A method for preparing a high-strength SiC-based composite ceramic material

Abstract

The application relates to a preparation method of a high-strength SiC-based composite ceramic material, comprising the following steps: (1) mixing SiC powder, WC powder, an aluminum source and a carbon source to obtain mixed powder; and (2) performing hot-pressing sintering on the mixed powder to obtain the high-strength SiC-based composite ceramic material.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of high-strength SiC-based composite ceramic material and belongs to the field of composite material preparation. BACKGROUND

[0002] SiC ceramic has a wide application in the industrial fields of petroleum chemical industry, aerospace, energy and environmental protection, and mechanical and electronic industries due to low density, high elastic modulus, high strength, low thermal expansion coefficient, excellent wear resistance and corrosion resistance. However, since silicon carbide is a stable compound with strong covalent bond, has low thermal diffusion coefficient and is difficult to sinter and densify, and the silicon carbide ceramic has defects of brittleness, crack and short service life, the application of the silicon carbide ceramic is limited. Therefore, it is urgent to develop a new type of high-density and high-strength silicon carbide ceramic.

[0003] Tungsten carbide (WC) has similar hardness to diamond, good toughness, high chemical stability, strong impact load resistance and friction and abrasion resistance. However, the density of WC is 15.63 g / cm 3 , which is much larger than the density of SiC ceramic 3.20 g / cm 3 , thereby limiting the application range of WC. The excellent mechanical properties of WC can effectively increase the strength and toughness of SiC ceramic. Chinese patent document 1 (publication number CN102173823A) discloses a silicon carbide / tungsten carbide composite material and a preparation method thereof. The composite powder is prepared by wrapping SiC with WC, but is limited to be used for reinforcing a metal matrix. Chinese patent document 2 (publication number CN101823882A) prepares a silicon carbide-tungsten carbide composite material with adjustable density, which is very suitable for being used as an iron-based reinforcing phase. However, the reinforcing effect of tungsten carbide as a second phase of the material cannot be reflected. Chinese patent document 3 (publication number CN106242574A) discloses a tungsten carbide-based composite ceramic mold material and a preparation method thereof. The material has excellent fracture toughness, bending strength and friction reduction performance. However, the mass percentage of tungsten carbide in the preparation method is much larger than that of silicon carbide, resulting in high density of the material. Chinese patent document 4 (publication number CN109809822A) adds tungsten carbide to prepare a high-strength and high-toughness silicon carbide ceramic carrier disc. However, the density of the material is not high. Therefore, it is an urgent problem to be solved by the application to prepare high-strength SiC-based composite ceramic material by using the low-density performance of silicon carbide and the excellent mechanical properties of tungsten carbide. SUMMARY

[0004] Therefore, the application provides a preparation method of high-strength SiC-based composite ceramic material, which comprises the following steps.

[0005] (1) mixing SiC powder, WC powder, an aluminum source and a carbon source to obtain a mixed powder;

[0006] (2) hot-press sintering the mixed powder to obtain the high-strength SiC-based composite ceramic material.

[0007] In the present application, WC is used as an excellent second-phase reinforcing body to prepare a high-strength SiC-based composite ceramic material by hot-press sintering. In the present application, Al enters the SiC crystal lattice by solid solution to reduce the grain boundary energy. Meanwhile, Al also has a deoxidizing effect, and with the increase of the content of WC, the solid solution effect is weakened and the deoxidizing effect is enhanced.

[0008] Preferably, the SiC powder is α-SiC powder with a particle size of ≤1 μm, and the WC powder has a particle size of ≤2 μm.

[0009] Preferably, the total mass of the SiC powder, the WC powder, the aluminum source and the carbon source is taken as 100 wt%, wherein the SiC powder accounts for 44% to 88%, and the WC powder accounts for 10% to 50%.

[0010] Preferably, the aluminum source is at least one of aluminum powder and aluminum oxide powder, and the aluminum source is added in an amount of 1 to 3 wt% of the total mass of the mixed powder.

[0011] Preferably, the carbon source is at least one of carbon black, activated carbon, graphite, glucose, starch and phenol formaldehyde, and the aluminum source is added in an amount of 1 to 3 wt% of the total mass of the mixed powder.

[0012] Preferably, the mixing method is ball-milling mixing.

