High-ionic-radius-difference multi-element high-entropy silicate ceramic and preparation method thereof

Abstract

The application provides a high-ionic-radius-difference multi-element high-entropy silicate ceramic and a preparation method thereof, and relates to the technical field of ceramic core preparation.The method comprises the following steps: mixing oxides corresponding to at least four cations selected from alkaline earth metals and 3d transition metals and having a maximum ionic radius difference of greater than or equal to 30% with silicon dioxide in a proportion, performing wet ball milling, drying and sieving to obtain a uniform powder; then dry pressing the powder to obtain a ceramic green body; finally, placing the ceramic green body on a cooling base, irradiating the ceramic green body with a high-energy beam, rapidly melting the surface of the ceramic green body and then rapidly solidifying the surface of the ceramic green body, and directly obtaining the high-entropy silicate ceramic. The method effectively overcomes the element segregation problem caused by the large difference in ionic radius and slow diffusion in traditional sintering, and successfully prepares the high-entropy ceramic with a single and uniform solid solution phase.

Description

Technical Field

[0001] This application relates to the field of ceramic core preparation technology, specifically to a high-ionic-radius-difference multi-element high-entropy silicate ceramic and its preparation method. Background Technology

[0002] High-entropy ceramics, as an emerging class of materials, are derived from the concept of high-entropy alloys. They typically refer to single-phase solid solution materials formed by the solid solution of four or more elements in approximately equimolar ratios. These materials exhibit numerous superior properties compared to traditional single-component or few-component ceramics due to their unique high-entropy effect, lattice distortion effect, slow diffusion effect, and "cocktail" effect. These properties include higher structural stability, better corrosion resistance, and tunable thermal and mechanical properties, making them promising for applications in high-temperature structural materials, thermal barrier coatings, catalysts, and dielectrics.

[0003] Especially in the field of alkali metal mineralizers for ceramic cores, the design of novel alkali metal mineralizers using a high-entropy strategy has shown unique potential. This strategy aims to solidify multiple elements into a single high-entropy phase, utilizing its unique structural stability and slow diffusion effect to reduce the impact on the room temperature performance of the core while ensuring effective promotion of cristobalite precipitation during the high-temperature casting stage. However, the successful preparation of high-entropy ceramics faces significant challenges: when the ionic radii between components differ greatly, conventional processes such as traditional resistance furnace sintering, due to slow heating and cooling rates and long high-temperature holding times, easily lead to the segregation of atoms in each component due to their different diffusion rates, making it difficult to achieve uniform solid solution. This not only hinders the formation of a single high-entropy phase but also often leads to the formation of various low-melting-point second phases or brittle phases, severely impairing the expected performance and high-temperature stability of the material.

[0004] Existing patent CN119430207A discloses a silicate-based high-entropy amorphous material and its preparation method. This method has a simple process and low energy consumption, but the combination of elements involved and the amorphous structure obtained are fundamentally different from the application scenarios of mineralizers that need to maintain a stable crystalline solid solution structure at high temperatures to perform specific functions.

[0005] Existing patent CN117551962A discloses a high-entropy rare earth monosilicate environmental barrier coating, which exhibits low thermal conductivity and high thermal stability. However, its composition design focuses on a specific combination of rare earth elements, and the preparation process aims to form the coating rapidly.

[0006] In summary, none of the existing patents mentioned above have solved the problem of how to effectively suppress elemental segregation and ensure the formation of a uniform and stable single high-entropy solid solution phase when preparing high-entropy alkali metal mineralizers containing components with large differences in ionic radii. Summary of the Invention

[0007] Based on the aforementioned problems in the existing technology, this application proposes a high-entropy silicate ceramic with high ionic radius difference and its preparation method. By using laser rapid melting and solidification to achieve instantaneous ultra-high temperature fusion and ultra-fast solidification of the high ionic radius difference multi-component system, component segregation is effectively suppressed, and high-entropy silicate ceramic with a single, uniform solid solution phase structure is successfully prepared.

