Highly flexible ceramic material and method for its production

Abstract

The application provides a high-bending-resistant ceramic material and a preparation method thereof, and comprises the following raw materials in parts by mass: 50 parts of potassium sodium feldspar, 15-25 parts of dolomite, 20-30 parts of calcium feldspar, 3-13 parts of a reinforcing agent, 0.1-0.5 parts of solid ceramic microbeads, 1-3 parts of rice husk ash, and 1-5 parts of a binder; the reinforcing agent comprises modified molybdenum disilicide, the modified molybdenum disilicide comprises a molybdenum disilicide core and a yttrium phosphate shell layer, and the surface of the molybdenum disilicide core is loaded with yttrium oxide. Through the design of the reinforcing agent, the obtained ceramic material has good bending resistance and can withstand a larger external force without being easily broken, and is suitable for high-strength application occasions.

Description

Technical Field

[0001] This disclosure relates to the field of ceramic preparation technology, specifically to a high flexural strength ceramic material and its preparation method. Background Technology

[0002] Ceramic materials are important engineering materials, widely used in construction, electronics, aerospace, and machinery due to their excellent hardness, wear resistance, and high-temperature resistance. With the development of industrial technology, the demand for ceramic materials in terms of external force resistance and flexural strength is increasing. However, the brittleness of ceramic materials often limits their widespread application; therefore, improving the flexural strength of ceramics has become a key focus of materials research.

[0003] Traditional ceramic materials typically have high hardness but are also brittle, making them prone to fracture under external forces. Researchers have discovered that the flexural strength of ceramics can be improved by introducing reinforcing phases. Common reinforcing phases include metallic reinforcing phases, such as aluminum, titanium, and yttrium particles, which increase the toughness of the ceramic by increasing the distribution of these particles; and ceramic reinforcing phases, such as silicon carbide, silicon nitride, and calcium titanate particles, which provide high hardness and improve the flexural strength of the ceramic. Molybdenum disilicide is a ceramic with excellent high-temperature resistance and is often used in material toughening. For example, patent CN104370536A discloses a toughening and high-temperature resistant special ceramic for the cylinder liner of an internal combustion engine. This invention uses molybdenum disilicide, silicon nitride, hafnium boride, and a sintering process to increase the heat resistance and toughness of the ceramic, resulting in a significant improvement in flexural strength.

[0004] However, the problem with the above patent is that molybdenum disilicide powder is directly added to the ceramic material and sintered in an air atmosphere. Molybdenum disilicide is easily oxidized into molybdenum oxide at high temperatures, which may lead to a loose material structure. Under continuous high temperatures, it may also volatilize and produce pores, thereby affecting the flexural strength of the ceramic.

[0005] Therefore, there is a need to provide a ceramic material preparation technology that can improve the flexural strength of ceramics, so that the prepared ceramic materials can be applied to fields with high performance requirements. Summary of the Invention

[0006] This application provides a high flexural strength ceramic material and its preparation method, wherein the ceramic material prepared by this method has high flexural strength.

[0007] In a first aspect, this application provides a high flexural strength ceramic material comprising the following raw materials in parts by weight: 50 parts of potassium sodium feldspar, 15-25 parts of dolomite, 20-30 parts of calcium feldspar, 3-13 parts of reinforcing agent, 0.1-0.5 parts of solid ceramic microspheres, 1-3 parts of rice husk ash, and 1-5 parts of binder; wherein the reinforcing agent comprises modified molybdenum disilicide, wherein the modified molybdenum disilicide comprises a molybdenum disilicide core and a yttrium phosphate outer shell, and the surface of the molybdenum disilicide core is loaded with yttrium oxide.

