Silicon carbide reinforced metal oxide composite and method of making same

Abstract

The application relates to the technical field of nuclear structural materials, and particularly discloses a silicon carbide reinforced metal oxide composite material and a preparation method thereof. The material comprises the following components in parts by weight: modified whiskers 2-8 parts, tungsten-molybdenum mixed powder 5-8 parts, and zirconium oxide-aluminum oxide mixed powder 80-98 parts; the modified whiskers are obtained by mixing silicon carbide whiskers and boron nitride whiskers in a weight ratio of 1:(0.2-0.8) and then performing a step of treatment with an amino reagent. The bending strength and fracture toughness of the material are significantly improved.

Description

Technical Field

[0001] This application relates to the technical field of nuclear structural materials, and more specifically, to a silicon carbide reinforced metal oxide composite material and a method for preparing the same. Background Technology

[0002] Fourth-generation nuclear energy systems include the following reactor types: lead-cooled fast reactors (LFR), sodium-cooled fast reactors (SFR), gas-cooled fast reactors (GFR), molten salt reactors (MSR), very high temperature reactors (VHTR), and supercritical water reactors (SCWR). Compared to second-generation commercial LWR reactors, the service temperature and radiation intensity of materials in fourth-generation nuclear energy systems and fusion nuclear energy systems have been significantly increased. Therefore, existing nuclear materials may not be applicable to advanced nuclear energy systems such as fourth-generation nuclear energy systems and fusion nuclear energy systems.

[0003] Materials used in the nuclear energy field need to possess properties such as high thermal conductivity, strong corrosion resistance, good radiation resistance, and thermal stability. Among these, radiation resistance is crucial for the safety of nuclear energy systems. Such materials, such as ceramics, have attracted widespread attention due to their high strength, high hardness, high temperature resistance, corrosion resistance, and good thermochemical stability. Some ceramics also exhibit low activity and low neutron absorption, making them potentially suitable for applications in high-temperature, high-radiation environments. Examples include metal oxide ceramics, and more specifically, alumina ceramics. Alumina ceramics possess high strength, high hardness, high resistivity, good thermal stability, wear resistance, low production cost, and mature technology.

[0004] However, alumina ceramics alone suffer from poor toughness. Therefore, related technologies often employ phase transformation toughening to improve the toughness of alumina, such as by adding zirconium oxide. However, the mechanical properties of materials obtained through single phase transformation toughening, when used as nuclear structural materials, do not meet the requirements. Therefore, further related technologies utilize phase transformation toughening and whisker toughening to further improve the toughness of alumina ceramics, thereby obtaining nuclear structural materials with excellent mechanical properties. For example, the addition of zirconium oxide and silicon carbide whiskers synergistically improves material properties; materials obtained using this method exhibit a flexural strength of 1150-1200 MPa and a fracture toughness of 3.3-3.6 MPa·m. 1 / 2 .

[0005] The silicon carbide reinforced metal oxide composite material prepared by this composition and method has relatively high flexural strength and fracture toughness. With the development of nuclear technology, the requirements for the mechanical properties of nuclear structural materials are also increasing. Therefore, it is necessary to provide a material with further improved mechanical properties. Summary of the Invention

[0006] To further improve the flexural strength and fracture toughness of silicon carbide-reinforced metal oxide composites for nuclear applications, this application provides a silicon carbide-reinforced metal oxide composite material and its preparation method.

[0007] In a first aspect, this application provides a silicon carbide reinforced metal oxide composite material, which adopts the following technical solution:

[0008] A silicon carbide-reinforced metal oxide composite material, the material comprising the following components in parts by weight:

[0009] 2-8 parts of modified whiskers, 5-8 parts of tungsten-molybdenum mixed powder, and 80-98 parts of zirconium oxide-alumina mixed powder; the modified whiskers are obtained by mixing silicon carbide whiskers and boron nitride whiskers in a weight ratio of 1:(0.2-0.8) and then treating them with an amino reagent.

