparation method, and its application. Background Technology

[0002] Double-ended bolts are essential components in industrial manufacturing and are widely used in electronic devices, mechanical products, digital products, power equipment, and electromechanical products. Bolts are prone to corrosion when in contact with moisture. Rusty or corroded bolts have reduced tightening effectiveness and can easily create safety hazards. Bolt surfaces are usually covered with an anti-corrosion coating to prevent rust and corrosion. However, because bolts need to be tightened with nuts, the pressure generated when the bolt and nut are engaged can easily cause the anti-corrosion coating at the threads to crack, exposing the bolt's metal substrate and reducing its corrosion resistance.

[0003] Chinese invention patent application CN112412943A discloses a corrosion-resistant bolt and its manufacturing process. The corrosion-resistant bolt is obtained by spraying a corrosion-resistant coating onto the surface of the bolt body after quenching and drying it in an oven. This improves the corrosion resistance and bonding ability, and the corrosion-resistant coating is not easy to fall off.

[0004] Chinese invention patent application CN117385356A discloses a corrosion-resistant bolt and its preparation method. The bolt is produced by converter smelting, continuous rolling, cold heading and other processes. Combined with the double coating design, it can provide excellent corrosion resistance and extend the service life of the bolt. However, the double coating will increase the coating thickness on the bolt surface, making it more prone to cracking during the tightening and screwing of the nut, resulting in a reduction in the corrosion resistance of the bolt.

[0005] In underground applications such as mine and tunnel construction, steel structures are required to support the shaft walls. The high humidity in the underground air easily corrodes the steel structures. Furthermore, during drilling and blasting operations, the steel structures vibrate, causing the bolts within them to be subjected to stress and vibration, which further damages the anti-corrosion coating on the bolt surfaces, leading to a decrease in corrosion resistance. To improve the corrosion resistance of double-ended bolts in this application scenario, a corrosion-resistant double-ended bolt with self-healing properties is needed to adapt to the application of steel structure support connectors in underground shafts. Summary of the Invention

[0006] The purpose of this invention is to solve the problem of how to improve the self-healing ability of the surface coating of corrosion-resistant double-ended studs, and to provide a corrosion-resistant double-ended stud, its preparation method and application.

[0007] This invention utilizes self-healing microspheres in the anti-corrosion coating to self-repair at the fracture site after being crushed by a nut, forming a new anti-corrosion coating. This reduces the impact of coating cracking due to nut crushing on anti-corrosion performance. Through the synergistic effect of corrosion inhibitor benzotriazole and corrosion-resistant composite layered powder, the anti-corrosion performance of corrosion-resistant double-ended bolts is improved.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A method for preparing a corrosion-resistant double-ended bolt includes the following steps:

[0010] Step 1: Composite MgAlCe-LDH, graphene oxide nanosheets and iron hydroxide nanosheets are combined to obtain composite layered powder. Zn-MOF is generated in situ on the surface of the composite layered powder to obtain Zn-MOF composite layered powder.

[0011] Step 2: After mixing Zn-MOF composite layered powder with dopamine hydrochloride and benzotriazole, add Span80 and stir to obtain an emulsion. Then mix with toluene diisocyanate and heat to react to obtain self-healing and anti-corrosion microspheres.

[0012] Step 3: Mix the self-healing anti-corrosion microspheres with epoxy resin and polyamide curing agent to obtain the anti-corrosion coating.

[0013] Step 4: Apply anti-corrosion coating to the surface of the double-ended bolt blank, with a coating thickness of 30-50μm, and cure at 55-60℃ for 3-4 hours. Apply anti-corrosion coating again, with a coating thickness of 30-50μm, and cure at 40-45℃ for 96-120 hours to obtain a corrosion-resistant double-ended bolt.

[0014] Furthermore, the anti-corrosion coating in step three is specifically prepared through the following steps:

[0015] In a reaction vessel, Zn-MOF composite layered powder was ultrasonically dispersed in deionized water. Dopamine hydrochloride and benzotriazole were added and stirred. Span80 was mixed with cyclohexane and then added to the reaction vessel. The mixture was stirred for 10-20 minutes to obtain an emulsion. Toluene diisocyanate was mixed with dichloromethane and then added to the reaction vessel. The mixture was heated to 50-60℃ and stirred for 2-3 hours. The precipitate was obtained by filtration, washed, and vacuum dried to obtain self-healing and corrosion-resistant microspheres.