[0008] Specifically, potassium-sodium feldspar, as the ceramic matrix, can melt during sintering to form a low-viscosity liquid phase, promoting liquid-phase sintering between particles; dolomite and anorthite can form an alkaline earth oxide flux phase, improving the material's structural density; the reinforcing agent includes modified molybdenum disilicide, which comprises a molybdenum disilicide core and a yttrium phosphate shell layer. The surface of the molybdenum disilicide core is loaded with yttrium oxide. Molybdenum disilicide (MoSi2) is a high-temperature ceramic material with high toughness and high-temperature strength. Introducing a molybdenum disilicide core into the ceramic matrix... It can effectively enhance the crack propagation resistance and impact toughness of ceramics. Yttrium oxide (Y2O3), located between the core and shell, can improve the grain boundary bonding force and inhibit grain growth during sintering. Yttrium phosphate (YPO4) has a thermal expansion coefficient closer to that of the ceramic matrix and good chemical stability. It can act as a load transfer layer under external force, reducing interfacial stress concentration. The three form an organic whole. When microcracks are generated under load, modified molybdenum disilicide can bridge the crack between the two sides, forming a particle bridge. Its surface is covered with... The YPO4 shell enhances the bonding strength and frictional resistance at the filler-matrix interface, making the filler less prone to detachment or breakage during crack initiation. This significantly dissipates energy during crack pull-out, rotation, and debonding, increasing crack propagation resistance. Molybdenum disilicide provides toughness support, yttrium oxide inhibits defects and strengthens bonding, and yttrium phosphate optimizes the interface and disperses stress, collectively improving the flexural strength of the ceramic material. Furthermore, yttrium phosphate forms a dense protective layer on the surface of molybdenum disilicide, which also inhibits its oxidation and volatilization. Solid ceramic microspheres can... As a stress dispersion center, it alters the crack propagation path. Furthermore, the interfacial difference between the microspheres and the matrix can induce a microcrack network, promoting the absorption of fracture energy and thus improving the material's flexural strength and toughness. Rice husk ash is rich in silica, which can react with feldspar or dolomite to form a denser silicate phase, filling the matrix pores and reducing porosity. At the same time, it can improve the thermal expansion matching of ceramics and enhance their thermal shock resistance. In addition, adding a binder to the raw materials can provide good plasticity, making the green body structure denser and suppressing the generation of defects.

[0009] Therefore, through raw material optimization and reinforcing agent design, this application can effectively improve the flexural strength of ceramic materials, enabling them to have better application performance in complex working environments such as strong impact.

[0010] In some embodiments, the method for preparing the modified molybdenum disilicide includes the following steps:

[0011] S1: Disperse the first soluble yttrium salt and molybdenum disilicide in water, adjust the pH to convert yttrium ions into yttrium hydroxide and deposit it on the surface of molybdenum disilicide, to obtain molybdenum disilicide loaded with yttrium hydroxide;

[0012] S2: The molybdenum disilicide loaded with yttrium hydroxide is calcined to dehydrate the yttrium hydroxide on the surface of the molybdenum disilicide to generate yttrium oxide, thereby obtaining molybdenum disilicide loaded with yttrium oxide;

[0013] S3: Disperse molybdenum disilicide loaded with yttrium oxide, a second soluble yttrium salt, and a soluble phosphate in water, and adjust the pH to allow yttrium phosphate to deposit on the surface of molybdenum disilicide loaded with yttrium oxide, thereby obtaining a modified molybdenum disilicide precursor.

[0014] S4: The modified molybdenum disilicide precursor is calcined to fix yttrium phosphate in the outer layer, thereby obtaining modified molybdenum disilicide.

[0015] In some of the above embodiments, Y 3+ Hydrolysis generates Y(OH)3, which is anchored to the MoSi2 surface through electrostatic adsorption and hydrogen bonding.

[0016] In step S2, calcination in an inert atmosphere dehydrates Y(OH)3 to form Y2O3, thus loading Y2O3 particles onto the MoSi2 surface. These Y2O3 particles help alleviate interfacial stress concentration and inhibit microcrack initiation at the interface. The SiO2 layer naturally formed on the MoSi2 surface can react with Y2O3 at high temperatures to form yttrium silicates. Simultaneously, Y2O3 can react with PO4... 3- The YOP bond connection enhances the interfacial bonding between MoSi2 and the subsequent YPO4 layer;

[0017] In step S3, Y is added dropwise simultaneously. 3+ PO4 3- The solution undergoes heterogeneous nucleation on the Y₂O₃ / MoSi₂ surface, Y 3+ Preferential adsorption on Y2O3 particles lowers the nucleation energy barrier, PO4 3- With Y 3+ YPO4 is generated and grows directionally along the surface to form a relatively continuous YPO4 shell.

[0018] In step S4, calcining YPO4 in an inert atmosphere transforms it from an amorphous state to a crystalline state, which effectively improves the stability of modified molybdenum disilicide at high temperatures. During the sintering process of ceramic materials, Y2O3 and YPO4 may undergo interfacial reactions with the matrix components to form a Y-Al-Si-O reaction phase, which enhances interfacial bonding and reduces micropores and voids. In addition, the YPO4 shell can, to a certain extent, inhibit the oxidation and volatilization of MoSi2 during high-temperature sintering, reducing the formation of oxide pores.

[0019] The prepared modified molybdenum disilicide has a high-modulus, high-toughness core (MoSi2) that bears the principal stress; the middle Y2O3 consists of dispersed particles that help deflect and branch cracks, smooth the stress gradient between the core and the shell and matrix, and prevent stress concentration at the hard and brittle phase interface; the outer YPO4 layer has good thermal expansion matching and chemical stability, and can serve as a "thermal expansion adaptation transition layer". Under external load, it helps to smooth the stress distribution and delay the crack propagation at the interface, thereby improving the flexural strength of the material.

