High-antibacterial-property ceramic bone nail and preparation method thereof

Abstract

The invention belongs to the technical field of silicon nitride ceramics, and particularly relates to a high-antibacterial-property ceramic bone nail and a preparation method thereof.The preparation method comprises the following steps that silicon nitride, a sintering aid, a metal reagent and a plasticizer are mixed, and a mixture is obtained; ball-milling and mixing the mixture, a solvent and grinding medium balls to obtain slurry; performing granulation treatment on the slurry to obtain spherical powder; injecting the spherical powder into a forming mold, and forming to obtain a biscuit; and the biscuit is subjected to powder burying sintering, and a ceramic bone nail finished product is obtained after processing.

Description

Technical Field

[0001] The present invention belongs to the technical field of silicon nitride ceramics, and in particular relates to a highly antibacterial ceramic bone nail and a preparation method thereof. Background Art

[0002] Existing bone screws are mostly made of metal, which offers excellent tensile strength and toughness, making it suitable for repairing hard tissue defects and enjoying widespread application. However, metal bone screws have drawbacks such as poor corrosion resistance, lack of effect on osteoblast adhesion and growth, and trace biotoxicity. Furthermore, metal materials can wear or corrode after implantation, producing toxic metal ions or particles that can easily lead to inflammatory cascades. Therefore, they are unsuitable for long-term implantation and repair of large bone defects. After bone repair, a secondary surgery is required to remove the metal bone screw to prevent complications such as inflammation. Summary of the Invention

[0003] In a first aspect, the present invention provides a method for preparing a highly antibacterial ceramic bone nail, comprising the following steps:

[0004] mixing silicon nitride, a sintering aid, a metal reagent, and a plasticizer to obtain a mixture;

[0005] ball milling the mixture, the solvent and grinding balls to obtain a slurry;

[0006] granulating the slurry to obtain spherical powder;

[0007] The spherical powder is injected into a forming mold to obtain a green blank after forming;

[0008] The green blank is subjected to powder embedding and sintering to obtain a finished ceramic bone screw.

[0009] Compared with the existing technology, the beneficial effects of the present invention are: silicon nitride is combined with a metal reagent, and the composite silicon nitride alloy (such as silicon magnesium nitride, titanium nitride, silicon nitride reinforced silver base, silicon nitride reinforced copper base) formed after sintering can retain the inert characteristics of ceramics and have excellent mechanical properties such as wear resistance and corrosion resistance; at the same time, it also has excellent biocompatibility (i.e., no cytotoxicity), and the particles and granules after wear will not cause an inflammatory cascade reaction, which greatly improves the antibacterial property of the ceramic bone nail and is beneficial to promoting bone growth.

[0010] Preferably, by weight, the silicon nitride is 85-97 parts, the sintering aid is 1-9 parts, the metal reagent is 1-9 parts, and the plasticizer is 1-9 parts.

[0011] Preferably, the sintering aid includes any one or more of calcium oxide, aluminum oxide, magnesium oxide, and yttrium oxide.

[0012] Preferably, the metal reagent includes any one or more of titanium ferrosilicon, magnesium aluminum alloy, silver nitrate and copper oxide.

[0013] The beneficial effects of this preferred embodiment are as follows: during the sintering process, the metal reagent can improve the bonding between the matrix and the silicon nitride aggregate, promoting the growth and development of nitride crystals. Among them, TiN and Fe formed by the nitridation of Ti in titanium ferrosilicon can accelerate the nitridation reaction, and ferrosilicide promotes the nitridation process by reacting with nitrogen by generating silicon vapor. Under certain conditions, Si and Fe can also form silicon nitride fibers or whiskers through a "gas-liquid-solid" mechanism, acting as a catalyst, which can effectively improve the densification and mechanical properties of the finished product.

[0014] Magnesium-aluminum alloy and silicon nitride aggregate decompose at high temperatures to produce Si ions and Mg ions. Under nitrogen conditions, Si ions and Mg ions have strong adsorption properties and can combine to form MgSiN2. MgSiN2 improves the toughness and strength of ceramic bone screws. The decomposition of N ions can also increase antibacterial properties, and Mg ions are beneficial to promote bone growth.

[0015] During the sintering process, silver nitrate is formed in situ, which reduces the agglomeration of Ag during the sintering process and reduces the Ag particle size, which is beneficial to accelerate the phase transformation rate of silicon nitride ceramics and enhance the antibacterial properties of ceramic bone nails.

[0016] During the sintering process, the Cu in copper oxide reacts with silicon nitride to form Cu3Si, which is beneficial to improving the wettability of the ceramic interface, increasing the density of the ceramic material, and enhancing the mechanical properties and thermal conductivity of the ceramic bone nail.

