A method and application of in-situ decarburization of SiC nanowires to reinforce dental all-ceramic materials

Abstract

This invention discloses a method and application for in-situ decarburization of SiC nanowires to reinforce dental all-ceramic materials, belonging to the field of biomedical ceramics technology. The method includes the following steps: first, SiC nanowires are prepared by polycondensation and carbothermal reduction using organosilicon and carbon sources as raw materials; then, they are mixed with a dispersion medium, dispersant, PVA solution, and 5Y-PSZ ceramic powder to prepare a composite powder; subsequently, a green body is prepared by spray granulation and dry pressing; finally, the finished product is obtained through atmospheric pressure sintering, decarburization treatment, and secondary sintering. This invention uses SiC nanowires as a precursor, doping and decarburizing 5Y-PSZ to in-situ transform the SiC nanowires into SiO2 nanowires. This achieves crack deflection, bridging, and pull-out strengthening of the nanowires themselves, while simultaneously forming synergistic strengthening with the compressive stress generated by decarburization, significantly improving the mechanical properties of the material. This solves the problems of insufficient strength and mismatch between the nano-reinforcing phase and the matrix interface in materials prepared by existing technologies.

Description

Technical Field

[0001] This invention relates to the field of biomedical ceramics technology, specifically to a method and application of in-situ decarburization of SiC nanowires to enhance dental all-ceramic materials. Background Technology

[0002] Zirconia dental all-ceramic materials have become important materials in the field of dental restoration due to their excellent biocompatibility, aesthetics, corrosion resistance, and high fracture toughness. In particular, 5Y-PSZ (5 mol% yttrium partially stabilized zirconia), as a new generation of zirconia dental all-ceramic materials, has a higher content of cubic phase and a lower content of tetragonal phase at room temperature compared to the traditional 3Y-TZP. This gives it not only good aesthetic properties but also superior hydrothermal stability and resistance to low-temperature aging, effectively avoiding the performance degradation caused by the t→m phase transition in physiological environments, and showing great potential in the field of dental restoration.

[0003] However, in order to improve its anti-aging and aesthetic properties, the 5Y-PSZ material has increased the stabilizer content, which to some extent sacrifices its phase transformation toughening effect, resulting in insufficient flexural strength. This deficiency in mechanical properties severely limits its widespread application in multi-unit bridges, implant abutments, and high-load-bearing bone repair scenarios.

[0004] Currently, the main methods for strengthening zirconia dental all-ceramic materials include second-phase particle dispersion strengthening, fiber strengthening, and nanowire strengthening. Among these, nanowire strengthening has received increasing attention in recent years and has gradually become one of the mainstream directions in 5Y-PSZ strengthening research. Unlike traditional particle or micron-sized fiber reinforcement, nanowire strengthening can improve the strength of all-ceramic materials without significantly affecting the original properties of the matrix material, through mechanisms such as crack deflection, bridging, and nanowire pull-out.

[0005] Current research on toughening and modifying zirconia dental all-ceramic materials using nanowires shows that while nanowires can improve fracture toughness and mechanical properties to some extent through mechanisms such as bridging, pull-out, and crack deflection, the overall toughening effect is still relatively limited. It falls significantly short of the stress-induced phase transformation toughening mechanism unique to zirconia itself, making it difficult to meet the mechanical performance requirements of prolonged chewing in the oral cavity. Furthermore, for aesthetic applications such as dental restorations, the introduced nanowires must achieve toughening while also considering the material's aesthetic properties.

[0006] Therefore, how to achieve more efficient and stable synergistic reinforcement is a bottleneck that urgently needs to be overcome in the current preparation technology of 5Y-PSZ zirconia dental all-ceramic materials. Summary of the Invention