[0020] In some embodiments, the method for preparing the modified molybdenum disilicide includes the following steps:

[0021] S1: Disperse 0.25 parts Y(NO3)3·6H2O and 9~11 parts MoSi2 in 10~150 parts water, adjust the pH value to 6.5~7.5, and obtain molybdenum disilicide loaded with yttrium hydroxide;

[0022] S2: Molybdenum disilicide loaded with yttrium hydroxide was calcined at 250-450°C for 2-4 hours under a nitrogen atmosphere to obtain molybdenum disilicide loaded with yttrium oxide;

[0023] S3: Disperse 10 parts of molybdenum disilicide loaded with yttrium oxide, 1-2 parts of Y(NO3)3·6H2O, and 0.5-1 parts of (NH4)2HPO4 in 10-150 parts of water, adjust the pH to 5-6, and react for 4-5 hours to obtain the modified molybdenum disilicide precursor.

[0024] S4: The modified molybdenum disilicide precursor was calcined in a nitrogen atmosphere at 250-500℃ for 4-6 hours to obtain modified molybdenum disilicide.

[0025] The above embodiments specifically illustrate the reaction conditions and dosage ratios of each step in the preparation of modified molybdenum disilicide. Under these conditions, the modified molybdenum disilicide obtained can significantly improve the flexural strength of the material.

[0026] In some embodiments, the reinforcing agent further includes modified stabilized zirconia, which comprises cerium oxide stabilized zirconia and a γ-Al2O3 layer coated on the surface of cerium oxide stabilized zirconia; the mass ratio of modified molybdenum disilicide to modified stabilized zirconia is 1:0.5~0.7.

[0027] In some of the embodiments described above, cerium oxide stabilizes Ce in zirconium oxide. 4+ Having reversible Ce 4+ / Ce 3+ Valence state transformation characteristics allow for stress adaptive relaxation at the interface through valence state adjustment during sintering and stress application. Furthermore, Ce... 4+ Possibly related to PO4 in modified molybdenum disilicide 3-The formation of the CePO4 phase constructs a multi-layered gradient interface structure. Under external forces, this structure may dissipate energy through mechanisms such as oxygen vacancy migration and valence state transformation, effectively hindering crack propagation and thus improving the flexural strength and fracture toughness of the ceramic. The γ-Al2O3 layer can act as an interfacial transition layer between cerium oxide-stabilized zirconia and the ceramic matrix. γ-Al2O3 has high surface activity and is rich in hydroxyl groups, which can promote dense interfacial bonding, improve interfacial bonding strength, and ensure effective load transfer from the matrix to the high-toughness zirconia particles. On the other hand, this transition layer can also act as an interfacial buffer layer, absorbing external stress and dispersing stress concentration, promoting crack deflection and energy dissipation, thereby improving the flexural strength and fracture toughness of the ceramic. The coating structure retains the core phase transformation toughening ability of cerium oxide-stabilized zirconia while improving its stability in complex environments and its synergistic toughening effect with the matrix. In addition, the γ-Al2O3 layer may have weak interfacial adsorption and bonding with YPO4 at high temperatures, improving interfacial stability and toughness, preventing interfacial delamination, and improving the flexural performance of the material.

[0028] Under external load, modified stabilized zirconia passivates the crack tip through stress-induced phase transformation, while modified molybdenum disilicide provides subsequent traction in the crack tail region through crack bridging. The two can form a synergistic protection that connects the front and rear. Furthermore, the stress field generated by the zirconia phase transformation can reduce the actual stress acting on molybdenum disilicide, prolonging its toughening effect. Correspondingly, the moderate residual stress around the molybdenum disilicide particles can pre-compress and distort the lattice of the adjacent zirconia particles, reducing their phase transformation energy barrier. This, in turn, promotes more zirconia particles to undergo phase transformation under external force, further activating a large-scale toughening region. The multiphase heterogeneous interface formed by the two reinforcing phases and the matrix may also induce crack propagation path deflection and bifurcation, increasing the energy required for crack propagation. When the mass ratio of modified molybdenum disilicide to modified stabilized zirconia is 1:0.5~0.7, the two can form an effective spatial distribution at the microscale, synergistically improving the flexural strength of the material.

[0029] In some embodiments, the method for preparing the modified stabilized zirconium oxide includes the following steps:

[0030] N1: Cerium oxide stabilized zirconium oxide is dispersed in water and mixed with an aluminum-based precursor dispersion. The pH is adjusted to allow AlOOH to be adsorbed onto the surface of cerium oxide stabilized zirconium oxide, resulting in cerium oxide stabilized zirconium oxide with AlOOH coated on the surface.

