Scalpel blade and preparation method thereof

Abstract

The invention belongs to the field of medical instruments, and discloses a scalpel blade and a preparation method thereof.The scalpel blade is of a three-layer composite structure which sequentially comprises a base layer, a reinforcing layer and a surface functional layer from inside to outside; the base layer is prepared from the following raw materials in parts by weight: 75-80 parts of cubic boron nitride, 15-20 parts of titanium alloy powder, 5-8 parts of tungsten carbide, 3-5 parts of silicon nitride and 1-2 parts of yttrium oxide; the reinforcing layer is prepared from the following raw materials in parts by weight: 8-12 parts of silicon carbide whiskers, 20-25 parts of cubic zirconium oxide, 10-15 parts of strontium titanate, 3-5 parts of molybdenum disilicide and 4-6 parts of zirconium nitride; the surface functional layer is prepared from the following raw materials in parts by weight: 10-15 parts of hydroxyapatite, 5-8 parts of bioactive glass, 3-5 parts of titanium nitride, 2-4 parts of titanium dioxide and 1-2 parts of silver powder; in order to solve the problems that an existing scalpel blade is insufficient in strength, poor in wear resistance and poor in biocompatibility, the strength, the wear resistance and the biocompatibility of the blade are synergistically improved through the design of a three-layer composite structure and optimization of a composite coating.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a surgical blade and its preparation method. Background Technology

[0002] Surgery is the core treatment method in surgery, and the scalpel, as the most basic instrument in surgery, directly affects the precision of the surgery and the patient's prognosis. Currently, most scalpel blades used clinically are made of a single metal or alloy. To ensure cutting sharpness, the blades are usually designed to be relatively thin, leading to the following drawbacks: 1. Insufficient strength can easily lead to bending, deformation, or even breakage during surgery, increasing surgical risks; 2. The surface has poor wear resistance, and its sharpness decreases significantly after repeated use, resulting in a short service life; 3. Insufficient biocompatibility: Some patients may have allergic reactions to the metal material, and bacteria can easily adhere to the blade surface, increasing the risk of postoperative infection.

[0003] To address these issues, existing technologies have attempted to improve strength by adjusting alloy composition, but this often fails to balance sharpness and strength. Some solutions employ surface coating technology to optimize performance, but the coating has poor adhesion to the substrate, is prone to peeling, and has not achieved a performance breakthrough from the perspective of blade body structural design.

[0004] Therefore, in order to solve the above problems, a surgical blade with high strength, high wear resistance, excellent biocompatibility and long-lasting sharpness has been proposed. Summary of the Invention

[0005] To address the problems of insufficient strength, poor wear resistance, and inadequate biocompatibility of existing surgical scalpel blades, this invention provides a surgical scalpel blade and its preparation method. Through a three-layer composite structure design and optimized composite coating, the blade's strength, wear resistance, and biocompatibility are synergistically improved.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The technical solution provided by this invention is: A surgical blade with a three-layer composite structure, consisting of a base layer, a reinforcing layer, and a surface functional layer from the inside out; The base layer is composed of the following raw materials in parts by weight: 75-80 parts cubic boron nitride, 15-20 parts titanium alloy powder, 5-8 parts tungsten carbide, 3-5 parts silicon nitride, and 1-2 parts yttrium oxide; The reinforcing layer is composed of the following raw materials in parts by weight: 8-12 parts silicon carbide whiskers, 20-25 parts cubic zirconium oxide, 10-15 parts strontium titanate, 3-5 parts molybdenum disilicide, and 4-6 parts zirconium nitride. The surface functional layer is composed of the following raw materials in parts by weight: 10-15 parts hydroxyapatite, 5-8 parts bioactive glass, 3-5 parts titanium nitride, 2-4 parts titanium dioxide, and 1-2 parts silver powder.

[0007] Furthermore, the titanium alloy powder is TC4 titanium alloy powder with a particle size of 50-100μm; the bioactive glass is 45S5 bioactive glass with a particle size of 20-50μm.

[0008] Furthermore, the length of the silicon carbide whiskers is 15-25 μm and the diameter is 0.8-1.2 μm; the particle size of the hydroxyapatite is 10-30 μm.

[0009] Furthermore, the thickness of the base layer is 0.12-0.15mm, the thickness of the reinforcing layer is 0.03-0.05mm, and the thickness of the surface functional layer is 0.02-0.03mm.

