Stainless steel material for medical devices and preparation process thereof

Abstract

The present invention belongs to the field of stainless steel technology, and more particularly to a kind of stainless steel material for medical devices and its preparation process. The stainless steel material for medical devices includes a stainless steel body, a microporous array layer and an alloy nanoparticle-MoS2 loaded carbon quantum dot composite layer, and the stainless steel body includes the following components by mass percentage: 8.3-10.5% Cr, 6.3-8.2% Co, 4-6% Mo, 2.3-3.6% Ni, 1.8-3% V, 0.8-1.2% Ti, 0.4-0.8% Ta, 0.2-0.4% B, 0.001-0.015% C, and the remainder is Fe and unavoidable impurities. The present application greatly improves the antibacterial and corrosion resistance of the stainless steel material surface by reasonable alloy composition and forming a coating on the surface of the stainless steel body.

Description

Technical Field

[0001] The present invention belongs to the technical field of stainless steel, and in particular relates to a stainless steel material for medical devices and a preparation process thereof. Background Art

[0002] Stainless steel is widely used in construction, medical equipment, automobiles and other fields due to its excellent properties such as low cost and high temperature resistance. Among them, the application of medical device stainless steel materials in surgical instruments, implants and other fields also places strict requirements on mechanical properties, corrosion resistance and antibacterial properties.

[0003] Traditional antibacterial stainless steel is mostly achieved by coating the surface with antibacterial agents such as silver and copper, or by introducing antibacterial metals such as silver and copper into the stainless steel matrix to achieve antibacterial and corrosion-resistant functionalization. However, conventional chemical plating or spraying processes make it difficult to form a uniform antibacterial layer on complex surfaces. Nanoparticles are prone to agglomeration, resulting in low antibacterial efficiency and poor corrosion resistance. The physically coated antibacterial layer is bonded to the matrix by van der Waals forces and is easily peeled off under mechanical friction or body fluid erosion, and has poor antibacterial durability. Introducing antibacterial metals such as silver and copper into the stainless steel matrix can easily lead to a decrease in the mechanical properties of the material, and may also precipitate coarse intermetallic compounds, reducing the corrosion resistance of the stainless steel. Summary of the Invention

[0004] In order to solve the above technical defects, the present invention has developed a preparation process of stainless steel materials for medical devices, which not only enables the prepared stainless steel materials to have excellent antibacterial ability and corrosion resistance, but also has good mechanical properties.

[0005] A stainless steel material for medical devices includes a stainless steel body, a microporous array layer, and an alloy nanoparticle-MoS2 loaded carbon quantum dot composite layer. The stainless steel body includes the following components in mass percentage: 8.3-10.5% Cr, 6.3-8.2% Co, 4-6% Mo, 2.3-3.6% Ni, 1.8-3% V, 0.8-1.2% Ti, 0.4-0.8% Ta, 0.2-0.4% B, 0.001-0.015% C, and the balance is Fe and unavoidable impurities.

[0006] A process for preparing stainless steel material for medical devices comprises the following steps:

[0007] Powder metallurgy of S1 stainless steel alloy: Cr, Co, Mo, Ni, V, Ti, Ta, B, C and Fe are mixed to prepare alloy powder, mixed with binder and injection molded, three-stage degreasing and sintering are carried out to obtain stainless steel body;

[0008] Aging treatment of S2 stainless steel and simultaneous microporous arraying of its surface: TiOSO4 and VCl3 are prepared into a metal complex solution. The stainless steel body is solid-dissolved and placed in the metal complex solution for multiple pull-downs to dry. The stainless steel body is then placed in an autoclave and hydrothermally treated in a composite growth solution prepared from isopropyl titanate and ammonium metavanadate. Annealing is performed to form a microporous array layer, thereby obtaining a microporous array layer stainless steel.

[0009] Preparation of S3 alloy nanoparticles and MoS2-loaded carbon quantum dots: Er(CH3CO2)3·4H2O and silver nitrate were heated in an oleic acid / octadecene mixed solvent, followed by the addition of an ethanolic H2O2 solution to obtain core-shell alloy nanoparticles. Ammonium molybdate tetrahydrate, thiourea, and citric acid were hydrothermally treated and then dialyzed to obtain MoS2-loaded carbon quantum dots.

[0010] Surface nanoembedding of S4 microporous array layer stainless steel: Curcumin and egg yolk lecithin are prepared by rotary evaporation to obtain a rotary evaporated film, which is then heated and allowed to stand in deionized water with core-shell alloy nanoparticles and MoS2-loaded carbon quantum dots, and then vacuum impregnated into the microporous array layer stainless steel to form an alloy nanoparticle-MoS2-loaded carbon quantum dot composite layer, thereby obtaining stainless steel material for medical devices.

[0011] Furthermore, step S1 of powder metallurgy of the stainless steel alloy comprises the following steps:

[0012] S1.1: In terms of weight percentage, 8.3-10.5% Cr, 6.3-8.2% Co, 4-6% Mo, 2.3-3.6% Ni, 1.8-3% V, 0.8-1.2% Ti, 0.4-0.8% Ta, 0.2-0.4% B, 0.001-0.015% C, and the balance Fe and unavoidable impurities are weighed as raw materials to prepare an alloy powder. The alloy powder is mixed with a binder at a mass ratio of 1:(0.1-0.15) and added to an internal mixer. The mixture is mixed at 175-180°C and 30-35 rpm for 2-2.5 hours, with the mixing direction changed every 0.5-1 hour. After cooling, the mixture is crushed in a crusher to obtain a mixture.

[0013] S1.2: Pour the mixture prepared in step S1.1 into an injection molding machine, adjust the nozzle temperature to 175-190°C, the pressure to 10-15 MPa, and the injection speed to 60-65 mm / s. Inject the feed into a mold at 95-105°C as required to obtain an injection blank. Place the injection blank in a catalytic degreasing furnace, adjust the furnace chamber temperature to 120-125°C, and treat for 30-45 minutes. Then, introduce fuming nitric acid at a rate of 3-3.2 g / min for 3-4 hours. After stopping the introduction of fuming nitric acid, continue treating at 120-125°C for 30-45 minutes to obtain a degreased blank.

