A rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate

Abstract

This invention provides a rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate. The method includes selecting rare-earth elements that can form a monoclinic β phase after equimolar doping of Yb₂Si₂O₇ materials as dopants, obtaining the average RE-O bond length; classifying dopants according to whether they increase or decrease the average bond length, and sorting them by doping weight; establishing a periodic table of orthogonally increasing doping elements based on the sorting results, where materials in the same period or group have the same increasing doping element relative to materials in the previous period or group; conducting material preparation and thermodynamic property experiments; summarizing the experimental results into the periodic table to form a thermodynamic property periodic table, and selecting the most suitable material or the element to be doped. This method can rapidly screen multi-component doped medium- or high-entropy materials, and based on the thermodynamic property periodic table, it can also determine the magnitude of the performance benefits of various dopants on medium- or high-entropy materials.

Description

Technical Field

[0001] This invention relates to the field of environmental barrier ceramic materials for extreme high-temperature environments, specifically a rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate, which visually displays the periodic table of thermo-mechanical properties and enables rapid material screening. Background Technology

[0002] With the continuous improvement of thrust-to-weight ratio in new-generation aero-engines, the internal combustion gas temperature has exceeded the tolerance limit of traditional nickel-based superalloys. Silicon carbide ceramic matrix composites (SiC CMCs) are currently the most promising high-temperature structural materials for hot-end components of aero-engines. Under the high-temperature environment of an engine, the SiO2 oxide film initially formed on the surface of SiC CMCs reacts with the water vapor produced by the combustion of aviation kerosene to generate gaseous silicon hydroxide, which is then carried away. Therefore, environmental barrier coatings (EBCs) are needed for surface protection.

[0003] The surface temperature of the hot-end components of the next-generation high thrust-to-weight ratio air engine will be no less than 1500℃. The development of multifunctional thermal barrier and environmental barrier integrated coatings (TEBCs) with excellent comprehensive performance can solve the composite requirements of thermal barrier coatings and environmental barrier coatings for ceramic matrix composite structural components in the extreme gas environment of aircraft, and significantly improve the thrust-to-weight ratio and long-term service stability of the engine.

[0004] In recent years, ytterbium disilicate (Yb₂Si₂O₇) has been considered one of the most promising environmental barrier coating materials. However, the high thermal conductivity of Yb₂Si₂O₇ requires further optimization. The concept of multi-component modification (or high entropy) has brought new opportunities. For multi-component materials, when (nRE) 1 / n When the number of rare earth cation species (n) in 2Si2O7 ceramic materials is n = 2-4 or n ≥ 5, they are respectively called medium-entropy or high-entropy disilicate materials (see reference [L. Sun, et al. A multicomponent γ-type (Gd) 1 / 6 Tb 1 / 6 Dy 1 / 6 Tm 1 / 6 Yb 1 / 6 Lu 1 / 6)2Si2O7 disilicate with outstanding thermalstability, Mater. Res. Lett. 8(11)(2020)424-430】). Multicomponent systems often have high mixing entropy, slow diffusion kinetics, severe lateral distortion and cocktail effect. Therefore, it has significant properties such as high melting point, excellent phase stability, high hardness, amorphous thermal conductivity and excellent wear resistance and corrosion resistance (see reference [C. Oses, et al. High-entropy ceramics, Nat. Rev. Mater. 5(4)(2020)295-309]).

[0005] For (nRE) 1 / n )2Si2O7 ceramic materials, some studies have pointed out that when the following conditions are met: (1) the average rare earth cation radius value is less than And (2) when the average deviation is sufficiently small, a β-type (nRE) can be formed. 1 / n )2Si2O7 ceramic material, and stable in the high temperature range (see reference [Y. Luo, et al. Phase formation capability and compositional design of beta-phase multiple rare-earth principal component disilicates, Nat. Commun. 14(1)(2023)1275]). Previous studies have also shown that, relative to Yb2Si2O7 material, (Y 0.5 Yb 0.5 )2Si2O7 materials can reduce thermal conductivity (see reference [LRTurcer, et al. Low thermal conductivity in high-entropy rare-earth pyrosilicate solid-solutions for thermal environmental barrier coatings, Scr. Mater. 191(2021)40-45]), (Ho x Yb 1-x )2Si2O7 can affect water vapor corrosion resistance (see reference [X.Lv, et al. Phase composition and property evolution of (Yb 1-x Ho x)2Si2O7 solid solution as environmental / thermal barriercoating candidates, J.Eur.Ceram.Soc.42(10)(2022)4377-4387】). In addition, some scholars have also studied the intermediate entropy (Sc 0.25 Y 0.25 Er 0.25 Yb 0.25 )2Si2O7 ceramic materials (see reference [X.Wang, et al. Preparation and corrosion resistance of high-entropy disilicate(Y)) 0.25 Yb 0.25 Er 0.25 Sc 0.25 )2Si2O7ceramics, Corros. Sci. 192 (2021)】) and high entropy (Sc 0.2 Y 0.2 Gd 0.2 Yb 0.2 Lu 0.2 )2Si2O7 ceramic materials (see reference [Y. Dong, et al. Interaction of multicomponent disilicate(Yb 0.2 Y 0.2 Lu 0.2 Sc 0.2 Gd 0.2 The study of 2Si2O7 with molten calcia-magnesia-aluminosilicate, J.Adv.Ceram.11(1)(2021)66-74] showed that they all exhibited excellent corrosion resistance in molten calcium-magnesia-aluminium-silicon (CMAS). Furthermore, previous first-principles calculations on single rare-earth element-doped Yb2Si2O7 (see K.Li, et al. First-principles calculations and thermal-mechanicalexperimental studies on middle-entropy rare-earth disilicates, Ceram.Int.50(13)(2024)22290-22305) indicated that the average bond length order of the RE-O bonds after doping was (Sc 0.5 Yb 0.5 )2Si2O7<(Yb 0.5 Lu0.5 )2Si2O7<(Y 0.5 Yb 0.5 )2Si2O7 <Yb2Si2O7<(Ho 0.5 Yb 0.5 )2Si2O7<(Tm 0.5 Yb 0.5 )2Si2O7<(Er 0.5 Yb 0.5 Yb₂Si₂O₇. In summary, doping Yb₂Si₂O₇ with other rare earth elements can alter its crystal structure, thereby yielding TEBCs materials with excellent comprehensive properties.

[0006] Because medium-entropy or high-entropy materials involve a large number of rare earth elements, especially the design and experimental verification of five or more rare earth elements, the number of different medium-entropy or high-entropy combinations can reach tens of thousands. Therefore, there is an urgent need for a new rapid screening method for medium-entropy or high-entropy materials and its theoretical basis for selection. Summary of the Invention

[0007] The purpose of this invention is to provide a rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate, so as to intuitively display the periodic table of thermo-mechanical properties and realize the rapid screening of medium- or high-entropy materials.

