Anti-electromagnetic interference high-nickel cold-rolled stainless steel and preparation method thereof

Abstract

The application discloses an anti-electromagnetic interference high-nickel cold-rolled stainless steel and a preparation method thereof, and relates to the technical field of stainless steel. The specific preparation steps are as follows: after steel raw materials are smelted to obtain ingots, the ingots are forged to obtain slabs, the slabs are sequentially subjected to hot rolling and solid solution treatment to obtain hot-rolled solid solution plates, the hot-rolled solid solution plates are subjected to water cooling, cold rolling and straightening, annealing and air cooling after the end, and the high-nickel cold-rolled stainless steel is obtained; the high-nickel cold-rolled stainless steel is sequentially subjected to polishing, pickling, sand blasting treatment, hot spraying, chemical etching, cleaning and drying after the etching is completed, and finally, surface treatment is performed to obtain the anti-electromagnetic interference high-nickel cold-rolled stainless steel; the powder raw material of the porous alloy coating is composed of iron-based amorphous alloy powder, iron-based nanocrystalline alloy powder and reinforcing phase particles with a mass ratio of 10: (1-2) : 1.

Description

Technical Field

[0001] This invention relates to the field of stainless steel technology, specifically to an electromagnetic interference-resistant high-nickel cold-rolled stainless steel and its preparation method. Background Technology

[0002] With the rapid development of 5G communication, precision electronic equipment and military equipment, the electromagnetic environment is becoming increasingly complex. Excessive electromagnetic radiation can not only cause electronic components to malfunction and signals to be distorted, but may also lead to the leakage of classified information and even threaten the battlefield survivability of high-end equipment. Therefore, electromagnetic interference (EMI) has become a key issue restricting the stability and safety of equipment.

[0003] High-nickel cold-rolled stainless steel, as a type of high-performance structural material, has natural potential in the field of electromagnetic shielding substrates due to its unique composition and processing advantages. High-nickel cold-rolled stainless steel is widely used in marine engineering, chemical equipment, electronic housings and other fields because of its excellent corrosion resistance, mechanical strength and formability. However, it has low conductivity and limited magnetic permeability, resulting in insufficient electromagnetic shielding effectiveness. Therefore, improving electromagnetic shielding effectiveness while retaining its mechanical performance advantages is of great practical significance. Summary of the Invention

[0004] The purpose of this invention is to provide an electromagnetic interference resistant high-nickel cold-rolled stainless steel and its preparation method, so as to solve the problems raised in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for preparing high-nickel cold-rolled stainless steel with electromagnetic interference resistance includes the following steps: smelting steel raw materials to obtain ingots, forging to obtain slabs, sequentially hot-rolling and solution treatment to obtain hot-rolled solution-treated plates, water-cooling followed by cold-rolling straightening, and finally annealing and air-cooling to obtain high-nickel cold-rolled stainless steel; sequentially grinding, pickling, and sandblasting the high-nickel cold-rolled stainless steel, followed by thermal spraying to obtain a porous alloy coating, then chemical etching, cleaning and drying after etching, and finally surface treatment to obtain the high-nickel cold-rolled stainless steel with electromagnetic interference resistance.

[0007] Preferably, the high-nickel cold-rolled stainless steel comprises the following chemical composition by mass percentage: C≤0.020%, Si≤0.1%, Mn: 2.0-3.5%, P≤0.01%, S≤0.01%, Cr: 23-25%, Ni: 18-22%, Mo: 7.0-7.25%, N: 0.5-0.55%, Co: 3-4.5%, Ce: 0.01-0.03%, and the balance being Fe;

[0008] Preferably, the thickness of the slab is 12mm; the thickness of the hot-rolled solution-treated plate is 5-8mm; and the thickness of the high-nickel cold-rolled stainless steel is 2-3mm.

[0009] Preferably, the hot rolling temperature is 1200-1250℃; the solution treatment temperature is 1250℃ and the solution treatment time is 1h; the annealing temperature is 1250℃ and the annealing holding time is 30-40min.

[0010] Preferably, the preparation steps of the powder raw material for the porous alloy coating are as follows: iron-based amorphous alloy powder, iron-based nanocrystalline alloy powder and reinforcing phase particles are weighed in sequence according to a mass ratio of 10:(1-2):1, placed in a ball material tank, and grinding balls are added according to a ball-material ratio of 10:1. The mixture is then ball-milled at a speed of 150-200 r / min for 2-5 hours.

