Stainless steel material for medical equipment and preparation process of stainless steel material

Abstract

The invention belongs to the technical field of stainless steel, and particularly relates to a stainless steel material for medical instruments and a preparation process thereof. The stainless steel material for the medical instrument comprises a stainless steel body, a micropore array layer and an alloy nanoparticle-MoS2 loaded carbon quantum dot composite layer, and the stainless steel body is prepared from, by mass, 8.3%-10.5% of Cr, 6.3%-8.2% of Co, 4%-6% of Mo, 2.3%-3.6% of Ni, 1.8%-3% of V, 0.8%-1.2% of Ti, 0.4%-0.8% of Ta, 0.2%-0.4% of B, 0.001%-0.015% of C and the balance Fe and inevitable impurities. Through reasonable alloy component composition and formation of the coating on the surface of the stainless steel body, the antibacterial performance and the corrosion resistance of the surface of the stainless steel material are greatly improved.

Description

Technical Field

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

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

[0003] Traditional antibacterial stainless steels mostly achieve antibacterial and corrosion-resistant functionalization by surface coating antibacterial agents such as silver and copper, or introducing antibacterial metals such as silver and copper into the stainless steel matrix composition. However, conventional electroless plating or spraying processes are difficult to form a uniform antibacterial layer on complex surfaces, nanoparticles are prone to agglomeration, the antibacterial efficiency is low, the corrosion resistance is poor, and 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 flushing, resulting in poor antibacterial persistence. Introducing antibacterial metals such as silver and copper into the stainless steel matrix composition easily leads to a decrease in the mechanical properties of the material, and at the same time, coarse intermetallic compounds may precipitate, 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 for a stainless steel material for medical devices, which can not only endow the prepared stainless steel material with excellent antibacterial ability and corrosion resistance, but also have 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 supported carbon quantum dot composite layer. The stainless steel body includes the following components in mass percentage: 8.3-10.5% of Cr, 6.3-8.2% of Co, 4-6% of Mo, 2.3-3.6% of Ni, 1.8-3% of V, 0.8-1.2% of Ti, 0.4-0.8% of Ta, 0.2-0.4% of B, 0.001-0.015% of C, and the balance is Fe and unavoidable impurities.

[0006] A preparation process for a stainless steel material for medical devices includes the following steps: S1 Powder metallurgy of stainless steel alloy: Mix Cr, Co, Mo, Ni, V, Ti, Ta, B, C, and Fe to prepare an alloy powder, mix it with a binder for injection molding, and perform three-stage degreasing and then sintering to obtain a stainless steel body; Ageing treatment of S2 stainless steel and synchronous microporous array formation on the surface: Prepare a metal complex solution from TiOSO4 and VCl3. After solution annealing of the stainless steel body, dip it into the metal complex solution multiple times and then dry it. Then place it in an autoclave and perform hydrothermal treatment in a composite growth solution prepared from isopropyl titanate and ammonium metavanadate, followed by annealing to form a microporous array layer, thus obtaining stainless steel with a microporous array layer. Preparation of alloy nanoparticles and carbon quantum dots loaded with MoS2: Heat Er(CH3CO2)3·4H2O and silver nitrate in a mixed solvent of oleic acid / octadecene, and then add an ethanol solution of H2O2 to obtain core-shell alloy nanoparticles. Hydrothermally treat ammonium molybdate tetrahydrate, thiourea, and citric acid and then dialyze to obtain carbon quantum dots loaded with MoS2. Surface nano-embedding of stainless steel with a microporous array layer: Prepare a rotary evaporation film from curcumin and egg yolk lecithin. Heat and let it stand in deionized water with core-shell alloy nanoparticles and carbon quantum dots loaded with MoS2, and then vacuum impregnate the stainless steel with a microporous array layer to form a composite layer of alloy nanoparticles - carbon quantum dots loaded with MoS2, thus obtaining a stainless steel material for medical devices.

[0007] Furthermore, the powder metallurgy of the stainless steel alloy in step S1 includes the following steps: S1.1: Weigh 8.3 - 10.5% of Cr, 6.3 - 8.2% of Co, 4 - 6% of Mo, 2.3 - 3.6% of Ni, 1.8 - 3% of V, 0.8 - 1.2% of Ti, 0.4 - 0.8% of Ta, 0.2 - 0.4% of B, 0.001 - 0.015% of C by weight percentage, with the balance being Fe and inevitable impurities as raw materials, and prepare alloy powder. Mix the alloy powder and the binder in a mass ratio of 1:(0.1 - 0.15) and add them to a mixer. Mix the materials at 175 - 180°C and 30 - 35 rpm for 2 - 2.5 hours. During the mixing process, change the mixing direction every 0.5 - 1 hour. After cooling, place it in a crusher to crush and obtain a mixed material. S1.2: Pour the mixed material obtained 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 according to requirements to form an injection blank. Place the injection blank in a catalytic debinding furnace, adjust the furnace cavity temperature to 120 - 125°C and treat it for 30 - 45 minutes. Then, introduce fuming nitric acid at an acid inlet rate of 3 - 3.2 g / min for 3 - 4 hours. After stopping the introduction of fuming nitric acid, continue to treat it at 120 - 125°C for 30 - 45 minutes to obtain a debound blank. S1.3: Place the degreased blank in a vacuum sintering furnace. First, heat it at a heating rate of 4 - 5 °C / min to 360 - 380 °C, hold for 40 - 45 minutes, then continue to heat at a heating rate of 2 - 3 °C / min to 620 - 650 °C, hold for 45 - 60 minutes, then heat at a heating rate of 6 - 8 °C / min to 1050 - 1100 °C, hold for 100 - 120 minutes, continue to heat to 1350 - 1400 °C, hold for 250 - 300 minutes, and then cool with the furnace to obtain the stainless steel body.