[0008] To achieve the above objectives, this invention provides a rapid screening method for medium-high entropy rare-earth disilicate materials of ytterbium disilicate, the specific steps of which are as follows:

[0009] S1: Select rare earth elements that can form a monoclinic β phase after equimolar doping of Yb2Si2O7 material as doping elements RE*, and calculate the average bond length of RE-O. RE-O includes the bond between Yb and O elements and the bond between the doping element and O elements.

[0010] S2: Dopants are divided into two categories based on whether they increase or decrease the average Yb-O bond length of Yb2Si2O7 material, and then sorted according to the doping weight.

[0011] S3: Establish a periodic table of orthogonally increasing doped elements based on the sorting results. Each unit of the periodic table corresponds to a material. Materials in the same period or group have the same increasing doping element relative to materials in the previous period or group.

[0012] S4: For each material in the periodic table, conduct material preparation and thermo-mechanical property experiments to obtain experimental results;

[0013] S5: Summarize the experimental results into the periodic table to form a periodic table of thermo-mechanical properties of medium- and high-entropy rare earth disilicate ceramic materials, and select the most suitable material or element to be doped from it according to the requirements.

[0014] In step S1, the selected doping elements include at least two rare earth elements with a radius greater than that of Yb and at least two rare earth elements with a radius smaller than that of Yb, and the selected doping elements may include at most Sc, Y, Ho, Er, Tm and Lu.

[0015] In step S1, the average bond length of RE-O is calculated, specifically by using first-principles calculations to determine the average bond length of RE-O in the doped material obtained by equimolar doping of Yb₂Si₂O₇ with dopant elements. In step S2, if the average bond length of RE-O is less than the average bond length of Yb-O in Yb₂Si₂O₇, the dopant element causes a decrease in the average bond length of Yb-O in Yb₂Si₂O₇; otherwise, the dopant element causes an increase in the average bond length of Yb-O in Yb₂Si₂O₇.

[0016] Preferably, the formula for calculating the doping weight W is:

[0017]

[0018] Where W represents the doping weight, and M represents the ionic radii of the dopant element RE* and the ytterbium element Yb, respectively. RE* and M Yb These represent the relative atomic masses of the dopant element RE* and the ytterbium element Yb, respectively. and These represent the average RE-O bond length of Yb₂Si₂O₇ material obtained by equimolar doping of the doping element RE* and the average Yb-O bond length of Yb₂Si₂O₇ material, respectively.

[0019] Step S3 specifically includes the following steps:

[0020] S31: Establish a periodic table with m×n units, where m is one of the number of dopants that increase bond length and the number of dopants that decrease bond length, and n is the other of the number of dopants that increase bond length and the number of dopants that decrease bond length.

[0021] S32: Set the unit of the first group of the first period of the periodic table to be Yb2Si2O7 material;

[0022] S33: In the first period of the periodic table, using one of the doping elements of a certain category, the Yb2Si2O7 material is doped in descending order of doping weight. The material obtained by each doping increment occupies one unit of a group in the periodic table, so as to obtain the material corresponding to the unit of different groups in the first period of the periodic table.

[0023] S34: In Group I of the periodic table, using another type of doping element, based on the Yb2Si2O7 material, the doping weight of the doping element is increased sequentially from large to small. Each time the doping weight is increased, the resulting material occupies one unit of one period of the periodic table, so as to obtain the material corresponding to the unit of different periods of Group I of the periodic table.

[0024] S35: Doping is performed according to the orthogonal increasing doping rule that the materials in the same period of the periodic table have the same increasing doping element relative to the materials in the previous period, and the materials in the same group of the periodic table have the same increasing doping element relative to the materials in the previous group, until the entire m×n units of the periodic table are filled.

[0025] In step S4, the experimental results of the thermo-mechanical property test include: experimental data on the physical properties, thermal properties, mechanical properties of the material, and the thermal mismatch stress values ​​generated when used as a coating on a SiC substrate; wherein, the physical properties include at least one of density, average cation radius, relative atomic mass, and type of dopant element; the thermal properties include at least one of coefficient of thermal expansion and thermal conductivity; and the mechanical properties include at least one of Young's modulus, microhardness, and fracture toughness.

[0026] In step S4, the material in the periodic table is a bulk ceramic material prepared by in-situ solid-state reaction method. The molar ratio of RE to Si in the raw material of the bulk ceramic material is 1:1.1, where RE represents Yb element, or a combination of one or more doping elements and Yb element.

[0027] In step S4, the specific steps for preparing the material using the in-situ solid-state reaction method are as follows:

[0028] S411: Prepared using one or more rare earth oxides and silica powder as raw materials, based on a RE:Si molar ratio of 1:1.1 (nRE) 1 / n The mass of rare earth oxides and silicon dioxide powder required for the 2Si2O7 ceramic material is weighed together, where RE represents Yb element, or a combination of one or more doping elements and Yb element; when RE represents multiple elements, the proportion of each element is equal.

[0029] S412: Using ethanol as the medium, silicon nitride grinding balls are added to a stainless steel ball mill jar. The original powder, ethanol, and grinding balls are mixed in a mass ratio of 1:1:1 or 1:1:2 and ball-milled for 6–24 hours to form a slurry. After drying and sieving, the resulting mixed powder is cold isostatically pressed into blanks. The blanks are then placed in a muffle furnace for pressureless sintering. The heating rate is 3–10 °C / min, the synthesis temperature is 1500–1650 °C, and the synthesis time is 10–20 hours. Finally, a medium-high entropy rare earth disilicate ceramic block material is obtained.

[0030] The thermo-mechanical property experiments include:

[0031] S421: The lattice constant, density, and cell volume of the theoretical disilicate phase of the material are obtained through XRD patterns, and the relative atomic mass and average cation radius of the material are calculated and determined.

[0032] S422: The density of the prepared material is measured by Archimedes' water displacement method, and the theoretical content of each phase of the material is calculated based on the proportion of the original powder used in the material preparation. Then, the density and porosity of the prepared material are calculated based on the theoretical density of the disilicate phase.

[0033] S423: The thermal diffusivity of the prepared material is measured by a laser thermal conductivity meter using the laser flash method. The specific heat capacity of the prepared material is calculated using the Neumann-Kopp rule. Then, the theoretical thermal conductivity is calculated and determined based on the thermal diffusivity, density, specific heat capacity and porosity of the prepared material.

[0034] S424: The coefficient of thermal expansion of the prepared material was measured by a thermal expansion meter using the linear expansion method;

[0035] S425: The crack length and Young's modulus of the indentation of the prepared material were measured by nanoindentation using the Oliver-Pharr method.

[0036] S426: The microhardness of the prepared material is measured by an indentation tester using a microhardness tester.

[0037] S427: The fracture toughness of the prepared material is determined by calculating the crack length of the indentation and Young's modulus;

[0038] S428: The thermal mismatch stress value generated when the prepared material is used as a coating on a SiC substrate is calculated based on the coefficient of thermal expansion, elastic modulus and Poisson's ratio. Due to the presence of pores, the elastic modulus when used as a coating is taken as 40% of the elastic modulus of the prepared material.