[0010] Silicon carbide whiskers (also β-SiC) are cubic whiskers, belonging to the same crystal form as diamond; they possess good toughness and hardness. Boron nitride whiskers have a structure similar to graphite whiskers, with a hexagonal boron nitride structure and high strength. When whiskers are added to prepare ceramic materials, a stress field exists around the whiskers due to the mismatch in elastic modulus or thermal expansion at the interface between the whiskers and the matrix. When cracks occur in the material, the presence of this stress prevents the crack from continuing to propagate in its original direction, causing it to deflect. After the crack deflects, the applied stress needs to be further increased to allow the crack to continue propagating; therefore, crack deflection can produce a toughening effect. This application incorporates two types of whiskers with different structures. Through the synergistic effect of these two whiskers, crack deflection is more likely to occur when a crack in the material is generated. Furthermore, whisker bridging (the formation of a bridging region at the crack tip after crack propagation to the whisker, where the bridging whiskers exert a force on the matrix to close the crack and prevent further propagation) is significantly enhanced, ultimately leading to a significant improvement in the material's fracture toughness. In this scheme, the two types of whiskers are treated with an amino reagent, thereby improving the bonding between the whiskers and the matrix interface. This significantly enhances crack deflection and whisker bridging after crack initiation, thus improving the material's flexural strength and fracture toughness. Therefore, the modified whiskers achieve their effect through two synergistic effects: firstly, the two types of whiskers are different, resulting in more complex crack deflection and whisker bridging; secondly, the improved bonding force between the modified whiskers and the matrix interface contributes to the improvement and enhancement of the material's mechanical properties.

[0011] Furthermore, when alumina ceramics are reinforced with whiskers, the presence of dislocations and lattice distortions at the interface between the metal oxide and the whiskers will negatively impact the material's strength. However, when tungsten-molybdenum mixed powder is added, the tungsten-molybdenum metals disperse at the matrix interface during sintering, filling the space between the metal oxide and the whiskers to compensate for the strength loss caused by dislocations and lattice distortions, thereby ultimately improving the material's mechanical strength.

[0012] Therefore, this application achieves the goal of improving the flexural strength and fracture toughness of silicon carbide-reinforced metal oxide composites for nuclear applications by utilizing the crack deflection and whisker bridging effects of two types of modified whiskers, combined with the interface improvement effect of modified whiskers and the dispersion strengthening effect of tungsten and molybdenum metals.

[0013] Optionally, the silicon carbide whiskers have a purity of 99 wt% or higher, a diameter of 0.5-10 μm, and a length of 10-100 μm.

[0014] In some embodiments, the diameter of the silicon carbide whiskers is 600-1000 nm, 1-5 μm, or 5-10 μm; in one embodiment, the diameter of the silicon carbide whiskers is 600 nm, 800 nm, 1000 nm, 2 μm, 5 μm, 7.5 μm, or 10 μm.

[0015] In some embodiments, the length of the silicon carbide whiskers is 10-30 μm, 20-50 μm, 40-70 μm, 60-80 μm, or 75-100 μm; in one embodiment, the length of the silicon carbide whiskers is 10 μm, 25 μm, 45 μm, 70 μm, 95 μm, or 100 μm.

[0016] Optionally, the boron nitride whiskers have a purity of 99 wt% or higher and a diameter of 1-10 μm.

[0017] In some embodiments, the diameter of the boron nitride whiskers is 1-3 μm, 2-6 μm, 5-8 μm or 7-10 μm; in one embodiment, the diameter of the boron nitride whiskers is 1 μm, 2.5 μm, 4.5 μm, 6 μm, 8.5 μm or 10 μm.

[0018] Optionally, the amino reagent is selected from either ethylenediamine or dimethylethylenediamine.

[0019] Optionally, the method for treating silicon carbide whiskers and boron nitride whiskers with an amino reagent specifically includes the following steps:

[0020] The silicon carbide whiskers and boron nitride whiskers are mixed to obtain a whisker mixture;

[0021] The amino reagent is dissolved in ethanol to obtain an amino reagent solution, wherein the mass fraction of the amino reagent in the amino reagent solution is 10-20 wt%.