[0014] S1.3: Place the degreased blank in a vacuum sintering furnace, first heat it to 360-380°C at a heating rate of 4-5°C / min, keep it warm for 40-45 minutes, then continue to heat it to 620-650°C at a heating rate of 2-3°C / min, keep it warm for 45-60 minutes, then heat it to 1050-1100°C at a heating rate of 6-8°C / min, keep it warm for 100-120 minutes, continue to heat it to 1350-1400°C, keep it warm for 250-300 minutes, then cool it with the furnace to obtain the stainless steel body.

[0015] Furthermore, step S2 of aging treatment of stainless steel and simultaneous microporous arraying of the surface comprises the following steps:

[0016] S2.1: Place TiOSO4 and VCl3 in a container, add a 15-18% by mass hydrochloric acid solution, and stir until the TiOSO4 and VCl3 are completely dissolved to obtain a composite salt solution with a TiOSO4 concentration of 45-50 mmol / L and a VCl3 concentration of 25-30 mmol / L. Add citric acid to the composite salt solution at a molar ratio of 1:(0.4-0.5) to the TiOSO4 molar ratio, and then add 0.08-0.1 wt% polyethylene glycol to obtain a metal complex solution.

[0017] S2.2: The stainless steel body obtained in step S1.3 is placed in an argon-shielded furnace and heated to 1050-1080°C. After holding at this temperature for 1-1.5 hours, the body is cooled to room temperature with oil. The body is then vertically immersed in a metal complex solution and subjected to a uniform immersion-pulling process at a rate of 2-3 cm / min. The pulling process is repeated 4-5 times. After each pulling process, the body is dried at 80-100°C for 10-15 minutes. After the final drying process, the body is placed in a tempering furnace and held at 530-550°C for 4-4.5 hours to obtain heterogeneous oxide stainless steel.

[0018] S2.3: Mix isopropyl titanate and hydrochloric acid (mass fraction 18-22%) at a volume ratio of 1: (40-50) in a container, and ultrasonically disperse at an ultrasonic frequency of 20-25 kHz for 20-25 minutes to obtain a mixed solution A. Dissolve ammonium metavanadate in an ethanol aqueous solution to prepare a mixed solution B with an ammonium metavanadate concentration of 60-65 mmol / L. Mix the mixed solution A and the mixed solution B at a volume ratio of 1: (0.4-0.5), and then add 0.05-0.07 wt% of ten Hexaalkyltrimethylammonium bromide is stirred for 30-35 minutes to obtain a composite growth solution, the heterogeneous oxide stainless steel is tilted against the inner wall of a reactor lined with Teflon and inlaid with FTO glass, and the composite growth solution is added until the heterogeneous oxide stainless steel is immersed. The heterogeneous oxide stainless steel is hydrothermally treated at 165-185°C for 2-3 hours. After being removed, it is cleaned with deionized water and dried, and then placed in a tempering furnace and kept warm at 450-500°C for 3-4 hours to form a microporous array layer, thereby obtaining microporous array layer stainless steel.

[0019] Furthermore, step S3 of preparing alloy nanoparticles and MoS2-loaded carbon quantum dots comprises the following steps:

[0020] S3.1: 0.4-0.6 mmol Er(CH3CO2)3·4H2O, 0.2-0.3 mmol silver nitrate, and 16-20 mL of an oleic acid / octadecene mixed solvent are mixed in a container, 0.4-0.5 mmol of stearic acid is added, and then the temperature is raised to 240-260°C at a heating rate of 8-10°C / min under an argon atmosphere. The mixture is kept at this temperature for 30-35 minutes and then naturally cooled to room temperature. 4-5 mL of an ethanol solution with a H2O2 content of 0.08-0.1 M is then injected, and the mixture is stirred at 60-65°C for 25-30 minutes. The product is separated by centrifugation and washed 2-3 times with ethanol to obtain core-shell alloy nanoparticles;

[0021] S3.2: Dissolve 0.1-0.15 mmol of ammonium molybdate tetrahydrate, 0.3-0.35 mmol of thiourea and 0.05-0.06 g of citric acid in 20-30 mL of deionized water, hydroheat at 200-220°C for 12-15 hours, then place in a dialysis bag with a molecular weight cutoff of 1500-2000 Da and dialyze in deionized water for 24-30 hours to obtain MoS2-loaded carbon quantum dots.

[0022] Furthermore, step S4 of nano-embedding the surface of the microporous array layer stainless steel comprises the following steps:

[0023] S4.1: Add curcumin and egg yolk lecithin in a mass ratio of 1: (4-5) to 10-15 times the mass of chloroform, stir until completely dissolved, and then rotary evaporate to obtain a rotary evaporated film, mix 0.8-1 parts by weight of core-shell alloy nanoparticles, 0.3-0.5 parts by weight of MoS2-loaded carbon quantum dots, and 600-800 parts by weight of deionized water in a container, and ultrasonically treat at 35-40 kHz for 20-25 minutes, then add 1-1.5 parts by weight of the rotary evaporated film, ultrasonically treat at 25-30 kHz for 8-10 minutes, and then stand at 60-65°C for 30-40 minutes to obtain a metal particle encapsulation dispersion;

[0024] S4.2: Place the microporous array layer stainless steel in a vacuum filtration bottle and maintain a vacuum state for 30-35 minutes, then add a metal particle encapsulation dispersion to immerse the microporous array layer stainless steel, continue to evacuate to a vacuum state and maintain for 1-1.5 hours, take out and vacuum dry to form an alloy nanoparticle-MoS2 loaded carbon quantum dot composite layer to obtain a stainless steel material for medical devices.

[0025] Furthermore, the method for preparing the alloy powder in step S1.1 is to mix the raw materials and perform vacuum induction melting, and then obtain the alloy powder by vacuum gas atomization after complete melting. 50 Particle size is 5-8μm, D 90 The particle size is 20-22μm.

[0026] Furthermore, the binder in step S1.1 is composed of polyoxymethylene, polypropylene, ethylene-butyl acrylate copolymer and stearic acid in a mass ratio of (65-70): (15-20): (8-10): (3-5).

[0027] Furthermore, the ethanol aqueous solution in which ammonium metavanadate is dissolved in step S2.3 has a concentration of 65-70% and contains 0.1 mol / L of ethylenediamine.

[0028] Furthermore, in step S3.1, the volume ratio of oleic acid to octadecene in the oleic acid / octadecene mixed solvent is 1:(2.5-3).