[0039] Step S5 further includes summarizing the chemical properties of the materials into the periodic table.

[0040] This invention's rapid screening method differs from single-variable methods that require numerous experiments. Based on previous simulation and experimental research, it designs and synthesizes a series of ytterbium disilicate and high-entropy rare-earth disilicate bulk ceramic materials with high density and high disilicate phase purity using an in-situ solid-state reaction method, following the weighting of rare-earth elements and a periodic orthogonal increasing doping pattern. Then, their grain size and thermo-mechanical properties, including high-temperature stability, density, thermal conductivity, coefficient of thermal expansion, microhardness, Young's modulus, and fracture toughness, are systematically analyzed and measured. Furthermore, a novel periodic table of corresponding thermo-mechanical properties is created for the first time, providing theoretical support for the rapid screening and composition design of medium-entropy or high-entropy TEBCs materials.

[0041] Unlike conventional single-variable methods that require extensive experiments, this invention employs a rapid screening method based on orthogonal incremental doping of factors according to element weights. This method not only fully utilizes the correlations between factors to quickly screen multi-component doped medium- or high-entropy materials, reducing unnecessary workload, but also enhances visualization through a thermo-mechanical property periodic table. Furthermore, the periodic table can be used to determine the relative benefits of certain properties in high-entropy materials. This invention provides theoretical support for the rapid screening and composition design of medium- or high-entropy environmental barrier coating materials.

[0042] When the number of material varieties obtained by the rapid screening method of the present invention is small, the physical properties, thermal properties, mechanical properties or chemical properties of these materials may be more extreme (very good or very poor) than those of other rare earth element materials with the same number of rare earth elements. Attached Figure Description

[0043] Figure 1 This is a flowchart comparing a rapid screening method for medium-high entropy rare earth disilicate materials of ytterbium disilicate according to an embodiment of the present invention with a conventional screening method for medium-high entropy rare earth disilicate materials of ytterbium disilicate based on a single variable method, wherein the required number of materials to be selected is shown in the comparison.

[0044] Figure 2 This is an example of (nRE) 1 / n XRD pattern of 2Si2O7 ceramic material in its prepared state. In the figure, the horizontal axis is the diffraction angle 2θ, and the vertical axis is the relative intensity (arb.unit).

[0045] Figure 3 This is an example of (nRE) 1 / n XRD pattern of 2Si2O7 ceramic material after hot corrosion at 1550℃ for 100 hours. In the figure, the horizontal axis is the diffraction angle 2θ, and the vertical axis is the relative intensity (arb.unit).

[0046] Figure 4 After 100 hours of hot corrosion at 1550℃ (nRE) 1 / n Grain morphology of 2Si2O7 ceramic material.

[0047] Figure 5 Yes (nRE) 1 / n The curve shows the change in the coefficient of thermal expansion of 2Si₂O₇ ceramic material with temperature. In the figure, the horizontal axis represents temperature (K), and the vertical axis represents the coefficient of thermal expansion (10⁻⁶ K). -6 K -1 ).

[0048] Figure 6 Yes (nRE) 1 / n The curve shows the thermal conductivity of 2Si₂O₇ ceramic material as a function of temperature. In the figure, the horizontal axis represents temperature (K), and the vertical axis represents thermal conductivity (W·m). -1 ·K -1 ).

[0049] Figure 7 Yes (nRE) 1 / n A bar graph showing the variation of the elastic modulus of Si₂O₇ ceramic material with the type of doping element. In the graph, the horizontal axis (nRE) represents the elastic modulus. 1 / n )2Si2O7 represents different disilicate materials, and the vertical axis represents Young's modulus (GPa).

[0050] Figure 8 Yes (nRE) 1 / n A bar graph showing the microhardness of Si₂O₇ ceramic material as a function of the type of doping element. In the graph, the horizontal axis (nRE) represents the microhardness of Si₂O₇ ceramic material. 1 / n )2Si2O7 represents different disilicate materials, and the vertical axis represents microhardness (GPa).

[0051] Figure 9 Yes (nRE) 1 / n A bar graph showing the fracture toughness of Si₂O₇ ceramic material as a function of the type of doping element. In the graph, the horizontal axis (nRE) represents the fracture toughness of Si₂O₇ ceramic material. 1 / n )2Si2O7 represents different disilicate materials, and the ordinate represents fracture toughness (MPa·m) 1 / 2 ).

[0052] Figure 10 It is drawn as a 4×4 (nRE) 1 / n Periodic table of thermo-mechanical properties of 2Si2O7 ceramic materials. Detailed Implementation

[0053] A preferred embodiment of the present invention is given below with reference to the accompanying drawings and tables, and described in detail. Obviously, the drawings described below are merely a preferred embodiment of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0054] The rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate in this invention is mainly based on the following design concept:

[0055] 1) From the perspective of material composition design, multiple rare earth elements are introduced into rare earth ytterbium disilicate. The high entropy effect, that is, the high mixing entropy under high temperature conditions, can effectively reduce the Gibbs free energy of the system and obtain a stable single phase.

[0056] 2) From the perspective of material performance design, by selecting various specific rare earth elements, the properties of the material are combined, and then the different sizes of various rare earth atoms are used to cause severe lattice distortion, thereby bringing physical, chemical, thermal and mechanical properties that are superior to those of traditional solid solutions.

[0057] 3) Considering the selection of doping elements and rapid screening methods, unlike the single-variable method which requires numerous experiments, this invention utilizes the natural law that extreme crystal structures often exhibit extreme properties. Based on literature, simulations, or experience, rare earth elements RE1, RE2, ..., REm and REI, REII, ..., REn are doped into Yb2Si2O7 according to the weighting of rare earth elements and the orthogonal incremental doping pattern, resulting in an m×n periodic table. The related physical properties and thermodynamic performance are then measured and a thermodynamic performance periodic table is plotted. This not only fully utilizes the correlation between various factors to rapidly screen multi-component doped medium- or high-entropy materials, reducing unnecessary workload, but also enhances the visualization effect through the thermodynamic performance periodic table presentation. Furthermore, based on the thermodynamic performance periodic table, the benefits of further doping of each doping element on top of medium- or high-entropy materials can be identified, allowing for further screening and iterative operations of the doping elements. These results can provide theoretical support for the rapid screening and composition design of environmental barrier coating materials.

[0058] like Figure 1 As shown, the rapid screening method for medium-high entropy rare earth disilicate materials of ytterbium disilicate of the present invention includes the following steps:

[0059] Step S1: Select rare earth elements that can form a monoclinic β phase after equimolar doping of Yb2Si2O7 material as doping elements RE*, and perform first-principles calculations to obtain the average bond length of RE-O. RE-O includes the bond between Yb and O elements and the bond between the doping element and O elements.

[0060] Step S2: Divide the doping elements into two categories based on whether they increase or decrease the average Yb-O bond length of the Yb2Si2O7 material, and sort them according to the doping weight.