[0008] To achieve the above objectives, the first aspect of this application proposes a method for preparing high-ionic-radius-difference multi-element high-entropy silicate ceramics, the specific technical solution of which is as follows:

[0009] A method for preparing high-ionic-radius-difference multi-element high-entropy silicate ceramics includes the following steps:

[0010] S1. Silicate raw material powder containing at least four cationic components is mixed to obtain a uniform mixed powder; wherein, the at least four cationic components are selected from alkaline earth metals and 3d transition metals, and the maximum ionic radius difference of the cationic components is ≥30%;

[0011] S2. The mixed powder is dry-pressed into a ceramic blank;

[0012] S3. The ceramic blank is placed on a cooling substrate, and the surface of the ceramic blank is irradiated with a high-energy beam. The irradiated area reaches a molten state and solidifies under the action of the cooling substrate to obtain a high-entropy silicate ceramic with a single solid solution phase.

[0013] In step S3, the energy density of the high-energy beam is 10. 3 -10 7 W / cm².

[0014] Furthermore, in step S1, the at least four cationic components include at least one alkaline earth metal and at least three 3d transition metals.

[0015] Furthermore, in step S1, the at least one alkaline earth metal is selected from Ca. 2+ Mg 2+ 、Sr 2+ Ba 2+ At least one of the three 3d transition metals; the at least three 3d transition metals are selected from Mn 2+ Fe 2+ Co 2+ Ni 2+ Cu 2+ Zn 2+ At least three of them.

[0016] Furthermore, in step S1, the silicate raw material powder is a mixed powder of oxides and silicon dioxide corresponding to each of the cationic components, and the purity of each raw material powder is at least 99.9% and the average particle size is less than 3μm.

[0017] Furthermore, in step S3, the energy density of the high-energy beam is 10. 6 -10 7 W / cm².

[0018] Furthermore, in step S3, the high-energy beam is a laser beam, the irradiation power of the laser beam is 100-300W, and the scanning speed is 10-30mm / s.

[0019] Furthermore, the laser beam is generated by a fiber laser, the wavelength of the laser beam is in the range of 1000-1200nm, and the spot diameter is 60-100μm.

[0020] To achieve the above objectives, the second aspect of this application proposes a high-ionic-radius-difference multi-element high-entropy silicate ceramic, the specific technical solution of which is as follows:

[0021] A high-ionic-radius-difference multi-element high-entropy silicate ceramic is prepared by the above-mentioned preparation method of high-ionic-radius-difference multi-element high-entropy silicate ceramic.

[0022] Furthermore, the at least four cation components include those selected from Ca... 2+ Mg 2+ 、Sr 2+ Ba 2+ At least one alkaline earth metal, and selected from Mn 2+ Fe 2+ Co 2+ Ni 2+ Cu 2+ Zn 2+ At least three 3d transition metals.

[0023] Furthermore, the at least four cation components are Ca 2+ Mg 2+ Mn 2+ Ni 2+ and Zn 2+ Ca, Mg, Mn, Ni, and Zn elements exist in a uniform atomic-level solid solution state in the silicate solid solution phase.

[0024] By applying the above-described technical solution of this application, at least the following technical effects are achieved:

[0025] 1. This application uses a high-energy laser beam as a heat source. Its instantaneous high energy input can make the powder quickly reach the melting temperature, realizing rapid and uniform mixing with liquid phase mass transfer as the main process. Subsequently, the melt is rapidly solidified under the rapid cooling effect of the cooling substrate, thereby "freezing" the uniform atomic distribution at high temperature and realizing the stable preparation of a single and uniform solid solution phase of high ionic radius difference multi-element high-entropy silicate ceramic.

[0026] 2. This application benefits from the instantaneous ultra-high temperature (e.g., about 1400°C) brought about by laser irradiation and the subsequent rapid cooling. This process significantly shortens the residence time of the material in the high-temperature zone and effectively suppresses the segregation tendency of each component due to the difference in diffusion rate, thereby achieving a component solid solution degree that is much higher than that of traditional sintering methods.

[0027] 3. The laser energy of this application is highly concentrated, which can achieve full melting of the green body and promote densification while precisely controlling the heat-affected zone, avoiding the adhesion problem between the sample and the crucible caused by traditional overall heating.