[0022] The whisker mixture was immersed in the amino reagent solution and ultrasonically mixed for 20-40 minutes. The solvent was removed and the mixture was dried to obtain modified whiskers.

[0023] By adopting the above technical solution, and using an appropriate amount of amino reagent solution to treat the whisker mixture by ultrasound, the modification effect of the amino reagent on the whiskers can be improved. Experimental results show that when the modified whiskers are used to prepare silicon carbide reinforced metal oxide composite materials, the toughness and mechanical properties of the materials are significantly improved.

[0024] In some embodiments, the amino reagent solution contains 10-13.5 wt%, 12-16.5 wt%, 14.5-18 wt%, or 17.8-20 wt% by mass; in one specific embodiment, the amino reagent solution contains 10 wt%, 12 wt%, 14.5 wt%, 17 wt%, or 19.5 wt% by mass.

[0025] Optionally, the zirconium oxide powder in the zirconium oxide-alumina powder is 13-27% of the alumina powder.

[0026] In the above technical solution, the alumina used is α-alumina.

[0027] Optionally, the particle size D of the zirconium oxide-alumina powder is: 0 < D < 75 μm.

[0028] Optionally, the zirconium oxide is specifically selected as yttrium-stabilized zirconium oxide, wherein the yttrium content of the zirconium oxide is 1-4 vol%.

[0029] In the above scheme, the yttrium content in the yttrium-stabilized zirconia is 3 vol%. This yttrium-stabilized zirconia is commercially available, and the raw material is readily available. Furthermore, this yttrium-stabilized zirconia exhibits excellent stability. By adopting the above technical solution, yttrium, an important structural element of zirconia, can enhance its wear resistance, improve its structural stability and high-temperature resistance, thereby giving zirconia excellent stability.

[0030] Optionally, the tungsten-molybdenum mixed powder contains the following components by weight percentage: 45-65% tungsten powder and 35-55% molybdenum powder.

[0031] Tungsten and molybdenum are metals with high strength and hardness. When added to materials, they can disperse into the ceramic phase to exert their effects.

[0032] Secondly, this application provides a method for preparing silicon carbide reinforced metal oxide composite materials, using the following technical solution:

[0033] A method for preparing a silicon carbide reinforced metal oxide composite material includes the following steps:

[0034] S1. Mix the tungsten-molybdenum mixed powder and the zirconium oxide-alumina mixed powder with ethanol, and wet ball mill to make the various powders mix evenly to obtain an initial slurry;

[0035] The modified whiskers were ultrasonically dispersed in ethanol for 20-40 minutes to obtain a whisker mixture slurry;

[0036] S2. After mixing the initial slurry and the whisker mixture slurry, the mixture is ball-milled, dried, pulverized, and sieved to obtain a composite powder;

[0037] S3. Vacuum sinter the composite powder to obtain the composite material.

[0038] By adopting the above technical solution, the matrix raw materials (tungsten-molybdenum mixed powder and zirconium oxide-alumina mixed powder) are first prepared into a slurry to achieve thorough mixing of the raw materials; secondly, the modified whiskers are also fully dispersed to facilitate uniform mixing in the later stage. Subsequently, the mixed powder is obtained through ball milling and other processes, so that the whiskers, tungsten-molybdenum mixed powder and zirconium oxide-alumina mixed powder are fully mixed to prepare a material with stable performance.

[0039] Optionally, the wet ball milling time in S1 is 20-35 hours, and the rotation speed is 120-190 rpm.

[0040] Optionally, the vacuum sintering conditions in S3 include: sintering temperature of 1600-1700℃, sintering time of 5-15min, vacuum degree of 2-10Pa, and sintering pressure of 35-45MPa.

[0041] Optionally, the specific steps of vacuum sintering in S3 include: heating to the sintering temperature at a rate of 80-105℃ / min, holding at that temperature and then stopping the heating, and allowing it to cool naturally to room temperature.