[0061] In this embodiment, the number of dopant elements that increase bond length is m, and the number of dopant elements that decrease bond length is n. In other embodiments, the number of dopant elements that increase bond length can be n, and the number of dopant elements that decrease bond length can be m.

[0062] Step S3: Based on the sorting results, establish a periodic table of m×n units with orthogonally increasing doping. Each unit of the periodic table corresponds to a material. Materials in the same period of the periodic table have the same increasing doping element relative to the materials in the previous period. Materials in the same group of the periodic table have the same increasing doping element relative to the materials in the previous group.

[0063] Step S4: For each material in the periodic table, conduct material preparation and thermo-mechanical property experiments to obtain experimental results;

[0064] Step S5: Summarize the experimental results into the periodic table to form a periodic table of thermo-mechanical properties of medium- and high-entropy rare earth disilicate ceramic materials, and select the most suitable material or element to be doped from it according to the requirements.

[0065] In step S1, rare earth elements that can form a monoclinic β phase after being equimolarly doped into Yb2Si2O7 material are selected as doping elements. Specifically, rare earth elements that can form a monoclinic β phase crystal structure when equimolarly doped into Yb2Si2O7 material are selected as doping elements to ensure the high-temperature stability of the phase from room temperature to the melting point of the doped material, that is, no phase transition occurs.

[0066] In this embodiment, for rare earth disilicate ceramic materials with multiple rare earth components, since only those with an average rare earth cation radius smaller than 10 ... Only under certain conditions can the β phase be formed. Therefore, among the fourteen rare earth elements in Group IIIB of the periodic table, only seven rare earth elements—Sc, Y, Ho, Er, Tm, Yb, and Lu—meet the requirements. Thus, the selected dopant elements include Sc, Y, Ho, Er, Tm, and Lu. In other embodiments, the dopant elements are generally selected from at least two rare earth elements with an atomic radius greater than that of Yb, and at least two rare earth elements with an atomic radius smaller than that of Yb. Furthermore, the selected dopant elements may include at most Sc, Y, Ho, Er, Tm, and Lu.

[0067] In step S1, the average bond length of RE-O is calculated, specifically including: using first-principles calculations, equimolarly doping of the doping element RE* in Yb2Si2O7 material to obtain the doped material (i.e., (RE*) 0.5 Yb 0.5 The average RE-O bond length of the 2Si2O7 crystal structure was calculated, where Yb is ytterbium and RE* is the selected dopant element. In this embodiment, the selected dopant elements include Sc, Y, Ho, Er, Tm, and Lu.

[0068] The average bond length of RE-O is less than the average bond length of Yb-O in Yb2Si2O7 material, indicating that the doping element leads to a decrease in the average bond length of Yb-O in Yb2Si2O7 material; conversely, it indicates that the doping element leads to an increase in the average bond length of Yb-O in Yb2Si2O7 material.

[0069] In step S2, the doping elements are divided into two categories based on whether they increase or decrease the average Yb-O bond length of the Yb2Si2O7 material. The starting point is that multi-component doping is used on ytterbium disilicate, a single-component material. The doping elements will cause the average Yb-O bond length of the Yb2Si2O7 lattice to increase or decrease, thereby improving the ytterbium disilicate material and obtaining a medium-to-high entropy rare earth disilicate material for modification and optimization.

[0070] In step S2, the doping weight W is calculated using the following formula:

[0071]

[0072] Where W represents the doping weight, and M represents the ionic radii of the dopant element RE* and the ytterbium element Yb, respectively. RE* and M Yb These represent the relative atomic masses of the dopant element RE* and the ytterbium element Yb, respectively. and These represent the average RE-O bond length of Yb₂Si₂O₇ material obtained by equimolar doping of the doping element RE* and the average Yb-O bond length of Yb₂Si₂O₇ material, respectively.

[0073] Therefore, in this invention, the formula for calculating the doping weight not only considers the atomic radius and relative atomic mass of the doping element itself, but also the influence of doping on the average Yb-O bond length of the Yb₂Si₂O₇ material. This better reflects the natural law of how doping elements affect the degree of change in crystal structure at the atomic scale. Furthermore, since extreme crystal structures often lead to extreme thermodynamic properties, rare earth element combinations with optimal thermodynamic properties should typically appear in extreme element doping combinations with high doping weights. Therefore, the order of the periods and groups of rare earth element doping combinations in the periodic table must be arranged in descending order of doping weight. This ensures that each rare earth doping combination exhibits extreme characteristics.

[0074] Specifically, step S3 includes the following steps:

[0075] Step S31: Establish a periodic table with m×n units, where m is one of the number of dopants that increase bond length and the number of dopants that decrease bond length, and n is the other of the number of dopants that increase bond length and the number of dopants that decrease bond length.

[0076] Therefore, the periodic table with m×n units consists of m periods horizontally (1, 2, 3, 4, ..., m) and n groups vertically (I, II, III, IV, ..., n), containing a total of m×n units, and thus will contain m×n kinds of rare earth disilicate ceramic materials.

[0077] Step S32: Set the unit of the first group of the first period of the periodic table to be Yb2Si2O7 material;

[0078] Step S33: In the first period of the periodic table, using one of the doping elements of a certain category, the Yb2Si2O7 material is doped in descending order of doping weight. The material obtained by each doping increment occupies one unit of a group in the periodic table, so as to obtain the material corresponding to the unit of different groups in the first period of the periodic table.

[0079] In other words, in the first period of the periodic table, the unit of group 2 represents the material obtained by doping Yb2Si2O7 with RE1 in an equal molar ratio, the unit of group 3 represents the material obtained by doping Yb2Si2O7 with RE1 and RE2 in an equal molar ratio, ..., until the last unit represents the material obtained by doping Yb2Si2O7 with m elements RE1, RE2, ... and REm in an equal molar ratio, where RE1, RE2, ... and REm represent doping elements arranged in descending order of doping weight, and all of them belong to the same category of doping elements.

[0080] The reason for using equimolar doping ratios here is twofold: firstly, equimolar doping is the traditional definition of medium- or high-entropy materials; secondly, equimolar doping results in the point defect concentration reaching its maximum, which is beneficial for reducing thermal conductivity. For details, please refer to the literature [C.Wan, W.Pan, Q.Xu, Y.Qin, J.Wang, Z.Qu, M.Fang, Effect of point defects on the thermal transport properties of (La x Gd 1-x [2Zr2O7 experiment and theoretical model, Phys.Rev.B 74(2006)144109]; In addition, equimolar doping also makes it easier to compare the benefits of different doping elements on thermo-mechanical properties at the same doping content.

[0081] Step S34: In Group I of the periodic table, using another type of doping element, based on the Yb2Si2O7 material, the doping weight of the doping element is increased sequentially from large to small. Each time the doping weight is increased, the resulting material occupies one unit of one period of the periodic table, so as to obtain the material corresponding to the unit of different periods of Group I of the periodic table.