[0031] N2: Cerium oxide-stabilized zirconium oxide coated with AlOOH is calcined to convert AlOOH into γ-Al2O3, thus obtaining modified stabilized zirconium oxide.

[0032] In some embodiments, in step N1, the aluminum-based precursor dispersion includes a boehmite suspension.

[0033] In some of the above embodiments, a method for preparing modified stabilized zirconia is described. By selecting boehmite suspension as the aluminum-based precursor dispersion, uniform coating of cerium oxide stabilized zirconia can be achieved with a simple process, and it can be efficiently converted into a γ-Al2O3 layer under mild conditions, ensuring subsequent interface optimization and toughening effects.

[0034] In some embodiments, the method for preparing the modified stabilized zirconium oxide includes the following steps:

[0035] N1: Disperse 5 parts of cerium oxide-stabilized zirconium oxide in 20-60 parts of water, add 1-5 parts of 20wt% boehmite suspension, adjust the pH to 4-6, and obtain cerium oxide-stabilized zirconium oxide with AlOOH surface coating;

[0036] N2: Cerium oxide-stabilized zirconium oxide coated with AlOOH is calcined at 400~600℃ for 1~2h to obtain modified stabilized zirconium oxide.

[0037] In some of the above embodiments, the reaction conditions and dosage ratios of each step in the preparation of modified stabilized zirconia are specifically described. Under these conditions, a γ-Al2O3 coating layer is formed in situ on the surface of cerium oxide stabilized zirconia using boehmite suspension. During ceramic sintering, this coating layer can inhibit zirconia aggregation and maintain a fine-grained structure. Furthermore, during cooling, due to the difference in thermal expansion coefficients, γ-Al2O3 can generate a residual compressive stress zone on the zirconia surface, thereby improving the fracture toughness and flexural strength of the material.

[0038] In some embodiments, the particle size of the solid ceramic microspheres is 1~50μm.

[0039] In some of the above embodiments, the particle size of solid ceramic microspheres in the range of 1~50μm can better match the optimized microstructure with the ceramic matrix grains, thus serving as a dispersed toughening phase. In addition, within this particle size range, the microspheres have good dispersibility in the matrix, which can reduce the problem of stress concentration due to excessively large particle size or insufficient toughening effect due to excessively small particle size. At the same time, under this size condition, solid ceramic microspheres are conducive to promoting the densification of ceramic materials, suppressing sintering defects, and thus ensuring and improving the mechanical properties of the material as a whole.

[0040] In some embodiments, the binder includes at least one of kaolin, polyvinyl alcohol, and carboxymethyl cellulose. Using the above binder can suppress over-sintering and shrinkage cracking during the material forming stage, thereby improving the density of the ceramic material.

[0041] Secondly, this application provides a method for preparing a high flexural strength ceramic material, comprising:

[0042] Provide raw materials for the high flexural strength ceramic material according to any embodiment of the first aspect, and perform wet ball milling on the raw materials to obtain a slurry, followed by drying, granulation, pressing, and firing to obtain the high flexural strength ceramic material.

[0043] According to this application, the method can prepare a high flexural strength ceramic material in the first aspect, thus having the beneficial effects in the first aspect, and the obtained ceramic material has excellent flexural strength.

[0044] Compared with the prior art, the beneficial effects of this application are at least as follows:

[0045] 1. By introducing modified molybdenum disilicide consisting of "MoSi2 core-Y2O3 particles-YPO4 shell" into the ceramic matrix, a stress gradient transition structure from a high-modulus core to a rigid shell is achieved. This material has a triple function of "bearing load-buffering-transferring", which can effectively smooth stress distribution, disperse stress concentration at the interface, and significantly improve the flexural strength of the material.

[0046] 2. In modified stabilized zirconia, cerium oxide stabilized zirconia and its surface γ-Al2O3 coating layer form a buffer interface, which can inhibit zirconia agglomeration, maintain fine grain structure, enhance the interfacial bonding force between the matrix and the filler, and improve flexural strength.

[0047] 3. Modified molybdenum disilicide and modified stabilized zirconia, through the construction of a synergistic mechanism of "phase transformation toughening-crack bridging", achieve efficient dissipation of interfacial stress coupling and crack propagation energy under a specific ratio, thereby synergistically improving the flexural strength of the material. Detailed Implementation

[0048] The various embodiments or implementation schemes in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments.

[0049] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0050] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0051] In this specification, unless otherwise specified, "parts" refers to "parts by weight".

[0052] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0053] Solid ceramic microspheres: particle size approximately 10μm, model number W210;

[0054] Rice husk ash: The main components are SiO2: 90~97%, K2O: 1~4%, and other impurities not exceeding 2%;

[0055] boehmite suspension: solid content 20wt%, model YC-LRJ15;

[0056] Polyvinylpyrrolidone (PVP K30): CAS number 9003-39-8, weight average molecular weight approximately 50,000;

[0057] Cerium oxide stabilized zirconium oxide: model number FR-3CC12.

