Core-spun stainless steel wire as well as preparation method and application thereof

Abstract

The invention discloses a cored stainless steel wire as well as a preparation method and application thereof. The cored stainless steel wire sequentially comprises a nickel-titanium alloy wire, a porous buffer layer, a bionic functional layer and an intelligent response layer from inside to outside, the invention relates to the technical field of stainless steel wire production. According to the core-spun stainless steel wire and the preparation method and application thereof, the nickel-titanium alloy wire serves as the shape memory alloy core layer, good biocompatibility is achieved, the Ti-N bond is combined with the boron nitride nanotube woven mesh, nickel-titanium phase change stress is absorbed, interface stripping is prevented, and the shape memory alloy core layer has the good biocompatibility. A stainless steel wire woven body is constructed in the mode that stainless steel melt permeates into boron nitride network pores, a pinning effect is formed after cooling, boron nitride is induced to be matched with stainless steel lattices through a pulsed magnetic field, the interface defects are reduced, meanwhile, a shell bionic structure is formed, the outer layer is high in hardness and resistant to abrasion, and the inner layer is high in ductility and absorbs impact; the anti-fatigue performance is improved, the functions are diversified, meanwhile, the fatigue life is effectively prolonged, and the interlayer structural strength is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of stainless steel wire production technology, specifically to a cored stainless steel wire, its preparation method, and its application. Background Technology

[0002] Core-spun stainless steel wire is a yarn with a special structure. It uses stainless steel filaments as the core, and through techniques such as ring spinning and air-jet core-spun, it is wrapped with twisted outer short fibers to form a "core-sheath" structure. It combines the electrical conductivity and electromagnetic shielding properties of stainless steel wire with the softness and ease of dyeing of the outer fibers. The core filament diameter is generally ≤10μm; excessively thick core filaments will lead to difficulties in wrapping. Furthermore, the weaker bond between the outer fibers and the core filament can easily result in problems such as "core-sheath slippage."

[0003] Traditional cored stainless steel wire has the following defects: Limited functionality: Most existing cored stainless steel wires adopt a double-layer structure, such as stainless steel wire + protective layer, which only achieves basic electromagnetic radiation protection and lacks dynamic response capability. Biocompatibility defects: Medical stainless steel wires lack temperature response characteristics, and vascular stents require external force to expand, which can easily cause vasospasm; Insufficient fatigue resistance: Homogeneous stainless steel wire is prone to breakage under cyclic loading, and its fatigue life is typically <10. 5 Second-rate; Process limitations: Traditional cored stainless steel wire often uses a step-by-step weaving + post-coating process, resulting in poor interlayer bonding.

[0004] Based on the above-mentioned information, a cored stainless steel wire, its preparation method, and its application are proposed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a cored stainless steel wire, its preparation method, and its application, solving the problems of traditional cored stainless steel wires, such as limited functionality, biocompatibility defects, insufficient fatigue resistance, and process limitations.

[0006] To achieve the above objectives, the present invention provides the following technical solution: On the one hand, a core-coated stainless steel wire, from the inside out, includes a nickel-titanium alloy wire, a porous buffer layer, a biomimetic functional layer, and a smart response layer; The shape memory alloy core layer is a nickel-titanium alloy wire; The porous buffer layer is a boron nitride nanotube woven mesh; The biomimetic functional layer is a stainless steel wire braid; The smart response layer is a polypyrrole-carbon quantum dot composite film.

[0007] The present invention is further configured such that the diameter of the nickel-titanium alloy wire is 50-150 μm.

[0008] The present invention is further configured such that the thickness of the boron nitride nanotube woven mesh is 1-15 μm.

[0009] The present invention is further configured such that: the stainless steel wire braid is made of Cr 23 Mn 14 N 0.2 Stainless steel, with an outer diameter of 200-350μm.

[0010] The present invention is further configured such that the thickness of the polypyrrole-carbon quantum dot composite film is 2-10 μm.