[0082] In other words, in Group I of the periodic table, the cell in the second period represents the material obtained by doping Yb2Si2O7 with an equimolar proportion of element REI, the cell in the third period represents the material obtained by doping Yb2Si2O7 with two elements REI and REII in an equimolar proportion, and so on, until the last cell represents the material obtained by doping Yb2Si2O7 with n elements REI, REII, ... and REn in an equimolar proportion, where REI, REII, ... and REn represent doping elements arranged in descending order of doping weight, and all of them are doping elements of another category.

[0083] Step S35: Perform doping according to the orthogonal increasing doping rule that the materials in the same period of the periodic table have the same increasing doping element relative to the materials in the previous period, and the materials in the same group of the periodic table have the same increasing doping element relative to the materials in the previous group, until the entire m×n units of the periodic table are filled.

[0084] In step S4, the experimental results of the thermo-mechanical performance test include: physical properties of the material (such as density, average cation radius, relative atomic mass, type of dopant element, etc.), thermal properties (such as coefficient of thermal expansion, thermal conductivity, etc.), mechanical properties (such as Young's modulus, microhardness, fracture toughness, etc.), and thermal mismatch stress values ​​generated when used as a coating on SiC substrate, etc., which are experimental data related to thermo-mechanical performance.

[0085] In step S4, the material in the periodic table (i.e., ytterbium disilicate and its high-entropy rare earth disilicate) is a bulk ceramic material prepared by in-situ solid-state reaction method, wherein the molar ratio of RE and Si in the raw material is 1:1.1, RE represents Yb element, or a combination of one or more doping elements and Yb element (i.e., a combination of two or more rare earth elements of the seven rare earth elements Sc, Y, Ho, Er, Yb and Lu).

[0086] In step S4, the specific steps for preparing the material using the in-situ solid-state reaction method are as follows:

[0087] Step S411: Using one or more rare earth oxides and silica powder as raw materials, prepare (nRE) according to the RE:Si molar ratio of 1:1.1. 1 / n The mass of rare earth oxides and silicon dioxide powder required for the 2Si2O7 ceramic material is weighed together, where RE represents Yb element, or a combination of one or more doping elements and Yb element; when RE represents multiple elements, the proportion of each element is equal.

[0088] The initial particle size of the raw materials is 1–5 μm, with a purity ≥99.9%. To ensure that the disilicate bulk ceramics possess both high density and disilicate phase purity, the RE:Si molar ratio in the raw materials is 1:1.1, where RE represents Yb, or a combination of one or more doping elements with Yb. When RE represents multiple elements, the proportions of each rare earth element are equal.

[0089] Step S412: Using ethanol as a medium, silicon nitride grinding balls are added to a stainless steel ball mill jar. The original powder, ethanol, and grinding balls are mixed in a mass ratio of 1:1:1 or 1:1:2 and ball-milled for 6–24 hours to form a slurry. After drying and sieving, the mixed powder obtained from the slurry is cold isostatically pressed into blanks. The blanks are then placed in a muffle furnace for pressureless sintering. The heating rate is 3–10 °C / min, the synthesis temperature is 1500–1650 °C, and the synthesis time is 10–20 hours. Finally, a medium-high entropy rare earth disilicate ceramic block material is obtained.

[0090] The entire preparation process is simple and easy to mass-produce.

[0091] The thermo-mechanical property experiments of materials mainly include eight aspects, and the experimental steps are as follows:

[0092] Step S421: Obtain the theoretical lattice constant, density, and cell volume of the disilicate phase of the material through XRD patterns, and calculate and determine the relative atomic mass and average cation radius of the material;

[0093] Step S422: The density of the prepared material is measured using the Archimedes displacement method, and the theoretical content of each phase of the material is calculated based on the proportion of the original powder used in the material preparation. Then, the density and porosity of the prepared material are calculated based on the theoretical density of the disilicate phase.

[0094] Step S423: The thermal diffusivity of the prepared material is measured by laser flare method using a laser thermal conductivity meter. The specific heat capacity of the prepared material is calculated by Neumann-Kopp rule. Then, the theoretical thermal conductivity is calculated and determined based on the thermal diffusivity, density, specific heat capacity and porosity of the prepared material.

[0095] Step S424: Measure the coefficient of thermal expansion of the prepared material using a thermal expansion meter via the linear expansion method;

[0096] Step S425: The crack length and Young's modulus of the indentation of the prepared material are measured using the Oliver-Pharr method with a nanoindenter.

[0097] Step S426: The microhardness of the prepared material is measured by an indentation tester.

[0098] Step S427: Calculate and determine the fracture toughness of the prepared material based on the crack length of the indentation and Young's modulus;

[0099] Step S428: Calculate the thermal mismatch stress value generated when the prepared material is used as a coating on a SiC substrate based on the coefficient of thermal expansion, elastic modulus and Poisson's ratio. Due to the presence of pores, the elastic modulus when used as a coating is taken as 40% of the elastic modulus of the prepared material.

[0100] Therefore, the experimental results should include at least the physical properties, thermal properties, and mechanical properties of the material.

[0101] The data compiled into the periodic table is not limited to the physical, thermal, and mechanical properties of materials. Therefore, step S5 also includes compiling the chemical properties of materials, such as resistance to corrosion by molten salts or water vapor, into the periodic table. Thus, the thermo-mechanical property periodic table of the present invention adds information about each material (such as physical properties, thermal properties, mechanical properties, chemical properties, etc.) around each material.

[0102] In step S5, for each material in the periodic table, the experimental results for that material are entered into the corresponding unit in the periodic table, thus forming a periodic table of thermo-mechanical properties of medium- and high-entropy rare-earth disilicate ceramic materials. Therefore, the chemical formula of ytterbium disilicate and its medium- and high-entropy rare-earth disilicate in the periodic table is (nRE). 1 / n)2Si2O7, where n≥1; RE represents Yb element, or a combination of one or more doping elements and Yb element (i.e., a combination of two or more rare earth elements of the seven rare earth elements Sc, Y, Ho, Er, Yb and Lu).

[0103] In step S5, the requirement corresponds to the information summarized in the thermo-mechanical properties periodic table, including at least one of the material's physical properties, thermal properties, mechanical properties, and chemical properties.

[0104] Experimental results:

[0105] This experiment uses the creation of a visually intuitive 4×4 periodic table of the thermo-mechanical properties of ytterbium disilicate and its high-entropy rare-earth disilicate materials as an example to illustrate a rapid screening method for selecting the medium-entropy or high-entropy materials with the best thermo-mechanical properties from the table. The general process is as follows: Figure 1 As shown.

[0106] Among them, by Figure 1 It can be seen that the single-variable method yielded 56 material combinations doped with the six rare earth elements Sc, Y, Ho, Er, Tm, and Lu in ytterbium disilicate (including the ytterbium disilicate control group, the same below), while the orthogonal incremental doping method, which judges by weight, yielded only 16 doping element combinations, improving efficiency by more than 70%. Therefore, the orthogonal incremental doping method, which sorts by weight, can greatly improve the screening of medium- and high-entropy ytterbium disilicate materials.