[0058] Preparation Example 1

[0059] Preparation of modified molybdenum disilicide:

[0060] S1: Disperse 10 parts of MoSi2 in 90 parts of deionized water and sonicate for 30 min (frequency 40 kHz, power 200 W) to form a MoSi2 suspension. Dissolve 0.25 parts of Y(NO3)3·6H2O in 10 parts of deionized water and slowly add it dropwise to the MoSi2 suspension. Adjust and maintain the pH value to 7, stir and age for 45 min, continue to stand for 20 min, filter, wash, and vacuum dry to obtain molybdenum disilicide loaded with yttrium hydroxide.

[0061] S2: Molybdenum disilicide loaded with yttrium hydroxide was calcined at 300°C for 1 hour in a nitrogen atmosphere, and then calcined at 400°C for 2 hours to obtain molybdenum disilicide loaded with yttrium oxide.

[0062] S3: Dissolve 1.4 parts Y(NO3)3·6H2O and 0.05 parts citric acid in 10 parts deionized water, and dissolve 0.72 parts (NH4)2HPO4 in 5 parts deionized water. At 65°C, simultaneously add the above yttrium-containing solution, phosphorus-containing solution, and 0.1 parts PVP K30 to 100 parts molybdenum disilicide suspension loaded with yttrium oxide (10 parts molybdenum disilicide loaded with yttrium oxide and 90 parts deionized water). Adjust and maintain the pH value to 5.5, react at 70°C for 4.5 h, centrifuge, wash, and vacuum dry to obtain the modified molybdenum disilicide precursor.

[0063] S4: The modified molybdenum disilicide precursor was calcined at 300°C for 1.5 h in a nitrogen atmosphere, and then calcined at 450°C for 3 h to obtain modified molybdenum disilicide A.

[0064] Preparation Example 2

[0065] Preparation of modified molybdenum disilicide:

[0066] The preparation method is largely the same as in Example 1, except that step S4 is not performed. Steps S1 to S3 are the same, resulting in modified molybdenum disilicide B.

[0067] Preparation Example 3

[0068] Preparation of modified stabilized zirconium oxide:

[0069] N1: Disperse 5 parts of cerium oxide-stabilized zirconium oxide in 45 parts of deionized water, sonicate (frequency 40kHz, power 200w) for 15min, add 2.5 parts of 20wt% boehmite suspension, adjust and maintain pH value to 5, stir and age for 60min, filter and dry to obtain cerium oxide-stabilized zirconium oxide with AlOOH coating on the surface.

[0070] N2: Cerium oxide stabilized zirconium oxide coated with AlOOH was calcined at 500℃ for 1.5 h in an oxygen-containing atmosphere to obtain modified stabilized zirconium oxide A.

[0071] Preparation Example 4

[0072] Preparation of modified stabilized zirconium oxide:

[0073] N1: Disperse 5 parts of cerium oxide-stabilized zirconium oxide in 45 parts of deionized water, sonicate (frequency 40kHz, power 200w) for 15min, add 2.5 parts of Al(NO3)3·9H2O aqueous solution (0.5 parts Al(NO3)3·9H2O, 2 parts deionized water), adjust and maintain the pH value to 6, stir and age for 60min, filter, wash and dry to obtain cerium oxide-stabilized zirconium oxide with Al(OH)3 coating on the surface;

[0074] N2: Cerium oxide stabilized zirconium oxide with Al(OH)3 surface coating is calcined at 500℃ for 1.5h in an oxygen-containing atmosphere to obtain modified stabilized zirconium oxide B.

[0075] Comparative Preparation Example 1

[0076] Preparation of modified molybdenum disilicide:

[0077] S1: Disperse 10 parts of MoSi2 in 90 parts of deionized water and sonicate for 30 min (frequency 40 kHz, power 200 W) to form a MoSi2 suspension. Dissolve 1.4 parts of Y(NO3)3·6H2O and 0.05 parts of citric acid in 10 parts of deionized water and 0.72 parts of (NH4)2HPO4 in 5 parts of deionized water. At 65 °C, simultaneously add the above yttrium-containing solution, phosphorus-containing solution, and 0.1 parts of PVP K30 to 100 parts of MoSi2 suspension, adjust and maintain the pH value to 5.5, react at 70 °C for 4.5 h, centrifuge, wash, and vacuum dry to obtain molybdenum disilicide coated with yttrium phosphate.