[0007] To address the aforementioned technical problems, the present invention aims to provide a method and application for in-situ decarburization of SiC nanowires to reinforce dental all-ceramic materials, thereby solving the problems of insufficient strength and mismatch between the nano-reinforcing phase and the matrix interface in the preparation of 5Y-PSZ zirconia dental all-ceramic materials using existing technologies.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A first aspect of the present invention provides a method for in-situ decarburization of SiC nanowires to reinforce dental all-ceramic materials, comprising the following steps: Preparation of SiC nanowires: First, a precursor solution was prepared using organosilicon and organocarbon sources as raw materials; then, a polycondensation reaction was carried out at low temperature; finally, a high-temperature carbothermic reduction reaction was carried out under a protective atmosphere to obtain SiC nanowires. S2. Preparation of composite powder: The SiC nanowires obtained in S1, the dispersion medium, the dispersant, the PVA solution, and the 5Y-PSZ ceramic powder were mixed and stirred, and the solvent was removed to obtain SiC nanowire / 5Y-PSZ composite powder. S3. Green body forming: The composite powder obtained from S2 was spray granulated, and then the granulated powder was dry-pressed to obtain SiC nanowires / 5Y-PSZ ceramic green body. S4, Atmospheric pressure sintering: The green body obtained from S3 was sintered under a protective atmosphere at atmospheric pressure to obtain SiC nanowires / 5Y-PSZ composite ceramics. S5, Decarbonization treatment: The composite ceramic obtained from S4 was decarburized to prepare SiO2 nanowire-doped 5Y-PSZ all-ceramic material. S6, Secondary sintering: The SiO2 nanowires obtained from S5 were doped with 5Y-PSZ all-ceramic material and sintered under normal pressure in an air atmosphere to prepare SiC nanowire in-situ decarburized reinforced dental all-ceramic material.

[0009] The beneficial effects of this invention are as follows: This invention proposes a method for preparing an in-situ decarburized and reinforced all-ceramic material for dental use using SiC nanowires. The method employs a sol-gel process, using the generated SiC nanowires as a precursor. By doping 5Y-PSZ and controlling the decarburization process, the SiC nanowires are in-situ transformed into SiO2 nanowires. This achieves crack deflection, bridging, and pull-out reinforcement of the nanowires themselves, while simultaneously forming synergistic reinforcement with the compressive stress generated by decarburization, significantly improving the mechanical properties of the 5Y-PSZ all-ceramic material.

[0010] Furthermore, in S1, the solvent in the precursor solution is anhydrous ethanol and deionized water, and the mass ratio of organosilicon source, organic carbon source, anhydrous ethanol and deionized water is 1:(0.5-1.5):(2-4):(0.2-0.8). The organosilicon source is tetraethyl orthosilicate, the organic carbon source is phenolic resin, and the pH of the precursor solution is 2-4.

[0011] Furthermore, the precursor solution in S1 is prepared by the following method: first, tetraethyl orthosilicate is dissolved in anhydrous ethanol, deionized water is added and the pH is adjusted with hydrochloric acid, then the mixture is stirred and hydrolyzed to form a transparent sol, and finally phenolic resin is added and stirred for 1 h to obtain the precursor solution.

[0012] Furthermore, the hydrolysis temperature is 40-50℃ and the time is 1-3 h.

[0013] Furthermore, in S1, the polycondensation reaction is carried out at a temperature of 75-85℃ for 18-24 hours.

[0014] Furthermore, in S1, the temperature of the high-temperature carbothermic reduction reaction is 1450-1550℃, the time is 2-4 h, and the flow rate of the protective gas is 100-300 mL / h.

[0015] Furthermore, the protective atmosphere in S1 is an argon atmosphere.

[0016] The beneficial effects of adopting the above-mentioned further technical solution are as follows: The present invention forms a Si-O-Si framework and carbon network interpenetrating structure by low-temperature heating and polycondensation reaction, and then obtains SiC nanowire structure by high-temperature carbothermic reduction reaction under argon atmosphere.

[0017] Furthermore, the mass ratio of SiC nanowires, 5Y-PSZ ceramic powder, dispersion medium, dispersant and PVA solution in S2 is (1-5):1000:(3000-5000):(0.3-0.5):(100-180), the dispersion medium is deionized water, the dispersant is polyethylene glycol, and the concentration of PVA solution is 20 wt%-40 wt%.

[0018] Furthermore, the preparation of SiC nanowire / 5Y-PSZ composite powder in S2 specifically includes the following steps: first, SiC nanowires are dispersed in deionized water, then a dispersant is added, and after ultrasonic dispersion, 5Y-PSZ ceramic powder and PVA solution are added. The mixture is then magnetically stirred at a constant temperature and heated until the solvent is completely evaporated and dried to obtain SiC nanowire / 5Y-PSZ composite powder.

