High-strength and high-toughness SiC ceramic material and preparation method thereof

Abstract

The application provides a novel high-strength and high-toughness SiC ceramic material and a preparation method, and relates to the technical field of structural ceramics.The novel high-strength and high-toughness SiC ceramic material is composed of 75-82 wt.% of SiC, 10-12 wt.% of Y2SiO5, 6-7 wt.% of Zr3Y4O 12 , and 1-2 wt.% of ZrC, and different molds can be used to prepare materials of different sizes.The preparation method comprises the following steps of sequentially performing raw material weighing, ball milling, drying and sieving, graphite mold preparation, and hot-pressing sintering.The application adds ZrO2 powder, Y2O3 powder and SiC whisker into alpha-SiC powder, and obtains a ceramic material composed of SiC, Y2SiO5, Zr3Y4O 12 , and ZrC in the subsequent hot-pressing sintering process, so that the density is more than 99%, the hardness is more than 20 GPa, the bending strength is more than 800 MPa, and the fracture toughness is more than 8 MPa.m 0.5 ; the process steps are simple, the operation is convenient, the process cycle is short, the cost is low, the efficiency is high, the process is easy to control, and the application is beneficial to industrial production.In particular, the process can be used to prepare SiC ceramics with high bending strength and fracture toughness, and greatly expands the application field of SiC ceramics.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of structural ceramics, and in particular to a novel high-strength and high-toughness SiC ceramic material and a preparation method thereof. BACKGROUND

[0002] SiC ceramics have high thermal conductivity, high temperature stability, chemical inertness and other characteristics. SiC-based composite materials prepared therefrom can be widely used in aerospace and energy industries. However, SiC ceramics have two drawbacks, i.e., difficulty in sintering densification (pure SiC can only be densified by hot-pressing sintering at 2300°C and 50MPa) and low fracture toughness (about 3MPa·m 0.5 ), which cannot meet the requirements of some industrial fields for structural components, thus seriously limiting the industrial application of the material.

[0003] Therefore, it is necessary to solve the two problems of difficulty in sintering densification and low fracture toughness of SiC ceramics. The prior art has tried various toughening methods to improve the fracture toughness of SiC ceramics, mainly including particle toughening and whisker toughening. However, the reported particle toughened SiC ceramics have not high improvement in fracture toughness. The preparation idea of using SiC whisker to toughen SiC ceramics is simply to mix the whisker with the powder uniformly, and to increase the fracture toughness by mechanisms such as pull-out and debonding of the SiC whisker after sintering.

[0004] For example, Chinese patent CN104140265A discloses a method for preparing a SiC ceramic with zirconia as a toughening phase by liquid phase sintering. This method belongs to the above-mentioned particle toughening method. However, the highest improvement in fracture toughness of SiC ceramic can only reach 5.97MPa·m 0.5 , which is obviously not high. And the highest bending strength can only reach 586MPa, which does not exceed 800MPa.

[0005] Chinese patent CN114516756A discloses a SiC composite ceramic material, a preparation method and application thereof. This method belongs to the way of synergistic toughening by particle toughening and whisker toughening. The sintering is divided into two steps, the process flow is long, the amount of acid solution consumed is large, the pressure is large, and the cost is high. And the mechanical properties of SiC ceramic obtained by this toughening method have almost reached the bottleneck, and the highest fracture toughness can only reach about 7.5MPa·m 0.5 . Although this invention has a complex process flow, the fracture toughness obtained is still unable to meet some extreme service conditions, such as the cladding material in China's new generation of nuclear reactors.

[0006] Chinese patent CN106977217A discloses a preparation method of high-strength and high-toughness silicon carbide fiber reinforced silicon carbide ceramic matrix composite. The method needs to weave three-dimensional silicon carbide fiber reinforcement, then deposit silicon carbide to obtain an initial silicon carbide matrix, impregnate slurry, and then pyrolyze after vacuum impregnation to obtain a silicon carbide matrix, and finally deposit a silicon carbide coating to obtain it. Obviously, this way improves the structure of silicon carbide fiber and the internal and external structure of the composite material. Although it can improve the fracture toughness of the composite material, the process flow is extremely long, the operation is difficult, the cost is high, and the efficiency is low. In addition, the SiC fiber used in this process is a soft long fiber, so it greatly improves the fracture toughness at the expense of the hardness and bending strength of the material to ensure that the material is not easy to break. But this material cannot meet the hardness requirements of structural parts in the industrial field. The low hardness will cause the material to be unable to withstand a large stress, thereby causing a destructive behavior.

[0007] Chinese patent CN116573940A discloses a high-toughness silicon carbide ceramic material and a preparation method thereof. The method is to ball mill a mixture of silicon carbide powder and sintering aid powder to obtain a silicon carbide slurry, dry and mechanically grind it, then press it into a green body, and then high-temperature vacuum sinter it to obtain a silicon carbide ceramic body, and low-temperature sintering to obtain a high-toughness silicon carbide ceramic material. Obviously, the fracture toughness of the prepared ceramic material does not exceed 8 MPa·m 0.5 , and the energy consumption of two sintering is large. SUMMARY

[0008] The technical problem to be solved by the present application is that the current silicon carbide ceramic material cannot simultaneously improve the density, bending strength and fracture toughness at low cost and high efficiency. The existing technology has little effect on improving the mechanical properties. Few processes can sinter SiC ceramic to a density of more than 99%, and the bending strength and fracture toughness cannot simultaneously exceed 800 MPa and 8 MPa·m 0.5 . Most of the current processes use particle toughening and whisker toughening, as well as synergistic toughening, and a small part uses three-dimensional silicon carbide fiber reinforcement, sintering aid and the internal and external structure of the ceramic material to enhance, which brings the technical defects of complex operation, high cost and low efficiency.

[0009] To solve the above technical problems, the technical solutions provided by the present application are as follows:

[0010] A new high-strength and high-toughness SiC ceramic material, which comprises 75-82 wt.% of SiC, 10-12 wt.% of Y2SiO5, 6-7 wt.% of Zr3Y4O 12 and 1-2 wt.% of ZrC, and different molds can be used to prepare materials of different sizes, and the size can be adjusted.

[0011] Optionally, the SiC is in the shape of equiaxed grains with a size of 1-1.5 μm; the rest of the second phase Y2SiO5, Zr3Y4O 12 and ZrC is dispersedly distributed and uniformly wrapped around the SiC grains with a size of 0.5-2 μm.