[0107] The orthogonal incremental doping method obtained in this invention yields only 16 combinations of doping elements. These 16 materials exhibit certain physical, thermal, mechanical, or chemical properties that may be more extreme (excellent or poor) than other materials with the same number of rare earth elements. This is because these 16 materials are selected from 56 materials, representing materials with extreme crystal structures for the same number of rare earth elements; therefore, their properties often exhibit extreme characteristics, with some properties being excellent while others are extremely poor. For example, ScYb-doped binary disilicates have the smallest average cation radius and the smallest cell volume. Specifically, for REYb binary doping, its crystal structure is extremely small, resulting in the highest microhardness and elastic modulus, and presumably the best thermal stability. However, ErYb is the opposite, possessing the largest cell volume / crystal structure under the β-phase condition. Similarly, in ternary doping, ScYbLu has an extremely small crystal structure compared to other ternary dopants such as ScHoYb, resulting in the largest coefficient of thermal expansion. This is the main basis for the screening of elements in the first period and group 1. For other combinations of elements in the periodic table, an element representing the opposite extreme is doped into the extreme crystal structure. The aim is to minimize the extreme nature of the crystal structure to achieve superior overall performance. For example, adding Er to ScYb material theoretically mitigates the negative impact of extreme crystal structure more effectively than adding Ho or Tm. Here, the quantification of the extreme properties of elements is the weighting formula in this invention.

[0108] The specific implementation steps of the rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate in this experiment are as follows:

[0109] In step S1, based on the equimolar doping of Yb₂Si₂O₇ with a single rare earth element, since the average radius of the rare earth element cations is smaller than that of the rare earth element cations... Only then can the β phase be formed (see [Y. Luo, et al. Phase formation capability and compositional design of beta-phase multiple rare-earth principal component disilicates, Nat. Commun. 14(1)(2023)1275]). Therefore, the rare earth elements to be doped are selected as six rare earth elements: Sc, Y, Ho, Er, Tm, and Lu. Among them, there are four rare earth elements with a radius greater than that of Yb: Y, Ho, Er, and Tm; and two rare earth elements with a radius smaller than that of Yb: Sc and Lu. Then, the equimolarly doped (RE) 0.5 Yb 0.5The average RE-O bond length in the Yb2Si2O7 crystal structure was calculated using first-principles calculations, where RE represents Sc, Y, Ho, Er, Tm, Yb, or Lu elements. The first-principles calculation process was based on previous work (see [K.Li, et al. First-principles calculations and thermal-mechanical experimental studies on middle-entropy rare-earth disilicates, Ceram.Int.50(13)(2024)22290-22305]). The calculation results show that the average RE-O bond length in Ho, Er, and Tm doped materials is greater than the average Yb-O bond length in the Yb2Si2O7 lattice, while the average RE-O bond length in Sc, Y, and Lu doped materials is less than the average Yb-O bond length in the Yb2Si2O7 lattice.

[0110] In step S2, the six rare earth elements Sc, Y, Ho, Er, Tm and Lu are divided into two categories according to whether they cause an increase or decrease in the average Yb-O bond length of the Yb2Si2O7 lattice, and then sorted in descending order of doping weight.

[0111] The calculation results of the average bond length of RE-O show that Ho, Er, and Tm elements can increase the average Yb-O bond length of the Yb₂Si₂O₇ lattice, while Sc, Y, and Lu elements can decrease the average Yb-O bond length of the Yb₂Si₂O₇ lattice. Furthermore, since the doping weights of Ho, Er, and Tm are 3.66, 4.66, and 2.87, respectively; and the doping weights of Sc, Y, and Lu are 135.36, 20.19, and 31.76, respectively, the order of doping weight is: Er > Ho > Tm; Sc > Lu > Y.

[0112] In step S3, a periodic table of 4×4 units with orthogonally ascending elemental doping is established based on the sorting results. Elements RE1, RE2, and RE3, which are ascendingly doped in different periods, are selected sequentially as Er, Ho, and Tm elements, respectively. Simultaneously, elements REI, REII, and REIII, which are ascendingly doped in different groups, are selected sequentially as Sc, Lu, and Y elements, respectively. This yields 16 disilicate materials in the periodic table, and their specific rare earth element doping combinations, codes, and predicted phases are shown in Table 1.

[0113] Table 1: Doping Combinations and Codes of Rare Earth Elements

[0114]

[0115] S4: Prepare bulk ceramic materials of the above 16 medium- and high-entropy rare earth disilicates and conduct thermo-mechanical property experiments.

[0116] The specific preparation process of the bulk ceramic materials is as follows: Based on the RE:Si molar ratio of 1:1.1 in the raw materials, the required mass of rare earth oxides and silicon dioxide powder for each type of bulk ceramic material is determined and weighed. Using anhydrous ethanol as the medium, silicon nitride grinding balls are added to a stainless steel ball mill jar, and the original powder, ethanol, and grinding balls are mixed at a mass ratio of 1:1:2 and ball-milled for 10 hours to form a slurry. The mixed oxide slurry is dried and sieved through an 80-mesh sieve. Then, a blocky, coin-shaped blank with dimensions of approximately Φ15mm × 2mm is prepared using a cold isostatic press. The pressing process is as follows: dry pressing at 6MPa for 5 minutes; oil pressing at 300MPa for 30 minutes. Finally, the blanks are sintered without pressure in a muffle furnace. The sintering process is as follows: the temperature is increased to 1550℃ at a rate of 3℃ / min and held for 10 hours to obtain 16 types of (nRE)... 1 / n )2Si2O7 disilicate ceramic bulk. The entire preparation process is simple and easy to mass-produce.

[0117] Then, the prepared (nRE) 1 / n XRD phase identification was performed on 2Si2O7 disilicate ceramic bulk to determine the physical properties of the material, such as lattice constant, theoretical density of disilicate phase, bulk ceramic density, average cation radius, relative atomic mass, and types of doping elements. Figure 2 Yes (nRE) 1 / n The XRD pattern of the prepared Si₂O₇ ceramic material shows that the prepared disilicate bulk material mainly consists of a large amount of disilicate phase and trace amounts of SiO₂ phase, and does not contain monosilicate phase. Through further analysis... Figure 2 Rietveld refinement of the XRD patterns yields the lattice constants and theoretical densities of different disilicate phases. Based on the theoretical density of the disilicate phases, the density of the bulk material measured using the Archimedes method, and the mass fraction of SiO2 in the raw materials, the purity of the disilicate phases in the bulk material can be calculated to be approximately 97%, and the density to be approximately 98%. This meets the requirements for subsequent performance testing.

