High-performance sintered neodymium-iron-boron magnet and preparation method thereof

Abstract

The invention relates to a high-performance sintered neodymium-iron-boron magnet. The high-performance sintered neodymium-iron-boron magnet is prepared by diffusing a diffusion source into a diffusion base material through a grain boundary, the grain boundary diffusion meets at least one of the following formulas: s * y2-z2 is greater than or equal to 0.2%; s * (y1 + y2) / (x1 + x2) > = 1.2%; (x2-z2) / (s * y2) > = 75%. Through innovative diffusion source design and diffusion process optimization, the coercive force is remarkably improved on the premise that residual magnetism is guaranteed, meanwhile, the use amount of heavy rare earth is reduced, efficient utilization of resources and reduction of the production cost are achieved, and remarkable economic and social benefits are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of magnets, and in particular to a high-performance sintered NdFeB magnet and a preparation method thereof. Background Art

[0002] With the widespread application of sintered NdFeB materials in industry and electronics, especially the booming development of new energy vehicles, industrial robots, and mobile intelligence, the performance requirements for NdFeB products are becoming increasingly stringent. Due to its excellent magnetic properties, sintered NdFeB magnets have become a key functional material driving the rapid development of these emerging industries.

[0003] However, sintered NdFeB magnets have low coercivity and poor temperature stability. Traditionally, heavy rare earth elements (such as Dy or Tb) are added to improve the coercivity and temperature resistance of the magnets. However, this method has many problems: on the one hand, the reserves of heavy rare earth elements are small and the price is high, which leads to a sharp increase in the preparation cost of NdFeB magnets and the high price of magnets; on the other hand, the incorporation of a large amount of heavy rare earth into the main phase grains will cause a significant decrease in remanence. In addition, this process consumes a large amount of expensive heavy rare earth resources, which is not conducive to the sustainable utilization of resources.

[0004] To address these issues, grain boundary diffusion (GBD) technology was developed. This technology forms a heavy rare earth film on the surface of the magnet and then uses vacuum heat treatment to propagate the heavy rare earths deep into the magnet along the grain boundaries. This approach reduces heavy rare earth usage while maintaining product performance. This process strengthens the weak grain surfaces, thereby reducing the amount of heavy rare earths present. It has since become an indispensable component of the industrial production of NdFeB permanent magnets.

[0005] Although grain boundary diffusion technology has many advantages, due to the high diffusion activation energy and low diffusion coefficient of heavy rare earth, its diffusion efficiency is low and the grain boundary diffusion effect is poor. A large amount of heavy rare earth accumulates on the surface of the magnet, and the amount of heavy rare earth entering the interior of the magnet is small, so it is impossible to form a high magnetocrystalline anisotropy field on the main phase surface. 14 B is a heavy rare earth-rich layer. This not only limits the improvement of coercivity, but also reduces the utilization rate of heavy rare earths, which restricts the further development and application of this technology.

[0006] Therefore, how to further optimize the grain boundary diffusion technology, improve the diffusion efficiency and utilization rate of heavy rare earths, and thus significantly enhance the coercive force of the magnet while ensuring the remanence, has become a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0007] The object of the present invention is to provide a high performance sintered NdFeB magnet and a preparation method thereof in view of the deficiencies in the prior art.

[0008] To achieve the above object, the technical solution adopted by the present invention is:

[0009] A first aspect of the present invention is to provide a high-performance sintered NdFeB magnet, wherein the high-performance sintered NdFeB magnet is produced by diffusing a diffusion source into the interior of a diffusion substrate through grain boundaries; the grain boundary diffusion satisfies at least one of formulas (I) to (III):

[0010] s×y2-z2≥0.2% (I)

[0011] s×(y1+y2) / (x1+x2)≥1.2% (II)

[0012] (x2-z2) / (s×y2)≥75% (III)

[0013] Where s×y2-z2 represents the heavy rare earth concentration gradient difference between the diffusion source and the diffusion substrate;

[0014] Where, s×(y1+y2) / (x1+x2) represents the rare earth concentration ratio;

[0015] Wherein, (x2-z2) / (s×y2) represents the diffusion absorption rate of heavy rare earth;

[0016] Where s represents the weight gain rate, s=(M1-M3) / M3 (IV)

[0017] Among them, M1 represents the mass of the high-performance sintered NdFeB magnet; M3 represents the mass of the diffusion substrate; x2 represents the mass percentage of Dy and Tb in the high-performance sintered NdFeB magnet; x1+x2 represents the mass percentage of rare earth elements in the high-performance sintered NdFeB magnet; y2 represents the mass percentage of Dy and Tb in the diffusion source; y1+y2 represents the mass percentage of rare earth elements in the diffusion source; z2 represents the mass percentage of Dy and Tb in the diffusion substrate; z1+z2 represents the mass percentage of rare earth elements in the diffusion substrate.