[0010] A method for preparing a surgical blade includes the following steps: S1: Raw material pretreatment: Weigh the raw materials of the base layer, reinforcing layer and surface functional layer according to the weight parts. First, coarsely crush the cubic boron nitride, tungsten carbide and silicon nitride in the base material to 100-150 mesh, then mix them with titanium alloy powder and yttrium oxide and put them into a ball mill. Then, ball mill them at a speed of 300-400 r / min for 1.5-2 hours to obtain the base layer mixed powder. After mixing the reinforcing layer raw materials, they are placed in a planetary ball mill and ball-milled at a speed of 500-600 r / min for 2-3 hours under nitrogen protection to obtain the reinforcing layer mixed powder. Hydroxyapatite, bioactive glass, and titanium dioxide in the surface functional layer raw materials are mixed and pulverized to 200 mesh, and then mixed with titanium nitride and silver powder to obtain surface functional layer mixed powder. S2: Layered powder spreading: The base layer mixed powder is evenly spread on the bottom of the sintering mold with a thickness controlled at 0.12-0.15mm. Then, the reinforcing layer mixed powder is evenly spread on the surface of the base layer mixed powder with a thickness of 0.03-0.05mm. Finally, the surface functional layer mixed powder is spread on the surface of the reinforcing layer mixed powder with a thickness of 0.02-0.03mm to form a multi-layered green body. S3: Segmented sintering: The mold containing the multi-layered billet is placed in a vacuum sintering furnace. First, the vacuum is drawn to 0.001-0.005MPa, the temperature is raised to 600℃ and held for 1 hour, then the temperature is raised to 1100-1200℃ and held for 2-3 hours, then the temperature is lowered to 800℃ and held for 1 hour, and finally the furnace is cooled to room temperature to produce multi-layered block billets. S4: Forming process: The multi-layered block blank is placed on a vertical grinding machine and ground to a total thickness of 0.2mm, and then cut into the prototype of a surgical scalpel blade by a CNC milling machine; S5: Surface treatment: The blade prototype is machine-sharpened at an angle of 15-20°. Then, a composite coating with a thickness of 3-5μm is sprayed onto its surface using plasma spraying technology. Finally, the sprayed blade is placed in a vacuum annealing furnace and kept at 400-500℃ for 1-2 hours. After cooling to room temperature in the furnace, it is polished to obtain the scalpel blade.

[0011] Furthermore, the ball-to-material ratio during ball milling of the base layer raw material in S1 is 5:1; the ball-to-material ratio during ball milling of the reinforcing layer raw material is 8:1.

[0012] Furthermore, the heating rate in S3 is 5-10℃ / min, and the cooling rate is 3-5℃ / min.

[0013] Furthermore, the S5 plasma spraying is completed through the following steps: the blade prototype is fixed on the spraying worktable, and an atmospheric plasma spraying equipment is used, with argon as the ion gas and hydrogen as the auxiliary gas. The ion gas flow rate is 30-40L / min, the auxiliary gas flow rate is 5-8L / min, the spraying current is 300-350A, the spraying voltage is 60-70V, the spraying distance is 100-120mm, and the powder feeding rate is 20-30g / min. The coating powder is uniformly sprayed onto the blade surface to form a composite coating with a thickness of 3-5μm.

[0014] Furthermore, the composite coating in S5 is prepared according to the following steps: hydroxyapatite powder and titanium nitride powder are weighed at a weight ratio of 7:3, and 2-3% of silica sintering aid is added to the total mass of the mixed powder. After mixing, the mixture is placed in a vacuum drying oven and dried at 80-100℃ for 2-3 hours. Then, it is placed in a ball mill and ball-milled at 300r / min for 1 hour. The ball-to-material ratio during ball milling is 4:1. The mixture is then passed through a 200-mesh sieve to obtain the coating powder.

[0015] The beneficial effects of this technical solution are: (1) The base layer is mainly composed of cubic boron nitride, which can give the blade excellent basic hardness and wear resistance, effectively resisting local wear during surgical cutting; combined with TC4 titanium alloy powder, its good mechanical toughness and biocompatibility can make up for the high brittleness of cubic boron nitride, achieving a performance balance of hardness without brittleness. At the same time, tungsten carbide and silicon nitride serve as auxiliary hard phases, further enhancing the overall hardness and deformation resistance of the base layer; yttrium oxide serves as a sintering active component, which can reduce the sintering temperature and promote the dense bonding between the particles of each component, avoiding the appearance of loose defects in the base layer and ensuring the structural stability of the blade body.

[0016] (2) The silicon carbide whiskers in the reinforcing layer have extremely high aspect ratio and tensile strength, which can form a three-dimensional network reinforcement structure inside the blade, significantly improving the bending strength and impact resistance of the blade, and effectively solving the problem of easy bending caused by the thinning of traditional blades; the synergistic effect of cubic zirconium oxide and strontium titanate further enhances the wear resistance and scratch resistance of the reinforcing layer, and prolongs the blade sharpness retention time; molybdenum disilicide and zirconium nitride have good interfacial compatibility, which can promote the diffusion and bonding of components between the reinforcing layer and the base layer and surface functional layer, avoid the delamination of the multi-layer structure, and ensure the overall structural integrity of the blade.

[0017] (3) The hydroxyapatite in the surface functional layer is similar to the composition of human bone tissue and has excellent biocompatibility, which can reduce the risk of allergic reactions when the blade comes into contact with human tissue; 45S5 bioactive glass can form a bone-like apatite layer in the body fluid environment, further improving biocompatibility and reducing postoperative tissue adhesion. At the same time, silver powder has broad-spectrum antibacterial properties and can inhibit the attachment and reproduction of common pathogenic bacteria such as Escherichia coli and Staphylococcus aureus; titanium dioxide can not only enhance the antibacterial effect, but also improve the chemical stability of the surface functional layer and avoid the components from dissolving and causing adverse effects on the human body; titanium nitride can enhance the hardness of the surface functional layer and avoid performance degradation caused by surface scratches during surgical operations.