[0012] Optionally, the new high-strength and high-toughness SiC ceramic material has a density of more than 99%, a density of 3.45-3.51 g / cm 3 , a hardness of more than 20 GPa, a bending strength of more than 800 MPa, and a fracture toughness of more than 8 MPa·m 0.5 .

[0013] A preparation method of the new high-strength and high-toughness SiC ceramic material is as follows:

[0014] S1, raw material weighing:

[0015] α-SiC powder, ZrO2 powder, Y2O3 powder, and SiC whisker are selected as raw material powders and weighed according to the components of the new high-strength and high-toughness SiC ceramic material to obtain a raw material mixed powder;

[0016] S2, ball milling:

[0017] The raw material mixed powder of S1 is wet ball milled to obtain a mixed slurry;

[0018] S3, drying and sieving:

[0019] The mixed slurry of S2 is dried and sieved to obtain a fine particle mixed powder;

[0020] S4, graphite mold preparation:

[0021] According to the product requirements of the prepared new high-strength and high-toughness SiC ceramic material, the shape and size of the graphite mold are determined, and a graphite mold meeting the product requirements is prepared. Then, the fine particle mixed powder of S3 is placed in the graphite mold and vibrated, and a layer of graphite paper is placed between the graphite mold and the powder to prevent the sample from adhering to the mold after sintering;

[0022] S5, hot-pressing sintering:

[0023] The fine particle mixed powder in the graphite mold filled with the fine particle mixed powder of S4 is subjected to hot-pressing sintering at a temperature of less than 1900 ℃, and the pressure is directly released after sintering to obtain the product of the new high-strength and high-toughness SiC ceramic material.

[0024] Optionally, the purity of the alpha-SiC powder in S1 is 98.5-99.9%, the average particle size is 0.05-0.2 microns; the purity of the ZrO2 powder is 98-99.9%, the average particle size is 0.01-0.06 microns; the purity of the Y2O3 powder is 98-99.9%, the average particle size is 0.01-0.03 microns; the purity of the SiC whisker is 99%, the length is 4-35 microns, and the diameter is 0.3-0.7 microns.

[0025] Optionally, the volume percentage of the ZrO2 powder and the Y2O3 powder in S1 in the raw material mixed powder is 13-17 vol%, and the ratio of the ZrO2 powder and the Y2O3 powder is 1:1 in mole ratio; the volume percentage of the added SiC whisker in the raw material mixed powder is between 40-50 vol.%.

[0026] Optionally, in S2, the wet ball milling needs to mix the raw material mixed powder with anhydrous ethanol and zirconium oxide ball milling beads (or silicon carbide milling beads, agate milling beads) according to a mass ratio of 1:1:1, and is placed in a nylon ball milling tank, and is mixed at a rotating speed of 250-350 r / min for 4-8 h.

[0027] Optionally, in S3, the drying temperature is 60-100℃, the drying time is 10-12 h, and the mesh number of the sieved product after drying is 80-100 mesh.

[0028] Optionally, in S4, the size of the cavity of the graphite mold is 0.4-0.5 mm larger than the size of the product appearance.

[0029] Optionally, in S5, the heating rate of the hot-pressing sintering is 5-10℃ / min, the sintering temperature is 1850-1900℃, the pressure is 40-60 MPa, and the holding time is 2-2.5 h.

[0030] The technical principle of the application is as follows:

[0031] The preparation method of the SiC whisker toughened SiC ceramic is improved, a new toughening method is obtained by changing the formula, and the mechanical properties of the SiC ceramic are greatly improved.

[0032] Unlike the SiCw toughened SiC ceramic reported at present, the powder of a specific type and content is added in the scheme, reacts with the added SiCw, and thus the relative density and mechanical properties (including bending strength and fracture toughness) of the SiC ceramic are greatly improved.

[0033] The key points of the technology are: ① the type and content of the added powder, the type is indispensable, and the change of the content will affect the progress of the secondary reaction, and finally affect the performance of the material. ② The sintering system of hot-pressing sintering, temperature, time and pressure are indispensable, and changing a parameter may also affect the secondary reaction and thus affect the performance of the final material.

[0034] The scheme selects adding ZrO2 powder, Y2O3 powder and SiC whisker in the α-SiC powder to react, and uses the reaction products to promote the densification of SiC ceramics and improve the mechanical properties of the material. In the sintering process, SiC whisker will react with added ZrO2 and Y2O3 as follows:

[0035] SiC+ZrO2→ZrC+SiO↑+CO↑(1)

[0036] SiO↑+ CO↑+ Y2O3→Y2SiO5(2)

[0037] ZrO2+Y2O3→Zr3Y4O 12 (3)

[0038] Note: SiC in reaction (1) represents SiC whisker, and only SiC whisker is added to occur the reaction, and thus the subsequent reaction (2) also occurs.

[0039] The generated product can play a role in filling the gap between SiC grains in the sintering process, thereby improving the density of SiC ceramics. In addition, the product generated after the reaction of the whisker and the added powder can refine the grains, thereby improving the bending strength of the ceramic. And the product generated after the reaction of the whisker and the added powder has appropriate bonding strength with the SiC matrix grains, so the fracture toughness can be improved.

[0040] Compared with the prior art, the above technical scheme has at least the following beneficial effects:

[0041] The above scheme provides a new type of high-strength and high-toughness SiC ceramic material and a preparation method, which overcomes the technical defects that the current SiC ceramic material cannot simultaneously improve the density, bending strength and fracture toughness at low cost and high efficiency, expands the application range of SiC ceramic materials, and is beneficial to industrial large-scale production and promotion.

[0042] The present application adds ZrO2 powder, Y2O3 powder and SiC whisker in the α-SiC powder to react in the hot-pressing sintering process, and obtains 75-82wt.% of SiC, 10-12wt.% of Y2SiO5, 6-7wt.% of Zr3Y4O 12ceramic material consisting of 1-2wt.% of ZrC; wherein Y2SiO5 plays a role of filling the interstitial space between SiC grains to ensure the density of the material. Zr3Y4O 12 plays a role of providing a proper interfacial bonding strength with the matrix SiC grains, thereby playing a role of improving the fracture toughness. ZrC can play a role of pinning the grain boundaries to refine the grains, thereby improving the bending strength of the material.

[0043] The present application can fully mix the powders by wet ball milling, and in particular, since the specific surface area of the SiC whiskers is large, the whiskers are extremely prone to agglomeration, thereby hindering the mass transfer during the sintering process, resulting in poor density of the SiC ceramic. The wet ball milling can ensure uniform dispersion of the whiskers, and the whiskers will not agglomerate during the sintering process.