[0008] Further, the aging treatment and surface synchronous microporous array formation of the stainless steel in step S2 include the following steps: S2.1: Place TiOSO4 and VCl3 in a container, add a hydrochloric acid solution with a mass fraction of 15 - 18%, stir until 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 in a molar concentration ratio of 1:(0.4 - 0.5) to TiOSO4, and then add 0.08 - 0.1 wt% of polyethylene glycol to obtain a metal complex solution; S2.2: Place the stainless steel body prepared in step S1.3 in an argon protection furnace, heat it to 1050 - 1080 °C, hold for 1 - 1.5 hours, then cool it to room temperature by oil cooling, then vertically immerse it in the metal complex solution, perform uniform dipping and pulling at a rate of 2 - 3 cm / min, repeat the pulling 4 - 5 times, dry it at 80 - 100 °C for 10 - 15 minutes after each pulling, and finally place it in a tempering furnace, hold it at 530 - 550 °C for 4 - 4.5 hours to obtain heterogeneous oxide stainless steel; S2.3: Mix isopropyl titanate and hydrochloric acid with a mass fraction of 18 - 22% in a volume ratio of 1:(40 - 50) and place them in a container, ultrasonically disperse them 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 in a volume ratio of 1:(0.4 - 0.5), then add 0.05 - 0.07 wt% of cetyltrimethylammonium bromide and stir for 30 - 35 minutes to obtain a composite growth solution. Lean the heterogeneous oxide stainless steel against the inner wall of a reaction kettle with a Teflon lining and inlaid with FTO glass, then add the composite growth solution until the heterogeneous oxide stainless steel is submerged, perform hydrothermal treatment at 165 - 185 °C for 2 - 3 hours, take it out, clean it with deionized water and dry it, then place it in a tempering furnace, hold it at 450 - 500 °C for 3 - 4 hours to form a microporous array layer, and obtain microporous array layer stainless steel.

[0009] Further, the preparation of alloy nanoparticles and MoS2-loaded carbon quantum dots in step S3 includes the following steps: S3.1: Mix 0.4 - 0.6 mmol of Er(CH3CO2)3·4H2O, 0.2 - 0.3 mmol of silver nitrate, and 16 - 20 mL of oleic acid / octadecene mixed solvent in a container, add 0.4 - 0.5 mmol of stearic acid, then heat it to 240 - 260 °C at a heating rate of 8 - 10 °C / min under an argon atmosphere, keep it warm for 30 - 35 minutes and then cool it naturally to room temperature. Then inject 4 - 5 mL of an ethanol solution with an H2O2 content of 0.08 - 0.1 M, stir it at 60 - 65 °C for 25 - 30 minutes, centrifuge the product and wash it 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, hydrothermally react it at 200 - 220 °C for 12 - 15 hours, and then load it into a dialysis bag with a molecular weight cut-off of 1500 - 2000 Da and dialyze it in deionized water for 24 - 30 hours to obtain MoS2-loaded carbon quantum dots.

[0010] Further, the surface nano-embedding of the microporous array layer stainless steel in step S4 includes 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 perform rotary evaporation to obtain a rotary evaporation film. Mix 0.8 - 1 part by weight of core-shell alloy nanoparticles, 0.3 - 0.5 part by weight of MoS2-loaded carbon quantum dots, and 600 - 800 parts by weight of deionized water in a container, ultrasonically treat it at 35 - 40 kHz for 20 - 25 minutes, then add 1 - 1.5 parts by weight of the rotary evaporation film, ultrasonically treat it at 25 - 30 kHz for 8 - 10 minutes, and then let it stand at 60 - 65 °C for 30 - 40 minutes to obtain a metal particle encapsulant dispersion; S4.2: Place the microporous array layer stainless steel in a vacuum filtration flask and maintain a vacuum state for 30 - 35 minutes. Then add the metal particle encapsulant dispersion to immerse the microporous array layer stainless steel, continue to pump to vacuum and maintain it for 1 - 1.5 hours. After taking it out, perform vacuum drying to form an alloy nanoparticle-MoS2-loaded carbon quantum dot composite layer, obtaining a stainless steel material for medical devices.

[0011] Further, the method for preparing alloy powder in step S1.1 is to mix the raw materials and perform vacuum induction melting. After complete melting, alloy powder is obtained by the vacuum gas atomization method. The D 50 particle size is 5 - 8 μm, and the D 90 particle size is 20 - 22 μm.

[0012] Further, 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).

[0013] Further, the ethanol aqueous solution for dissolving ammonium metavanadate in step S2.3 has a concentration of 65-70% and contains 0.1 mol / L of ethylenediamine.

[0014] Further, the volume ratio of oleic acid to octadecene in the oleic acid / octadecene mixed solvent in step S3.1 is 1:(2.5-3).