[0017] Preferably, the plasticizer includes any one or more of polyvinyl alcohol, methyl cellulose, and polyethylene glycol.

[0018] Preferably, the mass ratio of the mixture, solvent and grinding balls is 1:1:2, and the ball milling time is not less than 48 hours.

[0019] Preferably, the spherical powder is added to a rubber mold, and the rubber mold is placed in a cold isostatic press, under a pressure of 180 MPa or more, to obtain a silicon nitride blank after molding.

[0020] Preferably, the green blank is placed in embedding powder, and the embedding powder includes any one or more of graphite, silicon nitride, and boron nitride.

[0021] The sintering process is carried out under an inert protective atmosphere with a pressure of 0.8-10 MPa and a sintering temperature of 1680-1800°C.

[0022] Preferably, the processing includes grinding and sandblasting.

[0023] In a second aspect, the present invention further provides a highly antibacterial ceramic bone nail, which is prepared using the above-mentioned preparation method.

[0024] Compared with the prior art, the beneficial effect of the present invention is that the ceramic bone nail of the present invention not only retains the wear resistance and corrosion resistance of ceramics, but also has excellent biocompatibility and antibacterial properties, does not cause inflammation, and is conducive to promoting bone growth. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a flow chart of a method for preparing a highly antibacterial ceramic bone screw according to an embodiment of the present invention. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0027] Example 1

[0028] This embodiment provides a method for preparing a highly antibacterial ceramic bone nail, such as Figure 1 As shown, the following steps are included:

[0029] Step 1: Weigh 85 parts by weight of silicon nitride, 9 parts of a sintering aid, 9 parts of a metal reagent, and 9 parts of a plasticizer and mix them to obtain a mixture. The sintering aid includes calcium oxide and aluminum oxide, the metal reagent includes magnesium-aluminum alloy and titanium-silicon-iron, and the plasticizer includes polyvinyl alcohol, methyl cellulose, and polyethylene glycol.

[0030] Step 2: ball-milling the mixture, solvent, and grinding balls to obtain a slurry, wherein the mass ratio of the mixture, solvent, and grinding balls is 1:1:2, and the ball-milling time is not less than 48 hours.

[0031] Step 3: Add the slurry into the stirring barrel of the spray granulation tower, and spray granulate to obtain spherical powder of 40-70 μm.

[0032] Step 4: Add the spherical powder to a rubber mold vibrating on an artificial vibration platform; vibrate the powder until it is fully filled and compacted, then seal the mold. The rubber mold is then placed in a cold isostatic press and pressed at a pressure exceeding 180 MPa to form a silicon nitride blank. In this embodiment, the blank is preferably ground to approximately 1.2 times the size of the final product to reduce processing costs and allow for a sintering margin.

[0033] Step 5: Place the green blank in a embedding powder containing graphite, and sinter the green blank to obtain a blank. The sintering process is carried out under a nitrogen atmosphere at a pressure of 0.8 MPa and a sintering temperature of 1680°C.

[0034] Step 6: Process the blank according to the required bone screw size using a CNC machining center, and perform sandblasting using silicon nitride particles as raw materials to obtain a finished ceramic bone screw.

[0035] Example 2

[0036] This embodiment provides a method for preparing a highly antibacterial ceramic bone nail, such as Figure 1 As shown, the following steps are included:

[0037] Step 1: Weigh 90 parts by weight of silicon nitride, 5 parts of a sintering aid, 5 parts of a metal reagent, and 5 parts of a plasticizer and mix them to obtain a mixture. The sintering aid includes calcium oxide, aluminum oxide, magnesium oxide, and yttrium oxide; the metal reagent includes magnesium-aluminum alloy, titanium-silicon-iron, silver nitrate, and copper oxide; and the plasticizer includes polyvinyl alcohol and polyethylene glycol.

[0038] Step 2: ball-milling the mixture, solvent, and grinding balls to obtain a slurry, wherein the mass ratio of the mixture, solvent, and grinding balls is 1:1:2, and the ball-milling time is not less than 48 hours.

[0039] Step 3: Add the slurry into the stirring barrel of the spray granulation tower, and spray granulate to obtain spherical powder of 40-70 μm.

[0040] Step 4: Add the spherical powder to a rubber mold vibrating on an artificial vibration platform; vibrate the powder until it is fully filled and compacted, then seal the mold. The rubber mold is then placed in a cold isostatic press and pressed at 190 MPa to form a silicon nitride blank. In this embodiment, the blank is preferably ground to approximately 1.2 times the size of the final product to reduce processing costs and allow for a sintering margin.