[0013] The ball-milling mixing is performed by using an SM-QB planetary ball mill, and the parameters include: the ball-milling medium is anhydrous ethanol, the ball-milling medium and the mixed powder are in a ratio of (0.5 to 1) : 1, the ball-to-material ratio is (3 to 1) : 1, preferably 2:1, the ball-milling speed is 200 to 400 r / min, and the ball-milling time is 4 to 12 h.

[0014] Preferably, the grinding balls used in the ball-milling mixing are composed of large silicon carbide balls and small silicon carbide balls in a mass ratio of (0.1 to 10) : 1, wherein the large silicon carbide balls have a diameter of 10 mm to 30 mm, and the small silicon carbide balls have a diameter of 1 mm to 5 mm.

[0015] In addition, preferably, after the ball-milling mixing is completed, the mixed powder is subjected to drying and sieving treatment; the drying is performed at a temperature of 60 to 70 °C for 24 to 36 h; and the sieving is performed through a 80- to 200-mesh sieve.

[0016] Preferably, the parameters of the hot-press sintering include: a pressure of 30 to 40 MPa, a temperature of 2000 to 2150 °C, and a time of 30 to 60 min.

[0017] In addition, preferably, the parameters of the hot-press sintering include:

[0018] First, raise the temperature to 600-700℃ at a heating rate of 15-25℃ / min, and adjust the pressure to 10-20MPa;

[0019] Then raise the temperature to 1000℃~1100℃ at a heating rate of 15~25℃ / min;

[0020] When the heating rate is adjusted to 8-12℃ / min and the temperature is further increased to 1500-1800℃, the pressure is adjusted to 30-40MPa.

[0021] Adjust the heating rate to 5-7℃ / min and continue heating to 2000-2150℃, then hold the temperature and pressure for 30-60 minutes.

[0022] Finally, the furnace was cooled to room temperature and depressurized.

[0023] Beneficial effects:

[0024] 1. This invention uses a carbothermal reduction method to remove silicon oxide from the surface of SiC powder to obtain densified sintered silicon carbide ceramics;

[0025] 2. This invention utilizes the excellent mechanical properties of WC and the low density of SiC ceramics to enable WC / SiC composite ceramic materials to achieve relatively low density and high flexural strength and fracture toughness.

[0026] 3. This invention provides a method for preparing high-strength SiC-based composite ceramic materials. The method is simple and easy to operate, has a short preparation cycle, is highly practical, has low cost, and can be scaled up, which is beneficial for industrial production. Attached Figure Description

[0027] Figure 1 The image shows the XRD pattern of the SiC-WC composite ceramic. SiC and WC are the main phases present in all samples, with trace amounts of carbon also present.

[0028] Figure 2 The images show SEM images and corresponding EDS mappings of SiC-WC-40. Aggregation of aluminum elements can be observed in the EDS. Furthermore, the distributions of O and Al elements are very well matched; the SEM images show that O elements are bonded to Al at the grain boundaries. This indicates that the Al added to the sample acts as a deoxidizer.

[0029] Figure 3 The figures show the XPS Al2p spectra of (a) SiC-WC-0 and (b) SiC-WC-40. From the figures, we can see that the Al2p spectra... Figure 3 The value in (a) can be fitted to two peaks at 73.29 and 74.93 eV, which correspond to the Al-C bonds of Al solid solution entering the SiC lattice and the Al-O bonds of Al2O3 generated by Al deoxidation.Figure 3 The peak at 74.76 eV can be fitted in the middle (b), which is attributed to Al-O bond. The XPS results show that with the addition of WC, the solid solution (Al-C bond) disappears, and all the Al elements react with the oxides (SiO2, WO3) to form Al2O3 (Al-O);

[0030] Figure 4 The SEM images of the crack propagation of the Ar+ etched surface of SiC-WC composite materials. In the sample SiC-WC-50, the deviation and bridging of WC particles and the stopping of cracks by WC particles can be seen. However, in monolithic SiC, the crack extends rapidly, and grain penetration fracture is observed. This shows that WC as a second phase particle can increase crack deflection and bridging, which well inhibits crack propagation and improves the fracture toughness of the composite ceramic;

[0031] Figure 5 The Raman spectra of SiC and SiC-50wt%WC samples. From the figure, it can be seen that the W-O bond is generated on the wear surface of the SiC-50wt%WC sample, indicating that the SiO2 film on the wear surface is converted into a WO3 film;