[0015] The beneficial effects are as follows: 1. In the present invention, a metal complex solution is prepared from TiOSO4, VCl3, hydrochloric acid solution, citric acid, and polyethylene glycol. Then, the stainless steel body is solution-treated and placed in the metal complex solution for multiple times of dipping and drying to form a uniform and highly aligned Ti-V composite oxide layer on the surface. Then, a composite growth solution is prepared from titanium isopropoxide and ammonium metavanadate. The heterogeneous oxide stainless steel with the Ti-V composite oxide layer and the composite growth solution are subjected to a hydrothermal reaction in a high-pressure reactor. Under the guidance of the local electric field generated by the Ti-V composite oxide layer and the FTO glass, a highly oriented and dense TiO2 / V2O5 array is formed, and a large number of uniform through channels are constructed between the arrays. Moreover, the Ti-V composite oxide layer reduces the isoelectric point of the stainless steel surface and enhances the electrostatic adsorption of positively charged substances, thereby increasing the loading amount and adsorption capacity of the subsequent antibacterial nanoparticles on the stainless steel surface and significantly improving the antibacterial ability and corrosion resistance of the subsequent stainless steel material surface.

[0016] 2. In the present invention, a rotary evaporation film composed of curcumin and egg yolk lecithin, alloy nanoparticles, and MoS2-loaded carbon quantum dots are prepared, and then the three are combined to obtain a metal particle encapsulation. The metal particle encapsulation enters the inter-array pores on the surface of the microporous array layer stainless steel through vacuum impregnation. The formed liposomes dehydrate and shrink in the inter-array pores to form an "anchoring-winding" structure with the TiO2 / V2O5 array, enhancing the adhesion of the alloy nanoparticles and MoS2-loaded carbon quantum dots, and enabling the photodynamic antibacterial and anticorrosion particles combined by the two to synergistically perform effective sterilization.

[0017] 3. Through reasonable metal component ratios and the processes of degreasing, sintering, solution treatment, and synchronous microporous array formation during aging treatment, the present invention not only endows the stainless steel matrix prepared by powder metallurgy with good mechanical properties, but also makes the formed microporous array layer adhere tightly to the stainless steel surface and have a more uniform structure, further enhancing the antibacterial ability of the stainless steel. Description of the Drawings

[0018] Figure 1 Process flow chart for the preparation of stainless steel materials for medical devices adopted in the embodiments of the present invention. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] Embodiment 1 A stainless steel material for medical devices and its preparation process, as Figure 1 shown, includes the following steps: S1: Powder metallurgy of stainless steel alloy S1.1: By weight percentage, weigh 8.3% of Cr, 6.3% of Co, 4% of Mo, 2.3% of Ni, 1.8% of V, 0.8% of Ti, 0.4% of Ta, 0.2% of B, 0.001% of C, and the balance is Fe and inevitable impurities as raw materials. Mix the raw materials for vacuum induction melting. After complete melting, obtain alloy powder through vacuum gas atomization. The D 50 particle size of the alloy powder is 5μm, and the D 90 particle size is 20μm. Mix the alloy powder and the binder in a mass ratio of 1:0.1 and add them to a mixer. The binder is composed of polyoxymethylene, polypropylene, ethylene-butyl acrylate copolymer, and stearic acid in a mass ratio of 65:15:8:3. Mix the materials at 175°C and 30 rpm for 2 hours. Change the mixing direction every 0.5 hours during mixing. After cooling, place them in a crusher to crush and obtain a mixture; S1.2: Pour the mixture obtained 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. Inject the feed into a 95°C mold for molding according to requirements to obtain an injection blank. Place the injection blank in a catalytic debinding furnace, adjust the furnace chamber temperature to 120°C and process for 30 minutes, then introduce fuming nitric acid at an acid inlet rate of 3 g / min for 3 hours. After stopping the introduction of fuming nitric acid, continue to process at 120°C for 30 minutes to obtain a debound blank; S1.3: Place the debound blank in a vacuum sintering furnace. First, heat it at a heating rate of 4°C / min to 360°C and hold for 40 minutes. Then continue to heat it at a heating rate of 2°C / min to 620°C, hold for 45 minutes, then heat it at a heating rate of 6°C / min to 1050°C, hold for 100 minutes, continue to heat to 1350°C, hold for 250 minutes, and then cool it with the furnace to obtain a stainless steel body.

[0021] S2: Ageing treatment of stainless steel and surface synchronous micro-pore array formation S2.1: Place TiOSO4 and VCl3 in a container, add a hydrochloric acid solution with a mass fraction of 15%, 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 in a molar concentration ratio of 1:0.4 to TiOSO4, and then add 0.08 wt% of polyethylene glycol to obtain a metal complex solution; S2.2: Place the stainless steel body prepared in step S1.3 in an argon protection furnace and heat it to 1050 °C. After holding for 1 hour, cool it to room temperature in oil, then vertically immerse it in the metal complex solution, and perform uniform dipping and pulling at a rate of 2 cm / min. Repeat the pulling 4 times. After each pulling, dry it at 80 °C for 15 minutes. After the last drying, place it in a tempering furnace and hold it at 530 °C for 4 hours to obtain heterogeneous oxide stainless steel; S2.3: Mix isopropyl titanate and hydrochloric acid with a mass fraction of 18% in a volume ratio of 1:40 and place them in a container. Ultrasonically disperse them for 20 minutes at an ultrasonic frequency of 20 kHz to obtain a mixed solution A. Dissolve ammonium metavanadate in an ethanol aqueous solution with a concentration of 65% and containing 0.1 mol / L of ethylenediamine to prepare a mixed solution B with an ammonium metavanadate concentration of 60 mmol / L. Mix the mixed solution A and the mixed solution B in a volume ratio of 1:0.4, then add 0.05 wt% of cetyltrimethylammonium bromide and stir for 30 minutes to obtain a composite growth solution. Lean the heterogeneous oxide stainless steel against the inner wall of a reaction kettle with a Teflon liner and inlaid with FTO glass, and then add the composite growth solution until the heterogeneous oxide stainless steel is submerged. Perform hydrothermal treatment at 165 °C for 2 hours. After taking it out, clean it with deionized water and dry it, and then place it in a tempering furnace and hold it at 450 °C for 3 hours to form a micro-pore array layer, and obtain micro-pore array layer stainless steel.

