Alloy diffusion source, preparation method and application

Abstract

The invention discloses an alloy diffusion source. The alloy diffusion source comprises Re (100-a-b-c) Ga Al Cu < c >, wherein Re at least contains one or more of Dy, Tb, Pr and Nd; a + b + c is between 20 and 60, and a: b: c is 2: 1: 1. A diffusion source formula is adjusted, more Ga, Al and Cu elements are added, and the mass percent of the elements is strictly limited (the ratio of Ga to Al to Cu is 2: 1: 1), and the main reason is that Ga inhibits formation of a CeFe2 phase, reduces the melting point of a grain boundary phase and promotes diffusion of other elements; the tempering temperature can be increased by adding Al, the aging temperature can be reduced by adding Cu, meanwhile, the aging temperature sensitivity of the magnet can be weakened by adding a large amount of Al and Cu elements, the range of the aging temperature can be widened, and particularly, the range of 460-530 DEG C can be obviously influenced; after adjustment of the method, a conventional cerium-free magnet, a low-cerium magnet and a high-cerium-content magnet can achieve the optimal performance of the magnet within the temperature range of 470-490 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of magnetic processing, specifically an alloy diffusion source, a preparation method, and its application in the simultaneous mass production of magnets with different cerium contents. Background Technology

[0002] Currently, rare-earth permanent magnet sintered NdFeB has a wide range of applications in industrial production and daily life. With the introduction of energy conservation and emission reduction, the dual-carbon strategy, and the rational utilization of rare earth resources, various sintered NdFeB manufacturers have begun research on high-abundance cerium magnets. Due to the elemental characteristics of cerium, its addition amount has a significant impact on product performance. Laboratory studies have found that the phase structure changes of magnets with different cerium contents at aging temperatures are mainly due to grain boundary phase changes. Various trace elements combine to form non-magnetic phases in triangular grain boundaries and rare-earth-rich thin layers, which play a role in improving the coercivity of the product. Each trace element needs to be combined in a certain proportion. However, as the cerium content changes, the combination of elements in the grain boundary phase changes, requiring different temperatures to form the same grain boundary phase. That is, as the cerium content increases, the aging process of the corresponding magnet also changes significantly. Directly adjusting the content of trace elements in the matrix formula will lead to excessive entry into the main phase, destroying the original performance. This brings certain inconveniences to the formulation of the production process, and it is also difficult to produce multiple formulas simultaneously. Summary of the Invention

[0003] The technical problem to be solved by this invention is:

[0004] How to solve the problem of not being able to mass-produce magnets with different cerium contents at the same time.

[0005] To solve the above-mentioned technical problems, the inventors, through practice and summarization, derived the technical solution of this invention, which adopts the following technical solution:

[0006] An alloy diffusion source, the alloy diffusion source comprising Re （100-a-b-c） Ga a Al b Cu c ;

[0007] Wherein: Re contains at least one or more of Dy, Tb, Pr, and Nd;

[0008] The sum of a, b, and c is between 20 and 60, and the ratio of a to b to c is 2:1:1.

[0009] In the alloy diffusion source, the alloy diffusion source includes Re 80 Ga 10 Al5Cu5;

[0010] Wherein: Re contains at least one or more of Dy, Tb, Pr, and Nd.

[0011] In the alloy diffusion source, the alloy diffusion source includes Re 60 Ga 20 Al 10 Cu 10 ;

[0012] Wherein: Re contains at least one or more of Dy, Tb, Pr, and Nd.

[0013] A method for preparing an alloy diffusion source includes the following steps:

[0014] Weigh out the raw materials Re, Ga, Al, and Cu in proportion and mix them together.

[0015] After the raw materials are melted and refined at 1400℃, they are rapidly solidified to a thickness of 0.25-0.6mm by the sheet-throwing method to obtain alloy strip.

[0016] The alloy strip was subjected to air jet milling to obtain alloy powder with a particle size of 3-5 μm;

[0017] After mixing and stirring the organic solvent and organic resin binder evenly, alloy powder is slowly added and stirred thoroughly to prepare a slurry.

[0018] In the preparation method of the alloy diffusion source, the organic solvent is one or more of ethanol, acetone, and isopropanol.

[0019] In the preparation method of the alloy diffusion source, the organic resin binder is selected from one or more of PVA and PVP.

[0020] In the preparation method of the alloy diffusion source, the alloy: organic solvent: organic resin binder ratio is (60-80):(20-30):(1-5).