[0018] (4) The composite coating uses hydroxyapatite and titanium nitride in a 7:3 ratio. The hydroxyapatite extends the biocompatibility of the surface functional layer, while the high hardness of titanium nitride further improves the wear resistance of the blade surface, forming a dual surface protection of biocompatibility and wear resistance. The added silica sintering aid can reduce the sintering temperature of the coating, promote the dense accumulation of coating particles, reduce the porosity of the coating, improve the bonding strength between the coating and the surface functional layer, and prevent the coating from falling off and contaminating the surgical wound during the operation. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the preparation process of a surgical blade and its preparation method proposed in this invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The specific implementation process is as follows: Example 1: Please see Figure 1The present invention provides a technical solution: a surgical scalpel blade and its preparation method, comprising the following raw material ratios: Base layer: 375g cubic boron nitride, 75g TC4 titanium alloy powder, 25g tungsten carbide, 15g silicon nitride, 5g yttrium oxide; Reinforcing layer: 40g silicon carbide whiskers, 100g cubic zirconium oxide, 50g strontium titanate, 15g molybdenum disilicide, and 20g zirconium nitride; Surface functional layer: 50g hydroxyapatite, 25g 45S5 bioactive glass, 15g titanium nitride, 10g titanium dioxide, 5g silver powder; Composite coating: 350g hydroxyapatite, 150g titanium nitride, 10g silica (2% of the total mass of the mixed powder); The preparation steps are as follows: S1: Raw material pretreatment: Cubic boron nitride, tungsten carbide, and silicon nitride in the base layer raw material are coarsely crushed to 100 mesh using a jaw crusher, mixed with TC4 titanium alloy powder and yttrium oxide, and then placed in a ball mill. The mixture is ball-milled at 300 r / min and a ball-to-material ratio of 5:1 for 1.5 hours to obtain the base layer mixed powder. The reinforcing layer raw material is mixed and then placed in a planetary ball mill. Under nitrogen protection, the mixture is ball-milled at 500 r / min and a ball-to-material ratio of 8:1 for 2 hours to obtain the reinforcing layer mixed powder. Hydroxyapatite, 45S5 bioactive glass, and titanium dioxide in the surface functional layer raw material are pulverized to 200 mesh using an air jet mill. The mixture is then stirred with titanium nitride and silver powder in a stirred tank at 200 r / min for 30 minutes to obtain the surface functional layer mixed powder. S2: Layered powder spreading: An automatic powder spreading machine spreads a base layer mixed powder (0.12mm), a reinforcing layer mixed powder (0.03mm), and a surface functional layer mixed powder (0.02mm) to form a multi-layered green body; S3: Segmented sintering: The vacuum sintering furnace is evacuated to 0.001MPa, heated to 600℃ at 5℃ / min and held for 1 hour, then heated to 1100℃ and held for 2 hours, then cooled to 800℃ at 3℃ / min and held for 1 hour, and cooled with the furnace to obtain block billets. S4: Forming process: Grind to 0.2mm thickness with a vertical grinding machine, and cut into the blade shape by CNC milling machine; S5: Surface treatment: Automatic sharpening machine (15°); Prepare coating powder according to the formula (dry at 80℃ for 2 hours, ball mill at 300r / min for 1 hour, ball-to-material ratio 4:1, pass through 200 mesh sieve); Plasma spraying (argon 30L / min, hydrogen 5L / min, current 300A, voltage 60V, distance 100mm, powder feed 20g / min) to form a 3μm composite coating; Vacuum annealing at 400℃ for 1 hour, polishing treatment; Performance indicators Test Results Hardness (HV) 1750 Flexural strength (MPa) 2200 Antibacterial rate of Escherichia coli (%) 92 Cell viability (%) 88 Coating adhesion (MPa) 50 Composite coating thickness (μm) 3 Sharpening angle (°) 15 Total blade thickness (mm) 0.2 As shown in the table above, the surgical blade prepared in this embodiment meets the basic requirements for clinical use in all aspects; the hardness is HV1750, thanks to the synergistic effect of 375g of cubic boron nitride and 25g of tungsten carbide in the base layer, which provides good basic hardness for the blade; the bending strength reaches 2200MPa, and the 40g of silicon carbide whiskers and 100g of cubic zirconium oxide in the reinforcing layer effectively improve the blade's resistance to bending deformation, and after segmented sintering, the layers are tightly bonded without delamination; the antibacterial rate against Escherichia coli is 92%, and the surface functional layer... 5g of silver powder and 10g of titanium dioxide played the main antibacterial role; the cell survival rate was 88%, and 50g of hydroxyapatite and 25g of 45S5 bioactive glass ensured good biocompatibility; the composite coating thickness was precisely controlled at 3μm, and the coating adhesion was 50MPa, indicating that the plasma spraying parameters were set reasonably, the coating was firmly bonded to the substrate, and it could effectively improve the wear resistance and service life of the blade surface; overall, the process of this embodiment was stable, the raw material ratio was reasonable, and the product performance met the basic usage requirements of surgical blades.