[0029] The beneficial effects are as follows: 1. The present invention prepares a metal complex liquid by TiOSO4, VCl3, hydrochloric acid solution, citric acid and polyethylene glycol, then solid-solution-treats the stainless steel body in the metal complex liquid and pulls and dries it multiple times to form a uniform and highly uniformly arranged Ti-V composite oxide layer on the surface, and then prepares a composite growth liquid by isopropyl titanate and ammonium metavanadate, and hydrothermally reacts the heterogeneous oxide stainless steel with the Ti-V composite oxide layer and the composite growth liquid in a high-pressure reactor, and under the guidance of the local electric field generated by the Ti-V composite oxide layer and FTO glass, a highly oriented and dense TiO2 / V2O5 array is formed, and a large number of uniform through-holes are constructed between the arrays, and the Ti-V composite oxide layer reduces the isoelectric point of the stainless steel surface, enhances the electrostatic adsorption of positively charged substances, thereby increasing the loading capacity and adsorption capacity of the stainless steel surface for subsequent antibacterial nanoparticles, and greatly improving the subsequent antibacterial ability and corrosion resistance of the stainless steel material surface.

[0030] 2. The present invention prepares a rotary evaporated film composed of curcumin and egg yolk lecithin, alloy nanoparticles and MoS2 loaded carbon quantum dots, and then combines the three to obtain a metal particle encapsulation. The metal particle encapsulation is introduced into the inter-array pores of the stainless steel surface of the microporous array layer by vacuum impregnation. The formed liposomes dehydrate and shrink in the inter-array pores, forming an "anchoring-entanglement" structure with the TiO2 / V2O5 array, thereby enhancing the adhesion of the alloy nanoparticles and the MoS2 loaded carbon quantum dots, and enabling the combined photodynamic antibacterial and antiseptic particles to synergistically perform effective sterilization.

[0031] 3. The present invention adopts a reasonable metal component ratio, as well as a simultaneous microporous array process of degreasing, sintering, solid solution and aging treatment, so that the stainless steel matrix made by powder metallurgy has good mechanical properties, and the formed microporous array layer adheres tightly to the stainless steel surface, with a more uniform structure, further enhancing the antibacterial ability of the stainless steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a flow chart of the preparation process of the stainless steel material for medical devices used in the embodiments of the present invention. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Example 1

[0035] A stainless steel material for medical devices and its preparation process, such as Figure 1 As shown, the following steps are included:

[0036] S1: Powder Metallurgy of Stainless Steel Alloys

[0037] S1.1: According to weight percentage, weigh 8.3% Cr, 6.3% Co, 4% Mo, 2.3% Ni, 1.8% V, 0.8% Ti, 0.4% Ta, 0.2% B, 0.001% C, and the balance Fe and inevitable impurities as raw materials. Mix the raw materials and perform vacuum induction melting. After complete melting, use vacuum gas atomization to obtain alloy powder. The D of the alloy powder 50 The particle size is 5 μm, D 90 The particle size is 20 μm. The alloy powder and the binder are mixed in a mass ratio of 1:0.1 and added into an internal mixer. The binder is composed of polyoxymethylene, polypropylene, ethylene-butyl acrylate copolymer and stearic acid in a mass ratio of 65:15:8:3. The materials are mixed at 175° C. and 30 rpm for 2 hours. The mixing direction is changed every 0.5 hour during the mixing period. After cooling, the materials are crushed in a crusher to obtain a mixture.

[0038] S1.2: Pour the mixture prepared in step S1.1 into an injection molding machine, adjust the nozzle temperature to 175°C, the pressure to 10 MPa, and the injection speed to 60 mm / s. As required, inject the feed into a mold at 95°C to form an injection blank. Place the injection blank in a catalytic degreasing furnace at a chamber temperature of 120°C for 30 minutes. Then, introduce fuming nitric acid at a rate of 3 g / min for 3 hours. After stopping the introduction of fuming nitric acid, continue the treatment at 120°C for 30 minutes to obtain a degreased blank.

[0039] S1.3: Place the degreased blank in a vacuum sintering furnace, first heat it to 360°C at a heating rate of 4°C / min, keep it warm for 40 minutes, then continue to heat it to 620°C at a heating rate of 2°C / min, keep it warm for 45 minutes, then heat it to 1050°C at a heating rate of 6°C / min, keep it warm for 100 minutes, continue to heat it to 1350°C, keep it warm for 250 minutes, and then cool it in the furnace to obtain the stainless steel body.

[0040] S2: Aging treatment of stainless steel and simultaneous microporous arraying on the surface

[0041] S2.1: Place TiOSO4 and VCl3 in a container, add 15% by mass hydrochloric acid solution, and stir until TiOSO4 and VCl3 are completely dissolved to obtain a composite salt solution with a TiOSO4 concentration of 45 mmol / L and a VCl3 concentration of 25 mmol / L. Add citric acid to the composite salt solution at a molar ratio of 1:0.4 to TiOSO4, and then add 0.08 wt% polyethylene glycol to obtain a metal complex solution.

[0042] S2.2: The stainless steel body obtained in step S1.3 is heated to 1050°C in an argon-shielded furnace, kept at this temperature for 1 hour, and then cooled to room temperature with oil. The body is then vertically immersed in a metal complex solution and subjected to a uniform immersion-pulling process at a rate of 2 cm / min. This is repeated four times. After each pulling, the body is dried at 80°C for 15 minutes. After the final drying, the body is placed in a tempering furnace and kept at 530°C for 4 hours to obtain heterogeneous oxide stainless steel.

[0043] S2.3: Isopropyl titanate and 18% hydrochloric acid are mixed in a volume ratio of 1:40 and placed in a container. The mixture is ultrasonically dispersed at an ultrasonic frequency of 20 kHz for 20 minutes to obtain a mixed solution A. Ammonium metavanadate is dissolved in an ethanol aqueous solution having a concentration of 65% and containing 0.1 mol / L ethylenediamine to prepare a mixed solution B having an ammonium metavanadate concentration of 60 mmol / L. The mixed solution A and the mixed solution B are mixed in a volume ratio of 1:0.4, and 0.05 wt% of hexadecyltrimethylammonium bromide is added and stirred for 30 minutes to obtain a composite growth solution. The heterogeneous oxide stainless steel is tilted against the inner wall of a reactor lined with Teflon and inlaid with FTO glass, and the composite growth solution is added until the heterogeneous oxide stainless steel is immersed. The heterogeneous oxide stainless steel is hydrothermally treated at 165°C for 2 hours. After removal, it is cleaned with deionized water and dried, and then placed in a tempering furnace and kept at 450°C for 3 hours to form a microporous array layer, thereby obtaining a microporous array layer stainless steel.