[0018] In the present invention, the heavy rare earth concentration gradient difference between the diffusion source and the diffusion substrate must be at least 0.2%. During the diffusion process, the heavy rare earth concentration gradient difference serves as the main driving force; if it is less than 0.2%, insufficient diffusion power will result;

[0019] The rare earth concentration ratio in the present invention needs to be at least 1.2% to improve the diffusion absorption rate; if it is lower than 1.2%, it is not conducive to the diffusion process;

[0020] In the present invention, the diffusion absorption rate of heavy rare earth, that is, the utilization rate of heavy rare earth, must be at least 75% to achieve a significant leap in magnet performance; if it is lower than 75%, it may indicate that there is a mismatch between the formulation design of the diffusion substrate and the diffusion process, and further optimization and adjustment are required.

[0021] Preferably, the chemical formula of the diffusion source is

[0022] Wherein, RL represents at least one of Ce, La, or Pr; RH represents at least one of Dy or Tb; P represents at least one of Co, Fe, or Ni; Q represents at least one of Al, Cu, or Ga; y1, y2, γ, and δ all represent mass percentages;

[0023] Moreover, 5%≤y1≤50%; 5%<(y1+y2)≤98%; 0%<γ≤20%; 0%<δ≤20%.

[0024] The present invention utilizes a mixed diffusion source of heavy rare earths (Dy / Tb) and light rare earths (Ce / La / Pr). The low-melting-point light rare earth elements (Ce, La, and Pr) more readily infiltrate grain boundaries during the diffusion process, melting to form a liquid phase, increasing fluidity and paving the way for the subsequent diffusion of the high-melting-point heavy rare earths (Dy / Tb). This significantly improves the diffusion efficiency of the heavy rare earths, resulting in clearer and smoother grain boundaries and optimized diffusion.

[0025] The present invention also significantly improves the absorption rate of heavy rare earths by rationally adjusting the ratio of heavy rare earths to light rare earths in the diffusion source and controlling the concentration difference between the diffusion matrix and the diffusion source. This enhanced diffusion dynamics allows the heavy rare earths to diffuse more efficiently from the surface to the center of the magnet, reducing their surface accumulation and improving their utilization.

[0026] Preferably, the chemical formula of the diffusion substrate is

[0027] Wherein, RA represents a rare earth element, and RA is not Dy or Tb, and RA contains at least Nd and / or Pr; RB represents at least one of Dy and Tb; T represents Co and Fe; M represents a trace element, and the trace element is selected from at least one of Al, Cu, Ga, Mn, Nb, Sn, Ti, or Zr; B represents boron; z1, z2, θ, and ω all represent mass percentages;

[0028] Moreover, 28%≤z1≤32%; 0%≤z2≤1.5%; 0%<θ≤2.5%; 0.90%≤ω≤0.97%;

[0029] in, Indicates the mass percentage of Co.

[0030] Preferably, the chemical formula of the high performance sintered NdFeB magnet is in,

[0031] RA represents a rare earth element, and RA is not Dy or Tb, and RA contains at least Nd and / or Pr; RB represents at least one of Dy and Tb; T represents Co and Fe; M represents a trace element, and the trace element is selected from at least one of Al, Cu, Ga, Mn, Nb, Ni, Sn, Ti, and Zr; B represents boron; x1, x2, α, and β all represent mass percentages;

[0032] Moreover, 0.2%≤x2≤2.5%; 28%≤(x1+x2)≤33%;

[0033] 0%<α≤3%; 0.90%≤β≤0.96%;

[0034] in, Indicates the mass percentage of Co.