[0022] S3: Preparation of alloy nanoparticles and MoS2-loaded carbon quantum dots S3.1: Mix 0.4 mmol of Er(CH3CO2)3·4H2O, 0.2 mmol of silver nitrate and 16 mL of a mixed solvent of oleic acid / octadecene with a volume ratio of oleic acid to octadecene of 1:2.5 in a container. Add 0.4 mmol of stearic acid, then heat it to 240 °C at a heating rate of 8 °C / min under an argon atmosphere. After holding for 30 minutes, cool it to room temperature naturally. Then inject 4 mL of an ethanol solution with an H2O2 content of 0.08 M and stir at 60 °C for 25 minutes. After centrifuging the product, wash it 2 times with ethanol to obtain core-shell alloy nanoparticles; S3.2: Dissolve 0.1 mmol ammonium molybdate tetrahydrate, 0.3 mmol thiourea, and 0.05 g citric acid in 20 mL deionized water, perform hydrothermal treatment at 200 °C for 12 hours, and then load it into a dialysis bag with a molecular weight cut-off of 1500 Da and perform dialysis in deionized water for 24 hours to obtain carbon quantum dots loaded with MoS₂.

[0023] S4: Surface nano-embedding of microporous array layer stainless steel 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 carbon quantum dots loaded with MoS₂, and 600 parts by weight of deionized water in a container, 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 let it stand at 60 °C for 30 minutes to obtain a dispersion of metal particle encapsulates; S4.2: Place the microporous array layer stainless steel in a vacuum filtration flask and maintain a vacuum state for 30 minutes, then add the dispersion of metal particle encapsulates to immerse the microporous array layer stainless steel, continue to pump to vacuum and maintain for 1 hour, take it out and perform vacuum drying to form a composite layer of alloy nanoparticles - carbon quantum dots loaded with MoS₂, and obtain a stainless steel material for medical devices.

[0024] Example 2 A stainless steel material for medical devices and its preparation process, as Figure 1 shown, includes the following steps: S1: Powder metallurgy of stainless steel alloy S1.1: 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 by weight percentage, and the balance is Fe and unavoidable impurities as raw materials. Mix the raw materials for vacuum induction melting, and after complete melting, obtain alloy powder through vacuum gas atomization. The D 50 particle size of the alloy powder is 5 μm, and the D 90 particle size is 20 μm. Mix the alloy powder and the binder in a mass ratio of 1:0.15 and add them to a mixer. The binder is composed of polyoxymethylene, polypropylene, ethylene-butyl acrylate copolymer, and stearic acid in a mass ratio of 70:20:10:5. Mix at 175 °C and 30 rpm for 2 hours, change the mixing direction every 0.5 hours during mixing, cool and then place it in a crusher to crush to obtain a mixture; S1.2: Pour the mixture obtained 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. Inject the feedstock into a mold at 95 °C according to requirements for molding to obtain an injection blank. Place the injection blank in a catalytic debinding furnace, adjust the furnace chamber temperature to 120 °C and process for 30 minutes, then introduce fuming nitric acid at an acid feed rate of 3 g / min for 3 hours. After stopping the introduction of fuming nitric acid, continue to process at 120 °C for 30 minutes to obtain a debound blank; S1.3: Place the debound blank in a vacuum sintering furnace. First, heat it at a heating rate of 4 °C / min to 360 °C and hold for 40 minutes. Then continue to heat it at a heating rate of 2 °C / min to 620 °C, hold for 45 minutes, then heat it at a heating rate of 6 °C / min to 1050 °C, hold for 100 minutes, continue to heat to 1350 °C, hold for 250 minutes, and then cool it in the furnace to obtain a stainless steel body.