[0032] Figure 6 The friction coefficient curve (a), the average friction coefficient (b), the cross-sectional depth profile (c) and the specific wear rate (d) of SiC-WC composite ceramics with different WC contents. From Figure 6 The profile in (c) shows that the wear rate of the SiC-WC-50 sample is significantly lower than that of monolithic SiC ceramic. The specific wear rate Figure 6 (d) in (c) decreases from 15.23 x 10 -7 mm 3 -N -1 -m -1 to 6.67 x 10 -7 mm 3 -N -1 -m -1 , a decrease of 56.2%;

[0033] Figure 7 The XRD pattern of SiC-WC-10 with Al and B4C as sintering aids. From the figure, it can be seen that the sample with B4C has a W2B5 peak, indicating that the B element in WC and B4C reacts to form W2B5, thereby reducing the performance of the material;

[0034] Figure 8 The Gibbs free energy diagram of the reaction of WC and B4C. From the figure, it can be seen that the reaction can proceed spontaneously at a sintering temperature of 2150°C. DETAILED DESCRIPTION

[0035] The application will be further explained by the following embodiments, which are only used to illustrate the application but not to limit the application.

[0036] In the present disclosure, SiC and WC powders are mixed in proportion, an aluminum source and a carbon source are added for planetary ball milling, and a uniformly mixed raw material powder is obtained. After the uniformly mixed powder is sieved, the composite ceramic bulk is sintered. The present application significantly improves the bending resistance of the composite ceramic while maintaining the excellent low-density performance of SiC ceramic, so that the composite ceramic bulk has excellent mechanical properties.

[0037] The following exemplary describes the preparation method of the high-strength SiC-based composite ceramic material.

[0038] SiC powder (alpha-SiC powder), WC powder, and an aluminum source and a carbon source are added to a ball milling tank, and mixed uniformly to obtain a mixed slurry. The SiC accounts for 48% to 88%, and the WC accounts for 10% to 50%. Preferably, the particle size of the SiC powder is ≤1 μm; and the particle size of the WC powder is ≤2 μm. Preferably, the ball milling adopts a SM-QB planetary ball mill. Preferably, the ball milling parameters are as follows: the ball milling medium is anhydrous ethanol; the ball-to-material ratio is 2:1; the rotation speed of the ball mill is 200 to 400 r / min, and the ball milling time is 4 to 12 h. Preferably, the grinding balls are composed of large silicon carbide balls and small silicon carbide balls in a mass ratio of 0.1 to 10:1, the diameter of the large silicon carbide balls is 10 mm to 30 mm, and the diameter of the small silicon carbide balls is 1 mm to 5 mm.

[0039] The mixed slurry obtained by ball milling is dried and sieved to obtain a mixed powder. Preferably, the drying process is as follows: the mixed slurry after ball milling is evaporated and dried in a constant temperature oven at 60 to 70 °C for 12 to 24 h, and the ball milling medium is volatilized completely. Preferably, the sieving process is as follows: the mixed powder is sieved through an 80 to 200 mesh sieve.

[0040] The mixed powder is sintered by a hot-pressing sintering system to obtain the high-strength SiC-based composite ceramic material. The sintering process is as follows: the temperature is raised at a rate of 15 to 25 °C / min; when the temperature rises to 600 to 700 °C, the pressure is adjusted to 10 to 20 MPa, and the temperature continues to rise; when the temperature is 1000 to 1100 °C, the temperature rising rate is adjusted to 8 to 12 °C / min; when the temperature rises to 1500 to 1800 °C, the pressure is adjusted to 30 to 40 MPa, and the temperature rising rate is adjusted to 5 to 7 °C / min; when the temperature rises to 2000 to 2150 °C, the temperature and pressure are maintained for 30 to 60 min; then the furnace is cooled and depressurized to obtain a WC / SiC composite ceramic bulk.

[0041] In the present application, the density of the composite ceramic material obtained by the Archimedes drainage method is 99.02 to 99.26%, and the density is 3.12 to 5.16 g / cm-3 ;

[0042] The bending strength of the obtained composite ceramic material is 560.2-645.9 MPa by three-point bending method;

[0043] The elastic modulus of the obtained composite ceramic material is 406.5-433.2 GPa by pulse excitation method;

[0044] The fracture toughness of the obtained composite ceramic material is 4.31-7.49 MPa m by slotting method 1 / 2 ;

[0045] The average friction coefficient of the obtained composite ceramic material is 0.436-0.384 by ball-on-disc friction method; the specific wear rate is 15.23x10 -7 mm 3 ·N -1 ·m -1 ~ 6.67x10 -7 mm 3 ·N -1 ·m -1 .