[0028] 4. This application introduces a rapid manufacturing technology based on high-energy beams into the field of high-entropy ceramics. This process has outstanding advantages such as extremely short process, low energy consumption, and digitally controllable parameters. It not only provides an efficient synthesis tool for the research and development of high-entropy materials, but also lays the technological foundation for the direct forming of complex high-entropy ceramic components through advanced means such as additive manufacturing in the future.

[0029] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of the application. The illustrative embodiments and descriptions of the application are used to explain the application and do not constitute an undue limitation of the application. In the drawings:

[0031] Figure 1 A schematic flowchart of a method for preparing high ionic radius difference multi-element high-entropy silicate ceramics proposed in this application is shown;

[0032] Figure 2 Scanning electron microscope (SEM) images of the high-entropy silicate ceramic sample prepared in Example 1 of this application are presented;

[0033] Figure 3 Backscattered electron (BSE) images and corresponding energy-dispersive X-ray spectroscopy (EDS) elemental distribution maps of the high-entropy silicate ceramic samples prepared in Example 1 of this application are presented.

[0034] Figure 4High-resolution transmission electron microscopy (TEM) analysis images of the high-entropy silicate ceramic sample prepared in Example 1 of this application are presented;

[0035] Figure 5 The phase (XRD) analysis diagram of the high-entropy silicate ceramic sample prepared in Comparative Example 1 of this application is presented. Detailed Implementation

[0036] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0037] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0038] According to the first aspect of this application, a method for preparing high-ionic-radius-difference multi-element high-entropy silicate ceramics is proposed, see reference. Figure 1 As shown, the preparation method includes the following steps:

[0039] S1. The silicate raw material powder containing at least four cationic components is wet ball-milled and mixed, and then dried after ball milling to obtain a uniform mixed powder.

[0040] Specifically, at least four types of cation components, corresponding oxides, and silicon dioxide are used as raw materials and weighed and proportioned. The cation components are selected from alkaline earth metals and 3d transition metals, and the maximum ionic radius difference is not less than 30%. All ionic radii are Shannon radii under six-coordinate configurations. The maximum ionic radius difference is calculated as Δr = |r max -r min | / r max The purity of each oxide and silicon dioxide mentioned above is greater than 99.9%, and the particle size of the powder is less than 3μm. The prepared powder is mixed by wet ball milling: anhydrous ethanol is used as a grinding aid, and zirconia grinding beads with a diameter of 1-5mm and a purity of 99% are added. The ball-to-powder mass ratio is controlled at 6:1-10:1, and the mixture is ball-milled in a planetary ball mill at a speed of 150-300r / min for 6-12h. After ball milling, the resulting slurry is placed in an oven and dried at 65-100℃ for 8-12h. After crushing and sieving, a uniform mixed powder is obtained.

[0041] Among them, the alkaline earth metal cation component is selected from Ca 2+ Mg 2+ 、Sr 2+ Ba 2+ At least one of the following; the 3d transition metal cation component is selected from Mn 2+ Fe 2+ Co2+ Ni 2+ Cu 2+ Zn 2+ It contains at least three of the following, and the total number of cation species is ≥4.

[0042] Preferably, the ball-to-powder mass ratio is 8:1–10:1, the planetary ball mill speed is 200–250 r / min, and the milling time is 6–8 h, resulting in powder with uniform particle size reaching the submicron level.

[0043] S2. The mixed powder is refined and dry-pressed to obtain a dense ceramic blank.

[0044] Specifically, the powder is placed in an agate mortar and ground thoroughly until fine and without obvious particle texture. Then, it is passed through a 100-200 mesh sieve to obtain a molding powder with uniform particle size and morphology. An appropriate amount of powder is weighed and filled into a mold. The mold is then dry-pressed using a tablet press at a pressure of 6-10 MPa for 3-8 minutes to obtain a dense and regularly shaped ceramic blank.

[0045] S3. The ceramic blank is placed on a cooling substrate, and the surface of the ceramic blank is irradiated with a high-energy beam to reach a molten state. Then, under the action of the cooling substrate, ultra-fast solidification is achieved to obtain a high-entropy silicate ceramic with a single solid solution phase.