[0118] Next, grain size and high-temperature stability of the phases were tested. Environmental barrier coatings are typically used in extreme high-temperature environments, so good grain size and high-temperature stability of the phases are essential. Figure 3 and Figure 4 These are the results after 100 hours of hot corrosion at 1550℃ (nRE) 1 / nXRD patterns and grain morphology images of 2Si2O7 ceramic materials are shown. It can be seen that, except for Z03, the other 15 bulk ceramics containing only β-phase disilicates and trace amounts of SiO2 still maintain small grain sizes after heat treatment at 1550℃ for 100 h, generally within 20 μm, exhibiting excellent grain size stability. In Z03, the disilicate phase undergoes a phase transformation from β to γ ​​phase, resulting in severe internal grain coarsening and the formation of numerous cracks and pores. Therefore, Z03 has poor thermal stability and does not meet application requirements. However, the other 15 bulk ceramics containing only β-phase disilicates and trace amounts of SiO2 show good grain size stability due to their average rare earth cation radius being smaller than... The disilicate phase has a stable β phase, so no phase transformation occurs, which meets the application requirements of environmental barrier coatings in the aerospace field for grain size and high-temperature stability of the phase.

[0119] Then, measurements and calculations were performed on other thermal properties (such as coefficient of thermal expansion and thermal conductivity) and mechanical properties (such as Young's modulus, microhardness, and fracture toughness), and the results are as follows: Figures 5-9 As shown. Based on the measured coefficients of thermal expansion and elastic modulus of each disilicate bulk material and SiC, as well as parameters such as Poisson's ratio in the literature (K.Li, et al. First-principles calculations and thermal-mechanical experimental studies on middle-entropy rare-earth disilicates, Ceram. Int. 50(13)(2024) 22290-22305.), the thermal mismatch stress values ​​generated at 1400K for each disilicate material when used as an environmental barrier coating on SiC substrate were calculated, thus combining the thermo-mechanical properties of the material with the practical application of the environmental barrier coating.

[0120] S5: Summarize the above experimental results and plot a 4×4 graph of ytterbium disilicate and its high-entropy rare earth disilicates (nRE). 1 / n The periodic table of thermo-mechanical properties of 2Si2O7 ceramic materials, such as Figure 10 As shown.

[0121] Depend on Figure 10 It can be seen that, on the one hand, from the perspective of thermodynamic properties, materials with low thermal conductivity and low thermal stress are suitable for thermal environment barrier coatings (TEBCs) (TEBCs have both heat insulation and environmental barrier functions (generally referring to water vapor corrosion)). Therefore, Z14-(Sc 0.2 Y 0.2 Er 0.2 Yb 0.2 Lu 0.2Yb₂Si₂O₇ is the most ideal choice among these 16 extreme doping combinations for high-entropy rare-earth disilicate materials. Compared to Yb₂Si₂O₇, it not only has higher compressive stress (i.e., negative thermal stress, which helps prevent crack initiation and propagation) but also has lower overall thermal conductivity. On the other hand, from the perspective of elemental doping, we found that doping with Sc generally tends to reduce thermal conductivity, and a molar ratio of Sc to Sc exceeding 14% can have a significant effect. Therefore, to obtain medium-high entropy rare-earth disilicate materials with low thermal conductivity, a certain amount of Sc must be doped. Furthermore, it can be seen that doping with atoms with relatively smaller atomic radii than Yb, such as Sc and Lu, generally tends to increase thermal stress, while doping with Er and Ho, which have relatively larger atomic radii than Yb, tends to reduce thermal stress. Therefore, when designing the composition of medium-high entropy rare-earth disilicate materials, it is best to dop with both rare-earth elements with relatively larger and smaller atomic radii than Yb. Of course, we can also analyze the effects of doping elements on fracture toughness, microhardness, etc., and design other suitable medium-entropy or high-entropy environmental barrier coating materials.

[0122] The present invention provides a rapid screening method for medium-high entropy rare-earth disilicate materials of ytterbium disilicate. The prepared bulk ceramics exhibit high purity and density, and the grain size of the bulk ceramics with a single β phase exhibits good high-temperature stability. The medium-high entropy rare-earth disilicate bulk materials prepared by the present invention involve in-situ solid dissolution of multiple rare-earth elements into the β-phase lattice of ytterbium disilicate. When the average rare-earth cation radius is less than... It can form the β phase; when the average rare earth cation radius value is greater than This method can form a dual-phase ceramic material consisting of β and γ phases, with the β phase gradually transforming entirely into the γ phase at high temperatures. To simultaneously improve the bulk density, disilicate phase purity, and high-temperature thermal stability, a slight excess of SiO2 is included in the raw materials. The bulk material prepared by this method has a density of approximately 98%. Simultaneously, the prepared disilicate ceramic bulk material contains trace amounts of SiO2, with a mass fraction of approximately 3%. The prepared bulk ceramic containing only β-phase disilicate and trace amounts of SiO2 exhibits excellent grain size stability at room temperature and 1550°C. Even after heating at 1550°C for 100 hours, it still retains a small grain size, meeting the requirements for environmental barrier coating applications in the aerospace field.

[0123] The rapid screening method for medium-to-high entropy rare-earth disilicate materials of ytterbium disilicate of this invention, by sorting the added elements from largest to smallest weight and employing a periodically increasing doping method, helps to quickly obtain rare-earth element doping combinations with optimal comprehensive performance. Doping with different rare-earth elements can alter thermo-mechanical properties such as density, coefficient of thermal expansion, thermal conductivity, Young's modulus, microhardness, and fracture toughness. Moreover, extreme rare-earth element doping combinations can lead to even greater changes in thermo-mechanical properties. This invention departs from the simple, single-variable method requiring numerous experiments to find the optimal element combination. Instead, it sorts the added elements from largest to smallest weight (extremes) and employs a periodically orthogonally increasing doping method to further dope the raw material with other different rare-earth elements. This facilitates the rapid acquisition of rare-earth element doping combinations with optimal comprehensive performance.

[0124] This invention provides an intuitive periodic table of the thermo-mechanical properties of medium- and high-entropy rare-earth disilicates. This periodic table allows for the direct selection of suitable environmental barrier coating materials based on thermal and mechanical performance parameters. Furthermore, it enables iterative selection of new rare-earth element doping combinations based on the changing patterns of thermal and mechanical properties. It also allows for the identification of key elements for non-uniform doping design. This provides theoretical support for the rapid screening and composition design of other medium- or high-entropy environmental barrier coating materials.

[0125] In summary, unlike conventional single-variable methods that require numerous experiments, this invention employs a rapid screening method based on orthogonal incremental doping of factors according to element weights. This method not only fully utilizes the correlations between factors to rapidly screen multi-component doped medium- or high-entropy materials, reducing unnecessary workload, but also enhances visualization through a thermo-mechanical property periodic table. Furthermore, the thermo-mechanical property periodic table can be used to determine the performance benefits of each dopant element after doping medium- or high-entropy materials, allowing for further screening and iterative operations. This invention provides theoretical support for the rapid screening and composition design of medium- or high-entropy environmental barrier coating materials.