[0046] The following further examples are used to illustrate the application in detail. It should also be understood that the following examples are only used to further illustrate the application, and cannot be understood as limiting the scope of the application. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the application are within the scope of the application. The specific process parameters in the following examples are only one example in the appropriate range, i.e. those skilled in the art can select within the appropriate range according to the description herein, and are not limited to the specific values in the following examples. In the following examples, if not otherwise specified, the silicon carbide powder is α-SiC powder.

[0047] Example 1

[0048] 87g of silicon carbide powder, 10g of tungsten carbide powder (10wt%), 1g of aluminum powder and 2g of carbon black were mixed and added to a SM-QB planetary ball mill, and ball-to-material ratio of 2:1 was added to the ball milling beads and anhydrous ethanol; under the rotation speed of 300r / min, ball milling for 4h, the mixture was uniformly mixed to obtain a mixed slurry; the mixed slurry was poured into a porcelain basin. Put into an electric heating constant temperature drying oven, dry at 60℃ for 24h and pass through a 100 mesh screen to obtain a mixed powder;

[0049] Take 22 g of mixed powder into 40x40 mm hot pressing mold, with 20 ℃ / min to 600 ℃, then pass argon, continue to heat to 1000 ℃, then press 20 MPa; again with 10 ℃ / min to 1600 ℃, press 40 MPa, again with 5 ℃ / min to 1900 ℃ and keep pressure, finally with 3 ℃ / min to 2150 ℃ and keep pressure for 1 h, then cool down with furnace and release pressure, take out the sintered ceramic bulk, first use deionized water, then use ethanol to clean the ceramic surface, get SiC-based composite ceramic material. The composite ceramic bulk prepared in this example 1 is made into a sample for testing, and the test results are shown in Table 1.

[0050] Example 2

[0051] Mix 77 g of silicon carbide powder, 20 g of tungsten carbide powder (20 wt%), 1 g of aluminum powder and 2 g of carbon black, then add them into the SM-QB planetary ball mill, and add ball-to-material ratio 2:1 ball milling beads and anhydrous ethanol; under the speed of 300 r / min, ball mill for 4 h, mix uniformly to get mixed slurry; pour the mixed slurry into a porcelain basin. Put it into an electric heating constant temperature air drying oven, dry at 60 ℃ for 24 h and pass through a 100 mesh sieve to get mixed powder;

[0052] Take 24 g of mixed powder into 40x40 mm hot pressing mold, with 20 ℃ / min to 600 ℃, then pass argon, continue to heat to 1000 ℃, then press 20 MPa; again with 10 ℃ / min to 1600 ℃, press 40 MPa, again with 5 ℃ / min to 1900 ℃ and keep pressure, finally with 3 ℃ / min to 2150 ℃ and keep pressure for 1 h, then cool down with furnace and release pressure, take out the sintered ceramic bulk, first use deionized water, then use ethanol to clean the ceramic surface, get SiC-based composite ceramic material. The composite ceramic bulk prepared in this example 2 is made into a sample for testing, and the test results are shown in Table 1.

[0053] Example 3

[0054] Mix 67 g of silicon carbide powder, 30 g of tungsten carbide powder (30 wt%), 1 g of aluminum powder and 2 g of carbon black, then add them into the SM-QB planetary ball mill, and add ball-to-material ratio 2:1 ball milling beads and anhydrous ethanol; under the speed of 300 r / min, ball mill for 4 h, mix uniformly to get mixed slurry; pour the mixed slurry into a porcelain basin. Put it into an electric heating constant temperature air drying oven, dry at 60 ℃ for 24 h and pass through a 100 mesh sieve to get mixed powder;

[0055] Take 26 g of mixed powder into 40x40 mm hot pressing mold, with 20 ℃ / min to 600 ℃, then pass argon, continue to heat to 1000 ℃, then press 20 MPa; again with 10 ℃ / min to 1600 ℃, press 40 MPa, again with 5 ℃ / min to 1900 ℃ and keep pressure, finally with 3 ℃ / min to 2150 ℃ and keep pressure for 1 h, then cool down with furnace and release pressure, take out the sintered ceramic bulk, first use deionized water, then use ethanol to clean the ceramic surface, get SiC-based composite ceramic material. The composite ceramic bulk prepared in this example 3 is made into a sample for testing, and the test results are shown in Table 1.