[0011] Preferably, the preparation steps of the iron-based amorphous alloy powder are as follows: smelting pure metal raw materials to obtain alloy ingots, crushing and grinding them to a diameter of 1 mm, placing them in a heating coil, and evacuating to a vacuum of 6 × 10⁻⁶ mm. -3 Pa, argon gas is introduced, the roller speed is adjusted to 2500-4500 rpm, and an amorphous alloy strip with a thickness of 20-30 μm is obtained by single-roller belt spinning method. The strip is placed in a ball milling jar, and grinding balls are added at a ball-to-material ratio of 10:1. The strip is then ball-milled at a speed of 350-500 rpm for 20-60 h.

[0012] Preferably, the preparation steps of the iron-based nanocrystalline alloy powder are as follows: after heat-treating the amorphous alloy strip at 500-550℃ for 1-2 hours, it is placed in a ball mill jar, and grinding balls are added at a ball-to-material ratio of 10:1. The mixture is then ball-milled at a speed of 200-250 r / min for 10-12 hours.

[0013] Preferably, the amorphous alloy strip comprises the following chemical composition by mass percentage: Fe: 73.2-83.5%, Si: 4.5-16.5%, B: 6.0-9.0%, Cu: 0.5-1.0%, Nb: 3-4%;

[0014] Preferably, the reinforcing phase particles are one or more combinations of tungsten, tungsten carbide, silicon nitride, titanium nitride, and alumina;

[0015] Preferably, the process parameters for thermal spraying are: spray distance of 160-180mm, air pressure of 0.5-0.6MPa, fuel pressure of 0.4-0.5MPa; and powder feeding rate of 8-10rpm.

[0016] Preferably, the thickness of the porous alloy coating is 100-200 μm;

[0017] Preferably, chemical etching uses a 2% hydrochloric acid solution by volume and the etching time is 3-5 minutes.

[0018] Preferably, the surface treatment is as follows: a modified silicone resin slurry is coated onto the etched porous alloy coating surface; the preparation steps of the modified silicone resin slurry are as follows:

[0019] S1: Graphene oxide was placed in deionized water and stirred to disperse it. Hydrogen peroxide was added and heated in a water bath at 85°C for 1 hour. After filtration and washing, it was placed in deionized water and stirred to disperse it. Ascorbic acid and iron-based amorphous alloy powder were added and ultrasonicated for 1-2 hours. After heating in a water bath at 60°C for 4 hours, it was dried and then calcined under vacuum to obtain graphene composite amorphous alloy.

[0020] S2: After calcination, the graphene composite amorphous alloy was removed and placed in anhydrous ethanol solution. N-aminoethyl-3-aminopropylmethyldimethoxysilane was added and ultrasonically dispersed for 1 hour. The mixture was then magnetically stirred at 60°C for 12 hours. After filtration and drying, the mixture was ultrasonically dispersed in deionized water for 30-40 minutes. Aniline was then added and the mixture was magnetically stirred at 5°C for 30 minutes. Ammonium persulfate was then added dropwise and the reaction was continued for 6 hours. After filtration and washing, the modified graphene composite amorphous alloy was obtained by freeze-drying.

[0021] S3: After mixing and grinding the modified graphene composite amorphous alloy and iron oxide in a mass ratio of (1-2):(4-12), add it to the silicone resin at a mass percentage of 2-5%, add N-aminoethyl-3-aminopropylmethyldimethoxysilane and stir to disperse to obtain the modified silicone resin slurry.

[0022] Preferably, the mass ratio of graphene oxide, ascorbic acid, and iron-based amorphous alloy powder in S1 is 1:0.5:(0.1-0.5); the process parameters for vacuum calcination in S1 are: under an argon atmosphere, the temperature is raised to 160°C at a heating rate of 2°C / min, sintered for 3-4 hours, then raised to 300-350°C, and sintered for 10-12 hours.

[0023] Preferably, the mass ratio of graphene composite amorphous alloy, N-aminoethyl-3-aminopropylmethyldimethoxysilane and aniline in S2 is 1:3:(4-6).

[0024] Preferably, the thickness of the modified silicone resin slurry is 200-300 μm, and it is dried at 45-50℃ for 24 hours.

