阅读说明：本技术 低成本稀土磁体及制造方法 (Low-cost rare earth magnet and manufacturing method thereof ) 是由 王传申 杨昆昆 彭众杰 丁开鸿 于 2021-09-24 设计创作，主要内容包括：本发明涉及钕铁硼磁体技术领域,尤其涉及一种低成本稀土磁体及制造方法。低成本稀土磁体由钕铁硼合金及涂覆在所述钕铁硼合金表面的扩散源薄膜制备而成,所述钕铁硼合金由钕铁硼合金原料、低熔点粉料和其他添加剂混合制备而成,所述混合低熔点粉料含有CeCu、CeAl和CeGa,所述扩散源具有式R1-(x)R2-(y)H-(z)M-(1-x-y-z)所示的组成,其中R1是指Nd,Pr中的至少一种,R2为Ho、Gd中至少一种,H是指Tb,Dy中的至少一种,M是指Al、Cu、Ga、Ti、Co、Mg、Zn、Sn中至少一种,本发明的有益之处是较少重稀土含量的情况下,大幅增加磁体的矫顽力,降低磁体的生产成本。(The invention relates to the technical field of neodymium iron boron magnets, in particular to a low-cost rare earth magnet and a manufacturing method thereof. The low-cost rare earth magnet is prepared by neodymium iron boron alloy and coating at the diffusion source film on neodymium iron boron alloy surface, neodymium iron boron alloy is prepared by neodymium iron boron alloy raw materials, low-melting powder and other additives mixture, mix low-melting powder and contain CeCu, CeAl and CeGa, the diffusion source has formula R1 x R2 y H z M 1‑x‑y‑z The composition is shown, wherein R1 refers to at least one of Nd and Pr, R2 refers to at least one of Ho and Gd, H refers to at least one of Tb and Dy, and M refers to at least one of Al, Cu, Ga, Ti, Co, Mg, Zn and Sn.)

1. The utility model provides a low-cost tombarthite magnet, by neodymium iron boron alloy and coating the diffusion source film on neodymium iron boron alloy surface forms its characterized in that: the neodymium iron boron alloy is prepared by mixing neodymium iron boron alloy raw materials, low-melting-point powder and other additives, wherein the mixed low-melting-point powder contains CeCu, CeAl and CeGa, the weight percentage of each component is that CeCu is more than or equal to 0% and less than or equal to 3%, CeAl is more than or equal to 0% and less than or equal to 3%, and CeGa is more than or equal to 0% and less than or equal to 3%; the diffusion source has the formula R1_xR2_yHzM_1-x-y-zThe composition is shown in the specification, wherein R1 refers to at least one of Nd and Pr, R2 refers to at least one of Ho and Gd, H refers to at least one of Tb and Dy, M refers to at least one of Al, Cu, Ga, Ti, Co, Mg, Zn and Sn, x, y and z are weight percentages, wherein x is more than 15% and less than 50%, y is more than 0% and less than or equal to 10%, and z is more than or equal to 40% and less than or equal to z70％。

2. The low-cost rare earth magnet according to claim 1, wherein the raw material composition of the neodymium-iron-boron alloy includes rare earth R of 28% by weight or more and 30% by weight or less, R is at least two of Nd, Pr, Ho and Gd, B of 0.8% by weight or more and 1.2% by weight or less, M of 0% by weight or more and 3% by weight or less, wherein M is at least one of Co, Mg, Ti, Zr, Nb and Mo, and the balance is Fe.