[0042] In summary, this application has the following beneficial effects:

[0043] 1. This application prepares silicon carbide-reinforced metal oxide composite materials by adding two amino-modified whiskers to the raw materials to significantly improve the toughness of the material through the synergistic effect of the two whiskers. Simultaneously, this method also requires the dispersion reinforcement effect of tungsten-molybdenum mixed powder to ensure the strength of the material. Ultimately, the toughness of the material is significantly improved through the synergistic effect of the modified whiskers and the tungsten-molybdenum mixed powder, resulting in a significant increase in its flexural strength and fracture toughness.

[0044] 2. The modified whiskers used in this application are prepared by mixing and modifying two types of whiskers with different crystal structures and high hardness and strength: silicon carbide whiskers and boron nitride whiskers. It is recommended that the weight ratio of silicon carbide whiskers to boron nitride whiskers be set in the range of 1:(0.2-0.8) to achieve better toughening effect.

[0045] 3. When modifying the whiskers of this application, the mixed whiskers are modified with an amino reagent to improve the bonding between the whisker and the matrix interface, so that the crack deflection and whisker bridging effects are significantly improved after crack initiation. Detailed Implementation

[0046] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0047] In this application, wt% refers to weight percentage and Vol% refers to volume percentage.

[0048] Preparation example of modified whiskers

[0049] Boron nitride whiskers are commercially available, with CAS number 62063-02-9; the purity of the boron nitride whiskers is 99wt%, and the diameter is 1-10μm.

[0050] Silicon carbide whiskers are commercially available, with CAS number 409-21-2; the purity of silicon carbide whiskers is 99wt%, the diameter is 600nm, and the length is 10-50μm.

[0051] Preparation Example 1

[0052] The preparation method of modified whiskers is as follows:

[0053] 1. Silicon carbide whiskers and boron nitride whiskers were mixed in a weight ratio of 1:0.2 to obtain a whisker mixture. Dimethylethylenediamine was dissolved in ethanol to obtain an amino reagent solution, wherein the mass fraction of dimethylethylenediamine in the amino reagent solution was 10 wt%.

[0054] 2. Immerse the whisker mixture in an amino reagent solution and sonicate for 20 minutes. Then filter to leave the modified whiskers. Wash the modified whiskers with water, dry them at 60°C, and further pulverize them to obtain the modified whiskers.

[0055] Preparation Example 2

[0056] The preparation method of modified whiskers is as follows:

[0057] 1. Silicon carbide whiskers and boron nitride whiskers were mixed in a weight ratio of 1:0.5 to obtain a whisker mixture. Ethylenediamine was dissolved in ethanol to obtain an amino reagent solution, wherein the mass fraction of ethylenediamine in the amino reagent solution was 15 wt%.

[0058] 2. Immerse the whisker mixture in an amino reagent solution and sonicate for 30 minutes. Then filter to leave the modified whiskers. Wash the modified whiskers with water, vacuum dry, and further pulverize to obtain the modified whiskers.

[0059] Preparation Example 3

[0060] The preparation method of modified whiskers is as follows:

[0061] 1. Silicon carbide whiskers and boron nitride whiskers were mixed in a weight ratio of 1:0.8 to obtain a whisker mixture. Dimethylethylenediamine was dissolved in ethanol to obtain an amino reagent solution, wherein the mass fraction of dimethylethylenediamine in the amino reagent solution was 20 wt%.

[0062] 2. Immerse the whisker mixture in an amino reagent solution and sonicate for 40 minutes. Then filter to leave the modified whiskers. Wash the modified whiskers with water, vacuum dry, and further pulverize to obtain the modified whiskers.

[0063] Preparation Examples 4-7

[0064] The preparation method of the modified whiskers is the same as that of Preparation Example 2. The difference between each preparation example and Preparation Example 2 lies in the different weight ratios of silicon carbide whiskers and boron nitride whiskers, as detailed below:

[0065] In Preparation Example 4, the weight ratio of silicon carbide whiskers to boron nitride whiskers was 1:0.1;

[0066] In Preparation Example 5, the weight ratio of silicon carbide whiskers to boron nitride whiskers was 1:0.2;

[0067] In Preparation Example 6, the weight ratio of silicon carbide whiskers to boron nitride whiskers was 1:0.8;

[0068] In Preparation Example 7, the weight ratio of silicon carbide whiskers to boron nitride whiskers was 1:1.