[0016] Furthermore, the ratio of Zn-MOF composite layered powder, deionized water, dopamine hydrochloride, benzotriazole, Span80, cyclohexane, toluene diisocyanate, and dichloromethane is 3-5g: 500-600mL: 2-3g: 5-6g: 15-20g: 200-250mL: 5-6g: 200-250mL.

[0017] Furthermore, the Zn-MOF composite layered powder is specifically prepared by the following steps:

[0018] The composite layered powder was ultrasonically dispersed in deionized water in a reaction vessel, and after stirring and dissolving, zinc nitrate hexahydrate was added, and after stirring and dissolving, 2-methylimidazole was added. The temperature was raised to 120-130℃, the precipitate was collected by centrifugation, the precipitate was washed, and the Zn-MOF composite layered powder was obtained by vacuum drying.

[0019] Furthermore, the ratio of the composite layered powder, deionized water, zinc nitrate hexahydrate, and 2-methylimidazole is 2.5-4g: 700-800mL: 5-6g: 6-8g.

[0020] Furthermore, the composite layered powder is specifically prepared by the following steps:

[0021] Sodium dodecylbenzenesulfonate, iron hydroxide nanosheets, and graphene oxide nanosheets were ultrasonically dispersed in deionized water in a reaction vessel. A 0.1M sodium nitrate solution was added dropwise, followed by the addition of MgAlCe-LDH. The mixture was ultrasonically treated for 1-2 hours, and the precipitate was collected by centrifugation, washed, and vacuum dried to obtain a composite layered powder.

[0022] Furthermore, the ratio of sodium dodecylbenzenesulfonate, iron hydroxide nanosheets, graphene oxide nanosheets, deionized water, sodium nitrate solution, and MgAlCe-LDH is 2-3g: 1-1.5g: 1-2g: 1-1.5L: 10-20mL: 0.5-1g.

[0023] Furthermore, the iron hydroxide nanosheets are specifically prepared by the following steps:

[0024] Ferric sulfate heptahydrate and hexadecyltrimethylammonium bromide were dissolved in deionized water in a reaction vessel under stirring. 0.4M sodium borohydride aqueous solution was added and stirred for 20-24 hours. The precipitate was collected by centrifugation, washed, and dried to obtain ferric hydroxide nanosheets.

[0025] Furthermore, the ratio of ferric sulfate heptahydrate, hexadecyltrimethylammonium bromide, deionized water, and sodium borohydride aqueous solution is 4-4.5g: 18-20g: 500-600mL: 200-300mL.

[0026] Furthermore, MgAlCe-LDH is prepared by the following steps:

[0027] In a reaction vessel, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, cerium nitrate hexahydrate and 4-6g potassium nitrate were dissolved in deionized water. 2M potassium hydroxide aqueous solution was added dropwise until the pH value reached 10-10.8. The temperature was raised to 120-130℃ and reacted for 10-12h. The precipitate was collected by centrifugation, washed, and dried under vacuum to obtain MgAlCe-LDH.

[0028] Furthermore, the ratio of magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, cerium nitrate hexahydrate, potassium nitrate, and deionized water is 0.8-1g: 0.3-0.4g: 0.1-0.15g: 40-60mL.

[0029] A corrosion-resistant double-ended stud is made by coating a double-ended stud blank with an anti-corrosion coating. The raw material of the double-ended stud blank includes the following elements by weight percentage:

[0030] C: 0.15-0.25%, Si: 0.15-0.35%, Mn: 0.40-0.60%, Cr: 0.10-0.15%, Ni: 0.20-0.35%, Mo: 0.10-0.20%, Al: 0.02-0.03%, Zn: 0.02-0.03%, Zr: 0.01-0.02%, Ti: 0.15-0.16%, Ru: 0.10-0.15%, Rh: 0.15-0.30%, Ir: 0.10-0.15%, with the balance being iron and unavoidable impurities.

[0031] Application of a corrosion-resistant double-ended bolt in steel structure support connectors in underground wells.