3. A method for producing a low-cost rare earth magnet according to claim 1, comprising the steps of:

s1, preparing a neodymium iron boron alloy sheet by melting and rapidly solidifying a prepared neodymium iron boron alloy raw material, wherein the raw material comprises 28-30 wt% of rare earth R, R refers to at least two of Nd, Pr, Ho and Gd, the weight percentage of B is 0.8-1.2 wt% and the weight percentage of M is 0-3 wt%, M refers to at least one of Co, Mg, Ti, Zr, Nb and Mo, and the balance is Fe;

s2, mechanically crushing the neodymium iron boron alloy sheet into 150-400 mu m scale-shaped neodymium iron boron alloy sheet, mixing low-melting-point powder, wherein the mixed low-melting-point powder contains CeCu, CeAl and CeGa, the weight percentage of each component is that CeCu is more than or equal to 0% and less than or equal to 3%, CeAl is more than or equal to 0% and less than or equal to 3%, CeGa is more than or equal to 0% and less than or equal to 3%, after mixing, high-temperature dehydrogenation is absorbed, the low-melting-point powder is adhered on the scale-shaped neodymium iron boron alloy sheet, and the neodymium iron boron magnet is prepared in a mode of jet milling, magnetic field orientation molding, sintering and heat treatment;

s3, machining the sintered NdFeB magnet into a required shape, and then coating a diffusion source on the surface of the NdFeB magnet to form a diffusion source film, wherein the diffusion source has a formula R1_xR2_yH_zM_1-x-y-zThe composition is shown in the specification, wherein R1 refers to at least one of Nd and Pr, R2 refers to at least one of Ho and Gd, H refers to at least one of Tb and Dy, M refers to at least one of Al, Cu, Ga, Ti, Co, Mg, Zn and Sn, x, y and z are weight percentages, and x is more than 15% and less than 50%，0％＜y≤10％，40％≤z≤70％。

And S4, performing diffusion and aging treatment on the neodymium iron boron magnet coated with the diffusion source to obtain the low-cost rare earth magnet.

4. The method as claimed in claim 3, wherein the step S2 includes hydrogen absorption and dehydrogenation at a temperature of 100-300 ℃ and a dehydrogenation temperature of 400-600 ℃.

5. The method of producing a low-cost rare earth magnet according to claim 4, wherein in the high-temperature hydrogen gettering/desorption treatment, the hydrogen content is less than 1000ppm and the oxygen content is less than 500 ppm.

6. The method of producing a low-cost rare earth magnet as claimed in claim 3, wherein the low-melting point powder of step S2 has a particle size in the range of 200nm to 4 μm, and the jet mill has a D50 alloy powder particle size in the range of 3 to 5 μm.

7. The method of claim 3, wherein the sintering temperature of the sintering process of step S2 is 980-1060 ℃, the sintering time is 6-15h, the primary aging temperature is 850 ℃, the primary aging time is 3h, the secondary aging temperature is 450-660 ℃, and the aging time is 3 h.

8. The method of claim 3, wherein the diffusion source is prepared by pulverization, amorphous melt-spun pulverization, or ingot casting in step S3.

9. The method as claimed in claim 3, wherein the step S4 is performed at a diffusion temperature of 850-.

10. The method for manufacturing a low-cost rare earth magnet according to claim 9, wherein the temperature increase rate of the aging temperature of the neodymium-iron-boron magnet in step S4 is 1-5 ℃/min, and the temperature decrease rate is 5-20 ℃/min.

Technical Field

The invention relates to the technical field of neodymium iron boron magnets, in particular to a low-cost rare earth magnet and a manufacturing method thereof.

Background

The neodymium iron boron sintered permanent magnet is widely applied to high and new technical fields of electronic information, medical equipment, new energy automobiles, household appliances, robots and the like. During the development process of the past decades, the neodymium iron boron permanent magnet is rapidly developed and becomes an indispensable functional material in the current industry. As is known, in rare earth, the price of high-abundance Ce is far lower than that of pure Nd and PrNd, and if part of Ce is used for replacing pure Nd or PrNd, better commercial performance can still be achieved, and the raw material cost of the magnet can be greatly reduced.

Meanwhile, the cost is greatly increased because the traditional manufacturing process consumes a large amount of Tb or Dy heavy rare earth metal. The content of the heavy rare earth can be greatly reduced by a grain boundary diffusion technology, but the cost is still high along with the rising price of the current heavy rare earth Tb and Dy. Therefore, it is still important to continuously reduce the content of heavy rare earths. According to the diffusion mechanism, the Nd2Fe14B main phase is diffusion hardened by the heavy rare earth element, a large number of core-shell structures are formed, and the coercive force is increased. Therefore, research into magnets and diffusion sources has become a hot spot.