[0046] The high-energy beam described in this step is a directional energy beam capable of irradiating the surface of a ceramic green body with extremely high energy density and an extremely fast heating rate, thereby causing the irradiated area to instantly reach a molten state within a time scale of milliseconds to seconds. The energy density range of this high-energy beam is 10. 3 -10 7 W / cm². The purpose of this high-energy beam is to combine it with a cooling substrate with high thermal conductivity to achieve rapid melting and solidification, suppress segregation and phase separation of components with high ionic radius differences, and thus obtain a single high-entropy solid solution phase.

[0047] Specifically, the energy density of the high-energy beam is achieved at 10 through the following specific parameters. 6 -10 7The optimal control was achieved within the W / cm² range. The ceramic green body obtained in step S2 was placed on a water-cooled copper crucible and irradiated and solidified using a laser beam. The laser beam was generated by a fiber laser with a wavelength of 1080±20 nm and a spot diameter of 60-100 μm; the irradiation power was 100-300 W, and the scanning speed was 10–30 mm / s. The entire process was carried out in an air atmosphere. During irradiation, the laser energy rapidly molten the irradiated area of ​​the ceramic green body; after irradiation, the melt underwent ultra-rapid solidification under the rapid cooling effect of the water-cooled copper crucible. The sample was then allowed to cool to room temperature in air before being removed, thus obtaining a high-entropy silicate ceramic with a single solid solution phase structure.

[0048] It should be noted that those skilled in the art, after understanding the core idea of ​​this application—"utilizing the synergistic effect of high ionic radius difference and ultrafast solidification to form a single high-entropy phase"—can easily conceive of selecting other alkaline earth metal ions or other 3d transition metal ions with similar valence states and coordination characteristics to equivalently replace or add to the raw material components of the ceramic green body. Any high-entropy silicate ceramics with a single solid solution phase obtained by using the same principle, adjusting the type and proportion of cations, and through the high-energy beam melting and ultrafast solidification process, are equivalent variations of this application and should fall within the scope of protection of this application.

[0049] The following provides an exemplary description of this application in conjunction with specific raw material combinations and process parameters.

[0050] Example 1

[0051] This embodiment provides a method for preparing a high-ionic-radius-difference five-element high-entropy silicate ceramic, the cationic component of which includes Ca. 2+ Mg 2+ Mn 2+ Ni 2+ and Zn 2+ Among them, Ca 2+ with Ni 2+ The largest relative difference in ionic radii is found between them, which is approximately 31% based on Shannon's effective ionic radius calculation.

[0052] S1. CaO, MgO, MnO, NiO, ZnO, and SiO2 powders with a purity greater than 99.9% were used as raw materials and weighed and premixed according to the molar ratio of CaO:MgO:MnO:NiO:ZnO:SiO2 = 2:2:2:2:2:1. The average particle size of each raw material powder was less than 3 μm. Wet ball milling was then performed: anhydrous ethanol was used as the dispersion medium, and zirconia grinding beads with a diameter of 5 mm were added, controlling the mass ratio of balls to powder to be 8:1. The mixture was ball-milled in a planetary ball mill at a speed of 200 r / min for 12 hours. After ball milling, the resulting slurry was placed in an oven and dried at 65℃ for 12 hours to obtain a uniformly mixed composite powder.

[0053] S2. After crushing the dried powder blocks, pass them through a 120-mesh standard sieve to obtain a mixed powder with uniform composition and fine particle size. Weigh an appropriate amount of the mixed powder obtained in step S1 and fill it into a mold. Use a tablet press to dry press the powder under a pressure of 9 MPa for 5 minutes. After demolding, obtain a dense, regularly shaped, round ceramic blank.

[0054] S3. Place the ceramic green body obtained in step S2 on a water-cooled copper crucible and feed it into the laser processing system. Use a fiber laser with a wavelength of 1080nm, set the spot diameter to 80μm, and adjust the laser output power to 200W. Under these parameters, the energy density of the laser acting on the material surface is approximately 4.0×10⁻⁶. 6 W / cm². The surface of the green body was scanned and irradiated in air at a scanning speed of 15 mm / s. During irradiation, the high-energy-density laser beam molten the surface area of ​​the green body, followed by ultra-rapid solidification under the strong cooling effect of a water-cooled copper crucible. After the sample was allowed to cool to room temperature in air, it was removed to obtain the high-entropy silicate ceramic sample.