[0035] A second aspect of the present invention is to provide a method for preparing a high-performance sintered NdFeB magnet, comprising the following steps:

[0036] S1. Providing an oriented and formed diffusion substrate, wherein the chemical formula of the diffusion substrate is as described above;

[0037] S2. providing a diffusion source, wherein the chemical formula of the diffusion source is as described above;

[0038] S3, coating the diffusion source on the orientation surface of the diffusion substrate, and performing diffusion heat treatment to obtain the high-performance sintered NdFeB magnet;

[0039] Wherein, the diffusion heat treatment satisfies at least one of the aforementioned formulas (I)-(III).

[0040] Preferably, the coating amount of the diffusion source is 0.3 wt%-1.5 wt%.

[0041] Preferably, the diffusion source is coated by at least one of spraying, screen printing, or magnetron sputtering.

[0042] Preferably, the temperature of the diffusion heat treatment is 800° C.-950° C., and the duration of the diffusion heat treatment is 8 h-30 h.

[0043] Preferably, the diffusion heat treatment is followed by a tempering treatment.

[0044] Preferably, the steps of preparing the diffusion substrate include:

[0045] P0, preparing raw materials according to the chemical formula of the diffusion substrate;

[0046] P1, rapidly solidifying and smelting the raw materials to obtain a casting sheet;

[0047] P2, subjecting the cast sheet to hydrogen crushing and jet milling to obtain fine powder;

[0048] P3, orienting the fine powder and sintering it to obtain a blank;

[0049] P4. Double-side grinding, slicing, and cleaning the blank to obtain the diffusion substrate in sheet form.

[0050] The present invention adopts the above technical solution, which has the following technical effects compared with the prior art:

[0051] The present invention significantly improves the coercive force while ensuring remanence through innovative diffusion source design and diffusion process optimization, while reducing the use of heavy rare earths, achieving efficient resource utilization and reduced production costs, and has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 1 is a microstructure diagram of a sintered NdFeB magnet in Example 3 of the present invention;

[0053] Figure 2 This is a microstructure diagram of the sintered NdFeB magnet in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0054] The specific embodiments of the present invention will be described in detail below.

[0055] Unless otherwise defined, technical or scientific terms used in the claims and the specification shall have the same general meaning as understood by persons having ordinary skills in the technical field to which the present invention belongs.

[0056] The words "include" or similar used in the patent application specification and claims of the present invention mean that the items before "include" include the items listed after "include" or their equivalents, and do not exclude other items.

[0057] The numerical values mentioned in the present invention include all numerical values that increase by one unit from the lowest to the highest, assuming that there is at least two units between any lower value and the higher value. For example, if a component or a physical quantity is said to be from 1 to 100, preferably from 10 to 90, and most preferably from 20 to 80, it is intended that values such as 5 to 95, 14 to 76, 23 to 67, 32 to 58, and 41 to 49 are clearly listed in this specification; for values less than 1, 0.0001, 0.001, 0.01, or 0.1 are considered to be more appropriate units. The above examples are for illustrative purposes only. In fact, all numerical combinations between the lowest value and the highest value listed are considered to be clearly listed in this specification in a similar manner.

[0058] The present invention provides a high-performance sintered NdFeB magnet and a preparation method thereof, the preparation steps comprising:

[0059] S1. Provide oriented and formed diffusion substrate:

[0060] P0, according to the chemical formula of the diffusion substrate Prepare raw materials;

[0061] Wherein, RA represents a rare earth element, and RA is not Dy or Tb, and RA contains at least Nd and / or Pr; RB represents at least one of Dy and Tb; T represents Co and Fe; M represents a trace element, and the trace element is selected from at least one of Al, Cu, Ga, Mn, Nb, Sn, Ti, or Zr; B represents boron; z1, z2, θ, and ω all represent mass percentages;

[0062] Moreover, 28%≤z1≤32%; 0%≤z2≤1.5%; 0%<θ≤2.5%; 0.90%≤ω≤0.97%;

[0063] in, Indicates the mass percentage of Co;

[0064] P1, rapidly solidifying and smelting the raw materials to obtain a casting sheet;

[0065] P2, subjecting the cast sheet to hydrogen crushing and jet milling to obtain fine powder;

[0066] P3, orienting the fine powder and sintering it to obtain a blank;

[0067] P4, double-sided grinding, slicing, and cleaning the blank to obtain the diffusion substrate in sheet form;