[0041] Step 5: Place the green blank in a powder embedding process comprising silicon nitride, and sinter the green blank to obtain a blank. The sintering process is carried out under a nitrogen atmosphere at a pressure of 5 MPa and a sintering temperature of 1740°C.

[0042] Step 6: Process the blank according to the required bone screw size using a CNC machining center, and perform sandblasting using silicon nitride particles as raw materials to obtain a finished ceramic bone screw.

[0043] Example 3

[0044] This embodiment provides a method for preparing a highly antibacterial ceramic bone nail, such as Figure 1 As shown, the following steps are included:

[0045] Step 1: Weigh 97 parts by weight of silicon nitride, 1 part of a sintering aid, 1 part of a metal reagent, and 1 part of a plasticizer, and mix them to obtain a mixture. The sintering aid comprises aluminum oxide, the metal reagent comprises silver nitrate and copper oxide, and the plasticizer comprises polyvinyl alcohol.

[0046] Step 2: The mixture, solvent, and grinding balls are ball-milled to obtain a slurry, wherein the mass ratio of the mixture, solvent, and grinding balls is 1:1:2, and the ball-milling time is 50 hours.

[0047] Step 3: Add the slurry into the stirring barrel of the spray granulation tower, and spray granulate to obtain spherical powder of 40-70 μm.

[0048] Step 4: Add the spherical powder to a rubber mold vibrating on an artificial vibration platform; vibrate the powder until it is fully filled and compacted, then seal the mold. The rubber mold is then placed in a cold isostatic press and pressed at 200 MPa to form a silicon nitride blank. In this embodiment, the blank is preferably ground to approximately 1.2 times the size of the final product to reduce processing costs and allow for a sintering margin.

[0049] Step 5: Place the green blank into a powder embedding agent, wherein the powder embedding agent comprises silicon nitride, and sinter the green blank to obtain a blank. The sintering process is carried out under a nitrogen atmosphere at a pressure of 10 MPa and a sintering temperature of 1800°C.

[0050] Step 6: Process the blank according to the required bone screw size using a CNC machining center, and perform sandblasting using silicon nitride particles as raw materials to obtain a finished ceramic bone screw.

[0051] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions described in the above embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a highly antibacterial ceramic bone nail, characterized in that: The following steps are involved: mixing silicon nitride, a sintering aid, a metal reagent, and a plasticizer to obtain a mixture; ball milling the mixture, the solvent and grinding balls to obtain a slurry; granulating the slurry to obtain spherical powder; The spherical powder is injected into a forming mold to obtain a green blank after forming; The green blank is subjected to powder embedding and sintering to obtain a finished ceramic bone screw.

2. The method for preparing a highly antibacterial ceramic bone nail according to claim 1, characterized in that: In parts by weight, the silicon nitride is 85-97 parts, the sintering aid is 1-9 parts, the metal reagent is 1-9 parts, and the plasticizer is 1-9 parts.

3. The method for preparing a highly antibacterial ceramic bone nail according to claim 1, characterized in that: The sintering aid includes any one or more of calcium oxide, aluminum oxide, magnesium oxide, and yttrium oxide.

4. The method for preparing a highly antibacterial ceramic bone nail according to claim 1, wherein: The metal reagent includes any one or more of magnesium-aluminum alloy, titanium-ferrosilicon, silver nitrate and copper oxide.

5. The method for preparing a highly antibacterial ceramic bone nail according to claim 1, wherein: The plasticizer includes any one or more of polyvinyl alcohol, methyl cellulose, and polyethylene glycol.

6. The method for preparing a highly antibacterial ceramic bone nail according to claim 1, characterized in that: The mass ratio of the mixture, solvent and grinding balls is 1:1:2, and the ball milling time is not less than 48 hours.

7. The method for preparing a highly antibacterial ceramic bone nail according to claim 1, characterized in that: The spherical powder is added into a rubber mold, and the rubber mold is placed in a cold isostatic press, under a pressure of more than 180 MPa, to obtain a silicon nitride blank after molding.

8. The method for preparing a highly antibacterial ceramic bone nail according to claim 1, characterized in that: The green blank is placed in embedding powder, wherein the embedding powder includes any one or more of graphite, silicon nitride, and boron nitride. The sintering process is carried out under an inert protective atmosphere with a pressure of 0.8-10 MPa and a sintering temperature of 1680-1800°C.

9. The method for preparing a highly antibacterial ceramic bone nail according to claim 1, characterized in that: The processing includes grinding and sand blasting.

10. A highly antibacterial ceramic bone screw, characterized in that: The highly antibacterial ceramic bone nail is prepared using the preparation method described in any one of claims 1-9.

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