[0022] Example 2: Please see Figure 1 The present invention provides a technical solution: a surgical scalpel blade and its preparation method, comprising the following raw material ratios: Base layer: 400g cubic boron nitride, 100g TC4 titanium alloy powder, 40g tungsten carbide, 25g silicon nitride, 10g yttrium oxide; Reinforcing layer: 60g silicon carbide whiskers, 125g cubic zirconium oxide, 75g strontium titanate, 25g molybdenum disilicide, 30g zirconium nitride; Surface functional layer: 75g hydroxyapatite, 40g 45S5 bioactive glass, 25g titanium nitride, 20g titanium dioxide, 10g silver powder; Composite coating: 350g hydroxyapatite, 150g titanium nitride, 15g silica (3% of the total mass of the mixed powder); The preparation steps are as follows: S1: Raw material pretreatment: The base layer raw material is coarsely crushed to 150 mesh and ball-milled for 2 hours at 400 r / min and a ball-to-material ratio of 5:1; the reinforcing layer raw material is ball-milled for 3 hours at 600 r / min and a ball-to-material ratio of 8:1 under nitrogen protection; the surface functional layer raw material is crushed to 200 mesh and then stirred for 30 minutes. S2: Layered powder application: Apply base layer mixed powder (0.15mm), reinforcement layer mixed powder (0.05mm), and surface functional layer mixed powder (0.03mm). S3: Segmented sintering: Vacuum degree 0.005MPa, heat up to 600℃ at 10℃ / min and hold for 1 hour, then heat up to 1200℃ and hold for 3 hours, then cool down to 800℃ at 5℃ / min and hold for 1 hour, then cool with the furnace. S4: Shaping process: Grind to 0.2mm thickness and cut into the rough shape; S5: Surface treatment: Sharpening angle 20°; Coating powder dried at 100℃ for 3 hours, ball milled at 300r / min for 1 hour, ball-to-material ratio 4:1; Plasma spraying (argon 40L / min, hydrogen 8L / min, current 350A, voltage 70V, distance 120mm, powder feed 30g / min) to form a 5μm composite coating; Vacuum annealing at 500℃ for 2 hours, polishing; Performance indicators Test Results Hardness (HV) 1900 Flexural strength (MPa) 2500 Antibacterial rate of Escherichia coli (%) 98 Cell viability (%) 95 Coating adhesion (MPa) 60 Composite coating thickness (μm) 5 Sharpening angle (°) 20 Total blade thickness (mm) 0.2 The data in the table above show that the performance of the product in this embodiment is superior to that of Example 1; the hardness is increased to HV1900, mainly due to the increased amount of cubic boron nitride (400g) and tungsten carbide (40g) in the base layer, and the segmented sintering temperature is increased to 1200℃ and the holding time is extended to 3 hours, which significantly improves the compactness of the green body; the flexural strength reaches 2500MPa, the increased amount of silicon carbide whiskers (60g) and cubic zirconium oxide (125g) in the reinforcing layer, resulting in a more significant strengthening and toughening effect, while the 30g of zirconium nitride improves the interlayer bonding and avoids delamination failure; the antibacterial rate against E. coli is 98%. The cell survival rate is 95%. The increased amounts of hydroxyapatite (75g), 40g of 45S5 bioactive glass, and 10g of silver powder in the surface functional layer significantly optimize biocompatibility and antibacterial properties. The composite coating achieves a bonding strength of 60MPa, thanks to the increased spraying current to 350A and long-term annealing at 500℃, which enhances the metallurgical bond between the coating and the substrate. The coating thickness is 5μm with good uniformity, further improving surface wear resistance. This embodiment achieves a comprehensive improvement in product performance by optimizing the upper limit of raw material ratios and process parameters, resulting in excellent overall performance.

[0023] Example 3: Please see Figure 1 The present invention provides a technical solution: a surgical scalpel blade and its preparation method, comprising the following raw material ratios: Base layer: 385g cubic boron nitride, 90g TC4 titanium alloy powder, 30g tungsten carbide, 20g silicon nitride, 7.5g yttrium oxide; Reinforcing layer: 50g silicon carbide whiskers, 110g cubic zirconium oxide, 60g strontium titanate, 20g molybdenum disilicide, 25g zirconium nitride; Surface functional layer: 60g hydroxyapatite, 30g 45S5 bioactive glass, 20g titanium nitride, 15g titanium dioxide, 7.5g silver powder; Composite coating: 350g hydroxyapatite, 150g titanium nitride, and 12.5g silicon dioxide (accounting for 2.5% of the total mass of the mixed powder); The preparation steps are as follows: S1: Raw material pretreatment: The base layer raw material is coarsely crushed to 120 mesh, and then ball-milled for 1.8 hours at 350 r / min and a ball-to-material ratio of 5:1; the reinforcing layer raw material is ball-milled for 2.5 hours at 550 r / min and a ball-to-material ratio of 8:1 under nitrogen protection; the surface functional layer raw material is crushed to 200 mesh and then stirred for 30 minutes. S2: Layered powder application: Apply base layer mixed powder (0.13mm), reinforcement layer mixed powder (0.04mm), and surface functional layer mixed powder (0.025mm). S3: Segmented sintering: Vacuum degree 0.003MPa, heat up to 600℃ at 8℃ / min and hold for 1 hour, then heat up to 1150℃ and hold for 2.5 hours, cool down to 800℃ at 4℃ / min and hold for 1 hour, then cool with the furnace; S4: Shaping process: Grind to 0.2mm thickness and cut into the rough shape; S5: Surface treatment: 18° opening angle; coating powder drying at 90℃ for 2.5 hours, ball milling at 300r / min for 1 hour, ball-to-material ratio 4:1; plasma spraying (argon 35L / min, hydrogen 6L / min, current 320A, voltage 65V, distance 110mm, powder feed 25g / min) to form a 4μm composite coating; vacuum annealing at 450℃ for 1.5 hours, polishing; Performance indicators Test Results Hardness (HV) 1820 Flexural strength (MPa) 2350 Antibacterial rate of Escherichia coli (%) 95 Cell viability (%) 92 Coating adhesion (MPa) 55 Composite coating thickness (μm) 4 Sharpening angle (°) 18 Total blade thickness (mm) 0.2 This embodiment uses intermediate raw material ratios and intermediate process parameters. Experimental results show that the product performance is balanced and stable; the hardness is HV1820 and the flexural strength is 2350MPa. The ratio of 385g cubic boron nitride to 90g TC4 titanium alloy powder in the base layer is reasonable, ensuring both hardness and toughness; the 50g silicon carbide whiskers in the reinforcing layer are evenly dispersed without agglomeration, effectively playing a reinforcing role; the antibacterial rate of E. coli is 95% and the cell survival rate is 92%; the amount of each raw material in the surface functional layer is moderate, achieving a balance between biocompatibility and antibacterial properties; the composite coating thickness is 4μm with a deviation of only ±0.3μm, showing good uniformity; the coating adhesion is 55MPa, thanks to the optimized spraying parameters of 35L / min argon gas and 320A current, as well as annealing treatment at 450℃, ensuring a strong bond between the coating and the substrate; the 18° sharpening angle balances sharpness and edge strength, and the total blade thickness is precisely controlled at 0.2mm, meeting the size requirements of surgical blades; this embodiment has good process repeatability, stable performance, and is suitable for mass production.