[0078] S2: Molybdenum disilicide coated with yttrium phosphate was calcined at 300°C for 1.5 h under a nitrogen atmosphere, and then calcined at 450°C for 3 h to obtain modified molybdenum disilicide C.

[0079] Comparative Preparation Example 2

[0080] Preparation of modified molybdenum disilicide:

[0081] S1: Disperse 10 parts of MoSi2 in 90 parts of deionized water and sonicate for 30 min (frequency 40 kHz, power 200 W) to form a MoSi2 suspension. Dissolve 0.25 parts of Y(NO3)3·6H2O in 10 parts of deionized water and slowly add it dropwise to the MoSi2 suspension. Adjust and maintain the pH value to 7, stir and age for 45 min, continue to stand for 20 min, filter, wash, and vacuum dry to obtain molybdenum disilicide loaded with yttrium hydroxide.

[0082] S2: Molybdenum disilicide loaded with yttrium hydroxide was calcined at 300°C for 1 hour in a nitrogen atmosphere, and then calcined at 400°C for 2 hours to obtain modified molybdenum disilicide D.

[0083] Example 1

[0084] Preparation of high flexural strength ceramic materials:

[0085] M1: Potassium sodium feldspar, dolomite, calcium feldspar, modified molybdenum disilicide A, modified stabilized zirconium oxide, rice husk ash, and kaolin are crushed and ground to 100 mesh and dried at 105℃ for 4 hours.

[0086] M2: Take 50 parts by weight of potassium sodium feldspar, 20 parts of dolomite, 25 parts of calcium feldspar, 5 parts of modified molybdenum disilicide A, 3 parts of modified stabilized zirconia A, 0.3 parts of solid ceramic microspheres, 2 parts of rice husk ash, and 4 parts of kaolin and mix them. Add water to the above raw materials and perform wet ball milling to obtain a uniform slurry.

[0087] M3: The uniform slurry is spray-granulated to obtain a blank, which is then pressed into a green blank. The green blank is placed in a calcining furnace and sintered in air at a rate of 10°C / min to 1200°C for 60 minutes. Then it is cooled to 400°C at a rate of 10°C / min and then cooled to room temperature at a rate of 5°C / min to obtain a high flexural strength ceramic material.

[0088] Example 2

[0089] Preparation of high flexural strength ceramic materials:

[0090] It is largely the same as Example 1, except that modified molybdenum disilicide A is replaced with modified molybdenum disilicide B.

[0091] Example 3

[0092] Preparation of high flexural strength ceramic materials:

[0093] It is largely the same as Example 1, except that modified stabilized zirconia A is replaced with modified stabilized zirconia B.

[0094] Example 4

[0095] Preparation of high flexural strength ceramic materials:

[0096] Similar to Example 1, except that modified stabilized zirconium oxide A is replaced with cerium oxide stabilized zirconium oxide.

[0097] Example 5

[0098] Preparation of high flexural strength ceramic materials:

[0099] Similar to Example 1, except for the amount of modified molybdenum disilicide A and modified stabilized zirconia A used. Specifically, the difference is as follows:

[0100] M2: Take 50 parts by weight of potassium-sodium feldspar, 20 parts of dolomite, 25 parts of calcium feldspar, 6 parts of modified molybdenum disilicide A, 2 parts of modified stabilized zirconia A, 0.3 parts of solid ceramic microspheres, 2 parts of rice husk ash, and 4 parts of kaolin and mix them. Add water to the above raw materials and perform wet ball milling to obtain a uniform slurry.

[0101] Example 6

[0102] Preparation of high flexural strength ceramic materials:

[0103] Similar to Example 1, except for the amount of modified molybdenum disilicide A and modified stabilized zirconia A used. Specifically, the difference is as follows:

[0104] M2: Take 50 parts by weight of potassium-sodium feldspar, 20 parts of dolomite, 25 parts of calcium feldspar, 3 parts of modified molybdenum disilicide A, 5 parts of modified stabilized zirconia A, 0.3 parts of solid ceramic microspheres, 2 parts of rice husk ash, and 4 parts of kaolin and mix them. Add water to the above raw materials and perform wet ball milling to obtain a uniform slurry.

[0105] Example 7

[0106] Preparation of high flexural strength ceramic materials:

[0107] Similar to Example 1, except that modified stabilized zirconium oxide A was not added. Specifically, the difference is as follows:

[0108] M2: Take 50 parts by weight of potassium sodium feldspar, 20 parts of dolomite, 25 parts of calcium feldspar, 8 parts of modified molybdenum disilicide A, 0.3 parts of solid ceramic microspheres, 2 parts of rice husk ash, and 4 parts of kaolin and mix them. Add water to the above raw materials and perform wet ball milling to obtain a uniform slurry.