[0044] S3: Preparation of alloy nanoparticles and MoS2-loaded carbon quantum dots

[0045] S3.1: 0.4 mmol Er(CH3CO2)3·4H2O, 0.2 mmol silver nitrate, and 16 mL of an oleic acid / octadecene mixed solvent were mixed in a container, with the volume ratio of oleic acid to octadecene being 1:2.5. 0.4 mmol of stearic acid was added, and then the temperature was raised to 240°C at a heating rate of 8°C / min under an argon atmosphere. After holding the temperature for 30 minutes, the mixture was naturally cooled to room temperature. 4 mL of an ethanol solution with a 0.08 M H2O2 content was injected, and the mixture was stirred at 60°C for 25 minutes. The product was separated by centrifugation and washed twice with ethanol to obtain core-shell alloy nanoparticles.

[0046] S3.2: Dissolve 0.1 mmol of ammonium molybdate tetrahydrate, 0.3 mmol of thiourea, and 0.05 g of citric acid in 20 mL of deionized water, hydroheat at 200 °C for 12 h, and then place in a dialysis bag with a molecular weight cutoff of 1500 Da and dialyze in deionized water for 24 h to obtain MoS2-loaded carbon quantum dots.

[0047] S4: Surface nanoembedding of microporous array layers in stainless steel

[0048] S4.1: Add curcumin and egg yolk lecithin in a mass ratio of 1:4 to 10 times the mass of chloroform, stir until completely dissolved, and then perform rotary evaporation to obtain a rotary evaporation film. Mix 0.8 parts by weight of core-shell alloy nanoparticles, 0.3 parts by weight of MoS2-loaded carbon quantum dots, and 600 parts by weight of deionized water in a container, and ultrasonically treat at 35 kHz for 20 minutes. Then, add 1 part by weight of the rotary evaporation film, ultrasonically treat at 25 kHz for 8 minutes, and then stand at 60°C for 30 minutes to obtain a metal particle encapsulation dispersion.

[0049] S4.2: Place the microporous array layer stainless steel in a vacuum filtration bottle and maintain the vacuum state for 30 minutes, then add the metal particle encapsulation dispersion to immerse the microporous array layer stainless steel, continue to evacuate to vacuum and maintain for 1 hour, take out and vacuum dry to form an alloy nanoparticle-MoS2 loaded carbon quantum dot composite layer, and obtain stainless steel material for medical devices.

[0050] Example 2

[0051] A stainless steel material for medical devices and its preparation process, such as Figure 1 As shown, the following steps are included:

[0052] S1: Powder Metallurgy of Stainless Steel Alloys

[0053] S1.1: According to weight percentage, weigh 10.5% Cr, 8.2% Co, 6% Mo, 3.6% Ni, 3% V, 1.2% Ti, 0.8% Ta, 0.4% B, 0.015% C, and the balance Fe and inevitable impurities as raw materials. Mix the raw materials and perform vacuum induction melting. After complete melting, use vacuum gas atomization to obtain alloy powder. The D of the alloy powder 50 The particle size is 5 μm, D 90 The particle size is 20 μm. The alloy powder and the binder are mixed in a mass ratio of 1:0.15 and added to an internal mixer. The binder is composed of polyoxymethylene, polypropylene, ethylene-butyl acrylate copolymer and stearic acid in a mass ratio of 70:20:10:5. The materials are mixed at 175° C. and 30 rpm for 2 hours. The mixing direction is changed every 0.5 hour during the mixing period. After cooling, the materials are crushed in a crusher to obtain a mixture.

[0054] S1.2: Pour the mixture prepared in step S1.1 into an injection molding machine, adjust the nozzle temperature to 175°C, the pressure to 10 MPa, and the injection speed to 60 mm / s. As required, inject the feed into a mold at 95°C to form an injection blank. Place the injection blank in a catalytic degreasing furnace at a chamber temperature of 120°C for 30 minutes. Then, introduce fuming nitric acid at a rate of 3 g / min for 3 hours. After stopping the introduction of fuming nitric acid, continue the treatment at 120°C for 30 minutes to obtain a degreased blank.

[0055] S1.3: Place the degreased blank in a vacuum sintering furnace, first heat it to 360°C at a heating rate of 4°C / min, keep it warm for 40 minutes, then continue to heat it to 620°C at a heating rate of 2°C / min, keep it warm for 45 minutes, then heat it to 1050°C at a heating rate of 6°C / min, keep it warm for 100 minutes, continue to heat it to 1350°C, keep it warm for 250 minutes, and then cool it in the furnace to obtain the stainless steel body.

[0056] S2: Aging treatment of stainless steel and simultaneous microporous arraying on the surface

[0057] S2.1: Place TiOSO4 and VCl3 in a container, add 15% by mass hydrochloric acid solution, and stir until TiOSO4 and VCl3 are completely dissolved to obtain a composite salt solution with a TiOSO4 concentration of 50 mmol / L and a VCl3 concentration of 30 mmol / L. Add citric acid to the composite salt solution at a molar ratio of 1:0.5 to TiOSO4, and then add 0.1 wt% polyethylene glycol to obtain a metal complex solution.

[0058] S2.2: The stainless steel body obtained in step S1.3 is heated to 1050°C in an argon-shielded furnace, kept at this temperature for 1 hour, and then cooled to room temperature with oil. The body is then vertically immersed in a metal complex solution and subjected to a uniform immersion-pulling process at a rate of 2 cm / min. This is repeated four times. After each pulling, the body is dried at 80°C for 15 minutes. After the final drying, the body is placed in a tempering furnace and kept at 530°C for 4 hours to obtain heterogeneous oxide stainless steel.

[0059] S2.3: Isopropyl titanate and 18% hydrochloric acid are mixed in a volume ratio of 1:50 and placed in a container. The mixture is ultrasonically dispersed at an ultrasonic frequency of 20 kHz for 20 minutes to obtain a mixed solution A. Ammonium metavanadate is dissolved in an ethanol aqueous solution having a concentration of 65% and containing 0.1 mol / L ethylenediamine to prepare a mixed solution B having an ammonium metavanadate concentration of 65 mmol / L. The mixed solution A and the mixed solution B are mixed in a volume ratio of 1:0.5, and 0.07 wt% of hexadecyltrimethylammonium bromide is added and stirred for 30 minutes to obtain a composite growth solution. The heterogeneous oxide stainless steel is tilted against the inner wall of a reactor lined with Teflon and inlaid with FTO glass, and the composite growth solution is added until the heterogeneous oxide stainless steel is immersed. The heterogeneous oxide stainless steel is hydrothermally treated at 165°C for 2 hours. After removal, it is cleaned with deionized water and dried, and then placed in a tempering furnace and kept at 450°C for 3 hours to form a microporous array layer, thereby obtaining a microporous array layer stainless steel.