[0025] A high-nickel cold-rolled stainless steel with electromagnetic interference resistance is prepared by the above-described preparation method.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1. This invention designs a set of high-Ni, high-Cr cold-rolled stainless steel as the base material, adding Mo and Co elements to ensure high corrosion resistance and certain conductivity of the base material, providing structural support and basic conductive shielding; then, a porous alloy coating is thermally sprayed onto the surface of the base material. The powder raw material of this porous alloy coating is a compound combination of iron-based amorphous alloy powder, iron-based nanocrystalline alloy powder and reinforcing phase particles, obtained by ball milling; wherein the iron-based nanocrystalline alloy powder is obtained by further heat treatment of amorphous alloy strip; by changing the ball milling time of the powder raw material, the particle size is reduced to enhance the electromagnetic wave absorption performance of the compound powder; the addition of reinforcing phase particles, such as tungsten carbide, brings a hard phase to improve the wear resistance of the coating while assisting in electromagnetic wave attenuation; the thermally sprayed amorphous alloy and other compound powders form inherent pore defects, which can not only prolong electromagnetic propagation, but also achieve mechanical locking with the subsequent silicone resin coating after hydrochloric acid etching roughening, improving the adhesion stability of the silicone resin coating.

[0028] 2. This invention involves preparing a porous alloy coating on a steel substrate surface followed by applying a modified silicone resin slurry, which enhances electromagnetic shielding performance while protecting the inner layer. The modified resin slurry contains a modified graphene composite amorphous alloy. This material is obtained by etching graphene oxide to achieve a porous structure with hydrogen peroxide, then assembling it with iron-based amorphous alloy powder and ascorbic acid, followed by calcination, modification with a silane coupling agent, and polymerization with aniline. This constructs a conductive-magnetic dual-pathway, which, when mixed with iron oxide, is added to the silicone resin, giving the coating both magnetic and conductive losses, thus improving electromagnetic shielding effectiveness. Furthermore, the graphene composite iron-based amorphous alloy powder further enhances the mechanical properties of the coating. The addition of a silane coupling agent to the silicone resin slurry forms covalent bonds with the etched porous alloy coating, improving interfacial bonding. Detailed Implementation

[0029] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In the experiment, the preparation steps of the iron-based amorphous alloy powder were as follows: pure metal raw materials were melted to obtain alloy ingots, which were then crushed and polished to a diameter of 1 mm using a quartz tube nozzle. The ingots were then placed in a heating coil and evacuated to a vacuum of 6 × 10⁻⁶ mm. -3 Pa, argon gas was introduced, the roller speed was adjusted to 4000 rpm, and an amorphous alloy strip with a thickness of 30 μm was obtained by single-roller belt spinning method. The strip was placed in a ball milling jar, and corundum grinding balls were added at a ball-to-material ratio of 10:1. The strip was then ball-milled at a speed of 500 r / min for 40 h.

[0031] The amorphous alloy strip comprises the following chemical composition by mass percentage: Fe: 77.2%, Si: 12.5%, B: 6.5%, Cu: 0.8%, Nb: 3%;

[0032] The preparation steps of iron-based nanocrystalline alloy powder are as follows: after heat treatment at 500℃ for 2 hours, the amorphous alloy strip is placed in a ball mill jar, and corundum grinding balls are added at a ball-to-material ratio of 10:1. The mixture is then ball-milled at a speed of 250 r / min for 10 hours.

[0033] The preparation steps of the modified graphene composite amorphous alloy are as follows:

[0034] S1: 1g of graphene oxide was placed in 30mL of deionized water and stirred to disperse. 50mL of 30% hydrogen peroxide was added and heated in a water bath at 85℃ for 1h. After filtration and washing, the graphene oxide was placed in 50mL of deionized water and stirred to disperse. 0.5g of ascorbic acid and 0.4g of iron-based amorphous alloy powder were added and sonicated for 2h. The mixture was then heated in a water bath at 60℃ for 4h. After drying, the mixture was transferred to a tube furnace for vacuum calcination. Under an argon atmosphere, the temperature was increased to 160℃ at a heating rate of 2℃ / min. After sintering for 4h, the temperature was increased to 350℃ and sintered for 12h to obtain the graphene composite amorphous alloy.

[0035] S2: After calcination, 1g of graphene composite amorphous alloy was placed in 100mL of anhydrous ethanol solution, 3g of N-aminoethyl-3-aminopropylmethyldimethoxysilane was added and ultrasonically dispersed for 1h, and then magnetically stirred at 60℃ for 12h. After filtration and drying, the alloy was placed in 100mL of deionized water and ultrasonically dispersed for 30min. Then, 5g of aniline was added, and the alloy was magnetically stirred at 5℃ for 30min. After that, 10g of ammonium persulfate was added, and the reaction was continued for 6h. After filtration and washing, the alloy was freeze-dried to obtain the modified graphene composite amorphous alloy.