[0055] Microstructural characterization of the obtained samples: See [link / reference] Figure 2 The image shown is a scanning electron microscope (SEM) image of the obtained ceramic sample. The sample cross-section has a dense morphology and no obvious pores.

[0056] See Figure 3 As shown, Figure 3 In the middle (a), the backscattered electron (BSE) image of the obtained ceramic sample is shown. Its brightness (contrast) directly reflects the difference in the average atomic number of the observed area. The microstructure in the image has uniform contrast and no obvious contrast difference is observed. From the perspective of compositional contrast, it is preliminarily proven that the sample is a single phase. Figure 3 (b) is the surface distribution map of the energy dispersive X-ray spectrum (EDS) of all elements in the corresponding region. This image shows the total distribution of X-ray signals of the main elements in the sample. The signal intensity is uniform and continuous throughout the region, which intuitively reflects the overall uniformity of the distribution of all elements. Figure 3 (c) to Figure 3 The images in (i) show the surface distribution of the corresponding single-element energy dispersive X-ray spectra (EDS), sequentially displaying the independent spatial distribution of silicon (Si), oxygen (O), magnesium (Mg), manganese (Mn), calcium (Ca), nickel (Ni), and zinc (Zn). The signals representing each element in each image are highly dispersed and uniformly cover the entire analysis area, without any local aggregation or signal loss.

[0057] See Figure 4 The image shown is a comprehensive analysis of the obtained ceramic sample by transmission electron microscopy (TEM). In the image (a), a transmission electron microscope (TEM) image is shown, which shows clear, continuous and consistent lattice fringes, indicating that the region is a crystal with good crystallinity and complete structure. Figure 4 (b) is the corresponding Figure 4 The selected area electron diffraction pattern in region (a) shows a regular arrangement of diffraction spots, rather than diffraction rings corresponding to polycrystalline or amorphous states, which proves from a crystallographic perspective that it is a single phase. Figure 4 In the middle (c) to the fourth (h) in the figure, the images are processed in TEM mode. Figure 4 In the middle (a), the elemental distribution map of the energy dispersive X-ray spectroscopy (EDS) collected in the same micro-region shows that the signals of each element are still highly uniform and diffuse in the observation range from nanometer to atomic scale, and no areas of element enrichment or depletion are found.

[0058] Example 2

[0059] This embodiment provides a method for preparing a pentagonal high-entropy silicate ceramic, the cationic component of which is the same as that in Example 1, namely Ca. 2+ Mg 2+ Mn 2+ Ni 2+ and Zn 2+ This embodiment aims to verify that adjusting some core process parameters can still achieve the invention's objective.

[0060] S1. Using CaO, MgO, MnO, NiO, ZnO, and SiO2 powders with a purity of not less than 99.9% as raw materials, weigh and premix them according to the molar ratio of CaO:MgO:MnO:NiO:ZnO:SiO2 = 2:2:2:2:2:1. The average particle size D50 of each raw material powder is less than 3μm. Then, wet ball milling is performed: using anhydrous ethanol as the dispersion medium, zirconia grinding balls with a diameter of 3mm are added, controlling the mass ratio of balls to powder to be 9:1. The mixture is ball-milled in a planetary ball mill at a speed of 250 r / min for 10 hours. After ball milling, the resulting slurry is dried at 95℃ for 8 hours to obtain a uniformly mixed composite powder.

[0061] S2. After crushing the dried powder blocks, pass them through a 120-mesh standard sieve to obtain a mixed powder with uniform composition and fine particle size. Weigh an appropriate amount of the mixed powder obtained in step S1 and fill it into a mold. Use a tablet press to dry press the powder under a pressure of 6MPa for 8 minutes. After demolding, obtain a dense, regularly shaped, round ceramic blank.