[0025] S2: Ageing treatment and surface synchronous micro - pore array formation of stainless steel S2.1: Place TiOSO4 and VCl3 in a container, add a hydrochloric acid solution with a mass fraction of 15%, 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 concentration ratio of 1:0.5 to TiOSO4, and then add 0.1 wt% polyethylene glycol to obtain a metal complex solution; S2.2: Heat the stainless steel body obtained in step S1.3 in an argon - protected furnace to 1050 °C, hold for 1 hour and then air - cool to room temperature. Then vertically immerse it in the metal complex solution and perform uniform dipping and pulling at a rate of 2 cm / min, repeat the pulling 4 times. After each pulling, dry it at 80 °C for 15 minutes. After the last drying, place it in a tempering furnace and hold at 530 °C for 4 hours to obtain a stainless steel with heterogeneous oxides; S2.3: Mix isopropyl titanate and hydrochloric acid with a mass fraction of 18% in a volume ratio of 1:50 in a container, and ultrasonically disperse it for 20 minutes at an ultrasonic frequency of 20 kHz to obtain a mixed solution A. Dissolve ammonium metavanadate in an ethanol aqueous solution with a concentration of 65% and containing 0.1 mol / L of ethylenediamine to prepare a mixed solution B with an ammonium metavanadate concentration of 65 mmol / L. Mix the mixed solution A and the mixed solution B in a volume ratio of 1:0.5, then add 0.07 wt% of cetyltrimethylammonium bromide and stir for 30 minutes to obtain a composite growth solution. Lean the heterogeneous oxide stainless steel against the inner wall of a reaction kettle lined with Teflon and inlaid with FTO glass, and then add the composite growth solution until the heterogeneous oxide stainless steel is immersed. Conduct hydrothermal treatment at 165 °C for 2 hours, take it out, wash it clean with deionized water and dry it, then place it in a tempering furnace and keep it at 450 °C for 3 hours to form a microporous array layer, and obtain a microporous array layer stainless steel.

[0026] S3: Preparation of alloy nanoparticles and MoS2-loaded carbon quantum dots S3.1: Mix 0.6 mmol of Er(CH3CO2)3·4H2O, 0.3 mmol of silver nitrate and 20 mL of a mixed solvent of oleic acid / octadecene in a container. The volume ratio of oleic acid to octadecene is 1:3. Add 0.5 mmol of stearic acid, then heat it to 240 °C at a heating rate of 8 °C / min under an argon atmosphere, keep it warm for 30 minutes and then cool it naturally to room temperature. Then inject 5 mL of an ethanol solution with an H2O2 content of 0.08 M, stir it at 60 °C for 25 minutes, and after centrifuging the product, wash it twice with ethanol to obtain core-shell alloy nanoparticles; 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, conduct hydrothermal treatment at 200 °C for 12 hours, and then load it into a dialysis bag with a molecular weight cut-off of 1500 Da and conduct dialysis in deionized water for 24 hours to obtain MoS2-loaded carbon quantum dots.

[0027] S4: Surface nano-embedding of microporous array layer stainless steel S4.1: Add curcumin and egg yolk lecithin in a mass ratio of 1:5 to 10 times the mass of chloroform, stir until completely dissolved and then conduct rotary evaporation to obtain a rotary evaporation film. Mix 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 in a container, ultrasonically treat it at 35 kHz for 20 minutes, then add 1.5 parts by weight of the rotary evaporation film, ultrasonically treat it at 25 kHz for 8 minutes, and then let it stand at 60 °C for 30 minutes to obtain a metal particle encapsulant dispersion; S4.2: Place the stainless steel of the microhole array layer in a vacuum filtration flask and maintain a vacuum state for 30 minutes. Then add the dispersion of metal particle encapsulants to submerge the stainless steel of the microhole array layer, continue to pump to vacuum and maintain for 1 hour. After taking it out, perform vacuum drying to form an alloy nanoparticle-MoS2 loaded carbon quantum dot composite layer, and obtain the stainless steel material for medical devices.

[0028] Example 3 A stainless steel material for medical devices and its preparation process, as Figure 1 shown, including the following steps: S1: Powder metallurgy of stainless steel alloy S1.1: 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 by weight percentage, and the balance is Fe and inevitable impurities as raw materials. Mix the raw materials for vacuum induction melting. After complete melting, obtain alloy powder through vacuum gas atomization. The D 50 particle size of the alloy powder is 8μm, and the D 90 particle size is 22μm. Mix the alloy powder and the binder in a mass ratio of 1:0.1 and add them to a mixer. The binder is composed of polyoxymethylene, polypropylene, ethylene-butyl acrylate copolymer and stearic acid in a mass ratio of 65:15:8:3. Mix the materials at 180°C and 35 rpm for 2.5 hours, and change the mixing direction every 1 hour during mixing. After cooling, place them in a crusher to crush and obtain the mixed material; S1.2: Pour the mixed material obtained 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. Inject the feed into a mold at 105°C according to requirements for molding to obtain an injection blank. Place the injection blank in a catalytic debinding furnace, adjust the furnace chamber temperature to 125°C and process for 45 minutes, then pass in fuming nitric acid at an acid inlet rate of 3.2 g / min for 4 hours. After stopping passing in fuming nitric acid, continue to process at 125°C for 45 minutes to obtain a debound blank; S1.3: Place the debound blank in a vacuum sintering furnace. First, heat it up to 380°C at a heating rate of 5°C / min and hold for 45 minutes. Then continue to heat it up to 650°C at a heating rate of 3°C / min, hold for 60 minutes, then heat it up to 1100°C at a heating rate of 8°C / min, hold for 120 minutes, continue to heat up to 1400°C, hold for 300 minutes, and then cool it down with the furnace to obtain the stainless steel body.