[0024] Example 4: Please see Figure 1 The present invention provides a technical solution: a surgical scalpel blade and its preparation method, comprising the following raw material ratios: Base layer: 380g cubic boron nitride, 80g TC4 titanium alloy powder, 35g tungsten carbide, 17.5g silicon nitride, 6g yttrium oxide; Reinforcing layer: 45g silicon carbide whiskers, 105g cubic zirconium oxide, 55g strontium titanate, 17.5g molybdenum disilicide, and 22.5g zirconium nitride; Surface functional layer: 55g hydroxyapatite, 27.5g 45S5 bioactive glass, 17.5g titanium nitride, 12.5g titanium dioxide, 6g silver powder; Composite coating: 350g hydroxyapatite, 150g titanium nitride, and 11g silicon dioxide (accounting for 2.2% of the total mass of the mixed powder); The preparation steps are as follows: S1: Raw material pretreatment: The base layer raw material is coarsely crushed to 110 mesh and ball-milled at 320 r / min and a ball-to-material ratio of 5:1 for 1.6 hours; the reinforcing layer raw material is ball-milled at 520 r / min and a ball-to-material ratio of 8:1 under nitrogen protection for 2.2 hours; the surface functional layer raw material is crushed to 200 mesh and then stirred for 30 minutes. S2: Layered powder application: Apply base layer mixed powder (0.125mm), reinforcement layer mixed powder (0.035mm), and surface functional layer mixed powder (0.022mm); S3: Segmented sintering: Vacuum degree 0.002MPa, heat up to 600℃ at 6℃ / min and hold for 1 hour, then heat up to 1120℃ and hold for 2.2 hours, cool down to 800℃ at 3.5℃ / min and hold for 1 hour, then cool with the furnace; S4: Shaping process: Grind to 0.2mm thickness and cut into the rough shape; S5: Surface treatment: 16° ​​opening angle; coating powder drying at 85℃ for 2.2 hours, ball milling at 300r / min for 1 hour, ball-to-material ratio 4:1; plasma spraying (argon 32L / min, hydrogen 5.5L / min, current 310A, voltage 62V, distance 105mm, powder feed 22g / min) to form a 3.5μm composite coating; vacuum annealing at 420℃ for 1.2 hours, polishing; Performance indicators Test Results Hardness (HV) 1780 Flexural strength (MPa) 2250 Antibacterial rate of Escherichia coli (%) 93 Cell viability (%) 90 Coating adhesion (MPa) 52 Composite coating thickness (μm) 3.5 Sharpening angle (°) 16 Total blade thickness (mm) 0.2 The product in this embodiment exhibits stable and reliable performance, with all indicators within a reasonable range. Its hardness is HV1780, and the amount of tungsten carbide in the base layer is increased to 35g, further improving local hardness compared to Example 1. Its flexural strength is 2250MPa, and the appropriate amount of silicon carbide whiskers in the reinforcing layer (45g) is achieved. After ball milling at 520r / min for 2.2 hours, the whiskers are evenly dispersed, demonstrating significant reinforcement without agglomeration. It achieves a 93% antibacterial rate against E. coli and a 90% cell survival rate. The composite coating thickness is 3.5μm, and the spraying parameters are reasonably set, resulting in a uniform coating without pinholes. The coating adhesion is 52MPa, and annealing at 420℃ effectively eliminates internal stress during spraying, improving adhesion performance. The 16° sharpening angle provides the blade with excellent cutting sharpness, meeting the needs of delicate surgery. Overall, the raw material ratio and process parameters in this embodiment are reasonably designed, the product performance meets clinical requirements, and the safety of use is also taken into account, further verifying the universality and reliability of the technical solution of this invention.

[0025] Comparative Example 1: Please see Figure 1 The present invention provides a comparative scheme, including the following raw material ratio: Grassroots level: Same as Example 3; Surface functional layer: Same as in Example 3; Composite coating: Same as in Example 3; The preparation steps are as follows: Except for the layering of the base layer mixed powder (0.17 mm) and the surface functional layer mixed powder (0.03 mm) during the layered powder application, the remaining steps are the same as in Example 3; Performance indicators Test Results Hardness (HV) 1600 Flexural strength (MPa) 1800 Antibacterial rate of Escherichia coli (%) 92 Cell viability (%) 91 Coating adhesion (MPa) 53 Composite coating thickness (μm) 4 Sharpening angle (°) 18 Total blade thickness (mm) 0.2 The data in the table above show that the mechanical properties of this comparative example are significantly reduced due to the lack of a reinforcing layer; the hardness is only HV1600, which is 12.1% lower than that of Example 3; the bending strength is 1800MPa, which is 23.4% lower than that of Example 3. The main reason is the lack of the reinforcing and toughening effect of 50g of silicon carbide whiskers and the wear-resistant support effect of 110g of cubic zirconia in the reinforcing layer, which leads to a significant reduction in the bending deformation resistance of the blade; while the antibacterial rate of E. coli (92%) and cell survival rate (91%) are close to those of Example 3. Since the biocompatibility and antibacterial components of the surface functional layer and composite coating are not missing, it indicates that the surface functional layer plays a dominant role in biological performance; the coating adhesion is 53MPa, which is not much different from that of Example 3, indicating that the adhesion performance of the composite coating mainly depends on the spraying process and is not related to the presence or absence of the reinforcing layer.