[0032] The beneficial effects of this invention are:

[0033] 1. The anti-corrosion coating on the surface of the corrosion-resistant double-ended bolt prepared by this invention contains self-healing microspheres. After the self-healing microspheres are crushed by the nut, they self-repair at the crack and form a new anti-corrosion coating, reducing the impact of the coating cracking due to the nut crushing on the anti-corrosion performance. Through the synergistic effect of the corrosion inhibitor benzotriazole and the corrosion-resistant composite layered powder in the self-healing microspheres, the anti-corrosion performance of the corrosion-resistant double-ended bolt is improved, resulting in a long service life. It has a wide range of applications in machinery that requires long-term bolt fastening and has high economic benefits.

[0034] 2. The corrosion-resistant double-ended bolt prepared by this invention is obtained by intercalating and combining MgAlCe-LDH and iron hydroxide with anti-corrosion properties under the lubrication of graphene oxide nanosheets, resulting in a composite layered powder with good anti-corrosion performance. By generating Zn-MOF on the surface of the composite layered powder to form a micro / nano structure, the hydrophobicity of the self-healing microspheres after cracking is improved, thereby enhancing the anti-corrosion performance. Utilizing the adsorption capacity of Zn-MOF and the imidazole groups in the ligands, the corrosion inhibitor benzotriazole is grafted and adsorbed onto the Zn-MOF surface, thereby improving the corrosion resistance of the Zn-MOF composite layered powder. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments in the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1: A corrosion-resistant double-ended bolt, made by coating a double-ended bolt blank with an anti-corrosion coating. The raw material of the double-ended bolt blank includes the following elements by weight percentage: C: 0.15%, Si: 0.15%, Mn: 0.40%, Cr: 0.10%, Ni: 0.20%, Mo: 0.10%, Al: 0.02%, Zn: 0.02%, Zr: 0.01%, Ti: 0.15%, Ru: 0.10%, Rh: 0.15%, Ir: 0.10%, with the balance being iron and unavoidable impurities.

[0037] A method for preparing a corrosion-resistant double-ended bolt includes the following steps:

[0038] S1. In a reaction vessel, dissolve 0.8 g magnesium nitrate hexahydrate, 0.3 g aluminum nitrate nonahydrate, 0.1 g cerium nitrate hexahydrate and 4 g potassium nitrate in 40 mL of deionized water, add 2 M potassium hydroxide aqueous solution dropwise until the pH reaches 10, heat to 120 °C and react for 10 h, collect the precipitate by centrifugation, wash the precipitate with ethanol and deionized water, and dry it under vacuum at 60 °C for 10 h to obtain MgAlCe-LDH.

[0039] S2. In a reaction vessel, 4g of ferric sulfate heptahydrate and 18g of hexadecyltrimethylammonium bromide were dissolved in 500mL of deionized water. 200mL of 0.4M sodium borohydride aqueous solution was added, and the mixture was stirred for 20h. The precipitate was collected by centrifugation, washed with deionized water and methanol, and dried at 50℃ for 20h to obtain iron hydroxide nanosheets.

[0040] S3. In a reaction vessel, 2g of sodium dodecylbenzenesulfonate, 1g of iron hydroxide nanosheets and 1g of graphene oxide nanosheets were ultrasonically dispersed in 1L of deionized water. 10mL of 0.1M sodium nitrate solution was added dropwise, followed by 0.5g of MgAlCe-LDH. The mixture was ultrasonically treated for 1h, and the precipitate was collected by centrifugation. The precipitate was washed with ethanol and deionized water and vacuum dried at 60℃ for 10h to obtain a composite layered powder.

[0041] S4. In a reaction vessel, 2.5g of composite layered powder was ultrasonically dispersed in 700mL of deionized water. After stirring and dissolving, 5g of zinc nitrate hexahydrate was added. After stirring and dissolving, 6g of 2-methylimidazole was added. The temperature was raised to 120℃, the precipitate was collected by centrifugation, the precipitate was washed with ethanol and deionized water, and vacuum dried at 60℃ for 10h to obtain Zn-MOF composite layered powder.

[0042] S5. In a reaction vessel, 3g of Zn-MOF composite layered powder was ultrasonically dispersed in 500mL of deionized water. 2g of dopamine hydrochloride and 5g of benzotriazole were added and stirred. 15g of Span80 was mixed with 200mL of cyclohexane and added to the reaction vessel. The mixture was stirred for 10min to obtain an emulsion. 5g of toluene diisocyanate was mixed with 200mL of dichloromethane and added to the reaction vessel. The mixture was heated to 50℃ and reacted for 2h with stirring at 400rpm. After dilution with deionized water, the precipitate was obtained by filtration. The precipitate was washed with ethanol and dried under vacuum at 60℃ for 10h to obtain self-healing and corrosion-resistant microspheres.