[0069] Preparation Example 8

[0070] The difference between this preparation example and Preparation Example 2 is that the whiskers are only silicon carbide whiskers.

[0071] Specifically, the preparation method of modified whiskers is as follows:

[0072] 1. Take silicon carbide whiskers and set aside; dissolve ethylenediamine in ethanol to obtain an amino reagent solution, wherein the mass fraction of ethylenediamine in the amino reagent solution is 15 wt%.

[0073] 2. Immerse silicon carbide whiskers in an amino reagent solution and sonicate for 30 minutes. Then filter to leave the modified whiskers. Wash the modified whiskers with water, vacuum dry, and further pulverize to obtain the modified whiskers.

[0074] Preparation Example 9

[0075] The difference between this preparation example and Preparation Example 2 is that the whiskers are only boron nitride whiskers.

[0076] Specifically, the preparation method of modified whiskers is as follows:

[0077] 1. Take boron nitride whiskers and set aside; dissolve ethylenediamine in ethanol to obtain an amino reagent solution, wherein the mass fraction of ethylenediamine in the amino reagent solution is 15 wt%.

[0078] 2. Immerse boron nitride whiskers in an amino reagent solution and sonicate for 30 minutes. Then filter to leave the modified whiskers. Wash the modified whiskers with water, vacuum dry, and further pulverize to obtain the modified whiskers.

[0079] Example

[0080] Example 1

[0081] A silicon carbide-reinforced metal oxide composite material is prepared from the following raw materials: 2 kg of modified whiskers, 2 kg of tungsten-molybdenum mixed powder, and 80 kg of zirconium oxide-alumina mixed powder.

[0082] The modified whiskers were prepared using the method described in Example 1.

[0083] The content of each metal powder in the tungsten-molybdenum mixed powder is: 45wt% tungsten powder and 55wt% molybdenum powder. The tungsten powder and molybdenum powder are mixed in this ratio to obtain the tungsten-molybdenum mixed powder. The purity of the tungsten powder is 99.95wt%, and the particle size Dw is 0 < Dw < 40nm; the purity of the molybdenum powder is 99.95wt%, and the particle size Dm is 0 < Dm < 40nm.

[0084] In the zirconia-alumina mixed powder, 3Y-ZrO2 powder accounts for 13% of the volume of α-alumina powder. Here, 3Y-ZrO2 powder refers to yttrium-stabilized zirconia powder, and the amount of yttrium added to the zirconia powder is 3 vol% of the zirconia; 3Y-ZrO2 powder is commercially available. The particle size D of the zirconia-alumina mixed powder is 0 < D < 75 μm.

[0085] The preparation method of silicon carbide reinforced metal oxide composite material is as follows:

[0086] S1. According to the above amounts, mix the tungsten-molybdenum mixed powder and the zirconium oxide-alumina mixed powder with an appropriate amount of ethanol, and wet ball mill at 120 rpm for 20 hours to make the various powders evenly mixed and obtain the initial slurry.

[0087] The modified whiskers were dispersed in an appropriate amount of ethanol and ultrasonically dispersed for 20 minutes to obtain a whisker mixture slurry.

[0088] S2. After mixing the initial slurry and the whisker mixture, wet ball milling was performed at 120 rpm for 3 hours. After vacuum drying, the mixture was pulverized and passed through a 200-mesh sieve to obtain composite powder.

[0089] S3. Vacuum sinter the composite powder, control the vacuum degree to 2Pa, heat up to the sintering temperature of 1600℃ at a rate of 80℃ / min, and the sintering pressure is 45MPa. After reaching the sintering temperature, sinter for 15min, then stop heating and allow it to cool naturally to room temperature to obtain the composite material.

[0090] Example 2

[0091] A silicon carbide-reinforced metal oxide composite material is prepared from the following raw materials: 5 kg of modified whiskers, 6.5 kg of tungsten-molybdenum mixed powder, and 88 kg of zirconium oxide-alumina mixed powder.

[0092] The modified whiskers were prepared using the method described in Example 2.