[0019] Furthermore, the ultrasonic dispersion power is 300-500 W, and the time is 30-60 min.

[0020] Furthermore, the magnetic stirring speed is 600-800 rpm.

[0021] Furthermore, the magnetic stirring temperature is 40-60℃.

[0022] Furthermore, the dry pressing conditions in S3 are as follows: first, hold the pressure at 20-50 MPa for 3-8 minutes, then increase the pressure to 80-120 MPa and hold for 10-16 minutes, and finally increase the pressure to 160-190 MPa and hold for 20-30 minutes.

[0023] Furthermore, the sintering temperature in S4 at atmospheric pressure is 1250-1350℃, the heating rate is 5-10℃ / min, and the holding time is 8-10 h.

[0024] Furthermore, the protective atmosphere in S4 is an argon atmosphere.

[0025] Furthermore, the decarbonization reaction gas in S5 is a mixture of oxygen and argon, with the oxygen flow rate being 30-90 mL / h and the argon flow rate being 100-250 mL / h.

[0026] Furthermore, the decarburization treatment temperature is 1000-1200℃, the heating rate is 1-3℃ / min, and the holding time is 6-8 h.

[0027] Furthermore, the sintering temperature of S6 under normal pressure is 1400-1550℃, the heating rate is 3-5℃ / min, and the holding time is 8-12 h.

[0028] In a second aspect, the present invention provides an in-situ decarburized SiC nanowire-reinforced dental all-ceramic material, prepared by the above-described method.

[0029] A third aspect of the present invention provides the application of the above-mentioned SiC nanowire in-situ decarburization reinforced dental all-ceramic material in the preparation of dental restorative medical devices.

[0030] The beneficial effects of this invention are as follows: the SiC nanowire in-situ decarburization reinforced dental all-ceramic material prepared by this invention has high strength and is adjustable, easy to prepare, and has good aesthetic properties. It can be applied to the preparation of a variety of dental restorative medical devices and has a wide range of applications.

[0031] In a fourth aspect, the present invention provides a dental prosthetic medical device, which is made of the above-mentioned SiC nanowire in-situ decarburization-reinforced dental all-ceramic material.

[0032] The present invention has the following beneficial effects: 1. This invention proposes for the first time a preparation strategy of "first introducing SiC nanowires, then in-situ decarburizing to form SiO2 nanowires". On the one hand, SiO2 nanowires retain the high aspect ratio morphology of SiC nanowires, which can play a role in crack deflection, bridging, and pull-out in the ceramic matrix; on the other hand, the volume expansion accompanying the decarburization of SiC to form SiO2 creates compressive stress at the nanowire / matrix interface, which can effectively close microcracks and hinder crack propagation. The synergistic effect of these two strengthening mechanisms significantly improves the mechanical properties of 5Y-PSZ (biaxial bending strength increased by 31.2%).

[0033] 2. The process of this invention is highly controllable: the internal compressive stress of the zirconia dental all-ceramic material can be adjusted by controlling the amount of SiC nanowires introduced, thus achieving adjustable strength.

[0034] 3. This invention is simple to operate, uses readily available raw materials, produces no toxic or harmful waste, and can be mass-produced. Furthermore, the introduced SiO2 nanowires possess excellent aesthetic properties, making them suitable for dental restorations such as all-ceramic crowns and dentures. Attached Figure Description

[0035] Figure 1 A schematic diagram of the preparation process for in-situ decarburization of SiC nanowires to enhance dental all-ceramic materials; Figure 2 The image shows the XRD pattern of the SiC nanowires obtained in Example 3, S1. Figure 3 This is a scanning electron microscope image of the SiC nanowires obtained in Example 3, S1. Figure 4 This is the energy spectrum spot scan of the SiC nanowires obtained in Example 3, S1; Figure 5 Energy dispersive spectroscopy (EDS) spot scan of SiC nanowires after S5 decarburization in Example 3; Figure 6 The biaxial bending test equipment and the sample before the biaxial bending test in Example 3 are shown. Figure 7 The images show the damage after biaxial bending tests in Comparative Example 3 and Examples 1-3; Figure 8 Load-displacement curves of dental all-ceramic materials prepared for Comparative Example 3; Figure 9 The load-displacement curve of the in-situ decarburized SiC nanowire-reinforced dental all-ceramic material prepared in Example 1 is shown. Figure 10 The load-displacement curve of the in-situ decarburized SiC nanowire-reinforced dental all-ceramic material prepared in Example 2 is shown. Figure 11 The load-displacement curve is shown for the in-situ decarburization of SiC nanowires to reinforce the dental all-ceramic material prepared in Example 3. Detailed Implementation