[0011] On the other hand, a method for preparing a cored stainless steel wire specifically includes the following steps: S1. After pickling the nickel-titanium alloy wire with 15% hydrofluoric acid solution, preheat it in a vacuum environment at 200℃ for 30 minutes. S2. Using a three-channel microfluidic spinning machine, the inner channel transports nickel-titanium alloy wire at a speed of 12-15 m / min, the middle channel injects boron nitride precursor solution, and boron nitride nanotube braided mesh is grown in the reaction zone at 800℃ by chemical vapor deposition process. The outer channel sprays stainless steel melt through an annular nozzle to directionally weave stainless steel wire braid on the surface of boron nitride nanotube braided mesh to obtain the initial shaped wire material. S3. Immerse the pre-formed filament in liquid nitrogen for deep cooling for 2-6 hours. During the process, apply a 1.0T pulsed magnetic field at 10kHz. After deep cooling, heat the filament to 600℃ at a rate of 5℃ / min for tempering for 1-4 hours. After cooling to 80-100℃, pass it through a high-frequency induction coil and heat it to 900℃ within 0.5s. Then, spray it with deionized water at 20-25℃ for 5-6s for water cooling. Finally, spray it with polyacrylic acid coolant to form a temporary protective film and obtain the semi-finished filament. S4. The semi-finished filament is immersed in a 0.1M oxalic acid solution for surface cleaning, and then immersed in a mixed solution of ethylene glycol / deionized water containing 0.1 mol / L pyrrole monomer, 0.05 wt% carbon quantum dots, and 0.05 mol / L sodium p-toluenesulfonate, wherein the volume ratio of ethylene glycol to deionized water is 85:15, at a concentration of 0.3 mA / cm². 2 Electropolymerization at current density for 10–15 minutes results in self-assembly to form a spiral groove structure, thus obtaining cored stainless steel wire.

[0012] The present invention is further configured such that: the boron nitride precursor solution comprises a mixed solvent containing 10-20 wt% boron trioxide, 0.5 wt% nano-nickel catalyst, and ammonia, wherein the molar ratio of boron trioxide to ammonia is 1:3, and the mixed solvent is deionized water and ethanol in a volume ratio of 2:1.

[0013] This invention provides a cored stainless steel wire, its preparation method, and its application. It has the following beneficial effects: (1) This invention uses nickel-titanium alloy wire as the shape memory alloy core layer, which has good biocompatibility. The boron nitride nanotubes are woven into a mesh by Ti-N bond to absorb the nickel-titanium phase transformation stress and prevent interface peeling. The stainless steel wire braid is constructed by infiltrating stainless steel melt into the pores of the boron nitride network. After cooling, a pinning effect is formed. The boron nitride and stainless steel lattice are matched by a pulsed magnetic field to reduce interface defects and form a shell biomimetic structure. The outer layer has high hardness to resist wear, and the inner layer has high ductility to absorb impact, thereby improving fatigue resistance. While diversifying functions, it effectively improves fatigue life and interlayer structural strength.

[0014] (2) The present invention uses nickel-titanium alloy wire as the shape memory alloy core layer, which fits the human body comfort zone. After implantation of the medical stent, it can expand on its own, avoiding secondary surgery and has good biocompatibility.

[0015] (3) The present invention forms an electromagnetic wave reflection network through the braided structure of stainless steel wire braid, which is adapted to complex electromagnetic environment. In-situ electropolymerization is used to electrolyze and generate polypyrrole on the surface of the biomimetic functional layer, forming Fe-OC chemical bonds, which improves adhesion. At the same time, the spiral groove is embedded in the gap of stainless steel wire to ensure the interlayer bonding strength. Moreover, the color changes when the pressure is >2MPa, providing intuitive conditions for real-time monitoring of structural damage. Detailed Implementation

[0016] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] The embodiments of the present invention provide the following technical solutions: Example 1 A cored stainless steel wire comprises, from the inside out, a shape memory alloy core layer, a porous buffer layer, a biomimetic functional layer, and a smart response layer. The preparation method of this cored stainless steel wire specifically includes the following steps: S1. A nickel-titanium alloy wire with a diameter of 50 μm is pickled with 15% hydrofluoric acid solution to form a micron-level roughness on the surface of the nickel-titanium alloy wire. After pickling, Ti-O active sites are formed on the surface of the nickel-titanium wire, which promotes the heterogeneous nucleation of boron nitride nanotubes in S2. Then, it is preheated in a vacuum environment at 200℃ for 30 min. The preheating temperature of 200℃ forms a gradient transition with the CVD growth temperature of boron nitride in S2 to reduce interlayer delamination caused by interfacial thermal stress.