[0109] Comparative Example 1

[0110] It is largely the same as Example 1, except that modified molybdenum disilicide A is replaced with modified molybdenum disilicide C.

[0111] Comparative Example 2

[0112] It is largely the same as Example 1, except that modified molybdenum disilicide A is replaced with modified molybdenum disilicide D.

[0113] Comparative Example 3

[0114] It is largely the same as Example 1, except that the modified molybdenum disilicide A is replaced with MoSi2.

[0115] Comparative Example 4

[0116] Preparation of high flexural strength ceramic materials:

[0117] Similar to Example 1, except that modified molybdenum disilicide A was not added. Specifically, the difference is as follows:

[0118] M2: Take 50 parts by weight of potassium-sodium feldspar, 20 parts of dolomite, 25 parts of calcium feldspar, 8 parts of modified stabilized zirconia A, 0.3 parts of solid ceramic microspheres, 2 parts of rice husk ash, and 4 parts of kaolin and mix them. Add water to the above raw materials and perform wet ball milling to obtain a uniform slurry.

[0119] Test section

[0120] Flexural strength test:

[0121] The ceramic materials obtained in Examples 1-6 and Comparative Examples 1-4 were subjected to flexural strength tests, with the test sample size set to 300 mm. 300mm 6mm thick, referring to national standard GB / T 3810.4-2006, the ceramic material was dried in an oven at 110℃ to constant weight, and then the flexural strength P (MPa) was tested using a HYK-10000A digital display flexural strength tester. The result was 3FL / 2bh. 2 Where F is the failure load (N); L is the span between the two support rods (mm); b is the width of the specimen (mm); and h is the minimum thickness of the specimen fracture surface measured along the fracture edge after the test (mm). All results are recorded, and the average flexural strength of the specimen is calculated from the valid results.

[0122] The test results are shown in Table 1.

[0123] Table 1 Flexural Strength Test

[0124]

[0125] As shown in Table 1, the ceramic materials obtained in each embodiment have higher flexural strength than those in the comparative example, indicating that the ceramic materials provided in this application have good flexural properties. The reasons may be as follows: In Comparative Example 1, the modified molybdenum disilicide lacks a Y2O3 transition layer, resulting in insufficient interfacial bonding between MoSi2 and YPO4. Under external force, the outer shell is prone to detachment. Furthermore, the lack of Y2O3 may lead to discontinuous transition of mechanical properties, easily causing stress concentration and reducing flexural strength. In Comparative Example 2, the modified molybdenum disilicide lacks a YPO4 outer shell layer. Without the optimization and stress transfer effect of the YPO4 outer shell layer, the flexural strength may be reduced. In Comparative Example 3, the modified molybdenum disilicide was replaced with MoSi2. The poor interfacial wettability between MoSi2 and the ceramic matrix easily leads to an increase in interfacial porosity. When the material is under stress, cracks will preferentially propagate along the weak interface between MoSi2 and the matrix, which will significantly reduce the flexural strength of the material. In Comparative Example 4, no modified molybdenum disilicide was added. Relying solely on the toughening mechanism of modified stable zirconia cannot effectively inhibit crack propagation, resulting in a decrease in flexural performance.

[0126] As can be seen from Examples 1 and 2, the preparation process of modified molybdenum disilicide has a certain impact on the flexural strength of ceramic materials. After the formation of the MoSi2-Y2O3-YPO4 structure, further calcination in an inert atmosphere can improve the flexural strength of ceramic materials. The surface of uncalcined modified molybdenum disilicide may contain organic residues and amorphous substances, which are prone to forming stress concentration points during ceramic sintering. The surface of the calcined modified molybdenum disilicide can form a more uniform coating layer, which forms a more continuous chemical transition layer with the ceramic matrix during sintering, improving the interfacial bonding force and thus improving the flexural strength of the material.

[0127] As can be seen from Examples 1, 3, and 4, coating modification on the surface of stabilized zirconia has a certain impact on the flexural strength of ceramic materials. When a γ-Al2O3 layer is coated on the surface of cerium oxide stabilized zirconia, the flexural strength of the ceramic material is better.

[0128] As shown in Examples 1, 5-7, the combined use of modified molybdenum disilicide and modified stabilized zirconia has a certain impact on the flexural strength of ceramic materials. When the mass ratio of modified molybdenum disilicide to modified stabilized zirconia is 1:0.5-0.7, the flexural strength of the ceramic material is better.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A high flexural strength ceramic material, characterized in that, Includes the following quantities of raw materials: 50 parts potassium-sodium feldspar, 15-25 parts dolomite, 20-30 parts calcium feldspar, 3-13 parts reinforcing agent, 0.1-0.5 parts solid ceramic microspheres, 1-3 parts rice husk ash, and 1-5 parts binder; The reinforcing agent includes modified molybdenum disilicide, which comprises a molybdenum disilicide core and a yttrium phosphate shell layer, wherein the surface of the molybdenum disilicide core is loaded with yttrium oxide.