[0044] The sintering temperature of the hot-press sintering of the present application is lower than 1900℃, and the SiC ceramic with excellent performance is obtained on the basis of reducing the production cost.

[0045] The density of the new high-strength and high-toughness SiC ceramic material prepared in the present application is more than 99%, the density is 3.45-3.51g / cm 3 , the hardness is more than 20GPa, the bending strength is more than 800MPa, and the fracture toughness is more than 8MPa·m 0.5 .

[0046] In summary, the method of the present application, compared with other conventional methods, by adding ZrO2 powder, Y2O3 powder and SiC whiskers in the α-SiC powder, obtains the SiC ceramic material reinforced and toughened by Y2SiO5, Zr3Y4O 12 and ZrC as the second phase in the subsequent hot-press sintering process, on the basis of the density being more than 99%, the hardness being more than 20GPa, the bending strength being more than 800MPa, and the fracture toughness being more than 8MPa·m 0.5 ; the process steps are simple, easy to operate, short process cycle, low cost, high efficiency, easy to control, which is beneficial to industrial production, and the prepared SiC ceramic has the best comprehensive performance (especially the bending strength and the fracture toughness) reported so far. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the following embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative labor.

[0048] Figure 1 FIG. 1 is a morphology diagram of the starting sintering powder in the preparation method of the new high-strength and high-toughness SiC ceramic material of Embodiment 1 of the present application;

[0049] Figure 2 The XRD pattern of the product prepared by the preparation method of a new high-strength and high-toughness SiC ceramic material according to Embodiment 1 of the present application;

[0050] Figure 3 The fracture morphology diagram of the product prepared by the preparation method of a new high-strength and high-toughness SiC ceramic material according to Embodiment 1 of the present application;

[0051] Figure 4 The XRD pattern of the SiC ceramic prepared without adding SiC whiskers according to Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort belong to the scope of protection of the present application.

[0053] A new high-strength and high-toughness SiC ceramic material, which comprises 75-82 wt.% of SiC, 10-12 wt.% of Y2SiO5, 6-7 wt.% of Zr3Y4O 12 and 1-2 wt.% of ZrC, and different sizes of materials can be prepared using different molds, and the size is adjustable.

[0054] In particular, the SiC is in the shape of equiaxed grains with a size of 1-1.5 μm; and the remaining second phases Y2SiO5, Zr3Y4O 12 and ZrC are dispersedly distributed and uniformly wrapped around the SiC grains with a size of 0.5-2 μm.

[0055] In particular, the new high-strength and high-toughness SiC ceramic material has a density of more than 99%, a density of 3.45-3.51 g / cm 3 , a hardness of more than 20 GPa, a bending strength of more than 800 MPa, and a fracture toughness of more than 8 MPa·m 0.5 .

[0056] A preparation method of the new high-strength and high-toughness SiC ceramic material, which comprises the following steps:

[0057] S1, weighing of raw materials:

[0058] Selecting α-SiC powder, ZrO2 powder, Y2O3 powder, SiC whisker as raw material powder, according to the composition of the above-mentioned new high-strength and high-toughness SiC ceramic material, the raw material mixed powder is obtained by weighing and proportioning.

[0059] S2, ball milling:

[0060] The raw material mixed powder of S1 is wet ball milled to obtain a mixed slurry.

[0061] S3, drying and sieving:

[0062] The mixed slurry of S2 is dried and sieved to obtain a fine particle mixed powder.

[0063] S4, graphite mold preparation:

[0064] According to the product demand of the prepared new high-strength and high-toughness SiC ceramic material, the shape and size of the graphite mold are determined, and the graphite mold meeting the product demand is prepared. Then the fine particle mixed powder of S3 is placed in the graphite mold and vibrated, and a layer of graphite paper is needed between the graphite mold and the powder to prevent the sample from adhering to the mold after sintering.

[0065] S5, hot-pressing sintering:

[0066] The fine particle mixed powder in the graphite mold filled with fine particle mixed powder of S4 is subjected to hot-pressing sintering at a temperature below 1900℃, and the pressure is released directly after sintering to obtain the product of the new high-strength and high-toughness SiC ceramic material.

[0067] In particular, the purity of the α-SiC powder in S1 is 98.5-99.9%, and the average particle size is 0.05-0.2μm; the purity of the ZrO2 powder is 98-99.9%, and the average particle size is 0.01-0.06μm; the purity of the Y2O3 powder is 98-99.9%, and the average particle size is 0.01-0.03μm; the purity of the SiC whisker is 99%, the length is 4-35μm, and the diameter is 0.3-0.7μm.

[0068] In particular, the volume percentage content of ZrO2 powder and Y2O3 powder in the raw material mixed powder in S1 is 13-17vol.%, and the ratio of ZrO2 powder and Y2O3 powder is 1:1 in mole ratio; the volume percentage content of the added SiC whisker in the raw material mixed powder is between 40-50vol.%.

[0069] In particular, in S2, the raw material mixed powder, anhydrous ethanol and zirconia ball milling beads (or silicon carbide milling beads, agate milling beads) are mixed according to a mass ratio of 1:1:1, placed in a nylon milling jar, and mixed at a speed of 250-350r / min for 4-8h.

[0070] In particular, the drying temperature in S3 is 60-100℃, the drying time is 10-12h, and the mesh size of the sieved product is 80-100 mesh.

[0071] In particular, the size of the cavity of the graphite mold in S4 is 0.4-0.5mm larger than the size of the product appearance.

[0072] In particular, the heating rate of the hot-pressing sintering in S5 is 5-10℃ / min, the sintering temperature is 1850-1900℃, the pressure is 40-60MPa, and the holding time is 2-2.5h.

[0073] Example 1

[0074] A new high-strength and high-toughness SiC ceramic material, which is composed of 78wt.% of SiC, 10wt.% of Y2SiO5, 6wt.% of Zr3Y4O 12 and 1wt.% of ZrC.