[0093] The content of each metal powder in the tungsten-molybdenum mixed powder is: 55 wt% tungsten powder and 45 wt% molybdenum powder. The tungsten powder and molybdenum powder are mixed in this ratio to obtain the tungsten-molybdenum mixed powder. The tungsten powder and molybdenum powder are the same as in Example 1.

[0094] In the zirconia-alumina mixed powder, 3Y-ZrO2 powder accounts for 20% of the volume of α-alumina powder. The 3Y-ZrO2 powder is the same as in Example 1. The particle size D of the zirconia-alumina mixed powder is 0 < D < 75 μm.

[0095] The preparation method of silicon carbide reinforced metal oxide composite material is as follows:

[0096] S1. According to the above amounts, mix the tungsten-molybdenum mixed powder and the zirconium oxide-alumina mixed powder with an appropriate amount of ethanol, and wet ball mill at 150 rpm for 28 hours to make the various powders evenly mixed and obtain the initial slurry.

[0097] The modified whiskers were dispersed in an appropriate amount of ethanol and ultrasonically dispersed for 30 minutes to obtain a whisker mixture slurry.

[0098] S2. After mixing the initial slurry and the whisker mixture, wet ball milling was performed at 150 rpm for 3 hours. After vacuum drying, the mixture was pulverized and passed through a 200-mesh sieve to obtain composite powder.

[0099] S3. Vacuum sinter the composite powder, control the vacuum degree to 8 Pa, heat up to the sintering temperature of 1650℃ at a rate of 100℃ / min, and sinter at a pressure of 40MPa. After reaching the sintering temperature, sinter for 10 min, then stop heating and allow it to cool naturally to room temperature to obtain the composite material.

[0100] Example 3

[0101] A silicon carbide-reinforced metal oxide composite material is prepared from the following raw materials: 8 kg of modified whiskers, 8 kg of tungsten-molybdenum mixed powder, and 98 kg of zirconium oxide-alumina mixed powder.

[0102] The modified whiskers were prepared using the method described in Example 3.

[0103] The content of each metal powder in the tungsten-molybdenum mixed powder is: 65 wt% tungsten powder and 35 wt% molybdenum powder. The tungsten powder and molybdenum powder are mixed in this ratio to obtain the tungsten-molybdenum mixed powder. The tungsten powder and molybdenum powder are the same as in Example 1.

[0104] In the zirconia-alumina mixed powder, 3Y-ZrO2 powder accounts for 27% of the volume of α-alumina powder. The 3Y-ZrO2 powder is the same as in Example 1. The particle size D of the zirconia-alumina mixed powder is 0 < D < 75 μm.

[0105] The preparation method of silicon carbide reinforced metal oxide composite material is as follows:

[0106] S1. According to the above amounts, mix the tungsten-molybdenum mixed powder and the zirconium oxide-alumina mixed powder with an appropriate amount of ethanol, and wet ball mill at a speed of 190 rpm for 35 hours to make the various powders evenly mixed and obtain the initial slurry.

[0107] The modified whiskers were dispersed in an appropriate amount of ethanol and ultrasonically dispersed for 40 minutes to obtain a whisker mixture slurry.

[0108] S2. After mixing the initial slurry and the whisker mixture, wet ball milling was performed at 190 rpm for 3 hours. After vacuum drying, the mixture was pulverized and passed through a 200-mesh sieve to obtain composite powder.

[0109] S3. Vacuum sinter the composite powder, control the vacuum degree to 9 Pa, heat up to the sintering temperature of 1700℃ at a rate of 105℃ / min, and sinter at a pressure of 35MPa. After reaching the sintering temperature, sinter for 5 minutes, then stop heating and allow it to cool naturally to room temperature to obtain the composite material.

[0110] Examples 4-5

[0111] The following examples differ from Example 2 in that the source of the modified whiskers is different; otherwise, they are the same as in Example 2. Specifically:

[0112] The modified whiskers of Example 4 were prepared from Preparation Example 5; the modified whiskers of Example 5 were prepared from Preparation Example 6.