[0021] An alloy diffusion source is used for the simultaneous mass production of magnets with different cerium contents. The steps for the simultaneous mass production of cerium-content magnets are as follows:

[0022] Step 1: The alloy diffusion source prepared by the above method is screen-printed onto the surface of magnets with different cerium contents, dried, and the alloy weight gain percentage is controlled at 0.5% to 2%.

[0023] Step 2: After diffusion at high temperature of 890-920℃ for 5-20 hours, the diffusion source enters the interior of magnets with different cerium contents;

[0024] Step 3: After the same aging treatment, the magnets with different cerium contents achieve the best performance. The aging temperature is 470-490℃.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] Due to the characteristics of cerium, the tempering temperature of cerium-containing magnets changes significantly with higher cerium content, ranging from 460 to 530°C for conventional magnets and 600 to 680°C for high-cerium magnets. In conventional diffusion sources, heavy rare earth elements Dy and Tb account for a high proportion, while non-rare earth elements are less abundant, resulting in minimal change in tempering temperature after diffusion. This invention adjusts the diffusion source formulation by adding more Ga, Al, and Cu elements and strictly limiting their mass percentages (Ga:Al:Cu = 2:1:1). The main reasons are: Ga inhibits the formation of the CeFe2 phase, lowers the melting point of the grain boundary phase, and promotes the diffusion of other elements; the addition of Al increases the tempering temperature, while the addition of Cu decreases the aging temperature. Furthermore, the addition of a significant amount of Al and Cu weakens the magnet's inherent sensitivity to aging temperature, expanding the aging temperature range, especially the 460–530°C range, where it is significantly affected. After this adjustment, conventional cerium-free magnets, low-cerium magnets, and high-cerium magnets can all achieve optimal performance within the temperature range of 470–490°C. Detailed Implementation

[0027] Example 1

[0028] An alloy diffusion source, the alloy diffusion source comprising Re （100-a-b-c） Ga a Al b Cu c ;

[0029] Wherein: Re contains at least one or more of Dy, Tb, Pr, and Nd;

[0030] The sum of a, b, and c is between 20 and 60, and the ratio of a to b to c is 2:1:1.

[0031] In the alloy diffusion source, the alloy diffusion source includes Re 80 Ga 10 Al5Cu5;

[0032] Wherein: Re contains at least one or more of Dy, Tb, Pr, and Nd.

[0033] In the alloy diffusion source, the alloy diffusion source includes Re 60 Ga 20 Al 10 Cu 10 ;

[0034] Wherein: Re contains at least one or more of Dy, Tb, Pr, and Nd.

[0035] A method for preparing an alloy diffusion source includes the following steps:

[0036] Weigh out the raw materials Re, Ga, Al, and Cu in proportion and mix them together.

[0037] After the raw materials are melted and refined at 1400℃, they are rapidly solidified to a thickness of 0.25-0.6mm by the sheet-throwing method to obtain alloy strip.

[0038] The alloy strip was subjected to air jet milling to obtain alloy powder with a particle size of 3-5 μm;

[0039] After mixing and stirring the organic solvent and organic resin binder evenly, alloy powder is slowly added and stirred thoroughly to prepare a slurry.

[0040] In the preparation method of the alloy diffusion source, the organic solvent is one or more of ethanol, acetone, and isopropanol.

[0041] In the preparation method of the alloy diffusion source, the organic resin binder is selected from one or more of PVA and PVP.

[0042] In the preparation method of the alloy diffusion source, the alloy: organic solvent: organic resin binder ratio is (60-80):(20-30):(1-5).

[0043] A method for simultaneous batch production of magnets with different cerium contents includes the following steps:

[0044] Step 1: The alloy diffusion source prepared by the method described in claim 4 is coated onto the surface of magnets with different cerium contents by screen printing, dried, and the alloy weight gain percentage is controlled to be 0.5% to 2%.

[0045] Step 2: After diffusion at high temperature of 890-920℃ for 5-20 hours, the diffusion source enters the interior of magnets with different cerium contents;

[0046] Step 3: After the same aging treatment, the magnets with different cerium contents achieve the best performance. The aging temperature is 470-490℃.