[0075] A preparation method of the new high-strength and high-toughness SiC ceramic material described above, which comprises the following steps:

[0076] S1, raw material weighing:

[0077] The raw material mixture powder 50g is obtained by weighing and mixing according to the total content of ZrO2 powder and Y2O3 powder being 15vol.% (the ratio of ZrO2 powder and Y2O3 powder is 1:1 in mole), 40vol.% of SiC whisker and the rest of α-SiC powder; wherein the purity of the α-SiC powder is 98.9%, the average particle size is 0.09μm; the purity of the ZrO2 powder is 98.7%, the average particle size is 0.03μm; the purity of the Y2O3 powder is 98.3%, the average particle size is 0.012μm; the purity of the SiC whisker is 99%, the length is 4-35μm, and the diameter is 0.3-0.7μm;

[0078] S2, ball milling:

[0079] The raw material mixture powder of S1 is wet ball milled, and the wet ball milling needs to mix the raw material mixture powder with 50g of anhydrous ethanol and 50g of zirconium oxide milling beads according to a mass ratio of 1:1:1, put them into a nylon milling jar, mix them at a speed of 300r / min for 4h, and obtain a mixed slurry;

[0080] S3, drying and sieving:

[0081] The mixed slurry of S2 is dried and sieved, the drying temperature is 80℃, the drying time is 11h, and the mesh size of the sieved product is 80 mesh, to obtain a fine particle mixture powder;

[0082] S4, graphite mold preparation:

[0083] According to the product demand of the prepared new high-strength and high-toughness SiC ceramic material, the shape and size of the graphite mold are determined, the size of the mold cavity of the graphite mold is 0.4 mm larger than the appearance size of the product, the graphite mold meeting the product demand is prepared, and then the fine particle mixed powder of S3 is placed in the graphite mold and vibrated to obtain the graphite mold filled with the fine particle mixed powder;

[0084] S5, hot-pressing sintering:

[0085] The fine particle mixed powder in the graphite mold filled with the fine particle mixed powder of S4 is subjected to hot-pressing sintering at a high temperature lower than 1900℃, the temperature is raised to 200℃ for 30 min, then the temperature is raised to 1700℃ at a rate of 10℃ / min, and then the temperature is raised to 1880℃ at a rate of 5℃ / min, the temperature is kept at this temperature for 2 h, and then the furnace is cooled to room temperature naturally. During the whole temperature rising process, the pressure is gradually applied to 50 MPa, and when the sintering temperature reaches 1880℃, the applied pressure is just 50 MPa, the pressure is kept for 2 h, and then the pressure is directly released after sintering, to obtain the product of the new high-strength and high-toughness SiC ceramic material.

[0086] As shown in Figure 1 , it can be seen that the SiC whiskers in the form of obvious short rods are added to the mixed powder, and are uniformly mixed with other powders.

[0087] As shown in Figure 2 , it can be clearly obtained from the spectrum that the prepared SiC ceramic material contains SiC, Y2SiO5, Zr3Y4O 12 and ZrC. The product of the new high-strength and high-toughness SiC ceramic material prepared in this embodiment includes SiC, Y2SiO5, Zr3Y4O 12 and ZrC, which completely meets the several reaction products mentioned above.

[0088] As shown in Figure 3 , the dark grains are the matrix SiC grains, and the bright white grains wrapped around the matrix grains are the generated Y2SiO5, Zr3Y4O 12 and ZrC. Their sizes can be obtained by the scale statistics, which are 0.5-2 μm. In addition, it can be seen that the rod-shaped SiC whiskers in the starting powder do not exist, indicating that the whiskers have been completely reacted.

[0089] The density of the product of the new high-strength and high-toughness SiC ceramic material prepared in this embodiment is 99.2±0.01%, and the density is 3.48±0.02 g / cm 3, hardness of 21±0.2GPa, bending strength of 885±55MPa, and fracture toughness of 8.94±0.26MPa·m 0.5 .

[0090] Example 2

[0091] A new high-strength and high-toughness SiC ceramic material, which is composed of 75wt.% of SiC, 12wt.% of Y2SiO5, 7wt.% of Zr3Y4O 12 and 1.5wt.% of ZrC.

[0092] A preparation method of the new high-strength and high-toughness SiC ceramic material described above, which comprises the following steps:

[0093] S1, raw material weighing:

[0094] According to the total content of ZrO2 powder and Y2O3 powder being 17vol.% (the ratio of ZrO2 powder and Y2O3 powder is 1:1 in mole), 40vol.% of SiC whisker and the rest of α-SiC powder, the raw material mixture powder 50g is obtained by proportioning and weighing; wherein, the purity of the α-SiC powder is 99.2%, and the average particle size is 0.15μm; the purity of the ZrO2 powder is 98.6%, and the average particle size is 0.05μm; the purity of the Y2O3 powder is 98.3%, and the average particle size is 0.01μm; the purity of the SiC whisker is 99%, the length is 4-35μm, and the diameter is 0.3-0.7μm;

[0095] S2, ball milling:

[0096] The raw material mixture powder of S1 is wet ball milled, and the wet ball milling needs to mix the raw material mixture powder with 50g of anhydrous ethanol and 50g of zirconium oxide milling beads according to a mass ratio of 1:1:1, put them in a nylon ball mill tank, mix them at a rotating speed of 330r / min for 6h, and obtain a mixed slurry;

[0097] S3, drying and sieving:

[0098] The mixed slurry of S2 is dried and sieved, the drying temperature is 70℃, the drying time is 10h, and the mesh number of the sieving after drying is 80 meshes, and a fine particle mixture powder is obtained;

[0099] S4, graphite mold preparation:

[0100] According to the product demand of the prepared new high-strength and high-toughness SiC ceramic material, the shape and size of the graphite mold are determined, the size of the mold cavity of the graphite mold is 0.43 mm larger than the appearance size of the product, the graphite mold meeting the product demand is prepared, and then the fine particle mixed powder of S3 is placed in the graphite mold and vibrated to obtain the graphite mold filled with the fine particle mixed powder;

[0101] S5, hot-pressing sintering:

[0102] The fine particle mixed powder in the graphite mold filled with the fine particle mixed powder of S4 is subjected to hot-pressing sintering at a high temperature lower than 1900℃, the temperature is raised to 220℃ for 30 min, then the temperature is raised to 1650℃ at a temperature raising rate of 10℃ / min, and then the temperature is raised to 1860℃ at a temperature raising rate of 5℃ / min, the temperature is kept at 1860℃ for 2.2 h, and then the temperature is naturally cooled to room temperature along with the furnace. During the whole temperature raising process, the pressure is gradually applied to 52 MPa, the pressure applied when the sintering temperature reaches 1860℃ is just 52 MPa, the pressure is kept for 2.2 h, the pressure is directly released after the sintering is completed, and the product of the new high-strength and high-toughness SiC ceramic material is obtained.

[0103] The ceramic prepared in the embodiment has no obvious rod-shaped whiskers, indicating that the added whiskers have all reacted to generate the reaction products mentioned in the text. In the product of the new high-strength and high-toughness SiC ceramic material prepared in the embodiment, the SiC is in the shape of equiaxed grains with a size of 1.2 μm; the rest of the second phases Y2SiO5, Zr3Y4O 12 and ZrC are dispersedly distributed and uniformly wrapped around the SiC grains, and have a size of 1.35 μm.