[0036] The preparation steps of graphene oxide are as follows: Using the modified Hummers method, under ice-water bath and stirring conditions, 1.50 g of NaNO3 was dissolved in 50 mL of concentrated H2SO4 (98% by mass), 1 g of graphite was added to the above solution, and 8.00 g of KMnO4 was slowly added. The solution was kept at 35 °C for 6 h, and 200 mL of deionized water was added dropwise. After the addition was complete, the solution was kept at 80 °C for 30 min. After naturally cooling to room temperature, 20 mL of H2O2 and 200 mL of distilled water were added. After settling overnight, the supernatant was removed, and 30 mL of HCl (38% by mass) and 20 mL of deionized water were added. After washing, the solution was placed in an oven and dried at 60 °C for 24 h. The graphite with a specification of ≥100 mesh was purchased from Aladdin Shanghai.

[0037] Tungsten carbide passed through a 300-mesh sieve and was purchased from Hebei Guangtuo Welding Materials Co., Ltd.

[0038] The preparation steps of silicone resin are as follows: according to the mass parts, 20 parts of vinyltriethoxysilane, 5 parts of dimethyldimethoxysilane, 16 parts of anhydrous ethanol, 8 parts of deionized water and 1 part of citric acid are added to a three-necked flask in sequence, sonicated until the system is completely dissolved, stirred in a 40℃ water bath for 8 hours, and aged for 24 hours after the reaction is completed for later use.

[0039] Example 1: This example provides a method for preparing high-nickel cold-rolled stainless steel with electromagnetic interference resistance. The specific steps are as follows:

[0040] Step 1: After melting the steel raw material in a vacuum induction furnace to obtain an ingot, it is forged into a slab. The slab is then hot-rolled at 1200℃ and solution-treated at 1250℃ for 1 hour to obtain a hot-rolled solution-treated slab with a thickness of 6mm. After water cooling, it is cold-rolled and straightened. After the straightening is completed, it is annealed at 1250℃ for 30 minutes and then air-cooled to obtain a high-nickel cold-rolled stainless steel with a thickness of 3mm. The chemical composition of the high-nickel cold-rolled stainless steel is: C: 0.010%, Si: 0.05%, Mn: 2.54%, P: 0.005%, S: 0.005%, Cr: 23.14%, Ni: 18.35%, Mo: 7.13%, N: 0.52%, Co: 4.13%, Ce: 0.03%, and the balance is Fe.

[0041] Step 2: After grinding, pickling and alumina sandblasting, the high-nickel cold-rolled stainless steel is thermally sprayed to obtain a porous alloy coating with a thickness of 100μm. Then, it is placed in a 2vol% hydrochloric acid solution for chemical etching for 3 minutes. After etching, it is cleaned and dried with ethanol. Then, a modified silicone resin slurry with a thickness of 200μm is applied and dried at 45℃ for 24 hours to obtain electromagnetic interference resistant high-nickel cold-rolled stainless steel.

[0042] The preparation steps of the powder raw material for the porous alloy coating are as follows: iron-based amorphous alloy powder, iron-based nanocrystalline alloy powder and reinforcing phase particles are weighed in sequence according to a mass ratio of 10:1:1, placed in a ball feed jar, and corundum grinding balls are added according to a ball-to-material ratio of 10:1. The mixture is ball-milled at a speed of 200 r / min for 2 h. The process parameters for thermal spraying are: spray distance of 180 mm, air pressure of 0.6 MPa, fuel pressure of 0.5 MPa, and powder feeding rate of 8 rpm.

[0043] The preparation steps of the modified silicone resin slurry are as follows: the modified graphene composite amorphous alloy and iron oxide are mixed and ground at a mass ratio of 1:9, and then added to the silicone resin at a mass percentage of 3%. After adding N-aminoethyl-3-aminopropylmethyldimethoxysilane at a mass percentage of 2%, the mixture is stirred and dispersed.

[0044] Example 2: This example provides a method for preparing high-nickel cold-rolled stainless steel with electromagnetic interference resistance. The specific steps are as follows:

[0045] This embodiment provides a method for preparing high-nickel cold-rolled stainless steel with electromagnetic interference resistance. The specific steps are as follows:

[0046] Step 1: After melting the steel raw material in a vacuum induction furnace to obtain an ingot, it is forged into a slab. The slab is then hot-rolled at 1200℃ and solution-treated at 1250℃ for 1 hour to obtain a hot-rolled solution-treated slab with a thickness of 6mm. After water cooling, it is cold-rolled and straightened. After the straightening is completed, it is annealed at 1250℃ for 30 minutes and then air-cooled to obtain a high-nickel cold-rolled stainless steel with a thickness of 3mm. The chemical composition of the high-nickel cold-rolled stainless steel is: C: 0.010%, Si: 0.05%, Mn: 2.54%, P: 0.005%, S: 0.005%, Cr: 23.14%, Ni: 18.35%, Mo: 7.13%, N: 0.52%, Co: 4.13%, Ce: 0.03%, and the balance is Fe.