[0036] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer should be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0037] Example 1: A method for preparing in-situ decarburized SiC nanowires to reinforce dental all-ceramic materials (flow diagram shown) Figure 1 (As shown), including the following steps: Preparation of SiC nanowires: Weigh the raw materials according to the mass ratio of tetraethyl orthosilicate: phenolic resin: anhydrous ethanol: deionized water = 1:0.5:2:0.2. First, dissolve the tetraethyl orthosilicate in anhydrous ethanol and stir for 10 min; slowly add deionized water and adjust the pH to 2 with hydrochloric acid; stir and hydrolyze at 40℃ for 3 h to form a transparent sol. Then, slowly add the phenolic resin to the transparent sol, continue stirring for 10 min, place in an oven at 65℃ for 2 h to form a wet gel, then heat to 75℃ for condensation and dry for 24 h, and grind into a gel powder. Finally, the gel powder was placed in a crucible and then placed in a tube furnace. Argon gas was introduced (flow rate 100 mL / h), and the temperature was increased to 300℃ at a rate of 5℃ / min and held for 1 h to allow the phenolic resin to crosslink and cure. Then, the temperature was increased to 1000℃ at a rate of 5℃ / min and held for 1 h for pre-carbonization. Next, the temperature was increased to 1450℃ at a rate of 3℃ / min and held for 4 h. The mixture was then allowed to cool naturally to room temperature to obtain SiC nanowires.

[0038] Preparation of S2, SiC nanowires / 5Y-PSZ composite powder: The raw materials were weighed according to the mass ratio of SiC nanowires: 5Y-PSZ powder: deionized water: polyethylene glycol: PVA solution = 1:1000:3000:0.3:100. First, the SiC nanowires were dispersed in deionized water, and polyethylene glycol was added. The mixture was ultrasonically dispersed for 30 min at a power of 300 W. Then, 5Y-PSZ ceramic powder and PVA solution (concentration 20 wt%) were added. The mixture was magnetically stirred at 40℃ until dry at a stirring speed of 600 rpm to obtain the SiC nanowire / 5Y-PSZ composite powder.

[0039] S3. Green body forming: The SiC nanowire / 5Y-PSZ composite powder obtained from S2 was spray-granulated, and then the granulated powder was loaded into a stainless steel mold. It was first held at 20 MPa for 3 min, then the pressure was increased to 80 MPa and held for 10 min, and finally the pressure was increased to 160 MPa and held for 20 min to obtain the SiC nanowire / 5Y-PSZ preform.

[0040] S4, Atmospheric pressure sintering: First, the SiC nanowire / 5Y-PSZ preform obtained from S3 was placed in a tube furnace. After gas washing, argon gas was introduced at a flow rate of 100 mL / h. Then, the temperature was increased to 1250℃ at a rate of 5℃ / min and held for 10 h. After the holding period, the furnace was cooled to room temperature to obtain the SiC nanowire / 5Y-PSZ composite ceramic.

[0041] S5, Decarbonization treatment: First, the SiC nanowire / 5Y-PSZ composite ceramic obtained from S4 was placed in a tube furnace. After gas washing, argon gas was introduced at a flow rate of 100 mL / h. Then, the temperature was increased to 1000℃ at a heating rate of 1℃ / min, and a mixture of oxygen and argon gas was introduced, with the oxygen flow rate at 30 mL / h and the argon flow rate at 100 mL / h. After holding at this temperature for 6 h, the furnace was cooled to obtain the SiO2 nanowire-doped 5Y-PSZ all-ceramic material.