[0104] The product of the new high-strength and high-toughness SiC ceramic material prepared in the embodiment includes SiC, Y2SiO5, Zr3Y4O 12 and ZrC, and completely meets the several reaction products mentioned above.

[0105] The product of the new high-strength and high-toughness SiC ceramic material prepared in the embodiment has a density of 99.3±0.02%, a density of 3.49±0.02 g / cm 3 , a hardness of 22.3±0.2 GPa, a bending strength of 890±47 MPa, and a fracture toughness of 8.81±0.13 MPa·m 0.5 .

[0106] Example 3

[0107] A new high-strength and high-toughness SiC ceramic material includes 77 wt.% of SiC, 11.5 wt.% of Y2SiO5, 6.8 wt.% of Zr3Y4O 12 and 1.7 wt.% of ZrC.

[0108] A preparation method of the new high-strength and high-toughness SiC ceramic material is as follows:

[0109] S1, raw material weighing:

[0110] According to the total content of ZrO2 powder and Y2O3 powder being 16 vol.% (the ratio of ZrO2 powder and Y2O3 powder is 1:1 in mole), 45 vol.% SiC whisker and the balance of α-SiC powder, the raw material mixture powder 50g is weighed; wherein, the purity of the α-SiC powder is 99.5%, the average particle size is 0.17μm; the purity of the ZrO2 powder is 98.8%, the average particle size is 0.03μm; the purity of the Y2O3 powder is 99.3%, the average particle size is 0.0025μm; the purity of the SiC whisker is 99%, the length is 4-35μm, and the diameter is 0.3-0.7μm;

[0111] S2, ball milling:

[0112] The raw material mixture powder of S1 is wet ball milled, the raw material mixture powder is mixed with 50g of anhydrous ethanol, 50g of zirconium oxide milling beads according to a mass ratio of 1:1:1, placed in a nylon milling jar, mixed at a speed of 280r / min for 5h, and a mixed slurry is obtained;

[0113] S3, drying and sieving:

[0114] The mixed slurry of S2 is dried and sieved, the drying temperature is 90℃, the drying time is 10h, and the mesh size of the sieving after drying is 80 meshes, and a fine particle mixture powder is obtained;

[0115] S4, graphite mold preparation:

[0116] According to the product demand of the prepared new high-strength and high-toughness SiC ceramic material, the shape and size of the graphite mold are determined, the size of the mold cavity of the graphite mold is 0.46mm larger than the appearance size of the product, the graphite mold meeting the product demand is prepared, and then the fine particle mixture powder of S3 is placed in the graphite mold and vibrated, and a graphite mold filled with fine particle mixture powder is obtained;

[0117] S5, hot-pressing sintering:

[0118] The fine particle mixed powder in the graphite mold filled with the fine particle mixed powder of S4 is subjected to hot-press sintering at a high temperature below 1900℃, the temperature is raised to 250℃ for 30 min, then raised to 1720℃ at a temperature raising rate of 10℃ / min, then raised to 1870℃ at a temperature raising rate of 5℃ / min, and after being kept at the temperature for 2.4 h, it is naturally cooled to room temperature in the furnace. During the whole temperature raising process, the pressure is gradually applied to 50 MPa, and when the sintering temperature reaches 1870℃, the applied pressure is just 48 MPa, and the pressure is kept for 2.4 h, and after the sintering is finished, the pressure is directly released, to obtain the product of the new high-strength and high-toughness SiC ceramic material.

[0119] The ceramic prepared in the embodiment has no obvious rod-shaped whiskers, indicating that the added whiskers have all reacted to generate the reaction products mentioned in the text. In the product of the new high-strength and high-toughness SiC ceramic material prepared in the embodiment, the SiC is in the shape of equiaxed grains with a size of 1.2 μm; the rest of the second phases Y2SiO5, Zr3Y4O 12 and ZrC are dispersedly distributed and uniformly wrapped around the SiC grains with a size of 1.5 μm.

[0120] The product of the new high-strength and high-toughness SiC ceramic material prepared in the embodiment is composed of SiC, Y2SiO5, Zr3Y4O 12 and ZrC, which completely conforms to the several reaction products mentioned above.

[0121] The product of the new high-strength and high-toughness SiC ceramic material prepared in the embodiment has a density of 99.7±0.15%, a density of 3.48±0.01 g / cm 3 , a hardness of 20.8±0.3 GPa, a bending strength of 870±38 MPa, and a fracture toughness of 8.6±0.24 MPa·m 0.5 .

[0122] Example 4

[0123] A new high-strength and high-toughness SiC ceramic material, which contains 76 wt.% of SiC, 10.5 wt.% of Y2SiO5, 6.73 wt.% of Zr3Y4O 12 and 1.86 wt.% of ZrC.

[0124] A preparation method of the new high-strength and high-toughness SiC ceramic material, which comprises the following steps:

[0125] S1, raw material weighing:

[0126] The raw material mixed powder 50g is obtained by proportioning and weighing according to the total content of ZrO2 powder and Y2O3 powder being 14vol.% (the ratio of ZrO2 powder and Y2O3 powder is 1:1 in mole), 40vol.% SiC whisker and the balance of α-SiC powder; wherein the purity of the α-SiC powder is 99.6%, and the average particle size is 0.093μm; the purity of the ZrO2 powder is 99.5%, and the average particle size is 0.05μm; the purity of the Y2O3 powder is 99.3%, and the average particle size is 0.025μm; the purity of the SiC whisker is 99%, the length is 4-35μm, and the diameter is 0.3-0.7μm;

[0127] S2, ball milling:

[0128] The raw material mixed powder of S1 is subjected to wet ball milling, and the wet ball milling needs to mix the raw material mixed powder with 50g of anhydrous ethanol and 50g of zirconium oxide milling beads according to a mass ratio of 1:1:1, place in a nylon milling jar, and mix at a rotating speed of 320r / min for 4.5h to obtain a mixed slurry;

[0129] S3, drying and sieving:

[0130] The mixed slurry of S2 is subjected to drying and sieving, the drying temperature is 70℃, the drying time is 11.5h, and the mesh number of the sieving after drying is 80 meshes to obtain a fine particle mixed powder;

[0131] S4, graphite mold preparation:

[0132] According to the product demand of the prepared new high-strength and high-toughness SiC ceramic material, the shape and size of the graphite mold are determined, the size of the mold cavity of the graphite mold is 0.45mm larger than the appearance size of the product, the graphite mold meeting the product demand is prepared, and then the fine particle mixed powder of S3 is placed in the graphite mold and vibrated to obtain the graphite mold filled with the fine particle mixed powder;

[0133] S5, hot-pressing sintering:

[0134] The fine particle mixed powder in the graphite mold filled with the fine particle mixed powder of S4 is subjected to hot-pressing sintering at a high temperature lower than 1900℃, the temperature is raised to 300℃ for 30min, then raised to 1780℃ at a temperature rising rate of 10℃ / min, and then raised to 1895℃ at a temperature rising rate of 5℃ / min, and after being kept at the temperature for 2.3h, it is naturally cooled to room temperature with the furnace. In the whole temperature rising process, the pressure is gradually applied to 50MPa, and when the sintering temperature reaches 1895℃, the applied pressure is just 50MPa, and the pressure is kept for 2.3h, and after the sintering is finished, the pressure is directly released to obtain the product of the new high-strength and high-toughness SiC ceramic material.