[0060] S3: Preparation of alloy nanoparticles and MoS2-loaded carbon quantum dots

[0061] S3.1: 0.6 mmol Er(CH3CO2)3·4H2O, 0.3 mmol silver nitrate, and 20 mL of an oleic acid / octadecene mixed solvent were mixed in a container, with the volume ratio of oleic acid to octadecene being 1:3. 0.5 mmol of stearic acid was added, and then the temperature was raised to 240°C at a heating rate of 8°C / min under an argon atmosphere. After holding the temperature for 30 minutes, the mixture was naturally cooled to room temperature. 5 mL of an ethanol solution with a 0.08 M H2O2 content was then injected, and the mixture was stirred at 60°C for 25 minutes. The product was separated by centrifugation and washed twice with ethanol to obtain core-shell alloy nanoparticles.

[0062] S3.2: Dissolve 0.15 mmol of ammonium molybdate tetrahydrate, 0.35 mmol of thiourea and 0.06 g of citric acid in 20 mL of deionized water, hydroheat at 200°C for 12 hours, and then place in a dialysis bag with a molecular weight cutoff of 1500 Da and dialyze in deionized water for 24 hours to obtain MoS2-loaded carbon quantum dots.

[0063] S4: Surface nanoembedding of microporous array layers in stainless steel

[0064] S4.1: Curcumin and egg yolk lecithin were added to 10 times the mass of chloroform in a mass ratio of 1:5, stirred until completely dissolved, and then rotary evaporated to obtain a rotary evaporated film. 1 part by weight of core-shell alloy nanoparticles, 0.5 part by weight of MoS2-loaded carbon quantum dots, and 800 parts by weight of deionized water were mixed in a container and ultrasonically treated at 35 kHz for 20 minutes. Then, 1.5 parts by weight of the rotary evaporated film was added, ultrasonically treated at 25 kHz for 8 minutes, and then allowed to stand at 60°C for 30 minutes to obtain a metal particle encapsulation dispersion.

[0065] S4.2: Place the microporous array layer stainless steel in a vacuum filtration bottle and maintain the vacuum state for 30 minutes, then add the metal particle encapsulation dispersion to immerse the microporous array layer stainless steel, continue to evacuate to vacuum and maintain for 1 hour, take out and vacuum dry to form an alloy nanoparticle-MoS2 loaded carbon quantum dot composite layer, and obtain stainless steel material for medical devices.

[0066] Example 3

[0067] A stainless steel material for medical devices and its preparation process, such as Figure 1 As shown, the following steps are included:

[0068] S1: Powder Metallurgy of Stainless Steel Alloys

[0069] S1.1: According to weight percentage, weigh 8.3% Cr, 6.3% Co, 4% Mo, 2.3% Ni, 1.8% V, 0.8% Ti, 0.4% Ta, 0.2% B, 0.001% C, and the balance Fe and inevitable impurities as raw materials. Mix the raw materials and perform vacuum induction melting. After complete melting, use vacuum gas atomization to obtain alloy powder. The D of the alloy powder 50 The particle size is 8 μm, D 90 The particle size is 22 μm. The alloy powder and the binder are mixed in a mass ratio of 1:0.1 and added into an internal mixer. The binder is composed of polyoxymethylene, polypropylene, ethylene-butyl acrylate copolymer and stearic acid in a mass ratio of 65:15:8:3. The materials are mixed at 180° C. and 35 rpm for 2.5 hours. The mixing direction is changed every hour during the mixing period. After cooling, the materials are crushed in a crusher to obtain a mixture.

[0070] S1.2: Pour the mixture prepared in step S1.1 into an injection molding machine, adjust the nozzle temperature to 190°C, the pressure to 15 MPa, and the injection speed to 65 mm / s. As required, inject the feed into a mold at 105°C to form an injection blank. Place the injection blank in a catalytic degreasing furnace at a chamber temperature of 125°C for 45 minutes. Then, introduce fuming nitric acid at a rate of 3.2 g / min for 4 hours. After stopping the introduction of fuming nitric acid, continue the treatment at 125°C for 45 minutes to obtain a degreased blank.

[0071] S1.3: Place the degreased blank in a vacuum sintering furnace, first heat it to 380°C at a heating rate of 5°C / min, keep it at that temperature for 45 minutes, then continue to heat it to 650°C at a heating rate of 3°C / min, keep it at that temperature for 60 minutes, then heat it to 1100°C at a heating rate of 8°C / min, keep it at that temperature for 120 minutes, continue to heat it to 1400°C, keep it at that temperature for 300 minutes, and then cool it with the furnace to obtain the stainless steel body.

[0072] S2: Aging treatment of stainless steel and simultaneous microporous arraying on the surface

[0073] S2.1: Place TiOSO4 and VCl3 in a container, add 18% hydrochloric acid solution, and stir until TiOSO4 and VCl3 are completely dissolved to obtain a composite salt solution with a TiOSO4 concentration of 45 mmol / L and a VCl3 concentration of 25 mmol / L. Add citric acid to the composite salt solution at a molar ratio of 1:0.4 to TiOSO4, and then add 0.08 wt% polyethylene glycol to obtain a metal complex solution.

[0074] S2.2: The stainless steel body obtained in step S1.3 is placed in an argon-shielded furnace and heated to 1080°C. After holding at this temperature for 1.5 hours, the body is cooled to room temperature with oil. The body is then vertically immersed in a metal complex solution and subjected to a uniform immersion-pulling process at a rate of 3 cm / min. The pulling process is repeated five times. After each pulling process, the body is dried at 100°C for 10 minutes. After the final drying process, the body is placed in a tempering furnace and held at 550°C for 4.5 hours to obtain heterogeneous oxide stainless steel.