[0026] Comparative Example 2: Please see Figure 1 The present invention provides a comparative scheme, including the following raw material ratio: Grassroots level: Same as Example 3; Reinforcement layer: Same as in Example 3; Composite coating: Same as in Example 3; The preparation steps are as follows: Except for the layering of the base layer mixed powder (0.15mm) and the reinforcing layer mixed powder (0.05mm) during the layered powder application, the remaining steps are the same as in Example 3; Performance indicators Test Results Hardness (HV) 1800 Flexural strength (MPa) 2300 Antibacterial rate of Escherichia coli (%) 60 Cell viability (%) 75 Coating adhesion (MPa) 54 Composite coating thickness (μm) 4 Sharpening angle (°) 18 Total blade thickness (mm) 0.2 As shown in the table above, the biocompatibility of this comparative example is significantly deteriorated due to the lack of a surface functional layer; the antibacterial rate of E. coli is only 60%, a decrease of 36.8% compared to Example 3; the cell survival rate is 75%, a decrease of 18.5% compared to Example 3. The core reason is the lack of antibacterial components such as 7.5g of silver powder and 15g of titanium dioxide, as well as biocompatible components such as 60g of hydroxyapatite and 30g of 45S5 bioactive glass in the surface functional layer. The hydroxyapatite in the composite coating alone cannot compensate for the lack of biocompatibility. In terms of mechanical properties, the hardness HV1800 and bending strength 2300MPa are similar to those of Example 3, decreasing by 1.1% and 2.1% respectively. Since the mechanical support structure of the base layer and the reinforcing layer is intact, the reinforcing effect of silicon carbide whiskers and cubic zirconia is not affected, indicating that the reinforcing layer and the base layer are the key to ensuring the mechanical properties of the blade.

[0027] Comparative Example 3: Please see Figure 1 The present invention provides a comparative scheme, including the following raw material ratio: Base layer, reinforcement layer, surface functional layer: Same as in Example 3 The preparation steps are as follows: Except for the absence of composite coating preparation and subsequent annealing steps in surface treatment, the other steps are the same as in Example 3; Performance indicators Test Results Hardness (HV) 1700 Flexural strength (MPa) 2200 Antibacterial rate of Escherichia coli (%) 85 Cell viability (%) 88 Coating adhesion (MPa) none Sharpening angle (°) 18 Total blade thickness (mm) 0.2 The data in the table above show that the surface properties of this comparative example are significantly reduced due to the lack of a composite coating; the hardness HV1700 is 6.6% lower than that of Example 3; the antibacterial rate of E. coli is 85%, a decrease of 10.5% compared to Example 3; and the cell survival rate is 88%, a decrease of 4.3% compared to Example 3. This is mainly due to the lack of surface strengthening effect of titanium nitride in the composite coating and the biocompatibility supplementation of hydroxyapatite, resulting in a decrease in surface hardness, antibacterial properties, and biocompatibility. However, the bending strength is 2200 MPa, a decrease of only 6.4% compared to Example 3, indicating that the composite coating has little impact on the mechanical properties and sintering quality of the blade body. Its core function is to optimize surface properties, improve wear resistance, and extend service life.

[0028] A comprehensive comparative analysis of Examples 1-4 and Comparative Examples 1-3 reveals that Examples 1-4, with their complete three-layer structure, achieve a bending strength of 2200-2500 MPa and a hardness of HV1750-1900. In contrast, Comparative Example 1, lacking a reinforcing layer, suffers a sharp drop in bending strength (23.4%) and hardness (12.1%) due to the loss of the three-dimensional network reinforcement of silicon carbide whiskers and the wear-resistant support of cubic zirconia. This demonstrates that the synergistic combination of silicon carbide whiskers and cubic zirconia in the reinforcing layer effectively addresses the core problem of thin blades being prone to bending and deformation. Furthermore, the base layer in these examples, through the optimized ratio of cubic boron nitride to TC4 titanium alloy, retains the high hardness of cubic boron nitride while leveraging the toughness of titanium alloy to prevent brittle fracture, resulting in a bending strength increase of over 30% compared to traditional single-metal blades.

[0029] Examples 1-4 showed an antibacterial rate of 92%-98% and a cell survival rate of 88%-95% for E. coli. In contrast, Comparative Example 2, which lacked a surface functional layer, suffered a sharp drop in antibacterial rate (36.8%) and cell survival rate (18.5%) due to the absence of biocompatible components such as hydroxyapatite and 45S5 bioactive glass, as well as antibacterial components such as silver powder and titanium dioxide. This highlights that the precise combination of components in the surface functional layer effectively solves the clinical problems of allergies and postoperative infections caused by traditional metal blades. The similarity between hydroxyapatite and human bone tissue components, along with the broad-spectrum antibacterial properties of silver powder, provides a dual guarantee of biocompatibility and antibacterial protection.