[0029] S2: Aging treatment of stainless steel and surface synchronous microhole array formation S2.1: Place TiOSO4 and VCl3 in a container, add a hydrochloric acid solution with a mass fraction of 18%, 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 in a molar concentration ratio of 1:0.4 to TiOSO4, and then add 0.08 wt% polyethylene glycol to obtain a metal complex solution; S2.2: Place the stainless steel body prepared in step S1.3 in an argon protection furnace and heat it to 1080 °C. After holding for 1.5 hours, cool it to room temperature in oil, then vertically immerse it in the metal complex solution, perform uniform dipping and pulling at a rate of 3 cm / min, repeat the pulling 5 times, dry it at 100 °C for 10 minutes after each pulling, and finally place it in a tempering furnace and hold it at 550 °C for 4.5 hours to obtain heterogeneous oxide stainless steel; S2.3: Mix isopropyl titanate and hydrochloric acid with a mass fraction of 22% in a volume ratio of 1:50 and place them in a container. Ultrasonically disperse them for 25 minutes at an ultrasonic frequency of 25 kHz to obtain a mixed solution A. Dissolve ammonium metavanadate in an ethanol aqueous solution with a concentration of 70% and containing 0.1 mol / L ethylenediamine to prepare a mixed solution B with an ammonium metavanadate concentration of 60 mmol / L. Mix the mixed solution A and the mixed solution B in a volume ratio of 1:0.4, then add 0.05 wt% cetyltrimethylammonium bromide and stir for 35 minutes to obtain a composite growth solution. Lean the heterogeneous oxide stainless steel against the inner wall of a reaction kettle with a Teflon liner and inlaid with FTO glass, then add the composite growth solution until the heterogeneous oxide stainless steel is submerged. Perform hydrothermal treatment at 185 °C for 3 hours, take it out, wash it clean with deionized water and dry it, then place it in a tempering furnace and hold it at 500 °C for 4 hours to form a microporous array layer and obtain microporous array layer stainless steel.

[0030] S3: Preparation of alloy nanoparticles and MoS2-loaded carbon quantum dots S3.1: Mix 0.4 mmol Er(CH3CO2)3·4H2O, 0.2 mmol silver nitrate and 16 mL of a mixed solvent of oleic acid / octadecene with a volume ratio of oleic acid to octadecene of 1:3 in a container. Add 0.4 mmol stearic acid, then heat it to 260 °C at a heating rate of 10 °C / min under an argon atmosphere, hold it for 35 minutes and then cool it to room temperature naturally. Then inject 5 mL of an ethanol solution with an H2O2 content of 0.1 M, stir it at 65 °C for 30 minutes, centrifuge the product and wash it 3 times with ethanol to obtain core-shell alloy nanoparticles; 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, perform hydrothermal treatment at 220 °C for 15 hours, and then load it into a dialysis bag with a molecular weight cut-off of 2000 Da and perform dialysis in deionized water for 30 hours to obtain carbon quantum dots loaded with MoS2.

[0031] S4: Surface nano-embedding of microporous array layer stainless steel 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 evaporation film. Mix 0.8 parts by weight of core-shell alloy nanoparticles, 0.3 parts by weight of carbon quantum dots loaded with MoS2, and 600 parts by weight of deionized water in a container, perform ultrasonic treatment at 40 kHz for 25 minutes, then add 1.5 parts by weight of the rotary evaporation film, perform ultrasonic treatment at 30 kHz for 10 minutes, and then let it stand at 65 °C for 40 minutes to obtain a dispersion of metal particle encapsulates; S4.2: Place the microporous array layer stainless steel in a vacuum filtration flask and maintain a vacuum state for 35 minutes, then add the dispersion of metal particle encapsulates to immerse the microporous array layer stainless steel, continue to pump to vacuum and maintain for 1.5 hours, take it out and perform vacuum drying to form a composite layer of alloy nanoparticles - carbon quantum dots loaded with MoS2, and obtain a stainless steel material for medical devices.

[0032] Comparative Example 1: Compared with Example 1, the difference in Comparative Example 1 is that Comparative Example 1 removes steps S2.1 and S2.2, and replaces the heterogeneous oxide stainless steel in step S2.3 with a stainless steel body, and the remaining steps are the same as those in Example 1.

[0033] Comparative Example 2: Compared with Example 1, the difference in Comparative Example 2 is that Comparative Example 2 removes step S2.3, and replaces the subsequent microporous array layer stainless steel with heterogeneous oxide stainless steel, and the remaining steps are the same as those in Example 1.

[0034] Comparative Example 3: Compared with Example 1, the difference in Comparative Example 3 is that Comparative Example 3 removes step S3.1, and replaces the core-shell alloy nanoparticles in step S4.1 with the same mass of carbon quantum dots loaded with MoS2, and the remaining steps are the same as those in Example 1.

[0035] Comparative Example 4: Compared with Example 1, the difference in Comparative Example 4 is that Comparative Example 4 removes step S3.2, and replaces the carbon quantum dots loaded with MoS2 in step S4.1 with the same mass of core-shell alloy nanoparticles, and the remaining steps are the same as those in Example 1.

[0036] Comparative Example 5: Compared with Example 1, the difference in Comparative Example 5 is that step S1 is removed, the subsequent stainless steel body is replaced with 316 stainless steel, and the operation of heating to 1050 °C and holding for 1 hour and then air cooling in step S2.2 is removed. The remaining steps are the same as those in Example 1.

[0037] Replace the injection molding molds in Examples 1-3 and Comparative Examples 1-5 with molds having lengths, widths, and heights of 2 cm × 2 cm × 0.5 cm respectively to obtain samples.