[0135] The ceramic prepared in this embodiment has no obvious rod-shaped whiskers, indicating that the added whiskers have all reacted to form the reaction products mentioned in the text. The product of the new high-strength and high-toughness SiC ceramic material prepared in this embodiment is composed of SiC, Y2SiO5, Zr3Y4O 12 , and ZrC, and completely meets the several reaction products mentioned above.

[0136] The product of the new high-strength and high-toughness SiC ceramic material prepared in this embodiment is composed of SiC, Y2SiO5, Zr3Y4O 12 , and ZrC, and completely meets the several reaction products mentioned above.

[0137] The product of the new high-strength and high-toughness SiC ceramic material prepared in this embodiment has a density of 3.48±0.013 g / cm 3 , a hardness of 20.8±0.4 GPa, a bending strength of 850±25 MPa, and a fracture toughness of 8.4±0.30 MPa·m 0.5 .

[0138] Embodiment 5

[0139] A new high-strength and high-toughness SiC ceramic material, which comprises 77.5 wt.% of SiC, 11.5 wt.% of Y2SiO5, 6.88 wt.% of Zr3Y4O 12 , and 1.73 wt.% of ZrC.

[0140] A preparation method of the new high-strength and high-toughness SiC ceramic material, which comprises the following steps:

[0141] S1, raw material weighing:

[0142] The ZrO2 powder and Y2O3 powder are weighed according to a total content of 14.5 vol.% (the ratio of ZrO2 powder and Y2O3 powder is 1:1 in molar ratio), 45 vol.% of SiC whiskers, and the rest of α-SiC powder to obtain 50 g of raw material mixed powder; wherein the purity of the α-SiC powder is 99.3%, and the average particle size is 0.125 μm; the purity of the ZrO2 powder is 99.6%, and the average particle size is 0.04 μm; the purity of the Y2O3 powder is 99.4%, and the average particle size is 0.025 μm; the purity of the SiC whisker is 99%, the length is 4-35 μm, and the diameter is 0.3-0.7 μm;

[0143] S2, ball milling:

[0144] The raw material mixed powder of S1 is subjected to wet ball milling, which requires mixing the raw material mixed powder with 50 g of anhydrous ethanol and 50 g of zirconium oxide milling beads in a mass ratio of 1:1:1, placing them in a nylon milling jar, and mixing at a rotation speed of 300 r / min for 5 h to obtain a mixed slurry;

[0145] S3, drying and sieving:

[0146] The mixed slurry of S2 is subjected to drying and sieving, the drying temperature is 70℃, the drying time is 11 h, and the mesh size of the sieving after drying is 80 meshes to obtain a fine particle mixed powder;

[0147] S4, graphite mold preparation:

[0148] According to the product requirements of the prepared new high-strength and high-toughness SiC ceramic material, the shape and size of the graphite mold are determined, the size of the mold cavity of the graphite mold is 0.47 mm larger than the size of the product appearance, and the graphite mold meeting the product requirements is prepared. Then, the fine particle mixed powder of S3 is placed in the graphite mold and vibrated to obtain a graphite mold filled with fine particle mixed powder;

[0149] S5, hot-pressing sintering:

[0150] The fine particle mixed powder in the graphite mold filled with fine particle mixed powder of S4 is subjected to hot-pressing sintering at a temperature lower than 1900℃, the temperature is raised to 290℃ for 30 min, then raised to 1740℃ at a rate of 10℃ / min, and then raised to 1880℃ at a rate of 5℃ / min. After being kept at this temperature for 2.1 h, it is naturally cooled to room temperature with the furnace. During the whole temperature rising process, the pressure is gradually applied to 50 MPa, and when the sintering temperature reaches 1880℃, the applied pressure is just 50 MPa. After being kept for 2.1 h, the pressure is directly released, and the product of the new high-strength and high-toughness SiC ceramic material is obtained.

[0151] The ceramic prepared in this example has no obvious rod-shaped whiskers, indicating that the added whiskers have all reacted to form the reaction products mentioned in the text. In the product of the new high-strength and high-toughness SiC ceramic material prepared in this example, the shape of SiC is equiaxed grain, and the size is 1.23 μm; the rest of the second phase Y2SiO5, Zr3Y4O 12 and ZrC are dispersedly distributed and uniformly wrapped around the SiC grain, and the size is 1.57 μm.

[0152] The product of the new high-strength and high-toughness SiC ceramic material prepared in this example includes SiC, Y2SiO5, Zr3Y4O 12 and ZrC, which completely meets the several reaction products mentioned above.

[0153] The new high-strength and high-toughness SiC ceramic material prepared in the embodiment has a product density of 99.4±0.35%, a density of 3.47±0.015 g / cm 3 , a hardness of 20.7±0.2 GPa, a bending strength of 865±33 MPa, and a fracture toughness of 8.75±0.33 MPa·m 0.5 .

[0154] Embodiment 6

[0155] A new high-strength and high-toughness SiC ceramic material includes 78 wt.% of SiC, 10.8 wt.% of Y2SiO5, 7 wt.% of Zr3Y4O 12 , and 1.93 wt.% of ZrC.