[0068] S2. Provide a diffusion source, the chemical formula of which is

[0069] Wherein, RL represents at least one of Ce, La, or Pr; RH represents at least one of Dy or Tb; P represents at least one of Co, Fe, or Ni; Q represents at least one of Al, Cu, or Ga; y1, y2, γ, and δ all represent mass percentages;

[0070] Moreover, 5%≤y1≤50%; 5%<(y1+y2)≤98%; 0%<γ≤20%; 0%<δ≤20%;

[0071] S3, coating the diffusion source on the orientation surface of the diffusion substrate by at least one of spraying, screen printing, or magnetron sputtering, and performing diffusion heat treatment and tempering treatment to obtain the high-performance sintered NdFeB magnet, the chemical formula of which is

[0072] Wherein, RA represents a rare earth element, and RA is not Dy or Tb, and RA contains at least Nd and / or Pr; RB represents at least one of Dy and Tb; T represents Co and Fe; M represents a trace element, and the trace element is selected from at least one of Al, Cu, Ga, Mn, Nb, Ni, Sn, Ti, or Zr; B represents boron; x1, x2, α, and β all represent mass percentages;

[0073] Moreover, 0.2%≤x2≤2.5%; 28%≤(x1+x2)≤33%;

[0074] 0%<α≤3%; 0.90%≤β≤0.96%;

[0075] in, Indicates the mass percentage of Co;

[0076] Wherein, the diffusion heat treatment satisfies at least one of formulas (I) to (III):

[0077] s×y2-z2≥0.2% (I)

[0078] s×(y1+y2) / (x1+x2)≥1.2% (II)

[0079] (x2-z2) / (s×y2)≥75% (III)

[0080] Where s×y2-z2 represents the heavy rare earth concentration gradient difference between the diffusion source and the diffusion substrate;

[0081] Where, s×(y1+y2) / (x1+x2) represents the rare earth concentration ratio;

[0082] Wherein, (x2-z2) / (s×y2) represents the diffusion absorption rate of heavy rare earth;

[0083] Where s represents the weight gain rate, s=(M1-M3) / M3 (IV)

[0084] Wherein, M1 represents the mass of the high performance sintered NdFeB magnet; M3 represents the mass of the diffusion substrate;

[0085] The coating amount of the diffusion source is 0.3wt%-1.5wt%; the temperature of the diffusion heat treatment is 800℃-950℃, the duration of the diffusion heat treatment is 8h-30h; the temperature of the tempering treatment is 480℃-550℃.

[0086] Examples 1-7 & Comparative Examples 1-3

[0087] Table 1 Diffusion substrate

[0088]

[0089] Table 2 Diffusion sources

[0090]

[0091] Table 3 Diffusion heat treatment

[0092] Diffusion source coating amount (wt%) Diffusion heat treatment temperature (℃) Diffusion heat treatment duration (h) Example 1 0.4 910 18 Example 2 0.65 940 22 Example 3 1 910 24 Example 4 0.9 920 20 Example 5 0.75 850 16 Example 6 0.85 900 25 Example 7 1.2 880 23 Comparative Example 1 0.4 910 18 Comparative Example 2 0.65 940 22 Comparative Example 3 0.4 910 24

[0093] Table 4 Sintered NdFeB magnets

[0094]

[0095]

[0096] Table 5 Performance test

[0097]

[0098] Table 5 Performance test (continued)

[0099]

[0100]

[0101] Note: The performance test methods in Table 5 are based on GB / T 3217-2013.

[0102] It can be seen that in Example 1, the mass percentage of heavy rare earth in the diffusion substrate is 0, and the diffusion source Pr 20 Tb 74Co1Al5 was diffused, with a weight gain rate s of 0.40%. During diffusion, a positive heavy rare earth concentration gradient difference was formed between the surface and center of the substrate, with a heavy rare earth concentration difference of +0.3%, satisfying the formula s×y2-z2≥0.2%. Compared with Example 1, the diffusion substrate in Comparative Example 1 contained 1.0% Dy and used the same diffusion source and weight gain rate s, but a negative heavy rare earth concentration gradient difference was formed between the diffusion surface and center, with a heavy rare earth concentration difference of -0.7%, which did not satisfy the formula s×y2-z2≥0.2%. Under the same diffusion process, Example 1 achieved a coercivity increase of 6.6 kOe and a heavy rare earth absorption rate of 80.1%, while Comparative Example 1 achieved a coercivity increase of only 4.9 kOe and a heavy rare earth absorption rate of 73.0%. This shows that Example 1, which satisfies the heavy rare earth concentration difference s×y2-z2≥0.2%, has greater advantages in terms of coercivity increase and heavy rare earth absorption rate.