[0113] Comparative Example

[0114] Comparative Examples 1-4

[0115] The following comparative examples differ from Example 2 in that the source of the modified whiskers is different; otherwise, they are the same as in Example 2. Specifically:

[0116] The modified whiskers of Comparative Example 1 were prepared from Preparation Example 4; the modified whiskers of Comparative Example 2 were prepared from Preparation Example 7; the modified whiskers of Comparative Example 3 were prepared from Preparation Example 8; and the modified whiskers of Comparative Example 4 were prepared from Preparation Example 9.

[0117] Comparative Examples 5-6

[0118] The following comparative example differs from Example 2 in that the amount of modified whiskers used is different; otherwise, they are the same as in Example 2. Specifically:

[0119] In Comparative Example 5, the amount of modified whiskers used was 1 kg; in Comparative Example 6, the amount of modified whiskers used was 10 kg.

[0120] Comparative Example 7

[0121] The difference between this comparative example and Example 2 is that the raw materials for preparing the silicon carbide reinforced metal oxide composite material are replaced with whiskers of equal weight, while the rest is the same as in Example 2.

[0122] Specifically, the raw materials for preparing the silicon carbide reinforced metal oxide composite material are: 5 kg of whiskers, 6.5 kg of tungsten-molybdenum mixed powder, and 88 kg of zirconium oxide-alumina mixed powder. The whiskers are obtained by mixing silicon carbide whiskers and boron nitride whiskers in a weight ratio of 1:0.5. The preparation method is the same as in Example 2.

[0123] Comparative Example 8

[0124] The difference between this comparative example and Example 2 is that the raw materials for preparing the silicon carbide reinforced metal oxide composite material do not include tungsten-molybdenum mixed powder; otherwise, they are the same as in Example 2.

[0125] Specifically, the raw materials for preparing silicon carbide reinforced metal oxide composite materials are: 5 kg of modified whiskers and 88 kg of zirconium oxide-alumina mixed powder.

[0126] Material performance testing

[0127] 1. Detection Method

[0128] (1) The fracture toughness and flexural strength of the material shall be tested in accordance with the relevant requirements of ISO 14704:2016 Fine ceramics (advanced ceramics, advanced industrial ceramics) Test method for flexural strength of monolithic ceramics at room temperature.

[0129] (2) The Vickers hardness of the material shall be tested in accordance with the relevant requirements of ASTM C1327-15 "Standard Test Method for Vickers Indentation Hardness of Advanced Ceramics".

[0130] 2. Data Results

[0131] (1) The fracture toughness and bending strength of the materials in Examples 1-5 and Comparative Examples 1-8 were measured, and the specific results are shown in Table 1.

[0132] Table 1 Fracture toughness and flexural strength of different materials

[0133]

[0134] The data in Table 1 show that the material prepared in this application exhibits high fracture toughness and flexural strength. The fracture toughness ranges from 4.2 to 4.5 MPa·m. 1 / 2 Within this range, it is much higher than the comparative example of 3.0-3.6 MPa·m. 1 / 2 The fracture toughness of the sample was significantly improved; however, the flexural strength of the embodiment, ranging from 1360 to 1440 MPa, was much higher than that of the comparative example, which ranged from 1130 to 1195 MPa. Factors affecting the fracture toughness and flexural strength of the material include the type of modified whisker, whether the whiskers are modified, the amount of modified whiskers added, and the addition of tungsten-molybdenum alloy, as detailed below:

[0135] The data from Examples 2 and 4-5, and Comparative Examples 1-4, show that the weight ratio of silicon carbide whiskers to boron nitride whiskers is crucial in the preparation of modified whiskers. The reason for the synergistic effect of silicon carbide and boron nitride whiskers is that they are two different crystal structures. Adding these two different whiskers results in a disordered and anisotropic distribution of the whiskers within the material. This disordered distribution and the inherent differences in the whiskers themselves make the crack deflection caused by the whiskers more complex and disordered. Adjusting the ratio of the two types of whiskers can regulate the crack deflection. A better effect is achieved when the weight ratio of silicon carbide whiskers to boron nitride whiskers is in the range of 1:(0.2-0.8), resulting in excellent fracture toughness and flexural strength of the material. Furthermore, combining the data from Comparative Examples 3-4, the whisker toughening effect is superior when using two types of modified whiskers compared to using only one type.