[0062] S3. Place the ceramic green body obtained in step S2 on a water-cooled copper crucible and feed it into the laser processing system. Use a fiber laser with a wavelength of 1080nm, set the spot diameter to 60μm, and adjust the laser output power to 100W. Under these parameters, the energy density of the laser acting on the material surface is approximately 3.5-4.0 × 10⁻⁴. 6 W / cm². The surface of the green body was scanned and irradiated in air at a scanning speed of 55 mm / s. During irradiation, the high-energy-density laser beam molten the surface area of ​​the green body, followed by ultra-rapid solidification under the strong cooling effect of a water-cooled copper crucible. After the sample was allowed to cool to room temperature in air, it was removed to obtain the high-entropy silicate ceramic sample.

[0063] Result Characterization: The obtained ceramic sample underwent the same microstructure characterization as in Example 1. Scanning electron microscopy (SEM) images showed that its cross-sectional morphology was similar to that in Example 1. Figure 2 Similarly, the structure is dense. Backscattered electron (BSE) image (with...) Figure 3 The uniform contrast (similar to the observed contrast) and lack of significant differences in contrast indicate that the sample is a homogeneous single phase. Corresponding energy-dispersive X-ray spectroscopy (EDS) elemental distribution analysis further confirms that the five elements Ca, Mg, Mn, Ni, and Zn are highly uniformly distributed within the observation area, with no elemental segregation. These results demonstrate that, with adjustments to the process parameters provided in this application, the ultrafast solidification process can effectively suppress elemental segregation and obtain a single, homogeneous high-entropy silicate solid solution phase.

[0064] Example 3

[0065] This embodiment provides another method for preparing pentagonal high-entropy silicate ceramics, wherein the cation component is Ca. 2+ 、Sr 2 + Mn 2+ Fe 2+ and Zn 2+ This was to verify the applicability of this application to combinations of cations with different high ionic radius differences. Among them, Sr... 2+ With Zn 2+ The largest relative difference in ionic radius is approximately 37.3% based on Shannon's effective ionic radius calculation.

[0066] S1. Using CaO, SrO, MnO, FeO, ZnO, and SiO2 powders with a purity of not less than 99.9% as raw materials, weigh and premix them according to the molar ratio of CaO:SrO:MnO:FeO:ZnO:SiO2 = 2:2:2:2:2:1. The average particle size D50 of each raw material powder is less than 3μm. Then, wet ball milling is performed: using anhydrous ethanol as the dispersion medium, zirconia grinding balls with a diameter of 2mm are added, controlling the mass ratio of balls to powder to be 10:1. The mixture is ball-milled in a planetary ball mill at a speed of 300 r / min for 8 hours. After ball milling, the slurry is dried at 75℃ for 10 hours to obtain a uniformly mixed composite powder.

[0067] S2. After the dried powder blocks are crushed, they are passed through a 150-mesh standard sieve. An appropriate amount of powder is weighed and filled into a mold. The mold is then pressed using a tablet press at a pressure of 8 MPa for 4 minutes to obtain a round ceramic blank.

[0068] S3. Place the ceramic green body obtained in step S2 on a water-cooled copper crucible and feed it into the laser processing system. Use a fiber laser with a wavelength of 1080nm, set the spot diameter to 100μm, and adjust the laser output power to 300W. Under these parameters, the energy density of the laser acting on the material surface is approximately 3.8×10⁻⁶. 6 W / cm 2 The surface of the green blank was scanned and irradiated in an air atmosphere at a scanning speed of 20 mm / s. During irradiation, the high-energy-density laser beam molten the surface area of ​​the green blank, followed by ultra-rapid solidification under the strong cooling effect of a water-cooled copper crucible. After the sample was allowed to cool to room temperature in air, it was removed to obtain the high-entropy silicate ceramic sample.

[0069] Results Characterization: Microstructural analysis was performed on the obtained samples. Scanning electron microscopy (SEM) images showed a dense cross-sectional morphology. Backscattered electron (BSE) images exhibited uniform contrast with no significant differences in compositional contrast. Corresponding energy-dispersive X-ray spectroscopy (EDS) elemental distribution analysis confirmed that Ca, Sr, Mn, Fe, and Zn were highly uniformly distributed within the observed area. These results demonstrate that even when using different cation combinations with an ionic radius difference of up to 37%, and adjusting within a wide range of precursor and laser process parameter windows, the ultrafast solidification process employed in this application can still effectively suppress elemental segregation and successfully obtain a single, homogeneous high-entropy silicate solid solution phase.