[0047] Step 2: After grinding, pickling and alumina sandblasting, the high-nickel cold-rolled stainless steel is thermally sprayed to obtain a porous alloy coating with a thickness of 100μm. Then, it is placed in a 2vol% hydrochloric acid solution for chemical etching for 4min. After etching, it is cleaned and dried with ethanol. Then, a modified silicone resin slurry with a thickness of 200μm is scraped and dried at 45℃ for 24h to obtain electromagnetic interference resistant high-nickel cold-rolled stainless steel.

[0048] The preparation steps of the powder raw materials for the porous alloy coating are as follows: iron-based amorphous alloy powder, iron-based nanocrystalline alloy powder and reinforcing phase particles are weighed in sequence according to a mass ratio of 10:1.5:1, placed in a ball feed jar, and corundum grinding balls are added according to a ball-to-material ratio of 10:1. The mixture is ball-milled at a speed of 200 r / min for 3 h. The process parameters for thermal spraying are: spray distance of 180 mm, air pressure of 0.6 MPa, fuel pressure of 0.5 MPa, and powder feeding rate of 8 rpm.

[0049] The preparation steps of the modified silicone resin slurry are as follows: the modified graphene composite amorphous alloy and iron oxide are mixed and ground in a mass ratio of 1.5:8.5, and then added to the silicone resin at a mass percentage of 3%. After adding N-aminoethyl-3-aminopropylmethyldimethoxysilane at a mass percentage of 2%, the mixture is stirred and dispersed.

[0050] Example 3: This example provides a method for preparing high-nickel cold-rolled stainless steel with electromagnetic interference resistance. The specific steps are as follows:

[0051] Step 1: After melting the steel raw material in a vacuum induction furnace to obtain an ingot, it is forged into a slab. The slab is then hot-rolled at 1250℃ and solution-treated at 1250℃ for 1 hour to obtain a 6mm thick hot-rolled solution-treated slab. After water cooling, it is cold-rolled and straightened. Finally, it is annealed at 1250℃ for 30 minutes and then air-cooled to obtain a 3mm thick high-nickel cold-rolled stainless steel. The chemical composition of the high-nickel cold-rolled stainless steel is: C: 0.010%, Si: 0.05%, Mn: 2.54%, P: 0.005%, S: 0.005%, Cr: 23.14%, Ni: 18.35%, Mo: 7.13%, N: 0.52%, Co: 4.13%, Ce: 0.03%, with the balance being Fe.

[0052] Step 2: After grinding, pickling and alumina sandblasting, the high-nickel cold-rolled stainless steel is thermally sprayed to obtain a porous alloy coating with a thickness of 100μm. Then, it is placed in a 2vol% hydrochloric acid solution for chemical etching for 4min. After etching, it is cleaned and dried with ethanol. Then, a modified silicone resin slurry with a thickness of 200μm is scraped and dried at 45℃ for 24h to obtain electromagnetic interference resistant high-nickel cold-rolled stainless steel.

[0053] The preparation steps of the powder raw materials for the porous alloy coating are as follows: iron-based amorphous alloy powder, iron-based nanocrystalline alloy powder and reinforcing phase particles are weighed in sequence according to a mass ratio of 10:2:1, placed in a ball feed jar, and corundum grinding balls are added according to a ball-to-material ratio of 10:1. The mixture is ball-milled at a speed of 200 r / min for 5 h. The process parameters for thermal spraying are: spray distance of 180 mm, air pressure of 0.6 MPa, fuel pressure of 0.5 MPa, and powder feeding rate of 8 rpm.

[0054] The preparation steps of the modified silicone resin slurry are as follows: the modified graphene composite amorphous alloy and iron oxide are mixed and ground at a mass ratio of 2:8, and then added to the silicone resin at a mass percentage of 4%. After adding N-aminoethyl-3-aminopropylmethyldimethoxysilane at a mass percentage of 2%, the mixture is stirred and dispersed.

[0055] Comparative Example 1: As a control experiment for Example 3, no iron-based amorphous alloy was added to the modified silicone resin slurry. The specific steps are as follows:

[0056] Step 1: After melting the steel raw material in a vacuum induction furnace to obtain an ingot, it is forged into a slab. The slab is then hot-rolled at 1250℃ and solution-treated at 1250℃ for 1 hour to obtain a 6mm thick hot-rolled solution-treated slab. After water cooling, it is cold-rolled and straightened. Finally, it is annealed at 1250℃ for 30 minutes and then air-cooled to obtain a 3mm thick high-nickel cold-rolled stainless steel. The chemical composition of the high-nickel cold-rolled stainless steel is: C: 0.010%, Si: 0.05%, Mn: 2.54%, P: 0.005%, S: 0.005%, Cr: 23.14%, Ni: 18.35%, Mo: 7.13%, N: 0.52%, Co: 4.13%, Ce: 0.03%, with the balance being Fe.