[0030] The composite coatings in Examples 1-4 exhibited a bonding strength of 50-60 MPa, with uniform coating thickness and low surface roughness. In contrast, Comparative Example 3, which did not have a composite coating, showed a 6.6% decrease in hardness and a 40% reduction in blade sharpness retention time. This confirms that the 7:3 ratio of hydroxyapatite to titanium nitride in the composite coating not only maintains biocompatibility but also enhances surface wear resistance through the high hardness of titanium nitride. Furthermore, the coating density is improved by the silica sintering aid, effectively avoiding the defects of traditional coatings such as easy peeling and insufficient wear resistance.

[0031] Furthermore, Examples 1-4 achieved stable and excellent performance output through gradient adjustment of raw material ratios and optimization of process parameters, proving that the technical solution has good universality and controllability; it also achieved a tight bond of multi-layer structure, improving the interlayer bonding force by more than 20% compared with existing multi-layer coated blades. In summary, this invention raises key indicators such as mechanical properties, biocompatibility, and wear resistance to a new level, not only solving many technical defects of traditional blades, but also providing an industrializable technical path for the preparation of high-performance surgical blades.

[0032] The testing method is as follows: I. Hardness (HV) Test The Vickers hardness tester (model: HV-1000) was used for testing. The non-cutting edge area in the middle of the blade was selected as the test surface. Before the test, the surface was wiped with alcohol to remove oil stains. The test load was set to 500g and the holding time was 15s. Five different points were evenly selected in the test area for indentation testing. The hardness value of each point was recorded. The final result was the arithmetic mean of the five data points.

[0033] II. Bending Strength (MPa) Test A three-point bending test was conducted using a universal testing machine (model: WDW-10). The blade was cut into specimens 30mm long and 5mm wide. Both ends of the specimens were sanded smooth. The span was set to 20mm, the loading rate to 0.5mm / min, and the loading direction perpendicular to the blade plane. The maximum load at which the specimen fractured was recorded. The bending strength was determined using the formula: "Bending strength = 3FL / (2bh)". 2 (where F is the maximum load, L is the span, b is the specimen width, and h is the specimen thickness) Calculate the bending strength. Test 3 specimens in each group and take the average value of the results.

[0034] III. Escherichia coli antibacterial rate (%) test The membrane method was used for testing. *E. coli* (ATCC25922) was inoculated into LB liquid medium and cultured at 37°C in a shaker for 18 hours. The bacterial concentration was then adjusted to 1×10⁻⁶. 6 For each CFU / mL culture, 0.1 mL of bacterial suspension was evenly spread on the surface of a sterile culture dish. A blade sample (cut to 10 mm × 10 mm) was placed face down on the bacterial suspension and incubated at 37°C for 24 h. A blank control group without the sample was also set up. After incubation, the culture dish was rinsed with sterile physiological saline. The rinsing solution was serially diluted and spread onto LB solid medium. After incubation at 37°C for 24 h, the number of colonies was counted. The antibacterial rate was calculated according to the formula "Antibacterial rate = (Number of colonies in control group - Number of colonies in experimental group) / Number of colonies in control group × 100%". Each group was tested 3 times, and the average value was taken.

[0035] IV. Cell viability (%) test The MTT assay was used, with L929 mouse fibroblasts selected as test cells. Cells were seeded in 96-well plates at a density of 5 × 10⁶ cells / well. 3Cells were cultured in a 37℃, 5% CO2 incubator for 24 hours. The blade was then cut into 8mm diameter circular samples, sterilized with UV light, and placed in the well plate. The plates were cultured for another 48 hours. 20 μL of LTT solution (5 mg / mL) was added to each well, and after incubation for 4 hours, the supernatant was removed. 150 μL of dimethyl sulfoxide (DMSO) was added and the plates were shaken for 10 minutes. The absorbance was measured at 490 nm using an ELX800 microplate reader. Cell viability was calculated using the formula: "Cell viability = (Experimental group absorbance / Blank control group absorbance) × 100%". Five replicates were used for each group, and the average value was taken.

[0036] V. Coating adhesion (MPa) test The pull-off test was conducted. The surface of the blade sample was roughened with sandpaper, and the coated surface of the sample was bonded to the tensile test block (made of 45 steel) with epoxy resin adhesive. After curing at room temperature for 24 hours, the coating adhesion tester (model: PosiTestAT-M) was used for testing. The loading rate was set to 10 N / s, and the maximum tensile force when the coating peeled off was recorded. The coating adhesion force was calculated according to the formula "adhesion force = maximum tensile force / bonded area". Three samples were tested in each group, and the average value of the results was taken.

[0037] VI. Composite Coating Thickness (μm) Test The scanning electron microscope (SEM, model: SU1510) was used for testing. The blade sample was cut along the cross section, and after inlaying, grinding and polishing, it was sprayed with gold. The morphology of the coating in the cross section was observed under SEM. The coating thickness was measured at 5 different locations. The data were recorded and the arithmetic mean was taken. The thickness deviation (deviation = maximum value of |single measurement value - average value|) was calculated.

[0038] VII. Opening Angle (°) Test The test was conducted using a tool microscope (model: XTL-200). The blade was fixed on the stage with the cutting edge facing upwards. The microscope's focus was adjusted until the cross-section of the cutting edge was clear. The included angle between the two sides of the cutting edge was measured five times at different positions (2mm intervals) using the microscope's built-in angle measurement function. The average value of the results was taken.

[0039] 8. Test of total blade thickness (mm) The test was conducted using a digital micrometer (accuracy: 0.001mm). Three test points were selected at the middle of the blade, near the cutting edge, and near the connecting end of the blade holder. Each point was measured twice, and the arithmetic mean of the six data points was taken after recording the data.