[0070] Comparative Example 1

[0071] S1. Using CaO, MgO, MnO, NiO, ZnO, and SiO2 powders with a purity greater than 99.9% as raw materials, weigh and premix them according to the molar ratio of CaO:MgO:MnO:NiO:ZnO:SiO2 = 2:2:2:2:2:1. The average particle size of each raw material powder is less than 3μm. The mixed powder is then subjected to wet ball milling: using anhydrous ethanol as the dispersion medium, zirconia grinding beads with a diameter of 2mm are added, controlling the mass ratio of balls to powder to be 10:1, and ball milling is performed in a planetary ball mill at a speed of 300r / min for 6 hours. After ball milling, the resulting slurry is placed in an oven and dried at 65℃ for 8 hours.

[0072] S2. After the dried powder blocks are crushed, they are passed through a 120-mesh standard sieve to obtain a uniformly mixed powder. 0.3g of this powder is weighed and filled into a cylindrical mold with an inner diameter of 7mm. The mold is then dry-pressed using a tablet press at a pressure of 10MPa for 5 minutes, and then demolded to obtain a round ceramic blank.

[0073] S3. Place the ceramic green body obtained in step S2 into a muffle furnace and sinter it in air. Proceed to 1400℃ at a heating rate of 5℃ / min and hold at that temperature for 2 hours. After sintering, turn off the furnace power and allow the sample to cool naturally to room temperature before removing it.

[0074] The obtained samples were subjected to X-ray diffraction (XRD) analysis, see [reference]. Figure 5 As shown, the relationship between diffraction intensity and angle is illustrated, with the vertical axis representing diffraction intensity and the horizontal axis representing the angle range from 10° to 80°. A distinct strong diffraction peak is observed at 28°, and impurity phase diffraction peaks of varying intensities also appear at approximately 20°, 30°, 35°, 43°, and 50°. Comparison with standard powder diffraction cards reveals that these impurities mainly consist of incompletely reacted raw material oxides and thermodynamically more stable binary / ternary silicate intermediates, such as Ca2SiO4. The direct cause of this phenomenon lies in the slow heating and cooling process of traditional sintering, which provides ample time for thermodynamically driven diffusion and segregation of the various cations with large differences in ionic radius and diffusion rate. Specifically, the faster-diffusing Ni²⁺… + It readily agglomerates to form an independent NiO phase, while Ca²⁺… + Mg² + Elements tend to react locally with SiO2 to form traditional compounds with lower free energies, such as Ca2SiO4. Therefore, the multiple sharp impurity peaks in the XRD pattern are evidence of the diffusion-segregation-phase separation process that cannot be suppressed in conventional sintering. For the high ionic radius difference multi-component system described in this application, conventional sintering processes are limited by their inherently slow kinetics and cannot overcome the thermodynamic phase separation tendency, thus failing to prepare the single homogeneous high-entropy solid solution phase obtained in this invention.

[0075] In summary, for multi-component systems with high ionic radius differences, traditional sintering methods cannot achieve the preparation of homogeneous single-phase ceramics due to inherent limitations in slow diffusion and thermodynamic equilibrium processes. However, the laser rapid melting and solidification method employed in this application, with its ultra-fast non-equilibrium process, can effectively suppress elemental segregation and successfully synthesize a single, homogeneous high-entropy solid solution phase, thus solving the technical challenges that traditional methods cannot overcome.

[0076] According to a second aspect of this application, a high-entropy silicate ceramic with high ionic radius difference is proposed, which is prepared by the preparation method proposed in the first aspect above. The high-entropy silicate ceramic has a single high-entropy solid solution phase, which contains at least four different cation components, and the maximum ionic radius difference between the four cation components is ≥30%. At the same time, the at least four different cations are selected from alkaline earth metals and 3d transition metals.