[0103] Example 5 and Comparative Example 2 utilize the same diffusion substrate, with the mass percentage of heavy rare earth Dy in both substrates being 0.3%, and the same diffusion source. The weight gain s in Example 5 is 0.75%, and the diffusion source and the diffusion substrate form a positive concentration gradient difference of 0.24%, satisfying the formula s×y²-z²≥0.2%. Comparative Example 2, however, uses a different diffusion process, with a weight gain s of 0.45% and a concentration gradient difference of 0.02%. Although this is a positive concentration gradient, the gradient is too low and does not satisfy the formula s×y²-z²≥0.2%. Its coercivity increase is only 3.1 kOe, with an increase of 9.6 kOe per unit of heavy rare earth. In contrast, the coercivity increase in Example 5 is 6.6 kOe, with an increase of 12.2 kOe per unit of heavy rare earth. In comparison, Example 5 achieves a higher heavy rare earth utilization rate.

[0104] The microstructure of the magnet after diffusion in Example 3 is as follows: Figure 1 As shown, it can be seen that the heavy rare earth diffuses into the magnet to form a core-shell structure. Compared with Example 3, in Comparative Example 3, Dy is added to the diffusion substrate, and the mass percentage of heavy rare earth in the diffusion source is reduced, which does not satisfy the formula s×(y1+y2) / (x1+x2)≥1.2%. The microstructure of the magnet after diffusion is as follows Figure 2 As shown, there is no core-shell structure and the mass percentage of Tb is very small, which means that the heavy rare earth has not diffused into the magnet, and its coercive force increases by only 1.3 kOe.

[0105] In summary, the present invention significantly improves the coercive force while ensuring remanence through innovative diffusion source design and diffusion process optimization, while reducing the use of heavy rare earths, achieving efficient resource utilization and reduced production costs, and has significant economic and social benefits.

[0106] The above description is only a preferred embodiment of the present invention and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-performance sintered NdFeB magnet, wherein the high-performance sintered NdFeB magnet is produced by diffusing a diffusion source into the interior of a diffusion substrate through grain boundaries; characterized in that: The grain boundary diffusion satisfies at least one of formulas (I) to (III): s×y2-z2≥0.2%(I) s×(y1+y2) / (x1+x2)≥1.2%(II) (x2-z2) / (s×y2)≥75% (III) where s×y2-z2 represents the heavy rare earth concentration gradient difference between the diffusion source and the diffusion substrate; Where s×(y1+y2) / (x1+x2) represents the rare earth concentration ratio; Wherein, (x2-z2) / (s×y2) represents the diffusion absorption rate of heavy rare earth; Where s represents the weight gain rate, s=(M1-M3) / M3 (IV) Among them, M1 represents the mass of the high-performance sintered NdFeB magnet; M3 represents the mass of the diffusion substrate; x2 represents the mass percentage of Dy and Tb in the high-performance sintered NdFeB magnet; x1+x2 represents the mass percentage of rare earth elements in the high-performance sintered NdFeB magnet; y2 represents the mass percentage of Dy and Tb in the diffusion source; y1+y2 represents the mass percentage of rare earth elements in the diffusion source; z2 represents the mass percentage of Dy and Tb in the diffusion substrate; z1+z2 represents the mass percentage of rare earth elements in the diffusion substrate.

2. The high performance sintered NdFeB magnet according to claim 1, characterized in that: The chemical formula of the diffusion source is Wherein, RL represents at least one of Ce, La, or Pr; RH represents at least one of Dy or Tb; P represents at least one of Co, Fe, or Ni; Q represents at least one of Al, Cu, or Ga; y1, y2, γ, and δ all represent mass percentages; Moreover, 5%≤y1≤50%; 5%<(y1+y2)≤98%; 0%<γ≤20%; 0%<δ≤20%.