[0043] S6. Disperse 5g of self-healing anti-corrosion microspheres ultrasonically in 100mL of xylene, add 90g of epoxy resin and 60g of polyamide curing agent, stir and mix for 40min to obtain anti-corrosion coating.

[0044] S7. The double-ended bolt blank raw material is melted, smelted and refined at 1500℃ to obtain molten steel. The molten steel is cast into steel ingots and then subjected to slow cooling, heating and continuous rolling to obtain bar stock. After secondary slow cooling, the bar stock is processed to obtain bolt blanks. The bolt blanks are then threaded and heat-treated to obtain double-ended bolt blanks.

[0045] S8. Apply anti-corrosion coating to the surface of the double-ended bolt blank with a coating thickness of 30μm, cure at 55℃ for 3h, apply anti-corrosion coating again with a coating thickness of 30μm, and cure at 40℃ for 96h to obtain corrosion-resistant double-ended bolt.

[0046] Example 2: A corrosion-resistant double-ended stud bolt, made by coating a double-ended stud bolt blank with an anti-corrosion coating, wherein the raw material of the double-ended stud bolt blank includes the following elements by weight percentage:

[0047] C: 0.20%, Si: 0.25%, Mn: 0.50%, Cr: 0.125%, Ni: 0.275%, Mo: 0.15%, Al: 0.025%, Zn: 0.025%, Zr: 0.015%, Ti: 0.155%, Ru: 0.125%, Rh: 0.225%, Ir: 0.125%, with the balance being iron and unavoidable impurities.

[0048] A method for preparing a corrosion-resistant double-ended bolt includes the following steps:

[0049] S1. In a reaction vessel, dissolve 0.9 g magnesium nitrate hexahydrate, 0.35 g aluminum nitrate nonahydrate, 0.125 g cerium nitrate hexahydrate and 5 g potassium nitrate in 50 mL of deionized water. Add 2 M potassium hydroxide aqueous solution dropwise until the pH reaches 10.4. Heat to 125 °C and react for 11 h. Collect the precipitate by centrifugation, wash the precipitate with ethanol and deionized water, and dry it under vacuum at 65 °C for 11 h to obtain MgAlCe-LDH.

[0050] S2. In a reaction vessel, 4.25 g of ferric sulfate heptahydrate and 19 g of hexadecyltrimethylammonium bromide were dissolved in 550 mL of deionized water. 250 mL of 0.4 M sodium borohydride aqueous solution was added, and the mixture was stirred for 22 h. The precipitate was collected by centrifugation, washed with deionized water and methanol, and dried at 55 °C for 22 h to obtain iron hydroxide nanosheets.

[0051] S3. In a reaction vessel, 2.5 g of sodium dodecylbenzenesulfonate, 1.25 g of iron hydroxide nanosheets and 1.5 g of graphene oxide nanosheets were ultrasonically dispersed in 1.25 L of deionized water. 15 mL of 0.1 M sodium nitrate solution was added dropwise, followed by 0.75 g of MgAlCe-LDH. The mixture was ultrasonically treated for 1.5 h, and the precipitate was collected by centrifugation. The precipitate was washed with ethanol and deionized water and dried under vacuum at 65 °C for 11 h to obtain a composite layered powder.

[0052] S4. In a reaction vessel, 3.25g of composite layered powder was ultrasonically dispersed in 750mL of deionized water. After stirring and dissolving, 5.5g of zinc nitrate hexahydrate was added. After stirring and dissolving, 7g of 2-methylimidazole was added. The temperature was raised to 125℃, the precipitate was collected by centrifugation, the precipitate was washed with ethanol and deionized water, and vacuum dried at 65℃ for 11h to obtain Zn-MOF composite layered powder.