[0042] S6, Secondary Sintering The SiO2 nanowire-doped 5Y-PSZ all-ceramic material obtained from S5 was placed in a sintering furnace and heated to 1400℃ at a heating rate of 5℃ / min. It was held at that temperature for 12 h and then cooled with the furnace to obtain an in-situ decarburized and reinforced dental all-ceramic material made of SiC nanowires.

[0043] Example 2: A method for preparing in-situ decarburized SiC nanowires to reinforce dental all-ceramic materials (flow diagram shown) Figure 1 (As shown), including the following steps: Preparation of SiC nanowires: Weigh the raw materials according to the mass ratio of tetraethyl orthosilicate: phenolic resin: anhydrous ethanol: deionized water = 1:1:3:0.5. First, dissolve the tetraethyl orthosilicate in anhydrous ethanol and stir for 10 min; slowly add deionized water and adjust the pH to 3 with hydrochloric acid; stir and hydrolyze at 45℃ for 2 h to form a transparent sol. Then, slowly add the phenolic resin to the transparent sol, continue stirring for 10 min, place in an oven at 65℃ for 2 h to form a wet gel, then heat to 80℃ for condensation and dry for 21 h, and grind into a gel powder. Finally, the gel powder was placed in a crucible and then placed in a tube furnace. Argon gas was introduced (flow rate of 200 mL / h), and the temperature was increased to 300℃ at a rate of 5℃ / min and held for 1 h to allow the phenolic resin to crosslink and cure. Then, the temperature was increased to 1000℃ at a rate of 5℃ / min and held for 1 h for pre-carbonization. Next, the temperature was increased to 1500℃ at a rate of 3℃ / min and held for 3 h. The mixture was then allowed to cool naturally to room temperature to obtain SiC nanowires.

[0044] Preparation of S2, SiC nanowires / 5Y-PSZ composite powder: The raw materials were weighed according to the mass ratio of SiC nanowires: 5Y-PSZ powder: deionized water: polyethylene glycol: PVA solution = 3:1000:4000:0.4:140. First, the SiC nanowires were dispersed in deionized water, and polyethylene glycol was added. The mixture was ultrasonically dispersed for 45 min at a power of 400 W. Then, 5Y-PSZ ceramic powder and PVA solution (concentration 30 wt%) were added. The mixture was magnetically stirred at 50℃ until dry at a stirring speed of 700 rpm to obtain the SiC nanowire / 5Y-PSZ composite powder.

[0045] S3. Green body forming: The SiC nanowire / 5Y-PSZ composite powder obtained from S2 was spray-granulated, and then the granulated powder was loaded into a stainless steel mold. It was first held at 30 MPa for 5 min, then the pressure was increased to 100 MPa and held for 13 min, and finally the pressure was increased to 170 MPa and held for 25 min to obtain the SiC nanowire / 5Y-PSZ preform.

[0046] S4, Atmospheric pressure sintering: First, the SiC nanowire / 5Y-PSZ preform obtained from S3 was placed in a tube furnace. After gas washing, argon gas was introduced at a flow rate of 100 mL / h. Then, the temperature was increased to 1300℃ at a rate of 7℃ / min and held for 9 h. After the holding period, the furnace was cooled to room temperature to obtain the SiC nanowire / 5Y-PSZ composite ceramic.

[0047] S5, Decarbonization treatment: First, the SiC nanowire / 5Y-PSZ composite ceramic obtained from S4 was placed in a tube furnace. After gas washing, argon gas was introduced at a flow rate of 100 mL / h. Then, the temperature was increased to 1100℃ at a heating rate of 2℃ / min, and a mixture of oxygen and argon gas was introduced, with the oxygen flow rate at 60 mL / h and the argon flow rate at 200 mL / h. After holding at this temperature for 7 h, the furnace was cooled to obtain the SiO2 nanowire-doped 5Y-PSZ all-ceramic material.

[0048] S6, Secondary Sintering The SiO2 nanowire-doped 5Y-PSZ all-ceramic material obtained from S5 was placed in a sintering furnace and heated to 1450℃ at a heating rate of 4℃ / min. It was held for 10 h and then cooled with the furnace to obtain an in-situ decarburized and reinforced dental all-ceramic material made of SiC nanowires.