3. The high performance sintered NdFeB magnet according to claim 1, characterized in that: The chemical formula of the diffusion substrate is Wherein, RA represents a rare earth element, and RA is not Dy or Tb, and RA contains at least Nd and / or Pr; RB represents at least one of Dy and Tb; T represents Co and Fe; M represents a trace element, and the trace element is selected from at least one of Al, Cu, Ga, Mn, Nb, Sn, Ti, or Zr; B represents boron; z1, z2, θ, and ω all represent mass percentages; And, 28%≤z1≤32%; 0%≤z2≤1.5%; 0% <M Co1 ≤2.5%; 0%<θ≤2.5%; 0.90%≤ω≤0.97%; Among them, M Co1 Indicates the mass percentage of Co.

4. The high performance sintered NdFeB magnet according to any one of claims 1 to 3, characterized in that: The chemical formula of the high performance sintered NdFeB magnet is in, RA represents a rare earth element, and RA is not Dy or Tb, and RA contains at least Nd and / or Pr; RB represents at least one of Dy and Tb; T represents Co and Fe; M represents a trace element, and the trace element is selected from at least one of Al, Cu, Ga, Mn, Nb, Ni, Sn, Ti, and Zr; B represents boron; x1, x2, α, and β all represent mass percentages; Moreover, 0.2%≤x2≤2.5%; 28%≤(x1+x2)≤33%; 0%<α≤3%; 0.90%≤β≤0.96%; in, Indicates the mass percentage of Co.

5. A method for preparing high performance sintered NdFeB magnets, characterized in that the steps include: S1. Provide an oriented diffusion substrate, wherein the chemical formula of the diffusion substrate is Wherein, RA represents a rare earth element, and RA is not Dy or Tb, and RA contains at least Nd and / or Pr; RB represents at least one of Dy and Tb; T represents Co and Fe; M represents a trace element, and the trace element is selected from at least one of Al, Cu, Ga, Mn, Nb, Sn, Ti, or Zr; B represents boron; z1, z2, θ, and ω all represent mass percentages; Moreover, 28%≤z1≤32%; 0%≤z2≤1.5%; 0%<θ≤2.5%; 0.90%≤ω≤0.97%; in, Indicates the mass percentage of Co; S2. Provide a diffusion source, the chemical formula of which is Wherein, RL represents at least one of Ce, La, or Pr; RH represents at least one of Dy or Tb; P represents at least one of Co, Fe, or Ni; Q represents at least one of Al, Cu, or Ga; y1, y2, γ, and δ all represent mass percentages; Moreover, 5%≤y1≤50%; 5%<(y1+y2)≤98%; 0%<γ≤20%; 0%<δ≤20%; S3, coating the diffusion source on the orientation surface of the diffusion substrate, and performing diffusion heat treatment to obtain the high-performance sintered NdFeB magnet; Wherein, the diffusion heat treatment satisfies at least one of formulas (I) to (III): s×y2-z2≥0.2%(I) s×(y1+y2) / (x1+x2)≥1.2%(II) (x2-z2) / (s×y2)≥75% (III) wherein s represents the weight gain rate, s=(M1-M3) / M3 (IV) wherein M1 represents the mass of the high performance sintered NdFeB magnet; M3 represents the mass of the diffusion substrate.

6. The preparation method according to claim 5, characterized in that The coating amount of the diffusion source is 0.3 wt%-1.5 wt%.

7. The preparation method according to claim 5, characterized in that The diffusion source is coated by at least one of spraying, screen printing, and magnetron sputtering.

8. The preparation method according to claim 5, characterized in that The temperature of the diffusion heat treatment is 800° C.-950° C., and the duration of the diffusion heat treatment is 8 hours-30 hours.

9. The preparation method according to claim 5, characterized in that After the diffusion heat treatment, tempering treatment is also performed.

10. The preparation method according to claim 5, characterized in that The steps of preparing the diffusion substrate include: P0, preparing raw materials according to the chemical formula of the diffusion substrate; P1, rapidly solidifying and smelting the raw materials to obtain a casting sheet; P2, subjecting the cast sheet to hydrogen crushing and jet milling to obtain fine powder; P3, orienting the fine powder and sintering it to obtain a blank; P4. Double-side grinding, slicing, and cleaning the blank to obtain the diffusion substrate in sheet form.

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