[0075] S2.3: Isopropyl titanate and 22% by mass hydrochloric acid are mixed in a volume ratio of 1:50 and placed in a container. The mixture is ultrasonically dispersed at an ultrasonic frequency of 25 kHz for 25 minutes to obtain a mixed solution A. Ammonium metavanadate is dissolved in an ethanol aqueous solution having a concentration of 70% and containing 0.1 mol / L ethylenediamine to prepare a mixed solution B having an ammonium metavanadate concentration of 60 mmol / L. The mixed solution A and the mixed solution B are mixed in a volume ratio of 1:0.4, and 0.05 wt% of hexadecyltrimethylammonium bromide is added and stirred for 35 minutes to obtain a composite growth solution. The heterogeneous oxide stainless steel is tilted against the inner wall of a reactor lined with Teflon and inlaid with FTO glass, and the composite growth solution is added until the heterogeneous oxide stainless steel is immersed. The mixture is hydrothermally treated at 185°C for 3 hours. After removal, it is cleaned with deionized water and dried, and then placed in a tempering furnace and kept at 500°C for 4 hours to form a microporous array layer, thereby obtaining a microporous array layer stainless steel.

[0076] S3: Preparation of alloy nanoparticles and MoS2-loaded carbon quantum dots

[0077] S3.1: 0.4 mmol Er(CH3CO2)3·4H2O, 0.2 mmol silver nitrate, and 16 mL of an oleic acid / octadecene mixed solvent were mixed in a container, with the volume ratio of oleic acid to octadecene being 1:3. 0.4 mmol stearic acid was added, and then the mixture was heated to 260°C at a heating rate of 10°C / min under an argon atmosphere. After holding the mixture for 35 minutes, the mixture was naturally cooled to room temperature. 5 mL of an ethanol solution with a 0.1 M H2O2 content was then injected, and the mixture was stirred at 65°C for 30 minutes. The product was separated by centrifugation and washed three times with ethanol to obtain core-shell alloy nanoparticles.

[0078] S3.2: Dissolve 0.1 mmol of ammonium molybdate tetrahydrate, 0.3 mmol of thiourea and 0.05 g of citric acid in 20 mL of deionized water, hydroheat at 220°C for 15 hours, and then place in a dialysis bag with a molecular weight cutoff of 2000 Da and dialyze in deionized water for 30 hours to obtain MoS2-loaded carbon quantum dots.

[0079] S4: Surface nanoembedding of microporous array layers in stainless steel

[0080] S4.1: Add curcumin and egg yolk lecithin in a mass ratio of 1:4 to 15 times the mass of chloroform, stir until completely dissolved, and then perform rotary evaporation to obtain a rotary evaporated film. Mix 0.8 parts by weight of core-shell alloy nanoparticles, 0.3 parts by weight of MoS2-loaded carbon quantum dots, and 600 parts by weight of deionized water in a container, and ultrasonically treat at 40 kHz for 25 minutes. Then, add 1.5 parts by weight of the rotary evaporated film, ultrasonically treat at 30 kHz for 10 minutes, and then stand at 65°C for 40 minutes to obtain a metal particle encapsulation dispersion.

[0081] S4.2: Place the microporous array layer stainless steel in a vacuum filtration bottle and maintain a vacuum state for 35 minutes, then add a metal particle encapsulation dispersion to immerse the microporous array layer stainless steel, continue to evacuate to a vacuum state and maintain for 1.5 hours, take out and vacuum dry to form an alloy nanoparticle-MoS2 loaded carbon quantum dot composite layer to obtain a stainless steel material for medical devices.

[0082] Comparative Example 1: Compared with Example 1, the difference of Comparative Example 1 is that Step S2.1 and Step S2.2 are removed from Comparative Example 1, and the heterogeneous oxide stainless steel in Step S2.3 is replaced by a stainless steel body. The remaining steps are the same as those in Example 1.

[0083] Comparative Example 2: Compared with Example 1, the difference of Comparative Example 2 is that step S2.3 is removed in Comparative Example 2, and the subsequent microporous array layer stainless steel is replaced with heterogeneous oxide stainless steel. The remaining steps are the same as those in Example 1.

[0084] Comparative Example 3: Compared with Example 1, the difference of Comparative Example 3 is that step S3.1 is removed in Comparative Example 3, and the core-shell alloy nanoparticles in step S4.1 are replaced with an equal mass of MoS2-loaded carbon quantum dots. The remaining steps are the same as in Example 1.

[0085] Comparative Example 4: Compared with Example 1, the difference of Comparative Example 4 is that step S3.2 is removed in Comparative Example 4, and the MoS2-loaded carbon quantum dots in step S4.1 are replaced with shell-core alloy nanoparticles of equal mass. The remaining steps are the same as in Example 1.

[0086] Comparative Example 5: Compared with Example 1, the difference of Comparative Example 5 is that step S1 is removed in Comparative Example 5, and the subsequent stainless steel body is replaced with 316 stainless steel. At the same time, the operation of heating to 1050°C and keeping warm for 1 hour and oil cooling in step S2.2 is removed. The remaining steps are the same as in Example 1.

[0087] The injection molding molds in Examples 1-3 and Comparative Examples 1-5 were replaced with molds with a length, width, and height of 2 cm×2 cm×0.5 cm, respectively, to prepare samples.

[0088] Mechanical properties test: The samples prepared in Examples 1-3 were subjected to mechanical properties test. The test results are shown in Table 1.

[0089] Table 1: Mechanical properties of samples prepared in Example

[0090]

[0091] As can be seen from the data of Examples 1-3 in Table 1, the stainless steel materials for medical devices prepared in Examples 1-3 have good mechanical properties, which can prove that the reasonable metal component ratio and degreasing, sintering, solution treatment and aging treatment processes of the present application can make the stainless steel substrate prepared by powder metallurgy have good mechanical properties;

[0092] Corrosion resistance test: Two samples each prepared in Examples 1-3 and Comparative Examples 1-5 were subjected to a neutral salt spray test. The neutral solution used was a 5 wt% NaCl salt solution prepared by pure NaCl and deionized water. The test was carried out under normal pressure, the experimental time was 360 h, and the temperature was 35 ° C. After the test, the sample was placed in a natural indoor condition to dry for 2 h. After the sample was dried, the surface was rinsed with deionized water to remove the residue of the salt solution. The surface corrosion of the sample was observed. The test results are shown in Table 2.