[0018] S2. Using a three-channel microfluidic spinning machine, the inner channel delivers nickel-titanium alloy wire at a speed of 15m / min as a shape memory alloy core layer. A boron nitride precursor solution was injected into the central channel. The boron nitride precursor solution included a mixed solvent containing 20 wt% boron trioxide, 0.5 wt% nano-nickel catalyst, and ammonia gas. The molar ratio of boron trioxide to ammonia gas was 1:3. The mixed solvent was deionized water and ethanol in a volume ratio of 2:1. A boron nitride nanotube woven mesh was grown in the reaction zone at 800℃ using chemical vapor deposition. This mesh served as a porous buffer layer formed by the interweaving of boron nitride nanotubes, with a thickness of 15 μm. The outer channel ejects Cr through an annular nozzle. 23 Mn 14 N 0.2 Stainless steel melt is used to directionally weave a stainless steel wire braid with an outer diameter of 350 μm onto the surface of a boron nitride nanotube braided mesh, which serves as a biomimetic functional layer to obtain the initial shaped wire material.

[0019] S3. Immerse the pre-formed filament in liquid nitrogen for deep cooling for 6 hours. During the process, apply a 1.0T pulsed magnetic field at 10kHz to refine the grains. After deep cooling, heat the filament to 600℃ at a rate of 5℃ / min for tempering for 4 hours to eliminate residual stress. After cooling to 100℃, pass it through a 300kHz high-frequency induction coil. The outer layer is heated to 900℃ within 0.5s. Then, spray it with 25℃ deionized water for 6s for water cooling. Subsequently, spray it with polyacrylic acid coolant to form a temporary protective film to prevent oxidation and obtain the semi-finished filament.

[0020] S4. The semi-finished filament is immersed in a 0.1M oxalic acid solution for surface cleaning. Then, it is used as an electrolyte in a mixed solution of ethylene glycol / deionized water containing 0.1 mol / L pyrrole monomer, 0.05 wt% carbon quantum dots, and 0.05 mol / L sodium p-toluenesulfonate, with a volume ratio of ethylene glycol to deionized water of 85:15, at a flow rate of 0.3 mA / cm². 2 Electropolymerization at current density for 15 min resulted in the self-assembly of a spiral groove structure, which generated a 10 μm thick polypyrrole / carbon quantum dot composite film, leading to the acquisition of cored stainless steel wire.

[0021] For detailed explanation, at 0.3 mA / cm 2 Under the action of the anodic oxidation electric field, pyrrole monomers lose electrons to form cationic free radicals. Their conjugated structures are arranged in an orderly manner along the direction of the electric field lines, forming the prototype of polymer chains. Negatively charged carbon quantum dots migrate toward the anode in an electric field and combine with cationic free radicals through π-π stacking. Their nano-curvature radius forces the polypyrrole chains to curl and grow tangentially. When the semi-finished filament rotates at 120 rpm, the electrolyte generates a tangential velocity gradient. The polypyrrole and carbon quantum dot composite grows at an angle along the rotation direction under the action of Coriolis force, forming continuous grooves with a helix angle of 15-20°.

[0022] Example 2 The difference between this embodiment and Embodiment 1 is that: A method for preparing a cored stainless steel wire specifically includes the following steps: S1. A nickel-titanium alloy wire with a diameter of 100μm is pickled with 15% hydrofluoric acid solution to form a micron-level roughness on the surface of the nickel-titanium alloy wire. Then it is preheated in a vacuum environment at 200℃ for 30min. The phase transformation temperature of the nickel-titanium alloy wire is 25-40℃.