[0040] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific technical solutions or characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A surgical blade, characterized in that, It adopts a three-layer composite structure, consisting of a base layer, a reinforcement layer, and a surface functional layer from the inside out; The base layer is composed of the following raw materials in parts by weight: 75-80 parts cubic boron nitride, 15-20 parts titanium alloy powder, 5-8 parts tungsten carbide, 3-5 parts silicon nitride, and 1-2 parts yttrium oxide. The reinforcing layer is composed of the following raw materials in parts by weight: 8-12 parts silicon carbide whiskers, 20-25 parts cubic zirconium oxide, 10-15 parts strontium titanate, 3-5 parts molybdenum disilicide, and 4-6 parts zirconium nitride. The surface functional layer is composed of the following raw materials in parts by weight: 10-15 parts hydroxyapatite, 5-8 parts bioactive glass, 3-5 parts titanium nitride, 2-4 parts titanium dioxide, and 1-2 parts silver powder.

2. The scalpel blade according to claim 1, characterized in that, The titanium alloy powder is TC4 titanium alloy powder with a particle size of 50-100μm; the bioactive glass is 45S5 bioactive glass with a particle size of 20-50μm.

3. The scalpel blade according to claim 1, characterized in that, The silicon carbide whiskers have a length of 15-25 μm and a diameter of 0.8-1.2 μm; the hydroxyapatite has a particle size of 10-30 μm.

4. The scalpel blade according to claim 1, characterized in that, The thickness of the base layer is 0.12-0.15 mm, the thickness of the reinforcing layer is 0.03-0.05 mm, and the thickness of the surface functional layer is 0.02-0.03 mm.

5. A method for preparing a surgical blade as described in any one of claims 1-4, characterized in that, Includes the following steps: S1: Raw material pretreatment: Weigh the raw materials of the base layer, reinforcing layer and surface functional layer according to the weight parts. First, coarsely crush the cubic boron nitride, tungsten carbide and silicon nitride in the base material to 100-150 mesh, then mix them with titanium alloy powder and yttrium oxide and put them into a ball mill. Then, ball mill them at a speed of 300-400 r / min for 1.5-2 hours to obtain the base layer mixed powder. After mixing the reinforcing layer raw materials, they are placed in a planetary ball mill and ball-milled at a speed of 500-600 r / min for 2-3 hours under nitrogen protection to obtain the reinforcing layer mixed powder. Hydroxyapatite, bioactive glass, and titanium dioxide in the surface functional layer raw materials are mixed and pulverized to 200 mesh, and then mixed with titanium nitride and silver powder to obtain surface functional layer mixed powder. S2: Layered powder spreading: The base layer mixed powder is evenly spread on the bottom of the sintering mold with a thickness controlled at 0.12-0.15mm. Then, the reinforcing layer mixed powder is evenly spread on the surface of the base layer mixed powder with a thickness of 0.03-0.05mm. Finally, the surface functional layer mixed powder is spread on the surface of the reinforcing layer mixed powder with a thickness of 0.02-0.03mm to form a multi-layered green body. S3: Segmented sintering: The mold containing the multi-layered billet is placed in a vacuum sintering furnace. First, the vacuum is drawn to 0.001-0.005MPa, the temperature is raised to 600℃ and held for 1 hour, then the temperature is raised to 1100-1200℃ and held for 2-3 hours, then the temperature is lowered to 800℃ and held for 1 hour, and finally the furnace is cooled to room temperature to produce multi-layered block billets. S4: Forming process: The multi-layered block blank is placed on a vertical grinding machine and ground to a total thickness of 0.2mm, and then cut into the prototype of a surgical scalpel blade by a CNC milling machine; S5: Surface treatment: The blade prototype is machine-sharpened at an angle of 15-20°. Then, a composite coating with a thickness of 3-5μm is sprayed onto its surface using plasma spraying technology. Finally, the sprayed blade is placed in a vacuum annealing furnace and kept at 400-500℃ for 1-2 hours. After cooling to room temperature in the furnace, it is polished to obtain the scalpel blade.

6. The preparation method according to claim 5, characterized in that, The ball-to-material ratio during ball milling of the base layer raw material in S1 is 5:1; the ball-to-material ratio during ball milling of the reinforcing layer raw material is 8:

1.

7. The preparation method according to claim 5, characterized in that, The heating rate in S3 is 5-10℃ / min, and the cooling rate is 3-5℃ / min.

8. The preparation method according to claim 5, characterized in that, The S5 plasma coating is prepared through the following steps: the blade prototype is fixed on the spraying worktable, and atmospheric plasma spraying equipment is used, with argon as the ion gas and hydrogen as the auxiliary gas. The ion gas flow rate is 30-40L / min, the auxiliary gas flow rate is 5-8L / min, the spraying current is 300-350A, the spraying voltage is 60-70V, the spraying distance is 100-120mm, and the powder feeding rate is 20-30g / min. The coating powder is uniformly sprayed onto the blade surface to form a composite coating with a thickness of 3-5μm.

9. The preparation method according to claim 5, characterized in that, The composite coating in S5 is prepared according to the following steps: hydroxyapatite powder and titanium nitride powder are weighed at a weight ratio of 7:3, and 2-3% of silica sintering aid is added to the total mass of the mixed powder. After mixing, the powder is placed in a vacuum drying oven and dried at 80-100℃ for 2-3 hours. Then, it is placed in a ball mill and ball-milled at 300r / min for 1 hour. The ball-to-material ratio during ball milling is 4:

1. The powder is then passed through a 200-mesh sieve to obtain the coating powder.

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