[0056] Example 4

[0057] Mix 57 g of silicon carbide powder, 40 g of tungsten carbide powder (40 wt%), 1 g of aluminum powder and 2 g of carbon black, then add them into the SM-QB planetary ball mill, and add ball-to-material ratio 2:1 ball milling beads and anhydrous ethanol; under the speed of 300 r / min, ball mill for 4 h, mix uniformly to get mixed mud slurry; pour the mixed mud slurry into a porcelain basin. Put it into an electric heating constant temperature air drying oven, dry at 60 ℃ for 24 h and pass through a 100 mesh sieve to get mixed powder;

[0058] Take 29 g of mixed powder into 40x40 mm hot pressing mold, with 20 ℃ / min to 600 ℃, then pass argon, continue to heat to 1000 ℃, then press 20 MPa; again with 10 ℃ / min to 1600 ℃, press 40 MPa, again with 5 ℃ / min to 1900 ℃ and keep pressure, finally with 3 ℃ / min to 2150 ℃ and keep pressure for 1 h, then cool down with furnace and release pressure, take out the sintered ceramic bulk, first use deionized water, then use ethanol to clean the ceramic surface, get SiC-based composite ceramic material. The composite ceramic bulk prepared in this example 4 is made into a sample for testing, and the test results are shown in Table 1.

[0059] Example 5

[0060] Mix 47 g of silicon carbide powder, 50 g of tungsten carbide powder (50 wt%), 1 g of aluminum powder and 2 g of carbon black, then add them into the SM-QB planetary ball mill, and add ball-to-material ratio 2:1 ball milling beads and anhydrous ethanol; under the speed of 300 r / min, ball mill for 4 h, mix uniformly to get mixed mud slurry; pour the mixed mud slurry into a porcelain basin. Put it into an electric heating constant temperature air drying oven, dry at 60 ℃ for 24 h and pass through a 100 mesh sieve to get mixed powder;

[0061] Take 33 g of mixed powder into a hot-pressing mold of 40x40 mm, increase to 600℃ at 20℃ / min, then pass argon, continue to increase to 1000℃, then pressurize 20 MPa; increase to 1600℃ at 10℃ / min, pressurize 40 MPa, then increase to 1900℃ at 5℃ / min and keep pressure, finally increase to 2150℃ at 3℃ / min and keep pressure for 1 h, then cool down with the furnace and release pressure, take out the sintered ceramic bulk, first clean the ceramic surface with deionized water, then with ethanol, to obtain the SiC-based composite ceramic material. The composite ceramic bulk prepared in this Example 5 is made into a sample for testing, and the test results are shown in Table 1.

[0062] Comparative Example 1

[0063] The preparation process of the high-strength SiC-based composite ceramic material in this Comparative Example 1 is as described in Example 1, except that 87.4 g of silicon carbide powder, 10 g of tungsten carbide powder (10 wt%), 0.6 g of B4C powder, and 2 g of carbon black are mixed and then added to a SM-QB planetary ball mill, with a ball-to-material ratio of 2:1, ball milling beads, and anhydrous ethanol; the mixture is ball milled at a speed of 300 r / min for 4 h to obtain a mixed slurry; the mixed slurry is poured into a porcelain basin and dried in an electrically heated constant temperature air drying oven at 60℃ for 24 h and passed through a 100 mesh sieve to obtain a mixed powder.

[0064] Take 33 g of mixed powder into a hot-pressing mold of 40x40 mm, increase to 600℃ at 20℃ / min, then pass argon, continue to increase to 1000℃, then pressurize 20 MPa; increase to 1600℃ at 10℃ / min, pressurize 40 MPa, then increase to 1900℃ at 5℃ / min and keep pressure, finally increase to 2150℃ at 3℃ / min and keep pressure for 1 h, then cool down with the furnace and release pressure, take out the sintered ceramic bulk, first clean the ceramic surface with deionized water, then with ethanol, to obtain the SiC-based composite ceramic material. The composite ceramic bulk prepared in this Example 5 is made into a sample for testing, and the test results are shown in Table 1. In Comparative Example 1, the B element in B4C reacts with WC to form W2B5, which has lower performance than WC, and thus reduces the performance of the sample.