[0057] Step 2: After grinding, pickling and alumina sandblasting, the high-nickel cold-rolled stainless steel is thermally sprayed to obtain a porous alloy coating with a thickness of 100μm. Then, it is placed in a 2vol% hydrochloric acid solution for chemical etching for 4min. After etching, it is cleaned and dried with ethanol. Then, a modified silicone resin slurry with a thickness of 200μm is scraped and dried at 45℃ for 24h to obtain electromagnetic interference resistant high-nickel cold-rolled stainless steel.

[0058] The preparation steps of the powder raw materials for the porous alloy coating are as follows: iron-based amorphous alloy powder, iron-based nanocrystalline alloy powder and reinforcing phase particles are weighed in sequence according to a mass ratio of 10:2:1, placed in a ball feed jar, and corundum grinding balls are added according to a ball-to-material ratio of 10:1. The mixture is ball-milled at a speed of 200 r / min for 5 h. The process parameters for thermal spraying are: spray distance of 180 mm, air pressure of 0.6 MPa, fuel pressure of 0.5 MPa, and powder feeding rate of 8 rpm.

[0059] The preparation steps for modified silicone resin slurry are as follows:

[0060] S1: 1g of graphene oxide was placed in 30mL of deionized water and stirred to disperse. 50mL of 30% hydrogen peroxide was added and heated in a water bath at 85℃ for 1h. After filtration and washing, the graphene oxide was placed in 50mL of deionized water and stirred to disperse. 0.5g of ascorbic acid was added and sonicated for 2h. After heating in a water bath at 60℃ for 4h, the graphene oxide was dried and then transferred to a tube furnace for vacuum calcination. Under an argon atmosphere, the temperature was increased to 160℃ at a heating rate of 2℃ / min and sintered for 4h. After sintering, the temperature was increased to 350℃ and sintered for 12h to obtain pretreated graphene.

[0061] S2: After calcination, 1g of pretreated graphene was placed in 100mL of anhydrous ethanol solution, 3g of N-aminoethyl-3-aminopropylmethyldimethoxysilane was added and ultrasonically dispersed for 1h, and then magnetically stirred at 60℃ for 12h. After filtration and drying, the graphene was placed in 100mL of deionized water and ultrasonically dispersed for 30min. Then, 5g of aniline was added, and the graphene was magnetically stirred at 5℃ for 30min. After that, 10g of ammonium persulfate was added, and the reaction was continued for 6h. After filtration and washing, the graphene was freeze-dried to obtain the modified graphene.

[0062] S3: Modified graphene and iron oxide are mixed and ground at a mass ratio of 2:8, and then added to silicone resin at a mass percentage of 4%. After adding N-aminoethyl-3-aminopropylmethyldimethoxysilane at a mass percentage of 2%, the mixture is stirred and dispersed to obtain modified silicone resin slurry.

[0063] Comparative Example 2: As a control experiment for Example 3, the powder raw material of the porous alloy coating was replaced with iron-based amorphous alloy powder. The specific steps are as follows:

[0064] Step 1: After melting the steel raw material in a vacuum induction furnace to obtain an ingot, it is forged into a slab. The slab is then hot-rolled at 1250℃ and solution-treated at 1250℃ for 1 hour to obtain a 6mm thick hot-rolled solution-treated slab. After water cooling, it is cold-rolled and straightened. Finally, it is annealed at 1250℃ for 30 minutes and then air-cooled to obtain a 3mm thick high-nickel cold-rolled stainless steel. The chemical composition of the high-nickel cold-rolled stainless steel is: C: 0.010%, Si: 0.05%, Mn: 2.54%, P: 0.005%, S: 0.005%, Cr: 23.14%, Ni: 18.35%, Mo: 7.13%, N: 0.52%, Co: 4.13%, Ce: 0.03%, with the balance being Fe.

[0065] Step 2: After grinding, pickling and alumina sandblasting, the high-nickel cold-rolled stainless steel is thermally sprayed to obtain a porous alloy coating with a thickness of 100μm. Then, it is placed in a 2vol% hydrochloric acid solution for chemical etching for 4min. After etching, it is cleaned and dried with ethanol. Then, a modified silicone resin slurry with a thickness of 200μm is scraped and dried at 45℃ for 24h to obtain electromagnetic interference resistant high-nickel cold-rolled stainless steel.