[0047] This invention, while ensuring optimal magnet performance, rationally reduces the proportion of rare earth elements in the alloy, while increasing the overall proportion of auxiliary elements (Ga, Al, Cu). Rare earth elements (such as Tb and Dy) play a crucial role in the diffusion process. The rare earth element content is controlled between 40-80%. If the rare earth proportion is too low, Dy and Tb anti-shells may appear on the magnet surface after diffusion at the grain boundaries, reducing magnet performance. Similarly, excessive infiltration of Ga, Al, and Cu can damage the main phase grains and magnetic properties, reducing remanence. Conversely, a high rare earth proportion means insufficient Ga, Al, and Cu infiltration, which does not achieve the desired effect. Directly increasing the infiltrated Ga, Al, and Cu requires the simultaneous infiltration of more heavy rare earth elements like Dy and Tb, significantly increasing material costs and negating the cost-saving benefits of high-cerium magnet diffusion. Therefore, this study improves performance by incorporating a certain amount of Dy or Tb, and controls the tempering temperature by incorporating a certain amount of Ga, Al, and Cu. Both processes need to be carried out simultaneously. To better meet the condition of simultaneous benefit from both, the non-rare earth element content is controlled between 20-60%. Furthermore, Ga, Al, and Cu are added strictly in a 2:1:1 ratio, resulting in a thin and continuous grain boundary structure in the magnet. The Cu-enriched layer promotes grain boundary wettability, Al stabilizes the main phase, and Ga suppresses harmful phases. This structure effectively isolates the main phase grains, reduces magnetic coupling, and improves coercivity. The co-doping of Al and Cu expands the magnet's adaptability to aging temperatures. By adjusting the ratio of Al and Cu, the magnet can achieve optimal performance within the range of 450–490℃, eliminating the need to design multiple sets of process parameters for magnets with different clock content. After treatment with this proportion of diffusion source, conventional magnets, low-cerium magnets, and high-cerium magnets can all achieve significant improvements in coercivity, remanence, and other properties at aging temperatures of 470–490℃, achieving "broad-spectrum adaptability." If the Ga ratio is too high, it will lead to an excessively thick grain boundary phase, reducing the magnet's remanence; if the Al or Cu ratio deviates from 2:1:1, it will be impossible to effectively balance the heating and cooling effects, resulting in a narrower aging temperature range or performance degradation. By unifying the ratio, the production process is simplified, reducing the requirements for equipment precision and process control, making it suitable for large-scale industrial applications.

[0048] Comparative example:

[0049] Neodymium iron boron blanks with cerium contents of 0%, 3%, 5%, 7%, and 9% were selected and ground and sliced ​​into cubes measuring 30mm*20mm*5mm. These cubes were coated with commercially available DyH ink, controlling the Dy element weight gain to 0.7%. All samples were then subjected to grain boundary diffusion treatment at 910℃ for 15 hours. After diffusion, the aging treatment was carried out at temperatures ranging from 430-710℃, with one temperature point selected every 20℃, and a uniform holding time of 4 hours. After all aging treatments were completed, their performance was compared and tested simultaneously using an NIM-62000 testing equipment.

[0050] The test performance is shown in the table below:

[0051]

[0052] As can be seen from the comparative examples, the optimal aging temperature for magnets without cerium content after DyH diffusion is 490-510℃. As the cerium content increases, the optimal aging temperature first decreases and then increases sharply, showing a completely inconsistent trend. This clearly indicates that the production process is complex and cannot produce magnets with different cerium contents in the same batch.

[0053] Example 1:

[0054] Neodymium iron boron blanks with cerium contents of 0%, 3%, 5%, 7%, and 9% were selected and ground and sliced ​​into several cube samples with dimensions of 30mm*20mm*5mm. Dy 80 Ga 10 Al5Cu5 alloy was coated, with the Dy element weight gain controlled at 0.7%, and then uniformly subjected to grain boundary diffusion treatment at 910℃ for 15 hours. After diffusion, the aging treatment temperature range was selected from 430-710℃, with a temperature point selected every 20℃, and the holding time was uniformly 4 hours. After all aging treatments were completed, the performance was compared and tested simultaneously using an NIM-62000 testing equipment.

[0055] The test performance is shown in the table below:

[0056]

[0057] The data comparison in Example 1 shows that using Dy 80 Ga 10 After Al5Cu5 alloy coating diffusion, since the weight gain of Dy is the same as that of DyH, its optimal performance is not significantly improved. However, the 3%Ce and 5%Ce materials have increased in the optimal range at relatively low temperatures, while the 7%Ce and 9%Ce materials show stable performance and an increasing trend in the 450-490℃ range.

[0058] Example 2:

[0059] Neodymium iron boron blanks with cerium contents of 0%, 3%, 5%, 7%, and 9% were selected and ground and sliced ​​into several cube samples with dimensions of 30mm*20mm*5mm. Dy 60 Ga 20 Al 10 Cu 10 Alloy coating was applied, with the Dy element weight gain controlled at 0.7%. Then, a uniform grain boundary diffusion treatment was performed at 910℃ for 15 hours. After diffusion, the aging treatment was carried out at a temperature range of 430-710℃, with one temperature point selected every 20℃, and a uniform holding time of 4 hours. After all aging treatments were completed, the performance was compared and tested simultaneously using an NIM-62000 testing equipment.