[0156] A preparation method of the new high-strength and high-toughness SiC ceramic material includes the following steps:

[0157] S1, raw material weighing:

[0158] According to the total content of ZrO2 powder and Y2O3 powder being 13 vol.% (the ratio of ZrO2 powder and Y2O3 powder is 1:1 in mole), 40 vol.% of SiC whiskers, and the rest of α-SiC powder, the raw material mixture powder 50 g is weighed; wherein the purity of the α-SiC powder is 99.5%, and the average particle size is 0.13 μm; the purity of the ZrO2 powder is 99.6%, and the average particle size is 0.05 μm; the purity of the Y2O3 powder is 99.4%, and the average particle size is 0.015 μm; the purity of the SiC whisker is 99%, the length is 4-35 μm, and the diameter is 0.3-0.7 μm;

[0159] S2, ball milling:

[0160] The raw material mixture powder of S1 is wet ball milled, and the wet ball milling needs to mix the raw material mixture powder with 50 g of anhydrous ethanol and 50 g of zirconium oxide milling beads according to a mass ratio of 1:1:1, put them in a nylon ball mill tank, mix them at a speed of 280 r / min for 5 h, and obtain a mixed slurry;

[0161] S3, drying and sieving:

[0162] The mixed slurry of S2 is dried and sieved, the drying temperature is 70℃, the drying time is 11 h, and the mesh size of the sieving after drying is 80 meshes, and a fine particle mixture powder is obtained;

[0163] S4, graphite mold preparation:

[0164] According to the product demand of the prepared new high-strength and high-toughness SiC ceramic material, the shape and size of the graphite mold are determined, the size of the mold cavity of the graphite mold is 0.43 mm larger than the appearance size of the product, and the graphite mold meeting the product demand is prepared. Then the fine particle mixed powder of S3 is placed in the graphite mold and vibrated to obtain the graphite mold filled with the fine particle mixed powder;

[0165] S5, hot-pressing sintering:

[0166] The fine particle mixed powder in the graphite mold filled with the fine particle mixed powder of S4 is subjected to hot-pressing sintering at a high temperature lower than 1900℃, and the temperature is raised to 300℃ for 30 min, then raised to 1750℃ at a temperature raising rate of 10℃ / min, and then raised to 1900℃ at a temperature raising rate of 5℃ / min. After being kept at the temperature for 2.1 h, it is naturally cooled to room temperature with the furnace. During the whole temperature raising process, the pressure is gradually applied to 53 MPa, and the pressure applied when the sintering temperature reaches 1900℃ is just 53 MPa. The pressure is kept for 2.1 h, and then directly released after the sintering is finished, to obtain the product of the new high-strength and high-toughness SiC ceramic material.

[0167] The ceramic prepared in this example has no obvious rod-shaped whiskers, indicating that the added whiskers have all reacted to form the reaction products mentioned in the text. In the product of the new high-strength and high-toughness SiC ceramic material prepared in this example, the shape of SiC is equiaxed grain, and the size is 1.11 μm; the rest of the second phase Y2SiO5, Zr3Y4O 12 and ZrC are dispersedly distributed and uniformly wrapped around the SiC grain, and the size is 1.23 μm.

[0168] The product of the new high-strength and high-toughness SiC ceramic material prepared in this example includes SiC, Y2SiO5, Zr3Y4O 12 and ZrC, which completely meets the several reaction products mentioned above.

[0169] The product of the new high-strength and high-toughness SiC ceramic material prepared in this example has a density of 99.4±0.35%, a density of 3.48±0.015 g / cm 3 , a hardness of 20.9±0.3 GPa, a bending strength of 875±42 MPa, and a fracture toughness of 8.63±0.36 MPa·m 0.5 .

[0170] Comparative Example 1

[0171] A method for preparing a high-strength and high-toughness SiC ceramic material, the high-strength and high-toughness SiC ceramic material does not contain SiC whiskers, and therefore the generated SiC ceramic does not contain Y2SiO5 and ZrC. The addition amount of α-SiC powder, ZrO2 powder and Y2O3 powder is the same as that in Example 6, and the method for preparing the high-strength and high-toughness SiC ceramic material comprises the following steps:

[0172] S1, raw material weighing:

[0173] According to the total content of ZrO2 powder and Y2O3 powder being 13 vol.% (the ratio of ZrO2 powder and Y2O3 powder is 1:1 in mole) and the balance of α-SiC powder, the raw material mixture powder 50g is prepared by proportioning and weighing; wherein the purity of the α-SiC powder is 99.5%, and the average particle size is 0.13μm; the purity of the ZrO2 powder is 99.6%, and the average particle size is 0.05μm; the purity of the Y2O3 powder is 99.4%, and the average particle size is 0.015μm;

[0174] S2, ball milling:

[0175] The raw material mixture powder of S1 is wet ball milled, and the wet ball milling needs to mix the raw material mixture powder with 50g of anhydrous ethanol and 50g of zirconium oxide milling beads according to a mass ratio of 1:1:1, and is placed in a nylon ball mill tank, and is mixed at a speed of 280r / min for 5h to obtain a mixed slurry;

[0176] S3, drying and sieving:

[0177] The mixed slurry of S2 is dried and sieved, the drying temperature is 70℃, the drying time is 11h, and the mesh size of the sieving after drying is 80 meshes to obtain a fine particle mixture powder;

[0178] S4, graphite mold preparation:

[0179] According to the product demand of the prepared new high-strength and high-toughness SiC ceramic material, the shape and size of the graphite mold are determined, the size of the mold cavity of the graphite mold is 0.43mm larger than the appearance size of the product, the graphite mold meeting the product demand is prepared, and then the fine particle mixture powder of S3 is placed in the graphite mold and vibrated to obtain a graphite mold filled with fine particle mixture powder;

[0180] S5, hot-pressing sintering:

[0181] The fine-particle mixed powder of S4 was hot-pressed and sintered in a graphite mold filled with fine-particle mixed powder at a temperature below 1900℃. After 30 minutes, the temperature was raised to 300℃, then to 1750℃ at a rate of 10℃ / min, and then to 1900℃ at a rate of 5℃ / min. This temperature was held for 2.1 hours, and then allowed to cool naturally to room temperature in the furnace. Throughout the heating process, a pressure was gradually applied up to 53 MPa, reaching exactly 53 MPa when the sintering temperature reached 1900℃. The pressure was held for 2.1 hours, and then immediately released after sintering to obtain a high-strength, high-toughness SiC ceramic material.

[0182] like Figure 4 As shown, the high-strength and high-toughness SiC ceramic material prepared in this comparative example does not contain the second phases Y2SiO5 and ZrC.

[0183] The high-strength, high-toughness SiC ceramic material prepared in this embodiment has a density of 99.0 ± 0.35% and a density of 3.46 ± 0.015 g / cm³. 3 Its hardness is 20.4±0.3 GPa, its flexural strength is only 656±32 MPa, and its fracture toughness is 6.30±0.36 MPa·m. 0.5 .