[0126] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims of this patent. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate, characterized in that, The specific steps are as follows: S1: Select rare earth elements that can form a monoclinic β phase after equimolar doping of Yb₂Si₂O₇ material as doping elements. The average bond length of RE-O was calculated. RE-O includes bonds between Yb and O elements, as well as bonds between dopant elements and O elements. S2: Dopants are divided into two categories based on whether they increase or decrease the average Yb-O bond length of Yb2Si2O7 material, and then sorted according to the doping weight. S3: Establish a periodic table of orthogonally increasing doped elements based on the sorting results. Each unit of the periodic table corresponds to a material. Materials in the same period or group have the same increasing doping element relative to materials in the previous period or group. S4: For each material in the periodic table, conduct material preparation and thermo-mechanical property experiments to obtain experimental results; S5: Summarize the experimental results into the periodic table to form a periodic table of thermo-mechanical properties of medium- and high-entropy rare earth disilicate ceramic materials, and select the most suitable material or element to be doped from it according to the requirements. Step S3 specifically includes the following steps: Step S31: Establish a periodic table with m×n units, where m is one of the number of dopants that increase bond length and the number of dopants that decrease bond length, and n is the other of the number of dopants that increase bond length and the number of dopants that decrease bond length. Step S32: Set the unit of the first group of the first period of the periodic table to be Yb2Si2O7 material; Step S33: In the first period of the periodic table, using one of the doping elements of a certain category, the Yb2Si2O7 material is doped in descending order of doping weight. The material obtained by each doping increment occupies one unit of a group in the periodic table, so as to obtain the material corresponding to the unit of different groups in the first period of the periodic table. Step S34: In Group I of the periodic table, using another type of doping element, based on the Yb2Si2O7 material, the doping weight of the doping element is increased sequentially from large to small. Each time the doping weight is increased, the resulting material occupies one unit of one period of the periodic table, so as to obtain the material corresponding to the unit of different periods of Group I of the periodic table. Step S35: Perform doping according to the orthogonal increasing doping rule that the materials in the same period of the periodic table have the same increasing doping element relative to the materials in the previous period, and the materials in the same group of the periodic table have the same increasing doping element relative to the materials in the previous group, until the entire m×n units of the periodic table are filled.

2. The rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate according to claim 1, characterized in that, In step S1, the selected doping elements include at least two rare earth elements with a radius greater than that of Yb and at least two rare earth elements with a radius smaller than that of Yb, and the selected doping elements may include at most Sc, Y, Ho, Er, Tm and Lu.

3. The rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate according to claim 1, characterized in that, In step S1, the average bond length of RE-O is calculated, specifically including: using first principles, calculating the average bond length of RE-O in the doped material obtained by equimolar doping of Yb2Si2O7 material with doping elements; In step S2, if the average bond length of RE-O is less than the average bond length of Yb-O in Yb2Si2O7 material, the doping element causes the average bond length of Yb-O in Yb2Si2O7 material to decrease; otherwise, the doping element causes the average bond length of Yb-O in Yb2Si2O7 material to increase.

4. The rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate according to claim 1, characterized in that, The formula for calculating the doping weight W is: , in, Represents doping weight. and They represent doping elements. The ionic radius of ytterbium (Yb) and They represent doping elements. The relative atomic mass of ytterbium (Yb) and They represent doping elements. The average bond length of RE-O bonds in Yb2Si2O7 material obtained by equimolar doping and the average bond length of Yb-O in Yb2Si2O7 material.

5. The rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate according to claim 1, characterized in that, In step S4, the experimental results of the thermo-mechanical performance test include: experimental data on the physical properties, thermal properties, mechanical properties of the material, and the thermal mismatch stress values ​​generated when used as a coating on a SiC substrate. The physical properties include at least one of density, average cation radius, relative atomic mass, and type of doping element; the thermal properties include at least one of coefficient of thermal expansion and thermal conductivity; and the mechanical properties include at least one of Young's modulus, microhardness, and fracture toughness.

6. The rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate according to claim 1, characterized in that, In step S4, the material in the periodic table is a bulk ceramic material prepared by in-situ solid-state reaction method. The molar ratio of RE to Si in the raw material of the bulk ceramic material is 1:1.1, where RE represents Yb element, or a combination of one or more doping elements and Yb element.

7. The rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate according to claim 6, characterized in that, In step S4, the specific steps for preparing the material using the in-situ solid-state reaction method are as follows: Step S411: Using one or more rare earth oxides and silica powder as raw materials, determine the preparation method based on the RE:Si molar ratio of 1:1.

1. The mass of rare earth oxides and silica powder required for ceramic materials is weighed together, where RE represents Yb element, or a combination of one or more doping elements and Yb element; when RE represents multiple elements, the proportion of each element is equal. Step S412: Using ethanol as a medium, silicon nitride grinding balls are added to a stainless steel ball mill jar. The original powder, ethanol, and grinding balls are mixed in a mass ratio of 1:1:1 or 1:1:2 and ball-milled for 6–24 hours to form a slurry. After drying and sieving, the mixed powder obtained from the slurry is cold isostatically pressed into blanks. The blanks are then placed in a muffle furnace for pressureless sintering. The heating rate is 3–10 °C / min, the synthesis temperature is 1500–1650 °C, and the synthesis time is 10–20 hours. Finally, a medium-high entropy rare earth disilicate ceramic block material is obtained.

8. The rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate according to claim 5, characterized in that, The thermo-mechanical property experiments include: Step S421: Obtain the theoretical lattice constant, density, and cell volume of the disilicate phase of the material through XRD patterns, and calculate and determine the relative atomic mass and average cation radius of the material; Step S422: The density of the prepared material is measured using the Archimedes displacement method, and the theoretical content of each phase of the material is calculated based on the proportion of the original powder used in the material preparation. Then, the density and porosity of the prepared material are calculated based on the theoretical density of the disilicate phase. Step S423: The thermal diffusivity of the prepared material is measured by laser flare method using a laser thermal conductivity meter. The specific heat capacity of the prepared material is calculated by Neumann-Kopp rule. Then, the theoretical thermal conductivity is calculated and determined based on the thermal diffusivity, density, specific heat capacity and porosity of the prepared material. Step S424: Measure the coefficient of thermal expansion of the prepared material using a thermal expansion meter via the linear expansion method; Step S425: The crack length and Young's modulus of the indentation of the prepared material are measured using the Oliver-Pharr method with a nanoindenter. Step S426: The microhardness of the prepared material is measured by an indentation tester. Step S427: Calculate and determine the fracture toughness of the prepared material based on the crack length of the indentation and Young's modulus; Step S428: Calculate the thermal mismatch stress value generated when the prepared material is used as a coating on a SiC substrate based on the coefficient of thermal expansion, elastic modulus and Poisson's ratio. Since the presence of pores, the elastic modulus when used as a coating is taken as 40% of the elastic modulus of the prepared material.

9. The rapid screening method for medium- and high-entropy rare-earth disilicate materials of ytterbium disilicate according to claim 1, characterized in that, Step S5 further includes summarizing the chemical properties of the materials into the periodic table.

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