[0093] Table 2: Corrosion of sample surface under neutral salt spray test

[0094]

[0095] It can be seen from Table 2 that Examples 1-3 had no red rust or spot rust under the neutral salt spray test, while Comparative Examples 1-2 had spot rust, indicating that the Ti-V composite oxide layer and the composite growth liquid synergistically formed a highly oriented, dense array, thereby increasing the subsequent adsorption amount of alloy nanoparticles and MoS2-loaded carbon quantum dots on the stainless steel surface, and performing uniform adsorption, thereby improving the corrosion resistance of the stainless steel material. Comparative Examples 3-4 had no red rust or spot rust, proving that the alloy nanoparticles and MoS2-loaded carbon quantum dots both had good corrosion resistance. The reason for the small amount of spot rust in Comparative Example 5 may be that the 316 stainless steel substrate caused a small amount of uneven growth of the Ti-V composite oxide layer and the composite growth liquid, thereby affecting the loading uniformity of the alloy nanoparticles and MoS2-loaded carbon quantum dots, resulting in a decrease in corrosion resistance.

[0096] Antibacterial performance test: The plate count method was used to detect the antibacterial activity of the samples against Escherichia coli. The Escherichia coli cultured overnight was diluted to 10 −6 CFU·mL −1 Take two samples prepared in Examples 1-3 and Comparative Examples 1-5 respectively. All samples are sterilized on both sides by ultraviolet light for more than 30 minutes and placed in a 6-well plate. Then, take 8 mL of a solution with a concentration of 10 −6 CFU·mL −1 The bacterial solution was completely immersed in the sample surface. One sample was cultured under 980 nm light for 1 hour, and another sample was cultured in the dark for 1 hour. 50 μL of light-treated bacterial solution and dark-treated bacterial solution were taken from each well of a 6-well plate, and 50 μL of untreated bacterial solution were taken on LB solid culture medium. The bacterial solution was evenly spread using a coating rod. The LB solid culture medium with the bacterial solution was statically cultured in a 37°C constant temperature incubator for 24 hours. The E. coli on the solid culture medium was counted on the plate. The inhibition rate = (the number of cultures with untreated bacterial solution - the number of cultures after treatment on the sample surface) / the number of cultures with untreated bacterial solution × 100%. The average inhibition rate of each well plate was calculated, and the data were recorded and tabulated, as shown in Table 3.

[0097] Table 3: Antibacterial properties of samples

[0098]

[0099] It can be seen from Table 3 that Examples 1-3 all have excellent antibacterial capabilities, and it can be seen from Comparative Examples 1-2 that the antibacterial performance is greatly reduced after removing the Ti-V composite oxide layer or the composite growth liquid, indicating that the loading amount and adsorption capacity of the stainless steel material surface for subsequent antibacterial nanoparticles are greatly reduced, which can be proved that the Ti-V composite oxide layer and the composite growth liquid can improve the antibacterial ability of the stainless steel material surface. It can be seen from Comparative Examples 3-4 that when the alloy nanoparticles and MoS2-loaded carbon quantum dots are replaced in equal amounts, the antibacterial performance is reduced, proving that the two have a synergistic antibacterial effect. It can be seen from Comparative Example 5 that the stainless steel matrix material prepared in this application can make the formed microporous array layer adhere tightly to the stainless steel surface, and the structure is more uniform, further enhancing the antibacterial ability of stainless steel.

[0100] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by persons skilled in the art without departing from the spirit and technical concepts disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A process for preparing stainless steel material for medical devices, characterized in that: The following steps are involved: Powder metallurgy of S1 stainless steel alloy: Cr, Co, Mo, Ni, V, Ti, Ta, B, C and Fe are mixed to prepare alloy powder, mixed with binder and injection molded, three-stage degreasing and sintering are carried out to obtain stainless steel body; Aging treatment of S2 stainless steel and simultaneous microporous arraying of its surface: TiOSO4 and VCl3 are prepared into a metal complex solution. The stainless steel body is solid-dissolved and placed in the metal complex solution for multiple pull-downs to dry. The stainless steel body is then placed in an autoclave and hydrothermally treated in a composite growth solution prepared from isopropyl titanate and ammonium metavanadate. Annealing is performed to form a microporous array layer, thereby obtaining a microporous array layer stainless steel. Preparation of S3 alloy nanoparticles and MoS2-loaded carbon quantum dots: Er(CH3CO2)3·4H2O and silver nitrate were heated in an oleic acid / octadecene mixed solvent, followed by the addition of an ethanolic H2O2 solution to obtain core-shell alloy nanoparticles. Ammonium molybdate tetrahydrate, thiourea, and citric acid were hydrothermally treated and then dialyzed to obtain MoS2-loaded carbon quantum dots. Nano-embedding on the surface of S4 microporous array stainless steel: Curcumin and egg yolk lecithin are prepared by rotary evaporation to form a rotary evaporation film. The film is then heated and allowed to stand in deionized water with core-shell alloy nanoparticles and MoS2-loaded carbon quantum dots, and then vacuum impregnated into the microporous array stainless steel to form an alloy nanoparticle-MoS2-loaded carbon quantum dot composite layer, thereby obtaining a stainless steel material for medical devices. Step S2 specifically includes the following steps: S2.1: Place TiOSO4 and VCl3 in a container, add a 15-18% by mass hydrochloric acid solution, and stir until the TiOSO4 and VCl3 are completely dissolved to obtain a composite salt solution with a TiOSO4 concentration of 45-50 mmol / L and a VCl3 concentration of 25-30 mmol / L. Add citric acid to the composite salt solution at a molar ratio of 1:(0.4-0.5) to the TiOSO4 molar ratio, and then add 0.08-0.1 wt% polyethylene glycol to obtain a metal complex solution. S2.2: The stainless steel body obtained in step S1.3 is placed in an argon-shielded furnace and heated to 1050-1080°C. After holding at this temperature for 1-1.5 hours, the body is cooled to room temperature with oil. The body is then vertically immersed in a metal complex solution and subjected to a uniform immersion-pulling process at a rate of 2-3 cm / min. The pulling process is repeated 4-5 times. After each pulling process, the body is dried at 80-100°C for 10-15 minutes. After the final drying process, the body is placed in a tempering furnace and held at 530-550°C for 4-4.5 hours to obtain heterogeneous oxide stainless steel. S2.3: Mix isopropyl titanate and hydrochloric acid (mass fraction 18-22%) at a volume ratio of 1: (40-50) in a container, and ultrasonically disperse at an ultrasonic frequency of 20-25 kHz for 20-25 minutes to obtain a mixed solution A. Dissolve ammonium metavanadate in an ethanol aqueous solution to prepare a mixed solution B with an ammonium metavanadate concentration of 60-65 mmol / L. Mix the mixed solution A and the mixed solution B at a volume ratio of 1: (0.4-0.5), and then add 0.05-0.07 wt% of ten Stirring hexaalkyltrimethylammonium bromide for 30-35 minutes to obtain a composite growth solution, tilting the heterogeneous oxide stainless steel against the inner wall of a reactor lined with Teflon and inlaid with FTO glass, then adding the composite growth solution until the heterogeneous oxide stainless steel is immersed, performing a hydrothermal treatment at 165-185°C for 2-3 hours, removing the product and cleaning it with deionized water and drying it, then placing it in a tempering furnace and keeping it at 450-500°C for 3-4 hours to form a microporous array layer, thereby obtaining a microporous array layer stainless steel; Step S3 specifically includes the following steps: S3.1: 0.4-0.6 mmol Er(CH3CO2)3·4H2O, 0.2-0.3 mmol silver nitrate, and 16-20 mL of an oleic acid / octadecene mixed solvent are mixed in a container, 0.4-0.5 mmol of stearic acid is added, and then the temperature is raised to 240-260°C at a heating rate of 8-10°C / min under an argon atmosphere. The mixture is kept at this temperature for 30-35 minutes and then naturally cooled to room temperature. 4-5 mL of an ethanol solution with a H2O2 content of 0.08-0.1 M is then injected, and the mixture is stirred at 60-65°C for 25-30 minutes. The product is separated by centrifugation and washed 2-3 times with ethanol to obtain core-shell alloy nanoparticles; S3.2: Dissolve 0.1-0.15 mmol of ammonium molybdate tetrahydrate, 0.3-0.35 mmol of thiourea and 0.05-0.06 g of citric acid in 20-30 mL of deionized water, hydroheat at 200-220°C for 12-15 hours, then place in a dialysis bag with a molecular weight cutoff of 1500-2000 Da and dialyze in deionized water for 24-30 hours to obtain MoS2-loaded carbon quantum dots.