[0023] S2. Using a three-channel microfluidic spinning machine, the inner channel delivers nickel-titanium alloy wire at a speed of 14 m / min as a shape memory alloy core layer. A boron nitride precursor solution was injected into the central channel, and a boron nitride nanotube woven mesh was grown in the reaction zone at 800℃ using chemical vapor deposition. This mesh served as a porous buffer layer formed by the interweaving of boron nitride nanotubes, with a thickness of 8μm. The outer channel ejects Cr through an annular nozzle. 23 Mn 14 N 0.2 Stainless steel melt is used to directionally weave a stainless steel wire braid with an outer diameter of 250 μm onto the surface of a boron nitride nanotube braided mesh, which serves as a biomimetic functional layer to obtain the initial shaped wire material.

[0024] S3. Immerse the pre-formed filament in liquid nitrogen for deep cooling for 4 hours. During the process, apply a 1.0T pulsed magnetic field at 10kHz. After deep cooling, heat the filament to 600℃ at a rate of 5℃ / min for tempering for 3 hours. After cooling to 90℃, pass it through a high-frequency induction coil and heat it to 900℃ within 0.5s. Then, spray it with 23℃ deionized water for 6s for water cooling. Finally, spray it with polyacrylic acid coolant to form a temporary protective film and obtain the semi-finished filament.

[0025] S4. The semi-finished filament is immersed in a 0.1M oxalic acid solution for surface cleaning, and then immersed in a mixed solution of ethylene glycol / deionized water containing 0.1 mol / L pyrrole monomer, 0.05 wt% carbon quantum dots, and 0.05 mol / L sodium p-toluenesulfonate, wherein the volume ratio of ethylene glycol to deionized water is 85:15, at a concentration of 0.3 mA / cm². 2 Electropolymerization at current density for 13 min resulted in the self-assembly of a spiral groove structure, which generated a 7 μm thick polypyrrole / carbon quantum dot composite film, leading to the acquisition of cored stainless steel wire.

[0026] Example 3 The difference between this embodiment and Embodiment 1 is that: A method for preparing a cored stainless steel wire specifically includes the following steps: S1. A nickel-titanium alloy wire with a diameter of 150μm is pickled with 15% hydrofluoric acid solution to form a micron-level roughness on the surface of the nickel-titanium alloy wire, and then preheated in a vacuum environment at 200℃ for 30min.

[0027] S2. Using a three-channel microfluidic spinning machine, the inner channel delivers nickel-titanium alloy wire at a speed of 12m / min as a shape memory alloy core layer. A boron nitride precursor solution was injected into the central channel, and a boron nitride nanotube woven mesh was grown in the reaction zone at 800℃ using chemical vapor deposition. This mesh served as a porous buffer layer formed by the interweaving of boron nitride nanotubes, with a thickness of 1 μm. The outer channel ejects Cr through an annular nozzle. 23 Mn 14 N 0.2 Stainless steel melt is used to directionally weave a stainless steel wire braid with an outer diameter of 200 μm onto the surface of a boron nitride nanotube braided mesh, which serves as a biomimetic functional layer to obtain the initial shaped wire material.

[0028] S3. Immerse the pre-formed filament in liquid nitrogen for deep cooling for 2 hours. During the process, apply a 1.0T pulsed magnetic field at 10kHz. After deep cooling, heat the filament to 600℃ at a rate of 5℃ / min for tempering for 1 hour. After cooling to 80-100℃, pass it through a high-frequency induction coil and heat it to 900℃ within 0.5s. Then, spray it with 20℃ deionized water for 5s for water cooling. Finally, spray it with polyacrylic acid coolant to form a temporary protective film and obtain the semi-finished filament.

[0029] S4. The semi-finished filament is immersed in a 0.1M oxalic acid solution for surface cleaning, and then immersed in a mixed solution of ethylene glycol / deionized water containing 0.1 mol / L pyrrole monomer, 0.05 wt% carbon quantum dots, and 0.05 mol / L sodium p-toluenesulfonate, wherein the volume ratio of ethylene glycol to deionized water is 85:15, at a concentration of 0.3 mA / cm². 2 Electropolymerization at current density for 10 min resulted in the self-assembly of a spiral groove structure, which generated a 2 μm thick polypyrrole / carbon quantum dot composite film, leading to the acquisition of a cored stainless steel wire.