[0066] The powder raw material for the porous alloy coating is iron-based amorphous alloy powder, which is placed in a ball feed tank and corundum grinding balls are added at a ball-to-powder ratio of 10:1. The mixture is ball-milled at a speed of 200 r / min for 5 hours. The process parameters for thermal spraying are: spray distance of 180 mm, air pressure of 0.6 MPa, fuel pressure of 0.5 MPa, and powder feeding rate of 8 rpm.

[0067] The preparation steps of the modified silicone resin slurry are as follows: the modified graphene composite amorphous alloy and iron oxide are mixed and ground at a mass ratio of 2:8, and then added to the silicone resin at a mass percentage of 4%. After adding N-aminoethyl-3-aminopropylmethyldimethoxysilane at a mass percentage of 2%, the mixture is stirred and dispersed.

[0068] Testing and Experiment

[0069] 1. Shielding effectiveness test: Referring to GJB 6190-2008 "Method for measuring the shielding effectiveness of electromagnetic shielding materials", samples with dimensions of 200mm (length) × 100mm (width) were cut from the high-nickel cold-rolled stainless steel samples prepared in Examples 1-3 and Comparative Examples 1-2. The test range was 300MHz~18GHz, and the electromagnetic shielding performance (SE) was recorded. T The peak values ​​are shown in Table 1;

[0070] 2. Under a load of 10 mN and a displacement rate of 0.5 mN / s, nano-scratch tests were performed on the electromagnetic interference resistant high-nickel cold-rolled stainless steel prepared in Examples 1-3 and Comparative Examples 1-2 using a three-sided cone Berkovich indenter, and the friction coefficients were recorded in Table 1.

[0071] Table 1

[0072]

[0073] Conclusion: As can be seen from the above data, Example 3 achieves superior electromagnetic shielding effectiveness and wear resistance compared to the other examples. Comparative Example 1, as a control experiment of Example 3, did not add iron-based amorphous alloy to the coating, thus lacking the conductive synergistic effect between the amorphous alloy and graphene, resulting in a significant decrease in electromagnetic shielding effectiveness. At the same time, the absence of amorphous alloy also had a certain impact on the wear resistance of the coating. Comparative Example 2, as a control experiment of Example 3, adjusted the powder raw material in the porous alloy coating to a single iron-based amorphous alloy, resulting in a decrease in electromagnetic shielding effectiveness and a slight impact on wear resistance.

[0074] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for producing an electromagnetic interference resistant high nickel cold rolled stainless steel, characterized by, The preparation steps include: smelting a steel raw material to obtain an ingot, forging the ingot to obtain a slab, sequentially performing hot rolling and solid solution treatment to obtain a hot-rolled solid solution plate, performing water cooling, cold rolling and straightening, annealing and air cooling after the end to obtain a high-nickel cold-rolled stainless steel; performing grinding, pickling and sand blasting on the high-nickel cold-rolled stainless steel, then performing thermal spraying to obtain a porous alloy coating, performing chemical etching, cleaning and drying after the etching, and finally performing surface treatment to obtain the electromagnetic interference-resistant high-nickel cold-rolled stainless steel. The high-nickel cold-rolled stainless steel comprises the following chemical components in percentage by mass: C≤0.020%, Si≤0.1%, Mn: 2.0-3.5%, P≤0.01%, S≤0.01%, Cr: 23-25%, Ni: 18-22%, Mo: 7.0-7.25%, N: 0.5-0.55%, Co: 3-4.5%, Ce: 0.01-0.03%, and the balance of Fe. The preparation steps of the powder raw material of the porous alloy coating are as follows: iron-based amorphous alloy powder, iron-based nanocrystalline alloy powder and reinforcing phase particles are weighed according to a mass ratio of 10: (1-2): 1, placed in a ball mill tank, and grinding balls are added according to a ball-to-material ratio of 10:1, and the mixture is ball milled at a speed of 150-200 r / min for 2-5 h; the reinforcing phase particles are one or more combinations of tungsten, tungsten carbide, silicon nitride, titanium nitride and aluminum oxide. The surface treatment is scraping modified silicone resin slurry on the surface of the etched porous alloy coating; and the preparation steps of the modified silicone resin slurry are as follows: S1: graphene oxide is dispersed in deionized water by stirring, hydrogen peroxide is added, and the mixture is heated in a water bath at 85°C for 1 h, filtered, washed, and then dispersed in deionized water by stirring, ascorbic acid and iron-based amorphous alloy powder are added, and the mixture is ultrasonically treated for 1-2 h, and then heated in a water bath at 60°C for 4 h, dried, and vacuum calcined to obtain graphene composite amorphous alloy; S2: after the calcination is completed, the graphene composite amorphous alloy is taken out, added into anhydrous ethanol solution, ultrasonically dispersed for 1 h, magnetically stirred at 60°C for 12 h, filtered and dried, ultrasonically dispersed in deionized water for 30-40 min, added with aniline, magnetically stirred at 5°C for 30 min, added with ammonium persulfate dropwise, continuously reacted for 6 h, and then filtered, washed, and freeze-dried to obtain modified graphene composite amorphous alloy; S3: the modified graphene composite amorphous alloy and ferroferric oxide are mixed and ground according to a mass ratio of (1-2):(4-12), added into silicone resin according to a mass percentage of 2-5%, and then stirred and dispersed after adding N-aminoethyl-3-aminopropyl methyl dimethoxy silane to obtain modified silicone resin slurry.