[0184] The above-described solution provides a novel high-strength and high-toughness SiC ceramic material and its preparation method, overcoming the technical shortcomings of current SiC ceramic materials that cannot achieve low-cost and high-efficiency synergistic improvement of density, flexural strength, and fracture toughness. This expands the application range of SiC ceramic materials and facilitates large-scale industrial production and promotion.

[0185] This invention involves adding ZrO2 powder, Y2O3 powder, and SiC whiskers to α-SiC powder and reacting them during hot-pressing sintering to obtain a product consisting of 75-82 wt.% SiC, 10-12 wt.% Y2SiO5, and 6-7 wt.% Zr3Y4O5. 12 A ceramic material composed of 1-2 wt.% ZrC; wherein, Y2SiO5 plays the role of filling the voids between SiC grains, ensuring the material's density. 12 Its function is to provide just the right interfacial bonding strength with the SiC matrix grains, thereby improving fracture toughness. ZrC can pin grain boundaries, thus refining the grains and improving the flexural strength of the material.

[0186] This invention utilizes wet ball milling to thoroughly mix various powders. In particular, due to the large specific surface area of ​​SiC whiskers, they are highly prone to agglomeration, hindering mass transfer during sintering and resulting in poor density of SiC ceramics. Wet ball milling ensures uniform whisker dispersion, preventing agglomeration during sintering.

[0187] The sintering temperature of the hot-press sintering of the application is lower than 1900 DEG C, and the SiC ceramic with excellent performance is obtained on the basis of reducing the production cost.

[0188] The density of the new high-strength and high-toughness SiC ceramic material prepared by the application is more than 99%, the density is 3.45-3.51 g / cm 3 , the hardness is more than 20 GPa, the bending strength is more than 800 MPa, and the fracture toughness is more than 8 MPa.m 0.5 .

[0189] In summary, compared with other traditional methods, the method of the application adds ZrO2 powder, Y2O3 powder and SiC whisker in the α-SiC powder, and obtains the SiC ceramic material reinforced and toughened by Y2SiO5, Zr3Y4O 12 and ZrC as the second phase in the subsequent hot-press sintering process, on the basis of the density being more than 99%, the hardness being more than 20 GPa, the bending strength being more than 800 MPa, and the fracture toughness being more than 8 MPa.m 0.5 ; the process steps are simple, the operation is convenient, the process cycle is short, the cost is low, the efficiency is high, the control is easy, it is beneficial to industrial production, and the SiC ceramic with the best comprehensive performance (especially the bending strength and the fracture toughness) reported at present is prepared.

[0190] The above is the preferred embodiment of the application, and it should be pointed out that, for ordinary skilled in the art, without departing from the principles of the application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the application.

Claims

1. A high-strength, high-toughness SiC ceramic material, characterized in that, The high-strength and high-toughness SiC ceramic material comprises 75-82 wt.% SiC, 10-12 wt.% Y2SiO5, and 6-7 wt.% Zr3Y4O 12 With 1-2 wt.% ZrC, materials of different sizes can be prepared using different molds.

2. The high-strength, high-toughness SiC ceramic material according to claim 1, characterized in that, SiC is composed of equiaxed grains with a size of 1-1.5 μm; the remaining second phases are Y2SiO5 and Zr3Y4O. 12 ZrC and other elements are dispersed and uniformly wrapped around the SiC matrix grains, with a size of 0.5-2 μm.

3. The high-strength, high-toughness SiC ceramic material according to claim 1, characterized in that, The high-strength and high-toughness SiC ceramic material has a density exceeding 99%, with a density of 3.45-3.51 g / cm³. 3 Hardness exceeds 20 GPa, flexural strength exceeds 800 MPa, and fracture toughness exceeds 8 MPa·m. 0.5 .

4. A method for preparing a high-strength, high-toughness SiC ceramic material based on any one of claims 1-3, characterized in that, The preparation method of the high-strength and high-toughness SiC ceramic material is as follows: S1. Weighing of raw materials: α-SiC powder, ZrO2 powder, Y2O3 powder, and SiC whiskers were selected as raw material powders and weighed according to the specified ratio to obtain a raw material mixed powder. The purity of α-SiC powder was 98.5-99.9%, and the average particle size was 0.05-0.2 μm; the purity of ZrO2 powder was 98-99.9%, and the average particle size was 0.01-0.06 μm; the purity of Y2O3 powder was 98-99.9%, and the average particle size was 0.01-0.03 μm; the purity of SiC whiskers was 99%, the length was 4-35 μm, and the diameter was 0.3-0.7 μm; the volume percentage of ZrO2 powder and Y2O3 powder in the raw material mixed powder was 13-17 vol%, and the molar ratio of ZrO2 powder to Y2O3 powder was 1:1; the volume percentage of added SiC whiskers in the raw material mixed powder was between 40-50 vol.%. S2, ball mill: The raw material powder of S1 is wet ball-milled to obtain a mixed slurry; S3. Drying and sieving: The mixed slurry of S2 is dried and sieved to obtain a fine-particle mixed powder; S4. Preparation of graphite molds: Based on the product requirements of the high-strength and high-toughness SiC ceramic material to be prepared, the shape and size of the graphite mold are determined, and a graphite mold that meets the product requirements is prepared. Then, the fine particle mixed powder of S3 is placed in the graphite mold and vibrated. A layer of graphite paper needs to be placed between the graphite mold and the powder to prevent the sintered sample from sticking to the mold. S5. Hot pressing and sintering: The fine-particle mixed powder in the graphite mold filled with S4 is subjected to hot pressing sintering at a high temperature below 1900℃. The heating rate of hot pressing sintering is 5-10℃ / min, the sintering temperature is 1850-1900℃, the pressure is 40-60MPa, and the holding time is 2-2.5h. After sintering, the pressure is directly released and cooled to obtain a high-strength and high-toughness SiC ceramic material product.

5. The method for preparing high-strength and high-toughness SiC ceramic material according to claim 4, characterized in that, In S2, wet ball milling requires mixing the raw material powder with anhydrous ethanol, zirconia or silicon carbide grinding beads, and agate grinding beads in a mass ratio of 1:1:1, placing the mixture in a nylon ball milling jar, and mixing at a speed of 250-350 r / min for 4-8 hours.

6. The method for preparing high-strength and high-toughness SiC ceramic material according to claim 4, characterized in that, The drying temperature in S3 is 60-100℃, the drying time is 10-12h, and the mesh size after drying is 80-100 mesh.

7. The method for preparing high-strength and high-toughness SiC ceramic material according to claim 4, characterized in that, In S4, the mold cavity size of the graphite mold is 0.4-0.5mm larger than the product's external dimensions.

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