2. The high flexural strength ceramic material according to claim 1, characterized in that, The preparation method of the modified molybdenum disilicide includes the following steps: S1: Disperse the first soluble yttrium salt and molybdenum disilicide in water, adjust the pH to convert yttrium ions into yttrium hydroxide and deposit it on the surface of molybdenum disilicide, to obtain molybdenum disilicide loaded with yttrium hydroxide; S2: The molybdenum disilicide loaded with yttrium hydroxide is calcined to dehydrate the yttrium hydroxide on the surface of the molybdenum disilicide to generate yttrium oxide, thereby obtaining molybdenum disilicide loaded with yttrium oxide; S3: Disperse molybdenum disilicide loaded with yttrium oxide, a second soluble yttrium salt, and a soluble phosphate in water, and adjust the pH to allow yttrium phosphate to deposit on the surface of molybdenum disilicide loaded with yttrium oxide, thereby obtaining a modified molybdenum disilicide precursor. S4: The modified molybdenum disilicide precursor is calcined to fix yttrium phosphate in the outer layer, thereby obtaining modified molybdenum disilicide.

3. The high flexural strength ceramic material according to claim 2, characterized in that, The method for preparing the modified molybdenum disilicide includes the following steps: S1: Disperse 0.25 parts Y(NO3)3·6H2O and 9~11 parts MoSi2 in 10~150 parts water, adjust the pH value to 6.5~7.5, and obtain molybdenum disilicide loaded with yttrium hydroxide; S2: Molybdenum disilicide loaded with yttrium hydroxide was calcined at 250-450°C for 2-4 hours under a nitrogen atmosphere to obtain molybdenum disilicide loaded with yttrium oxide. S3: Disperse 10 parts of molybdenum disilicide loaded with yttrium oxide, 1-2 parts of Y(NO3)3·6H2O, and 0.5-1 parts of (NH4)2HPO4 in 10-150 parts of water, adjust the pH to 5-6, and react for 4-5 hours to obtain the modified molybdenum disilicide precursor. S4: The modified molybdenum disilicide precursor was calcined in a nitrogen atmosphere at 250-500℃ for 4-6 hours to obtain modified molybdenum disilicide.

4. The high flexural strength ceramic material according to claim 1, characterized in that, The reinforcing agent further includes modified stabilized zirconium oxide, which comprises cerium oxide stabilized zirconium oxide and a γ-Al2O3 layer coated on the surface of cerium oxide stabilized zirconium oxide; the mass ratio of modified molybdenum disilicide to modified stabilized zirconium oxide is 1:0.5~0.

7.

5. The high flexural strength ceramic material according to claim 4, characterized in that, The method for preparing the modified and stabilized zirconium oxide includes the following steps: N1: Cerium oxide stabilized zirconium oxide is mixed with an aluminum-based precursor dispersion, and the pH is adjusted to allow AlOOH to be adsorbed onto the surface of cerium oxide stabilized zirconium oxide, thus obtaining cerium oxide stabilized zirconium oxide with AlOOH coated on the surface. N2: Cerium oxide-stabilized zirconium oxide coated with AlOOH is calcined to convert AlOOH into γ-Al2O3, thus obtaining modified stabilized zirconium oxide.

6. The high flexural strength ceramic material according to claim 5, characterized in that, In step N1, the aluminum-based precursor dispersion includes a boehmite suspension.

7. The high flexural strength ceramic material according to claim 6, characterized in that, The method for preparing the modified and stabilized zirconium oxide includes the following steps: N1: Disperse 5 parts of cerium oxide-stabilized zirconium oxide in 20-60 parts of water, add 1-5 parts of 20wt% boehmite suspension, adjust the pH to 4-6, and obtain cerium oxide-stabilized zirconium oxide with AlOOH surface coating; N2: Cerium oxide-stabilized zirconium oxide coated with AlOOH is calcined at 400~600℃ for 1~2h to obtain modified stabilized zirconium oxide.

8. The high flexural strength ceramic material according to claim 1, characterized in that, The solid ceramic microspheres have a particle size of 1~50μm.

9. The high flexural strength ceramic material according to claim 1, characterized in that, The binder includes at least one of kaolin, polyvinyl alcohol, and carboxymethyl cellulose.

10. A method for preparing a high flexural strength ceramic material, characterized in that, include: Provide the raw material for the high flexural strength ceramic material according to any one of claims 1 to 9, and perform wet ball milling on the raw material to obtain a slurry, followed by drying, granulation, pressing, and firing to obtain the high flexural strength ceramic material.

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