[0049] Example 3: A method for preparing in-situ decarburized SiC nanowires to reinforce dental all-ceramic materials (flow diagram shown) Figure 1 (As shown), including the following steps: Preparation of SiC nanowires: Weigh the raw materials according to the mass ratio of tetraethyl orthosilicate: phenolic resin: anhydrous ethanol: deionized water = 1:1.5:4:0.8. First, dissolve the tetraethyl orthosilicate in anhydrous ethanol and stir for 10 min; slowly add deionized water and adjust the pH to 4 with hydrochloric acid; stir and hydrolyze at 50℃ for 3 h to form a transparent sol. Then, slowly add the phenolic resin to the transparent sol, continue stirring for 10 min, place in an oven at 65℃ for 2 h to form a wet gel, then heat to 85℃ for condensation and dry for 18 h, and grind into a gel powder. Finally, the gel powder was placed in a crucible and then placed in a tube furnace. Argon gas was introduced (flow rate 300 mL / h), and the temperature was increased to 300℃ at a rate of 5℃ / min and held for 1 h to allow the phenolic resin to crosslink and cure. Then, the temperature was increased to 1000℃ at a rate of 5℃ / min and held for 1 h for pre-carbonization. Next, the temperature was increased to 1550℃ at a rate of 3℃ / min and held for 2 h. The mixture was then allowed to cool naturally to room temperature to obtain SiC nanowires.

[0050] Preparation of S2, SiC nanowires / 5Y-PSZ composite powder: The raw materials were weighed according to the mass ratio of SiC nanowires: 5Y-PSZ powder: deionized water: polyethylene glycol: PVA solution = 5:1000:5000:0.5:180. First, the SiC nanowires were dispersed in deionized water, and polyethylene glycol was added. The mixture was ultrasonically dispersed for 60 min at a power of 500 W. Then, 5Y-PSZ ceramic powder and PVA solution (concentration 40 wt%) were added. The mixture was magnetically stirred at 60℃ until dry at a stirring speed of 800 rpm to obtain the SiC nanowire / 5Y-PSZ composite powder.

[0051] S3. Green body forming: The SiC nanowire / 5Y-PSZ composite powder obtained from S2 was spray granulated, and then the granulated powder was loaded into a stainless steel mold. It was first held at 50 MPa for 8 min, then the pressure was increased to 120 MPa and held for 16 min, and finally the pressure was increased to 190 MPa and held for 30 min to obtain the SiC nanowire / 5Y-PSZ preform.

[0052] S4, Atmospheric pressure sintering: First, the SiC nanowire / 5Y-PSZ preform obtained from S3 was placed in a tube furnace. After gas washing, argon gas was introduced at a flow rate of 100 mL / h. Then, the temperature was increased to 1350℃ at a rate of 10℃ / min and held for 8 h. After the holding period, the furnace was cooled to room temperature to obtain the SiC nanowire / 5Y-PSZ composite ceramic.

[0053] S5, Decarbonization treatment: First, the SiC nanowire / 5Y-PSZ composite ceramic obtained from S4 was placed in a tube furnace. After gas washing, argon gas was introduced at a flow rate of 100 mL / h. Then, the temperature was increased to 1200℃ at a heating rate of 3℃ / min, and a mixture of oxygen and argon gas was introduced, with an oxygen flow rate of 90 mL / h and an argon flow rate of 250 mL / h. After holding at this temperature for 8 h, the furnace was cooled to obtain the SiO2 nanowire-doped 5Y-PSZ all-ceramic material.

[0054] S6, Secondary Sintering The SiO2 nanowire-doped 5Y-PSZ all-ceramic material obtained from S5 was placed in a sintering furnace and heated to 1550℃ at a heating rate of 3℃ / min. It was held at that temperature for 8 h and then cooled with the furnace to obtain an in-situ decarburized and reinforced dental all-ceramic material made of SiC nanowires.

[0055] Comparative Example 1: A zirconia dental all-ceramic material is prepared in a manner that differs from that of Example 1 in that S1 is not included in this comparative example, and SiC nanowires are not added in S2. The remaining steps are the same as in Example 1.