[0077] In some embodiments, at least four cationic components include those selected from Ca. 2+ Mg 2+ 、Sr 2+ Ba 2+ At least one alkaline earth metal, and selected from Mn 2+ Fe 2+ Co 2+ Ni 2+ Cu 2+ Zn 2+ At least three 3d transition metals.

[0078] In a preferred embodiment, at least four cationic components include Ca 2+ Mg 2+ and at least two of the ingredients selected from Mn 2+ Ni 2+ Zn 2+ Co 2+ ions.

[0079] In a further preferred embodiment, at least four cation components are Ca. 2+ Mg 2+ Mn 2+ Ni 2+ and Zn 2+ .

[0080] In the ceramics prepared according to any of the above embodiments, each metal element exists in an atomically homogeneous solid solution state within the silicate solid solution phase. The ceramic structure is dense, and its X-ray diffraction pattern shows only diffraction peaks of a single silicate phase. Analysis by scanning electron microscopy combined with energy-dispersive spectroscopy and transmission electron microscopy confirmed that each metal cation is uniformly distributed at the atomic scale, with no elemental agglomeration.

[0081] Based on its single solid solution phase, excellent phase purity, structural uniformity, and high-temperature stability, this high-entropy silicate ceramic has application potential in high-temperature structural components, thermal barrier coatings, and ceramic core mineralizers.

[0082] The above are merely several specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this application, based on the technical solution and inventive concept of this application, should be included within the scope of protection of this application.

[0083] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0084] It should be noted that, in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that 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. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

Claims

1. A method for preparing high-ionic-radius-difference multi-element high-entropy silicate ceramics, characterized in that, Includes the following steps: S1. Silicate raw material powder containing at least four cationic components is mixed to obtain a uniform mixed powder; wherein, the at least four cationic components are selected from alkaline earth metals and 3d transition metals, and the maximum ionic radius difference of the cationic components is ≥30%; S2. The mixed powder is dry-pressed into a ceramic blank; S3. The ceramic blank is placed on a cooling substrate, and the surface of the ceramic blank is irradiated with a high-energy beam. The irradiated area reaches a molten state and solidifies under the action of the cooling substrate to obtain a high-entropy silicate ceramic with a single solid solution phase. In step S1, the silicate raw material powder is a mixed powder of oxides and silicon dioxide corresponding to each of the cationic components; the at least four cationic components include at least one alkaline earth metal and at least three 3d transition metals; the at least one alkaline earth metal is selected from Ca²⁺. + Mg² + Sr² + Ba² + At least one of the three 3d transition metals; the at least three 3d transition metals are selected from Mn² + Fe² + Co² + Ni² + Cu² + Zn² + At least three of them; In step S3, the energy density of the high-energy beam is 10. 6 -10 7 The high-energy beam is a laser beam with an irradiation power of 100-300W and a scanning speed of 10-30mm / s.

2. The method for preparing high-ionic-radius-difference multi-element high-entropy silicate ceramics according to claim 1, characterized in that: In step S1, the purity of each raw material powder is at least 99.9%, and the average particle size is less than 3μm.

3. The method for preparing high-ionic-radius-difference multi-element high-entropy silicate ceramics according to claim 1, characterized in that: The laser beam is generated by a fiber laser, and the wavelength of the laser beam is in the range of 1000-1200nm, with a spot diameter of 60-100μm.

4. A high-ionic-radius-difference multi-element high-entropy silicate ceramic, prepared by the method described in any one of claims 1-3, characterized in that: It is a silicate having a single solid solution phase containing at least four cations, and the maximum ionic radius difference between the cations is ≥30%.

5. The high ionic radius difference multi-element high-entropy silicate ceramic according to claim 4, characterized in that: The at least four cations include those selected from Ca²⁺. + Mg² + Sr² + Ba² + At least one alkaline earth metal, and selected from Mn² + Fe² + Co² + Ni² + Cu² + Zn² + At least three 3d transition metals.

6. The high ionic radius difference multi-element high-entropy silicate ceramic according to claim 5, characterized in that: The at least four cations are Ca² + Mg² + Mn² + Ni² + and Zn² + The Ca, Mg, Mn, Ni, and Zn elements are in an atomically homogeneous solid solution state in the silicate solid solution phase.

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