[0053] S5. In a reaction vessel, 4g of Zn-MOF composite layered powder was ultrasonically dispersed in 550mL of deionized water. 2.5g of dopamine hydrochloride and 5.5g of benzotriazole were added and stirred. 17.5g of Span80 was mixed with 225mL of cyclohexane and added to the reaction vessel. The mixture was stirred for 15min to obtain an emulsion. 5.5g of toluene diisocyanate was mixed with 225mL of dichloromethane and added to the reaction vessel. The temperature was raised to 55℃ and reacted for 2.5h with stirring at 450rpm. After dilution with deionized water, the precipitate was obtained by filtration. The precipitate was washed with ethanol and dried under vacuum at 65℃ for 11h to obtain self-healing and corrosion-resistant microspheres.

[0054] S6. Disperse 5.5g of self-healing anti-corrosion microspheres ultrasonically in 110mL of xylene, add 95g of epoxy resin and 65g of polyamide curing agent, stir and mix for 50min to obtain anti-corrosion coating.

[0055] S7. The double-ended bolt blank raw material is melted, smelted and refined at 1550℃ to obtain molten steel. The molten steel is cast into steel ingots and then subjected to slow cooling, heating and continuous rolling to obtain bar stock. After secondary slow cooling, the bar stock is processed to obtain bolt blanks. The bolt blanks are then threaded and heat-treated to obtain double-ended bolt blanks.

[0056] S8. Apply anti-corrosion coating to the surface of the double-ended bolt blank with a coating thickness of 40μm, cure at 57.5℃ for 3.5h, apply anti-corrosion coating again with a coating thickness of 40μm, and cure at 42.5℃ for 108h to obtain a corrosion-resistant double-ended bolt.

[0057] Example 3: A corrosion-resistant double-ended bolt, made by coating a double-ended bolt blank with an anti-corrosion coating. The raw material of the double-ended bolt blank includes the following elements by weight percentage: C: 0.25%, Si: 0.35%, Mn: 0.60%, Cr: 0.15%, Ni: 0.35%, Mo: 0.20%, Al: 0.03%, Zn: 0.03%, Zr: 0.02%, Ti: 0.16%, Ru: 0.15%, Rh: 0.30%, Ir: 0.15%, with the balance being iron and unavoidable impurities.

[0058] A method for preparing a corrosion-resistant double-ended bolt includes the following steps:

[0059] S1. In a reaction vessel, dissolve 1g magnesium nitrate hexahydrate, 0.4g aluminum nitrate nonahydrate, 0.15g cerium nitrate hexahydrate and 6g potassium nitrate in 60mL of deionized water, add 2M potassium hydroxide aqueous solution dropwise until the pH reaches 10.8, heat to 130℃ and react for 12h, collect the precipitate by centrifugation, wash the precipitate with ethanol and deionized water, and dry it under vacuum at 70℃ for 12h to obtain MgAlCe-LDH.

[0060] S2. In a reaction vessel, 4.5 g of ferric sulfate heptahydrate and 20 g of hexadecyltrimethylammonium bromide were dissolved in 600 mL of deionized water. 300 mL of 0.4 M sodium borohydride aqueous solution was added, and the mixture was stirred for 24 h. The precipitate was collected by centrifugation, washed with deionized water and methanol, and dried at 60 °C for 24 h to obtain iron hydroxide nanosheets.

[0061] S3. In a reaction vessel, 3g of sodium dodecylbenzenesulfonate, 1.5g of iron hydroxide nanosheets and 2g of graphene oxide nanosheets were ultrasonically dispersed in 1.5L of deionized water. 20mL of 0.1M sodium nitrate solution was added dropwise, followed by 1g of MgAlCe-LDH. The mixture was ultrasonically treated for 2h, and the precipitate was collected by centrifugation. The precipitate was washed with ethanol and deionized water and vacuum dried at 70℃ for 12h to obtain a composite layered powder.

[0062] Under the action of surfactants, graphene oxide nanosheets with lubricating properties promote the intercalation and bonding of iron hydroxide nanosheets and MgAlCe-LDH, forming a composite layered powder with good corrosion resistance.

[0063] S4. In a reaction vessel, 4g of composite layered powder was ultrasonically dispersed in 800mL of deionized water. After stirring and dissolving, 6g of zinc nitrate hexahydrate was added. After stirring and dissolving, 8g of 2-methylimidazole was added. The temperature was raised to 130℃, the precipitate was collected by centrifugation, the precipitate was washed with ethanol and deionized water, and vacuum dried at 70℃ for 12h to obtain Zn-MOF composite layered powder.