[0056] Comparative Example 2: A zirconia dental all-ceramic material is prepared in a manner that differs from that of Example 2 in that S1 is not included in this comparative example, and SiC nanowires are not added in S2. The remaining steps are the same as in Example 2.

[0057] Comparative Example 3: A zirconia dental all-ceramic material is prepared in a manner that differs from that of Example 3 in that S1 is not included in this comparative example, and SiC nanowires are not added in S2. The remaining steps are the same as in Example 3.

[0058] Experimental Example 1: XRD, Scanning Electron Microscopy and Energy Dispersive Spectroscopy Spot Scan Analysis The products obtained in Comparative Examples 1-3 of this invention have essentially the same characteristics. The following test is conducted using the sample obtained in Comparative Example 3 as an example: XRD, scanning electron microscopy, and energy dispersive spectroscopy were performed on the zirconia dental all-ceramic material prepared in Comparative Example 3 and the substance generated in S1 in Example 3, respectively. The results are as follows: Figure 2-4 As shown in the figure. Energy dispersive spectroscopy (EDS) spot scan analysis was performed on the products formed by S5, and the results are shown in the figure. Figure 5 As shown.

[0059] The results showed that the material formed by S1 in Example 3 was indeed SiC nanowires, and the product formed by S5 after decarburization treatment was SiO2 nanowires.

[0060] Test Example 2: Biaxial Bending Test Biaxial bending tests were performed on the zirconia dental all-ceramic materials prepared in Examples 1-3 and Comparative Examples 1-3, respectively.

[0061] According to the biaxial bending strength test standard in ISO 6872:2024, the international standard for dental ceramic materials, a universal testing machine was used for biaxial bending strength testing. The sample size was Φ15 (±0.5) mm × 1.5 (±0.3) mm, the loading range was 2 kN, the loading speed was 0.5 mm / min, and the preload force was set to 5 N. The computer collected relevant data through load and displacement sensors. The biaxial bending strength was obtained by the following calculation formula:

[0062] in:

[0063] In the formula: σ is the biaxial bending strength, MPa; P is the maximum load, N; b is the thickness of the sample, in mm; υ is the Poisson's ratio of the material, taken as 0.25; r1 is the radius of the supporting circle, in mm; r2 is the radius of the load area, in mm; r3 is the sample radius, in mm.

[0064] The biaxial bending performance test process is as follows: Figure 6 As shown, it includes a biaxial bending test equipment and a sample image of Example 3 before testing.

[0065] The products obtained from Comparative Examples 1-3 have basically the same characteristics. The following analysis of bending failure behavior is based on Comparative Example 3 as an example: The actual images of the fracture failures of Examples 1-3 and Comparative Example 3 after biaxial bending tests are shown below. Figure 7 As shown, the load-displacement correlation data during biaxial bending tests of different materials are respectively as follows: Figures 8-11 As shown in Table 1, the biaxial bending strength results are as follows.

[0066] Table 1. Results of Biaxial Bending Strength Test

[0067] Depend on Figures 8-11 It can be seen that the zirconia dental all-ceramic materials reinforced by in-situ decarburization of SiC nanowires in Examples 1-3 still maintain the brittle fracture behavior characteristic of ceramic materials. Table 1 shows that the biaxial bending strength of the zirconia dental all-ceramic materials reinforced by in-situ decarburization of SiC nanowires prepared according to the process of the present invention is greater than 500 MPa, which meets the strength requirements for dental all-ceramic materials in the international standard for dental ceramic materials ISO 6872:2024 (greater than 100 MPa for anterior teeth and greater than 500 MPa for molars). Among them, the sample reinforced by in-situ decarburization of SiC nanowires in Example 3 has the highest biaxial bending strength of 724 MPa, while the corresponding biaxial bending strength of the unreinforced zirconia dental all-ceramic material is only 552 MPa. The biaxial bending strength of the samples obtained in the examples of the present invention is improved by 31.2%, and the mechanical properties are significantly improved.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for in-situ decarburization of SiC nanowires to reinforce dental all-ceramic materials, characterized in that, Includes the following steps: Preparation of SiC nanowires: First, a precursor solution is prepared using organosilicon and organocarbon sources as raw materials; then, a polycondensation reaction is carried out by heating at low temperature. Finally, a high-temperature carbothermic reduction reaction was carried out under a protective atmosphere to obtain SiC nanowires; S2. Preparation of composite powder: The SiC nanowires obtained in S1, the dispersion medium, the dispersant, the PVA solution, and the 5Y-PSZ ceramic powder were mixed and stirred, and the solvent was removed to obtain SiC nanowire / 5Y-PSZ composite powder. S3. Green body forming: The composite powder obtained from S2 was spray granulated, and then the granulated powder was dry-pressed to obtain SiC nanowires / 5Y-PSZ ceramic green body. S4, Atmospheric pressure sintering: The green body obtained from S3 was sintered under a protective atmosphere at atmospheric pressure to obtain SiC nanowires / 5Y-PSZ composite ceramics. S5, Decarbonization treatment: The composite ceramic obtained from S4 was decarburized to prepare SiO2 nanowire-doped 5Y-PSZ all-ceramic material. S6, Secondary sintering: The SiO2 nanowires obtained from S5 were doped with 5Y-PSZ all-ceramic material and sintered under normal pressure in an air atmosphere to prepare SiC nanowire in-situ decarburized reinforced dental all-ceramic material.