2. The method of claim 1, wherein the high-nickel cold-rolled stainless steel is prepared by the steps of: preparing a high-nickel cold-rolled stainless steel; and performing a surface treatment on the high-nickel cold-rolled stainless steel. The thickness of the slab is 12 mm; the thickness of the hot-rolled solid solution plate is 5-8 mm; and the thickness of the high-nickel cold-rolled stainless steel is 2-3 mm.

3. The method for preparing high-nickel cold-rolled stainless steel with electromagnetic interference resistance according to claim 1, characterized in that, The temperature of the hot rolling is 1200-1250°C; the temperature of the solid solution treatment is 1250°C, and the solid solution treatment time is 1 h; and the annealing temperature is 1250°C, and the annealing holding time is 30-40 min.

4. The method for preparing high-nickel cold-rolled stainless steel with electromagnetic interference resistance according to claim 1, characterized in that, The preparation steps of the iron-based amorphous alloy powder are: smelting raw materials to obtain an alloy ingot, crushing, polishing to a diameter of 1mm, loading into a heating coil, vacuumizing to 6×10 -3 Pa, adjusting the roller speed to 2500-4500rmp, obtaining an amorphous alloy strip with a thickness of 20-30μm by a single roller tape casting method, placing in a ball mill jar, adding grinding balls according to a ball-to-material ratio of 10:1, and ball milling at a speed of 350-500r / min for 20-60h; the preparation steps of the iron-based nanocrystalline alloy powder are: placing the amorphous alloy strip after heat treatment at 500-550℃ for 1-2h, adding grinding balls according to a ball-to-material ratio of 10:1, and ball milling at a speed of 200-250r / min for 10-12h.

5. The method of producing an electromagnetic interference resistant high nickel cold rolled stainless steel according to claim 4, characterized in that, The non-crystalline alloy strip comprises the following chemical components by mass percentage: Fe: 73.2-83.5%, Si: 4.5-16.5%, B: 6.0-9.0%, Cu: 0.5-1.0%, Nb: 3-4%.

6. The method for preparing high-nickel cold-rolled stainless steel with electromagnetic interference resistance according to claim 1, characterized in that, The process parameters of the thermal spraying are as follows: a spraying distance is 160-180 mm, an air pressure is 0.5-0.6 MPa, a fuel pressure is 0.4-0.5 MPa, a powder feeding rate is 8-10 rpm, a porous alloy coating thickness is 100-200 μm, and a chemical etching uses a hydrochloric acid solution with a volume percentage concentration of 2% and an etching time is 3-5 min.

7. The method for preparing high-nickel cold-rolled stainless steel with electromagnetic interference resistance according to claim 1, characterized in that, The mass ratio of graphene oxide, ascorbic acid and iron-based amorphous alloy powder in S1 is 1:0.5:(0.1-0.5); the process parameters of vacuum calcination in S1 are as follows: under argon atmosphere, the temperature is raised to 160℃ at a rate of 2℃ / min, sintering for 3-4 h, then the temperature is raised to 300-350℃, sintering for 10-12 h; the mass ratio of graphene composite amorphous alloy, N-aminoethyl-3-aminopropyl methyl dimethoxy silane and aniline in S2 is 1:3:(4-6); the blade coating thickness of the modified silicone resin slurry is 200-300 μm, and the drying is carried out at 45-50℃ for 24 h.

8. An electromagnetic interference resistant high nickel cold rolled stainless steel characterized by, Prepared by the preparation method of any one of claims 1-7. Prepared by the preparation method of any one of claims 1-7.

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