[0038] Mechanical property test: Conduct mechanical property tests on the samples obtained in Examples 1-3. The test results are shown in Table 1.

[0039] Table 1: Mechanical properties of the samples prepared in the examples

[0040] From the data of Examples 1-3 in Table 1, it can be seen that the stainless steel materials for medical devices prepared in Examples 1-3 have good mechanical properties, which can prove the reasonable metal component ratio and the degreasing, sintering, solution treatment, and aging treatment processes of this application, enabling the stainless steel matrix prepared by powder metallurgy to have good mechanical properties. Corrosion resistance test: Conduct neutral salt spray tests on two samples each obtained in Examples 1-3 and Comparative Examples 1-5. The neutral solution used is a 5wt% NaCl salt solution prepared with pure NaCl and deionized water. The test is carried out under normal pressure, the experimental time is 360 h, the temperature is 35 °C. After the test, the samples are dried under natural conditions indoors for 2 h. After the samples are dried, they are rinsed with deionized water to remove the residues of the salt solution, and the corrosion conditions on the surfaces of the samples are observed. The test results are shown in Table 2.

[0041] Table 2: Rusting conditions on the surfaces of the samples under the neutral salt spray test

[0042] It can be seen from Table 2 that no red rust or pitting rust appears in Examples 1-3 under the neutral salt spray test, while pitting rust appears in Comparative Examples 1-2, indicating that the Ti-V composite oxide layer and the composite growth solution synergistically form a highly oriented and dense array, thereby increasing the adsorption amount of subsequent alloy nanoparticles and MoS2-loaded carbon quantum dots on the stainless steel surface and performing uniform adsorption, thus improving the corrosion resistance of the stainless steel material. Comparative Examples 3-4 have no red rust or pitting rust formation, proving that both the alloy nanoparticles and the MoS2-loaded carbon quantum dots have good corrosion resistance. The reason for the appearance of a small amount of pitting rust in Comparative Example 5 may be that the 316 stainless steel matrix causes a small amount of non-uniform growth of the Ti-V composite oxide layer and the composite growth solution, thereby affecting the loading uniformity of the alloy nanoparticles and the MoS2-loaded carbon quantum dots and resulting in a decrease in corrosion resistance.

[0043] Antibacterial performance test: The antibacterial activity of the samples against Escherichia coli was detected by the plate counting method. The Escherichia coli cultured overnight was diluted to 10 −6 CFU·mL −1 using sterile LB liquid medium. Two samples prepared in Examples 1-3 and Comparative Examples 1-5 were taken respectively. Both the front and back sides of all samples were disinfected with ultraviolet light for more than 30 min and placed in a 6-well plate. Then, 8 mL of a bacterial solution with a concentration of 10 −6 CFU·mL −1 was taken to completely immerse the surface of the samples. One sample was cultured under 980 nm light irradiation for 1 h, and one sample was cultured in the dark for 1 h. 50 μL of the light-treated bacterial solution and the dark-treated bacterial solution were taken from each well of the 6-well plate, and 50 μL of the untreated bacterial solution was taken onto the LB solid medium. The bacterial solution was evenly spread using a spreading rod. The LB solid medium with the spread bacterial solution was statically cultured in a constant temperature incubator at 37 °C for 24 h. The Escherichia coli on the solid medium was counted by plate counting. The antibacterial rate = (the number of colonies cultured from the untreated bacterial solution - the number of colonies cultured after treatment on the sample surface) / the number of colonies cultured from the untreated bacterial solution × 100%. The average value of the antibacterial rate of each well plate was calculated, and the data was recorded in a table as shown in Table 3.

[0044] Table 3: Antibacterial performance of the samples

[0045] As can be seen from Table 3, Examples 1-3 all have excellent antibacterial ability. And from Comparative Examples 1-2, it can be seen that after removing the Ti-V composite oxide layer or the composite growth solution, the antibacterial performance drops significantly, indicating that the loading amount and adsorption ability of the subsequent antibacterial nanoparticles on the surface of the stainless steel material drop significantly. It can be proved that the Ti-V composite oxide layer and the composite growth solution can improve the antibacterial ability of the stainless steel material surface. From Comparative Examples 3-4, it can be seen that when the alloy nanoparticles and MoS2-loaded carbon quantum dots are replaced equally, the antibacterial performance both decreases, proving that the two have a synergistic antibacterial effect. From Comparative Example 5, it can be seen 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 the stainless steel.

[0046] The above examples only illustrate the principle and its efficacy of the present invention, rather than limiting the present invention. Any person familiar with this technology can modify or change the above examples without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A stainless steel material for medical devices, characterized in that: 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, wherein 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 remainder is Fe and unavoidable impurities.

2. 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 a binder for injection molding, and sintered after three-stage degreasing to obtain a stainless steel body; Aging treatment of S2 stainless steel and synchronous microporous arraying of the surface: TiOSO4 and VCl3 are prepared into a metal complex solution, and the stainless steel body is solid-dissolved and placed in the metal complex solution for multiple pulling and drying, and then placed in an autoclave for hydrothermal treatment in a composite growth solution prepared from isopropyl titanate and ammonium metavanadate, and annealed to form a microporous array layer to obtain 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, and then an ethanol solution of H2O2 was added 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. Surface nano-embedding 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 to obtain stainless steel material for medical devices.