[0030] Application Example 1 Medical stents were fabricated using the cored stainless steel wire prepared in the above embodiments. β-titanium alloy was laser-welded to the intersection of the cored stainless steel wires. The shape memory alloy core layer absorbed heat and expanded, pushing the stent to expand. When the expansion stress was >2MPa, the smart response layer changed from red to blue, with a color difference ΔE≥8, providing real-time feedback on the wall adhesion status.

[0031] The test was conducted using diameter expansion rate, endothelialization cycle and colorimetric response error as indicators. The diameter expansion rate was obtained by placing the stent in a simulated body fluid at 37°C, recording the diameter change in real time using a laser scanner, and calculating the ratio of the peak expansion diameter to the initial diameter. The endothelialization cycle was obtained by implanting a stent into a porcine coronary artery model, observing the time point when the endothelial coverage area was >90% using OCT optical coherence tomography, and verifying it by tissue section staining. The colorimetric response error was obtained by applying a radial pressure of 2-10 MPa using an Instron 5943 pressure loading device, capturing the coating chromaticity coordinates using a hyperspectral camera, and comparing them with the stent profile data from the DSA angiography machine.

[0032] The test results are shown in Table 1: Table 1 index Test Results Diameter expansion rate 320% Endothelialization cycle 28d Colorimetric response error ≤0.1mm It is evident that this invention provides promising applications of cored stainless steel wire in medical stents.

[0033] Application Example 2 The cored stainless steel wire and Kevlar fiber prepared using the above embodiments are used to weave synchronous belts at a volume ratio of 4:1, that is, the cored stainless steel wire is spirally wound around the Kevlar fiber with a pitch angle of 55° to construct aerospace antennas, which can be deployed into a mesh reflective surface.

[0034] The folding volume ratio, lunar surface temperature difference deformation, and vibration fatigue life are used as indicators. The folding volume ratio is obtained by placing the antenna in a vacuum tank in a folded state to simulate the space environment, acquiring point cloud data by three-dimensional laser scanning, and calculating the volume ratio of the unfolded state to the folded state. The lunar surface temperature difference deformation was obtained by conducting 50 thermal vacuum cycle tests within the range of -180℃ to +120℃, and using a laser interferometer to measure the RMS accuracy of the reflecting surface in order to calculate the amount of deformation. The vibration fatigue life is obtained by simulating rocket launch load with an electromagnetic vibration table, monitoring structural damage with fiber optic strain sensors, and determining failure when stiffness decreases by more than 15% or the structure fractures.

[0035] The test results are shown in Table 2: Table 2 index Test Results Folding volume ratio <![CDATA[0.08m 3 ]]> Lunar surface temperature difference deformation ≤0.12mm / m Vibration fatigue life <![CDATA[>1×10 7 Next It is evident that this invention provides promising applications for cored stainless steel wire in aerospace antennas.

[0036] Application Example 3 The cored stainless steel wire prepared in the above embodiments was woven into a cable sheath to simulate the bridge cable stress detection environment. When the local pressure exceeded 2 MPa, the intelligent response layer triggered color development. After multiple tests, the average response time was 82ms, which is less than ≤200ms required by clause 4.3.2 of JT / T 1037-2022 "Technical Specification for Bridge Structural Health Monitoring System". It can be seen that the present invention provides a good application prospect for cored stainless steel wire in industrial sensing fabrics.

[0037] Simulation Experiment The mechanical properties, interfacial characteristics, functional response, and environmental durability of the cored stainless steel wire prepared according to the method provided in the above embodiments were tested, and the test results are shown in Table 3. Performance dimension Key Indicators Reference Standard Simulation / Experimental Methods Mechanical properties Tensile strength ≥ 1.8 GPa ASTM E8 / E8M-24 Virtual tensile test <![CDATA[Fracture toughness ≥ 105 MPa·m 1 / 2 > ASTM E399-23 Compact stretch model Interface features Interlaminar shear strength ≥350MPa ISO 527-5:2023 Double cantilever beam simulation Interface mismatch ≤3% GB / T 13301-2022 XRD lattice parameter fitting Functional response Coefficient of friction ≤ 0.08 XRD lattice parameter fitting Molecular dynamics simulation Resistance temperature sensitivity coefficient: 2.3% / ℃ IEC 60571-2018 Thermoelectric coupling field Environmental durability Salt spray corrosion rate ≤ 0.001 mm / y ISO 9227-2024 Phase-field corrosion model <![CDATA[Irradiation swelling rate ≤ 0.5% (1023n / m 2 ).]]> ASTM E521-20 Monte Carlo simulation In summary, the cored stainless steel wire provided by this invention has excellent performance in terms of mechanical properties, interfacial characteristics, functional response, and environmental durability, and has good application prospects in medical stents, aerospace antennas, and industrial sensing fabrics.