[0064] The hydroxyl groups on the surface of the composite layered powder can chelate with zinc ions. By grafting zinc ions onto the surface of the composite layered powder, Zn-MOF is synthesized in situ on the surface of the composite layered powder through the hydrothermal reaction of zinc ions with 2-methylimidazole, forming a nano / micro composite structure. This hydrophobic structure is beneficial to improving the corrosion resistance, thus obtaining Zn-MOF composite layered powder.

[0065] S5. In a reaction vessel, 5g of Zn-MOF composite layered powder was ultrasonically dispersed in 600mL of deionized water. 3g of dopamine hydrochloride and 6g of benzotriazole were added and stirred. 20g of Span80 was mixed with 250mL of cyclohexane and added to the reaction vessel. The mixture was stirred for 20min to obtain an emulsion. 6g of toluene diisocyanate was mixed with 250mL of dichloromethane and added to the reaction vessel. The temperature was raised to 60℃ and reacted for 3h with stirring at 500rpm. The precipitate was obtained by diluting with deionized water and filtering. The precipitate was washed with ethanol and dried under vacuum at 70℃ for 12h to obtain self-healing and corrosion-resistant microspheres.

[0066] The Zn-MOF on the surface of the Zn-MOF composite layered powder has an adsorption effect, and the highly imidazole groups in the Zn-MOF ligand can be linked with the corrosion inhibitor benzotriazole through methylene chains. This allows the corrosion inhibitor benzotriazole to be adsorbed and grafted into the Zn-MOF on the surface of the Zn-MOF composite layered powder. 2-Methylimidazole and benzotriazole can have a synergistic effect to improve the corrosion resistance. Microcapsules are formed through interfacial polymerization of toluene diisocyanate and emulsion, resulting in self-healing and corrosion-resistant microspheres with both corrosion-resistant and slow-release effects.

[0067] S6. Disperse 6g of self-healing anti-corrosion microspheres ultrasonically in 120mL of xylene, add 100g of epoxy resin and 70g of polyamide curing agent, stir and mix for 60min to obtain anti-corrosion coating.

[0068] S7. The double-ended bolt blank raw material is melted, smelted and refined at 1600℃ to obtain molten steel. The molten steel is cast into steel ingots and then subjected to slow cooling, heating and continuous rolling to obtain bar stock. After secondary slow cooling, the bar stock is processed to obtain bolt blanks. The bolt blanks are then threaded and heat-treated to obtain double-ended bolt blanks.

[0069] S8. Apply anti-corrosion coating to the surface of the double-ended bolt blank with a coating thickness of 50μm, cure at 60℃ for 4h, apply anti-corrosion coating again with a coating thickness of 50μm, and cure at 45℃ for 120h to obtain corrosion-resistant double-ended bolt.

[0070] Comparative Example 1: The difference from Example 1 is that in S3, oxyhydrogen oxidized iron nanosheets are not added, while the other steps remain unchanged, and a corrosion-resistant double-ended bolt is obtained.

[0071] Comparative Example 2: The difference from Example 1 is that graphene oxide nanosheets are not added in S3, while the other steps remain unchanged, and a corrosion-resistant double-ended bolt is obtained.

[0072] Comparative Example 3: The difference from Example 1 is that in S5, an equal mass of Zn-MOF composite layered powder is replaced with composite layered powder, while the other steps remain unchanged, and a corrosion-resistant double-ended bolt is obtained.

[0073] The graphene oxide nanosheets, with a diameter of 2-5 μm, were purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.

[0074] The epoxy resin was grade E44, and the polyamide curing agent was grade TY-650, both purchased from China National Pharmaceutical Chemical Reagent Co., Ltd.

[0075] The corrosion-resistant double-ended bolts prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests. Tensile strength was determined according to standard GB / T228.1-2010 "Metallic materials, tensile testing—Part 1: Test methods at room temperature". The experimental procedure was as follows: the specimen diameter was 16 mm and the length was 50 mm. The specimen was clamped on the testing machine, the tensile testing machine was started, and the tensile load was gradually increased at a loading rate of 1 mm / s until the bolt broke. Hardness was determined according to standard GB / T230.1-2018 "Metallic materials, Rockwell hardness testing—Part 1: Test methods". The experimental procedure was as follows: the specimen thickness was 15 mm. A 10 mm thick cemented carbide ball was pressed into the specimen surface under a test force of 3000 N. After holding for 10 seconds, the test force was removed, the diameter of the indentation on the specimen surface was measured, and the hardness was calculated.