[0136] Examples 2 and Comparative Examples 5-6 mainly demonstrate that when preparing this material, the amount of modified whiskers is recommended to be set in the range of 2-8 parts to achieve excellent results in improving the fracture toughness and flexural strength of the material.

[0137] Furthermore, Comparative Example 7 demonstrates the necessity of modifying the whiskers. The results of Comparative Example 8 show that the addition of the tungsten-molybdenum mixed powder ensures that the material exhibits excellent fracture toughness and flexural strength.

[0138] (2) The Vickers hardness of the materials of Example 2, Comparative Example 3, Comparative Example 4 and Comparative Example 7 was measured, and the specific results are shown in Table 2.

[0139] Table 2 Vickers hardness of different materials

[0140]

[0141] The results in Table 2 show that the material prepared in this application has a high Vickers hardness, which meets the requirements.

[0142] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A silicon carbide-reinforced metal oxide composite material, characterized in that, The material comprises the following components in parts by weight: 2-8 parts modified whiskers, 5-8 parts tungsten-molybdenum mixed powder, and 80-98 parts zirconium oxide-alumina mixed powder; The modified whiskers are obtained by mixing silicon carbide whiskers and boron nitride whiskers in a weight ratio of 1:(0.2-0.8) and then treating them with an amino reagent. The tungsten-molybdenum mixed powder contains the following components by weight percentage: 45-65% tungsten powder and 35-55% molybdenum powder; The zirconium oxide-alumina mixed powder contains 13-27% zirconium oxide powder (13-27 Vol) of alumina powder.

2. The silicon carbide reinforced metal oxide composite material according to claim 1, characterized in that, The amino reagent is selected from either ethylenediamine or dimethylethylenediamine.

3. The silicon carbide reinforced metal oxide composite material according to claim 1, characterized in that, The method for treating silicon carbide whiskers and boron nitride whiskers with amino reagents specifically includes the following steps: The silicon carbide whiskers and boron nitride whiskers are mixed to obtain a whisker mixture; The amino reagent is dissolved in ethanol to obtain an amino reagent solution, wherein the mass fraction of the amino reagent in the amino reagent solution is 10-20 wt%. The whisker mixture was immersed in the amino reagent solution and ultrasonically mixed for 20-40 minutes. The solvent was removed and the mixture was dried to obtain modified whiskers.

4. The silicon carbide reinforced metal oxide composite material according to claim 1, characterized in that, The particle size D of the zirconium oxide-alumina powder is: 0 < D < 75 micrometers.

5. A method for preparing a silicon carbide reinforced metal oxide composite material according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Mix the tungsten-molybdenum mixed powder and the zirconium oxide-alumina mixed powder with ethanol, and wet ball mill to make the various powders mix evenly to obtain an initial slurry; The modified whiskers were ultrasonically dispersed in ethanol for 20-40 minutes to obtain a whisker mixture slurry; S2. After mixing the initial slurry and the whisker mixture slurry, the mixture is ball-milled, dried, pulverized, and sieved to obtain a composite powder; S3. Vacuum sinter the composite powder to obtain the composite material.

6. The method for preparing a silicon carbide reinforced metal oxide composite material according to claim 5, characterized in that, The wet ball milling time in S1 is 20-35 hours, and the rotation speed is 120-190 rpm.

7. The method for preparing a silicon carbide reinforced metal oxide composite material according to claim 5, characterized in that, The conditions for vacuum sintering in S3 include: sintering temperature of 1600-1700℃, sintering time of 5-15min, vacuum degree of 2-10Pa, and sintering pressure of 35-45MPa.

8. The method for preparing a silicon carbide reinforced metal oxide composite material according to claim 5, characterized in that, The specific steps of vacuum sintering in S3 include: heating to the sintering temperature at a rate of 80-105℃ / min, holding at that temperature, stopping the heating, and allowing it to cool naturally to room temperature.

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