[0065] Comparative Example 2

[0066] The preparation process of the high-strength SiC-based composite ceramic material in the present comparative example 2 refers to example 1, the only difference is that 97 g of silicon carbide powder, 0 g of tungsten carbide powder (0 wt%), 1 g of Al powder and 2 g of carbon black are mixed and then added into the SM-QB planetary ball mill, and the ball-to-material ratio is 2:1, ball milling beads and anhydrous ethanol are added; under the rotation speed of 300 r / min, ball milling for 4 h, the mixture is uniformly mixed to obtain a mixed slurry; the mixed slurry is poured into a porcelain basin, placed in an electric heating constant temperature drying oven, dried at 60℃ for 24 h and sieved through a 100 mesh screen to obtain a mixed powder;

[0067] Take 22 g of the mixed powder and put it into a hot-pressing mold of 40x40 mm, increase the temperature to 600℃ at a rate of 20℃ / min, then pass argon gas, continue to increase the temperature to 1000℃, then pressurize at 20 MPa; then increase the temperature to 1600℃ at a rate of 10℃ / min, pressurize at 40 MPa, then increase the temperature to 1900℃ at a rate of 5℃ / min and keep the pressure, finally increase the temperature to 2150℃ at a rate of 3℃ / min and keep the pressure, then cool down with the furnace and release the pressure, take out the sintered ceramic block, first clean the ceramic surface with deionized water, then with ethanol, to obtain the SiC-based composite ceramic material. The composite ceramic block obtained in the present comparative example 1 is made into a test sample for testing, and the test results are shown in table 1.

[0068] Table 1 is the performance of the SiC-based composite ceramic material prepared by the present application:

[0069]

Claims

1. A method for producing a high-strength SiC-based composite ceramic material, characterized by, The method comprises the following steps: (1) mixing SiC powder, WC powder, an aluminum source and a carbon source to obtain a mixed powder; the total mass of the SiC powder, the WC powder, the aluminum source and the carbon source is 100 wt%, wherein the SiC powder accounts for 44-88%, and the WC powder accounts for 10-50%; (2) the mixed powder is subjected to hot-press sintering to obtain the high-strength SiC-based composite ceramic material; the density of the obtained SiC-based composite ceramic material is 99.02-99.26% by Archimedes drainage method; the bending strength of the obtained composite ceramic material is 560.2-645.9 MPa by three-point bending method; -3 ; the bending strength of the obtained composite ceramic material is 560.2-645.9 MPa by three-point bending method; The parameters of the hot-pressing sintering include: firstly, increasing the temperature to 600-700℃ at a temperature increasing rate of 15-25℃ / min, and adjusting the pressure to 10-20MPa; then, increasing the temperature to 1000-1100℃ at a temperature increasing rate of 15-25℃ / min; continuously increasing the temperature to 1500-1800℃ at a temperature increasing rate of 8-12℃ / min, and adjusting the pressure to 30-40MPa; continuously increasing the temperature to 2000-2150℃ at a temperature increasing rate of 5-7℃ / min, and keeping the temperature and pressure for 30-60min; finally, cooling to room temperature and releasing the pressure.

2. The production method according to claim 1, characterized by, The SiC powder is α-SiC powder with a particle size of ≤1μm; the WC powder has a particle size of ≤2μm.

3. The preparation method according to claim 1, characterized in that, The aluminum source is at least one of aluminum powder and aluminum oxide powder; the aluminum source is added in an amount of 1-3wt% of the total mass of the mixed powder.

4. The method of claim 1, wherein, The carbon source is at least one of carbon black, activated carbon, graphite, glucose, starch and phenolic; the carbon source is added in an amount of 1-3wt% of the total mass of the mixed powder.

5. The preparation method according to claim 1, characterized in that, The mixing method is ball-milling mixing; the ball-milling mixing is performed by using an SM-QB planetary ball mill, and the parameters include: the ball-milling medium is anhydrous ethanol, the ball-milling medium and the mixed powder are in a ratio of (0.5-1):1, the ball-to-material ratio is (3-1):1, the ball-milling speed is 200-400r / min, and the ball-milling time is 4-12h.

6. The preparation method according to claim 5, characterized in that, The ball-to-material ratio is 2:

1.

7. The preparation method according to claim 5, characterized in that, The grinding balls used in the ball-milling mixing are composed of large silicon carbide balls and small silicon carbide balls in a mass ratio of (0.1-10):1; the diameter of the large silicon carbide balls is 10-30mm, and the diameter of the small silicon carbide balls is 1-5mm.

8. The preparation method according to claim 5, characterized in that, After the ball-milling mixing, drying and sieving are performed; the drying is performed at a temperature of 60-70℃ for 24-36h; the sieving is performed through a 80-200 mesh sieve.

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