[0076] After surface cleaning and drying, the sample was placed in a 0.01 mol / L sodium bisulfite solution with a pH of 4, a temperature of 45℃, and a humidity of 70% RH for 48 hours to conduct a corrosion resistance test. After the test, the sample was removed and dried, and the original mass of the sample before corrosion and the mass of the sample after corrosion were measured. The corrosion weight loss rate was calculated as (original mass of the sample before corrosion - mass of the sample after corrosion) / (corrosion area × test time). The sample was screwed onto a nut until the nut could not be turned. The sample with the nut screwed on was mixed with a 1 mm hard alloy ball in a shaker and shaken for 24 hours. The sample was then removed and subjected to a corrosion resistance test again under the same conditions. The corrosion weight loss rate after wear was calculated.

[0077] The results are shown in Table 1:

[0078] Table 1: Performance Test Results

[0079]

[0080]

[0081] As can be seen from Table 1, the corrosion-resistant double-ended bolts prepared by the present invention have good physical properties and low corrosion weight loss rate, indicating good corrosion resistance. After the nut is screwed in and the hard alloy ball is vibrated and worn, the corrosion weight loss rate increases only slightly, indicating that the corrosion-resistant double-ended bolts prepared by the present invention have good self-repair performance after wear. The coating formed by self-repair improves the corrosion resistance of the corrosion-resistant double-ended bolts.

[0082] Comparative Example 1, due to the absence of added iron hydroxide nanosheets, could not achieve a synergistic effect with MgAlCe-LDH, resulting in reduced corrosion resistance.

[0083] Comparative Example 2 did not include graphene oxide nanosheets. Graphene oxide nanosheets have a lubricating effect, which can improve the intercalation bonding between MgAlCe-LDH and oxyhydrogen oxidase nanosheets. This results in a lower degree of composite layered powder and reduced corrosion resistance.

[0084] In Comparative Example 3, since Zn-MOF was not synthesized in the composite layered powder, the composite layered powder had a weak adsorption capacity for the corrosion inhibitor benzotriazole, resulting in a faster release rate of the corrosion inhibitor, reduced corrosion resistance, and a greater increase in the rate of corrosion weight loss after wear.

[0085] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method of producing a corrosion-resistant stud, characterized by, Comprise the following steps: Step one, MgAlCe-LDH, graphene oxide nanosheet and iron hydroxyl oxide nanosheet are compounded to obtain a composite layered powder, and Zn-MOF is generated in situ on the surface of the composite layered powder to obtain Zn-MOF composite layered powder; Step two, after the Zn-MOF composite layered powder is mixed with dopamine hydrochloride and benzotriazole, Span80 is added to stir to obtain an emulsion, then toluene diisocyanate is mixed and reacted to obtain self-repairing anticorrosive microspheres; Step three, the self-repairing anticorrosive microspheres are mixed with epoxy resin and polyamide curing agent to obtain an anticorrosive coating; Step four, the anticorrosive coating is coated on the surface of a double-end bolt blank with a coating thickness of 30-50 mu m, and is cured at 55-60 DEG C for 3-4 h, then the anticorrosive coating is coated again with a coating thickness of 30-50 mu m, and is cured at 40-45 DEG C for 96-120 h to obtain a corrosion-resistant double-end bolt; The Zn-MOF composite layered powder is prepared by the following steps: The composite layered powder is ultrasonically dispersed in deionized water in a reaction kettle, and after stirring and dissolving, zinc nitrate hexahydrate is added, then 2-methylimidazole is added, the temperature is raised to 120-130 DEG C, the precipitate is collected by centrifugation, the precipitate is washed, and vacuum drying is performed to obtain Zn-MOF composite layered powder; The amount ratio of the composite layered powder, deionized water, zinc nitrate hexahydrate and 2-methylimidazole is 2.5-4 g: 700-800 mL: 5-6 g: 6-8 g; The composite layered powder is prepared by the following steps: Sodium dodecyl benzene sulfonate, iron hydroxyl oxide nanosheet and graphene oxide nanosheet are ultrasonically dispersed in deionized water in a reaction kettle, 0.1M sodium nitrate solution is added dropwise, then MgAlCe-LDH is added, ultrasonic treatment is performed for 1-2 h, the precipitate is collected by centrifugation, the precipitate is washed, and vacuum drying is performed to obtain a composite layered powder; The amount ratio of sodium dodecyl benzene sulfonate, iron hydroxyl oxide nanosheet, graphene oxide nanosheet, deionized water, sodium nitrate solution and MgAlCe-LDH is 2-3 g: 1-1.5 g: 1-2 g: 1-1.5 L: 10-20 mL: 0.5-1 g.