3. The process for preparing a stainless steel material for medical devices according to claim 2, characterized in that: Step S1: powder metallurgy of stainless steel alloy, comprising the following steps: S1.1: According to weight percentage, weigh 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 inevitable impurities as raw materials, prepare alloy powder, mix the alloy powder with the binder at a mass ratio of 1: (0.1-0.15) and add them into an internal mixer, mix for 2-2.5 hours at 175-180℃ and 30-35rpm, change the mixing direction every 0.5-1 hour during the mixing, and crush in a crusher after cooling to obtain a mixture; S1.2: Pour the mixture obtained in step S1.1 into an injection molding machine, adjust the nozzle temperature to 175-190°C, the pressure to 10-15MPa, and the injection speed to 60-65mm / s, and 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, treat for 30-45 minutes, then introduce fuming nitric acid at an acid feed rate of 3-3.2g / min for 3-4 hours, stop introducing fuming nitric acid, and continue to treat 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 a stainless steel body.

4. The process for preparing a stainless steel material for medical devices according to claim 2, characterized in that: Step S2: Aging treatment of stainless steel and synchronous microporous arraying of the surface, including the following steps: S2.1: Place TiOSO4 and VCl3 in a container, add a hydrochloric acid solution with a mass fraction of 15-18%, and stir until TiOSO4 and VCl3 are completely dissolved to obtain a composite salt solution with a TiOSO4 concentration of 45-50mmol / L and a VCl3 concentration of 25-30mmol / L, add citric acid to the composite salt solution at a molar ratio of 1:(0.4-0.5) to TiOSO4, and then add 0.08-0.1wt% of polyethylene glycol to obtain a metal complex solution; S2.2: The stainless steel body obtained in step S1.3 is placed in an argon protection furnace and heated to 1050-1080°C. After keeping the temperature for 1-1.5 hours, the body is cooled to room temperature by oil, and then vertically immersed in a metal complex liquid, and uniformly immersed and pulled at a rate of 2-3 cm / min. The pulling is repeated 4-5 times. After each pulling, the body is dried at 80-100°C for 10-15 minutes. After the last drying, the body is placed in a tempering furnace and kept at 530-550°C for 4-4.5 hours to obtain heterogeneous oxide stainless steel. S2.3: Mix isopropyl titanate and hydrochloric acid with a mass fraction of 18-22% at a volume ratio of 1: (40-50) and place them in a container. Ultrasonic dispersion is performed at an ultrasonic frequency of 20-25kHz for 20-25 minutes to obtain a mixed liquid A. Ammonium metavanadate is dissolved in an ethanol aqueous solution to prepare a mixed liquid B with an ammonium metavanadate concentration of 60-65mmol / L. Mix the mixed liquid A and the mixed liquid B at a volume ratio of 1: (0.4-0.5). Then, 0.05-0.07wt% 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, and a hydrothermal treatment is performed at 165-185° C. for 2-3 hours. After being taken out, 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 to obtain a microporous array layer stainless steel.

5. The process for preparing a stainless steel material for medical devices according to claim 2, characterized in that: Step S3: Preparation of alloy nanoparticles and MoS2-loaded carbon quantum dots, comprising the following steps: S3.1: 0.4-0.6mmolEr(CH3CO2)3·4H2O, 0.2-0.3mmolsilver nitrate and 16-20mL of oleic acid / octadecene mixed solvent are mixed and placed in a container, 0.4-0.5mmolstearic acid is added, and then the temperature is increased to 240-260°C at a heating rate of 8-10°C / min under an argon atmosphere, and the mixture is naturally cooled to room temperature after being kept warm for 30-35 minutes, and then 4-5mL of ethanol solution with a H2O2 content of 0.08-0.1M is injected, and the mixture is stirred at 60-65°C for 25-30 minutes. After centrifugation, the product is separated and washed with ethanol for 2-3 times to obtain core-shell alloy nanoparticles; S3.2: Dissolve 0.1-0.15mmol ammonium molybdate tetrahydrate, 0.3-0.35mmol thiourea and 0.05-0.06g citric acid in 20-30mL deionized water, hydroheat at 200-220℃ for 12-15 hours, then put into a dialysis bag with a molecular weight cutoff of 1500-2000Da and dialyze in deionized water for 24-30 hours to obtain MoS2-loaded carbon quantum dots.

6. The process for preparing a stainless steel material for medical devices according to claim 2, 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 perform rotary evaporation to obtain a rotary evaporation 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, perform ultrasonic treatment at 35-40 kHz for 20-25 minutes, then add 1-1.5 parts by weight of the rotary evaporation film, perform ultrasonic treatment 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 the vacuum state for 30-35 minutes, then add the metal particle encapsulation dispersion to immerse the microporous array layer stainless steel, continue to evacuate to vacuum and maintain for 1-1.5 hours, take out and vacuum dry to form an alloy nanoparticle-MoS2 loaded carbon quantum dot composite layer to obtain stainless steel material for medical devices.

7. The process for preparing a stainless steel material for medical devices according to claim 3, characterized in that: The method for preparing 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. The D50 particle size of the alloy powder is 5-8μm, and the D90 particle size is 20-22μm.

8. The process for preparing a stainless steel material for medical devices according to claim 3, 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).

9. The process for preparing a stainless steel material for medical devices according to claim 4, 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.

10. The process for preparing a stainless steel material for medical devices according to claim 5, 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).

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