[0038] 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 alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A core-coated stainless steel wire, characterized in that, From the inside out, it consists of a shape memory alloy core layer, a porous buffer layer, a biomimetic functional layer, and a smart response layer; The shape memory alloy core layer is a nickel-titanium alloy wire; The porous buffer layer is a boron nitride nanotube woven mesh; The biomimetic functional layer is a stainless steel wire braid; The smart response layer is a polypyrrole-carbon quantum dot composite film.

2. The core-coated stainless steel wire according to claim 1, characterized in that, The diameter of the nickel-titanium alloy wire is 50-150 μm.

3. The core-coated stainless steel wire according to claim 1, characterized in that, The thickness of the boron nitride nanotube woven mesh is 1-15 μm.

4. The core-coated stainless steel wire according to claim 1, characterized in that, The stainless steel wire braided body is made of Cr 23 Mn 14 N 0.2 Stainless steel, with an outer diameter of 200-350μm.

5. The core-coated stainless steel wire according to claim 1, characterized in that, The thickness of the polypyrrole-carbon quantum dot composite film is 2-10 μm.

6. A core-coated stainless steel wire according to any one of claims 1-5, characterized in that, Its preparation method specifically includes the following steps: S1. After pickling the nickel-titanium alloy wire with 15% hydrofluoric acid solution, preheat it in a vacuum environment at 200℃ for 30 minutes. S2. Using a three-channel microfluidic spinning machine, the inner channel transports nickel-titanium alloy wire at a speed of 12-15 m / min, the middle channel injects boron nitride precursor solution, and boron nitride nanotube braided mesh is grown in the reaction zone at 800℃ by chemical vapor deposition process. The outer channel sprays stainless steel melt through an annular nozzle to directionally weave stainless steel wire braid on the surface of boron nitride nanotube braided mesh to obtain the initial shaped wire material. S3. Immerse the pre-formed filament in liquid nitrogen for deep cooling for 2-6 hours. During the process, apply a 1.0T pulsed magnetic field at 10kHz. After deep cooling, heat the filament to 600℃ at a rate of 5℃ / min for tempering for 1-4 hours. After cooling to 80-100℃, pass it through a high-frequency induction coil and heat it to 900℃ within 0.5s. Then, spray it with deionized water at 20-25℃ for 5-6s for water cooling. Finally, spray it with polyacrylic acid coolant to form a temporary protective film and obtain the semi-finished filament. S4. The semi-finished filament is immersed in a 0.1M oxalic acid solution for surface cleaning, and then immersed in a mixed solution of ethylene glycol / deionized water containing 0.1 mol / L pyrrole monomer, 0.05 wt% carbon quantum dots, and 0.05 mol / L sodium p-toluenesulfonate, wherein the volume ratio of ethylene glycol to deionized water is 85:15, at a concentration of 0.3 mA / cm². 2 Electropolymerization at current density for 10–15 minutes results in self-assembly to form a spiral groove structure, thus obtaining cored stainless steel wire.

7. A core-coated stainless steel wire according to claim 6, characterized in that, The boron nitride precursor solution comprises a mixed solvent containing 10-20 wt% boron trioxide, 0.5 wt% nano-nickel catalyst, and ammonia, wherein the molar ratio of boron trioxide to ammonia is 1:3, and the mixed solvent is deionized water and ethanol in a volume ratio of 2:

1.

8. A core-coated stainless steel wire according to claim 6, characterized in that, Application of this cored stainless steel wire in medical stents.

9. A core-coated stainless steel wire according to claim 6, characterized in that, Application of this cored stainless steel wire in aerospace antennas.

10. A core-coated stainless steel wire according to claim 6, characterized in that, Application of this cored stainless steel wire in industrial sensing fabrics.