2. The method of claim 1, wherein the corrosion-resistant stud is prepared by the steps of: The self-repairing anticorrosive microspheres in step two are prepared by the following steps: The Zn-MOF composite layered powder is ultrasonically dispersed in deionized water in a reaction kettle, dopamine hydrochloride and benzotriazole are added, stirring and mixing are performed, Span80 is mixed with cyclohexane and then added to the reaction kettle, stirring and mixing are performed for 10-20 min to obtain an emulsion, toluene diisocyanate is mixed with dichloromethane and then added to the reaction kettle, the temperature is raised to 50-60 DEG C, stirring and reaction are performed for 2-3 h, the precipitate is collected by filtration, the precipitate is washed, and vacuum drying is performed to obtain self-repairing anticorrosive microspheres.

3. The method of claim 2, wherein the corrosion resistant stud is prepared by the steps of: The amount ratio of the Zn-MOF composite layered powder, deionized water, dopamine hydrochloride, benzotriazole, Span80, cyclohexane, toluene diisocyanate and dichloromethane is 3-5 g: 500-600 mL: 2-3 g: 5-6 g: 15-20 g: 200-250 mL: 5-6 g: 200-250 mL.

4. The method of claim 1, wherein the corrosion resistant stud is prepared by the steps of: The iron hydroxyl oxide nanosheet is prepared by the following steps: Iron oxyhydroxide nanosheets were obtained by stirring and dissolving ferric sulfate heptahydrate and cetyltrimethylammonium bromide in deionized water, adding 0.4M sodium borohydride aqueous solution, stirring for 20-24h, collecting the precipitate by centrifugation, washing the precipitate, and drying to obtain iron oxyhydroxide nanosheets; The ferric sulfate heptahydrate, cetyltrimethylammonium bromide, deionized water, and sodium borohydride aqueous solution are used in a ratio of 4-4.5g: 18-20g: 500-600mL: 200-300mL.

5. The method of claim 1, wherein the corrosion resistant stud is prepared by the steps of: The MgAlCe-LDH is specifically prepared by the following steps: MgAlCe-LDH was prepared by dissolving magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, cerium nitrate hexahydrate, and potassium nitrate in deionized water in a reaction kettle, adding 2M potassium hydroxide aqueous solution dropwise until the pH value reached 10-10.8, heating to 120-130℃ for 10-12h, collecting the precipitate by centrifugation, washing the precipitate, and vacuum drying to obtain MgAlCe-LDH; The magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, cerium nitrate hexahydrate, potassium nitrate, and deionized water are used in a ratio of 0.8-1g: 0.3-0.4g: 0.1-0.15g: 4-6g: 40-60mL.

6. A corrosion resistant stud, characterized by, The corrosion-resistant double-headed bolt is prepared by the method for preparing a corrosion-resistant double-headed bolt according to any one of claims 1-5.

7. A corrosion resistant stud as defined in claim 6 wherein, The corrosion-resistant double-headed bolt is prepared by coating the double-headed bolt blank with corrosion-resistant paint, and the double-headed bolt blank raw material comprises the following elements by weight percentage: C: 0.15-0.25%, Si: 0.15-0.35%, Mn: 0.40-0.60%, Cr: 0.10-0.15%, Ni: 0.20-0.35%, Mo: 0.10-0.20%, Al: 0.02-0.03%, Zn: 0.02-0.03%, Zr: 0.01-0.02%, Ti: 0.15-0.16%, Ru: 0.10-0.15%, Rh: 0.15-0.30%, Ir: 0.10-0.15%, and the balance being iron and unavoidable impurities.

8. The use of the corrosion-resistant double-headed bolt according to claim 7 as a steel structure support connector in an underground well.

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