2. The method for in-situ decarburization of SiC nanowires to reinforce dental all-ceramic materials according to claim 1, characterized in that, In S1, the solvent in the precursor solution is anhydrous ethanol and deionized water, and the mass ratio of organosilicon source, organic carbon source, anhydrous ethanol and deionized water is 1:(0.5-1.5):(2-4):(0.2-0.8). The organosilicon source is tetraethyl orthosilicate, the organic carbon source is phenolic resin, and the pH of the precursor solution is 2-4. The temperature for polycondensation is 75-85℃; The high-temperature carbothermic reduction reaction is carried out at a temperature of 1450-1550℃ for 2-4 hours, with a protective gas flow rate of 100-300 mL / h.

3. The method for in-situ decarburization of SiC nanowires to reinforce dental all-ceramic materials according to claim 1, characterized in that, The mass ratio of SiC nanowires, 5Y-PSZ ceramic powder, dispersion medium, dispersant and PVA solution in S2 is (1-5):1000:(3000-5000):(0.3-0.5):(100-180). The dispersion medium is deionized water, the dispersant is polyethylene glycol, and the concentration of PVA solution is 20 wt%-40 wt%.

4. The method for in-situ decarburization of SiC nanowires to reinforce dental all-ceramic materials according to claim 1, characterized in that, The dry pressing conditions in S3 are as follows: first, maintain pressure at 20-50 MPa for 3-8 minutes, then increase the pressure to 80-120 MPa and maintain pressure for 10-16 minutes, and finally increase the pressure to 160-190 MPa and maintain pressure for 20-30 minutes.

5. The method for in-situ decarburization of SiC nanowires to reinforce dental all-ceramic materials according to claim 1, characterized in that, The temperature for atmospheric pressure sintering in S4 is 1250-1350℃, the heating rate is 5-10℃ / min, and the holding time is 8-10 h.

6. The method for in-situ decarburization of SiC nanowires to reinforce dental all-ceramic materials according to claim 1, characterized in that, The decarbonization reaction gas in S5 is a mixture of oxygen and argon, with an oxygen flow rate of 30-90 mL / h and an argon flow rate of 100-250 mL / h. The decarburization treatment temperature is 1000-1200℃, the heating rate is 1-3℃ / min, and the holding time is 6-8 h.

7. The method for in-situ decarburization of SiC nanowires to reinforce dental all-ceramic materials according to claim 1, characterized in that, The temperature for atmospheric pressure sintering in S6 is 1400-1550℃, the heating rate is 3-5℃ / min, and the holding time is 8-12 h.

8. A SiC nanowire in-situ decarburization reinforced dental all-ceramic material, characterized in that, It is prepared by the preparation method according to any one of claims 1-7.

9. The application of the SiC nanowire in-situ decarburization reinforced dental all-ceramic material according to claim 8 in the preparation of dental restorative medical devices.

10. A medical device for dental restoration, characterized in that, The material is prepared by in-situ decarburization of SiC nanowires to enhance the dental all-ceramic material as described in claim 8.

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