[0060] The test performance is shown in the table below:

[0061]

[0062] The data comparison in Example 2 shows that, under the premise of ensuring the best performance of the magnet, by reasonably reducing the proportion of rare earth elements in the alloy and increasing the overall proportion of auxiliary elements (Ga, Al, Cu), after the same Dy weight-increasing diffusion aging, the performance of each cerium content in the low-temperature range is almost consistent, and the performance of the low-temperature range with higher cerium content reaches the performance of conventional high-temperature aging.

[0063] Example 3

[0064] Neodymium iron boron blanks with cerium contents of 0%, 3%, 5%, 7%, and 9% were selected and ground and sliced ​​into several cube samples with dimensions of 30mm*20mm*5mm. Dy 40 Ga 30 Al 15 Cu 15 Alloy coating was applied, with the Dy element weight gain controlled at 0.7%. Then, a uniform grain boundary diffusion treatment was performed at 910℃ for 15 hours. After diffusion, the aging treatment was carried out at temperatures ranging from 430-710℃, with one temperature point selected every 20℃, and a uniform holding time of 4 hours. After all aging treatments were completed, the performance was compared and tested simultaneously using an NIM-62000 testing equipment.

[0065] The test performance is shown in the table below:

[0066]

[0067] The data comparison in Example 3 shows that by further reducing the proportion of rare earth elements in the alloy and increasing the overall proportion of auxiliary elements, the magnet aging temperature still maintains a wide range and the coercivity remains at a high level after the same Dy weight-increasing diffusion aging, but the remanence Br has decreased significantly.

[0068] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. The substitutions may be replacements of some structures, devices, or method steps, or they may be complete technical solutions. Equivalent substitutions or modifications made to the technical solutions and inventive concepts of the present invention should all be covered within the scope of protection of the present invention.

Claims

1. An alloy diffusion source, characterized in that, The alloy diffusion source includes Re （100-a-b-c） Ga a Al b Cu c ; Wherein: Re contains at least one or more of Dy, Tb, Pr, and Nd; The sum of a, b, and c is between 20 and 60, and the ratio of a to b to c is 2:1:

1.

2. The alloy diffusion source according to claim 1, characterized in that, The alloy diffusion source includes Re 80 Ga 10 Al5Cu5; Wherein: Re contains at least one or more of Dy, Tb, Pr, and Nd.

3. The alloy diffusion source according to claim 1, characterized in that, The alloy diffusion source includes Re 60 Ga 20 Al 10 Cu 10 ; Wherein: Re contains at least one or more of Dy, Tb, Pr, and Nd.

4. A method for preparing an alloy diffusion source as described in claim 1, characterized in that, Includes the following steps: Weigh out the raw materials Re, Ga, Al, and Cu in proportion and mix them together. After the raw materials are melted and refined at 1400℃, they are rapidly solidified to a thickness of 0.25-0.6mm by the sheet-throwing method to obtain alloy strip. The alloy strip was subjected to air jet milling to obtain alloy powder with a particle size of 3-5 μm; After mixing and stirring the organic solvent and organic resin binder evenly, alloy powder is slowly added and stirred thoroughly to prepare a slurry.

5. The alloy diffusion source according to claim 4, characterized in that, The organic solvent is one or more of ethanol, acetone, and isopropanol.

6. The alloy diffusion source according to claim 4, characterized in that, The organic resin adhesive is selected from one or more of PVA and PVP.

7. The alloy diffusion source according to claim 4, characterized in that, The alloy composition is (60-80):(20-30):(1-5) of the organic solvent and organic resin binder.

8. An application of an alloy diffusion source for the simultaneous mass production of magnets with different cerium contents, characterized in that, The steps for the simultaneous mass production of magnets with different cerium contents are as follows: Step 1: The alloy diffusion source prepared by the method described in claim 4 is coated onto the surface of magnets with different cerium contents by screen printing, dried, and the alloy weight gain percentage is controlled to be 0.5% to 2%. Step 2: After diffusion at high temperature of 890-920℃ for 5-20 hours, the diffusion source enters the interior of magnets with different cerium contents; Step 3: After the same aging treatment, the magnets with different cerium contents achieve the best performance. The aging temperature is 470-490℃.

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