2. The process for preparing stainless steel material for medical devices according to claim 1, characterized in that: Step S1: powder metallurgy of stainless steel alloy, comprising the following steps: S1.1: In terms of weight percentage, 8.3-10.5% Cr, 6.3-8.2% Co, 4-6% Mo, 2.3-3.6% Ni, 1.8-3% V, 0.8-1.2% Ti, 0.4-0.8% Ta, 0.2-0.4% B, 0.001-0.015% C, and the balance Fe and unavoidable impurities are weighed as raw materials to prepare an alloy powder. The alloy powder is mixed with a binder at a mass ratio of 1:(0.1-0.15) and added to an internal mixer. The mixture is mixed at 175-180°C and 30-35 rpm for 2-2.5 hours, with the mixing direction changed every 0.5-1 hour. After cooling, the mixture is crushed in a crusher to obtain a mixture. S1.2: Pour the mixture prepared in step S1.1 into an injection molding machine, adjust the nozzle temperature to 175-190°C, the pressure to 10-15 MPa, and the injection speed to 60-65 mm / s. Inject the feed into a mold at 95-105°C as required to obtain an injection blank. Place the injection blank in a catalytic degreasing furnace, adjust the furnace chamber temperature to 120-125°C, and treat for 30-45 minutes. Then, introduce fuming nitric acid at a rate of 3-3.2 g / min for 3-4 hours. After stopping the introduction of fuming nitric acid, continue treating at 120-125°C for 30-45 minutes to obtain a degreased blank. S1.3: Place the degreased blank in a vacuum sintering furnace, first heat it to 360-380°C at a heating rate of 4-5°C / min, keep it warm for 40-45 minutes, then continue to heat it to 620-650°C at a heating rate of 2-3°C / min, keep it warm for 45-60 minutes, then heat it to 1050-1100°C at a heating rate of 6-8°C / min, keep it warm for 100-120 minutes, continue to heat it to 1350-1400°C, keep it warm for 250-300 minutes, then cool it with the furnace to obtain the stainless steel body.

3. The process for preparing a stainless steel material for medical devices according to claim 1, characterized in that: Step S4 embeds nanostructures on the surface of the microporous array layer of stainless steel, comprising the following steps: S4.1: Add curcumin and egg yolk lecithin in a mass ratio of 1: (4-5) to 10-15 times the mass of chloroform, stir until completely dissolved, and then rotary evaporate to obtain a rotary evaporated film, mix 0.8-1 parts by weight of core-shell alloy nanoparticles, 0.3-0.5 parts by weight of MoS2-loaded carbon quantum dots, and 600-800 parts by weight of deionized water in a container, and ultrasonically treat at 35-40 kHz for 20-25 minutes, then add 1-1.5 parts by weight of the rotary evaporated film, ultrasonically treat at 25-30 kHz for 8-10 minutes, and then stand at 60-65°C for 30-40 minutes to obtain a metal particle encapsulation dispersion; S4.2: Place the microporous array layer stainless steel in a vacuum filtration bottle and maintain a vacuum state for 30-35 minutes, then add a metal particle encapsulation dispersion to immerse the microporous array layer stainless steel, continue to evacuate to a vacuum state and maintain for 1-1.5 hours, take out and vacuum dry to form an alloy nanoparticle-MoS2 loaded carbon quantum dot composite layer to obtain a stainless steel material for medical devices.

4. The process for preparing stainless steel material for medical devices according to claim 2, characterized in that: The method for preparing alloy powder in step S1.1 is to mix the raw materials and perform vacuum induction melting. After complete melting, the alloy powder is obtained by vacuum gas atomization. The D 50 Particle size is 5-8μm, D 90 The particle size is 20-22μm.

5. The process for preparing stainless steel material for medical devices according to claim 2, characterized in that: The binder in step S1.1 is composed of polyoxymethylene, polypropylene, ethylene-butyl acrylate copolymer and stearic acid in a mass ratio of (65-70): (15-20): (8-10): (3-5).

6. The process for preparing stainless steel material for medical devices according to claim 1, characterized in that: The ethanol aqueous solution in which ammonium metavanadate is dissolved in step S2.3 has a concentration of 65-70% and contains 0.1 mol / L of ethylenediamine.

7. The process for preparing stainless steel material for medical devices according to claim 1, characterized in that: Step S3.1: The volume ratio of oleic acid to octadecene in the oleic acid / octadecene mixed solvent is 1:(2.5-3).

8. A stainless steel material for medical devices, characterized in that: The medical device stainless steel material is prepared by the preparation process of the medical device stainless steel material according to any one of claims 1 to 7.

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