However, after pure Nd or PrNd is partially replaced by Ce, the coercivity performance of the magnet is obviously lower than that before replacement. The effect of improving the coercive force is most remarkable by diffusion of heavy rare earth, but the abundance of the heavy rare earth is low and the price is high. Therefore, more and more researchers can diffuse by preparing the heavy rare earth alloy as a diffusion source to enable the neodymium iron boron magnet to achieve the same performance. Meanwhile, the Ce-containing magnet has a lower crystal boundary melting point and a lower melting point of the diffusion source, and the diffused magnet has poorer high-temperature resistance. For example, patent CN 108417380A has Cex (LREahre1-a) yM100-x-y as magnet surface coating alloy, and the alloy is Ce-containing magnet which achieves the effects of reducing cost and improving high temperature resistance of the magnet through diffusion; in patent CN 111640549 a, heavy rare earth elements, cobalt elements and trace elements are added jointly to effectively regulate and control the magnetic moment and microstructure of the material, and optimize the structure of the grain boundary phase and grain boundary of the sintered rare earth permanent magnetic material, so as to form a sintered rare earth permanent magnetic material with cobalt-containing amorphous grain boundary and high temperature stability. But there are few methods for achieving a large increase in coercivity and good high temperature stability by diffusing low-cost magnets with low-melting diffusion sources.

Disclosure of Invention

In order to solve the technical problems, the invention provides a low-cost rare earth magnet and a manufacturing method thereof.

In order to achieve the purpose, the invention provides the following technical scheme:

a low-cost rare earth magnet is prepared from neodymium iron boron alloy and a diffusion source film coated on the surface of the neodymium iron boron alloy, wherein the neodymium iron boron alloy is prepared by mixing neodymium iron boron alloy raw materials, low-melting-point powder and other additives, the mixed low-melting-point powder contains CeCu, CeAl and CeGa, the weight percentage of each component is that CeCu is more than or equal to 0% and less than or equal to 3%, CeAl is more than or equal to 0% and less than or equal to 3%, and CeGa is more than or equal to 0% and less than or equal to 3%; the diffusion source has the formula R1_xR2_yH_zM_1-x-y-zThe composition is shown in the specification, wherein R1 refers to at least one of Nd and Pr, R2 refers to at least one of Ho and Gd, H refers to at least one of Tb and Dy, M refers to at least one of Al, Cu, Ga, Ti, Co, Mg, Zn and Sn, x, y and z are weight percentages, wherein x is more than 15% and less than 50%, y is more than 0% and less than or equal to 10%, and z is more than or equal to 40% and less than or equal to 70%.

The neodymium iron boron alloy comprises the following raw materials of rare earth R, wherein the weight percentage of R is more than or equal to 28% and less than or equal to 30%, R refers to at least two of Nd, Pr, Ho and Gd, the weight percentage of B is more than or equal to 0.8% and less than or equal to 1.2%, the weight percentage of M is more than or equal to 0% and less than or equal to 3%, wherein M refers to at least one of Co, Mg, Ti, Zr, Nb and Mo, and the balance of Fe.

The invention also provides a manufacturing method of the low-cost rare earth magnet, which comprises the following steps:

s1, preparing a neodymium iron boron alloy sheet by melting and rapidly solidifying a prepared neodymium iron boron alloy raw material, wherein the raw material comprises 28-30 wt% of rare earth R, R refers to at least two of Nd, Pr, Ho and Gd, the weight percentage of B is 0.8-1.2 wt% and the weight percentage of M is 0-3 wt%, M refers to at least one of Co, Mg, Ti, Zr, Nb and Mo, and the balance is Fe;

s2, mechanically crushing the neodymium iron boron alloy sheet into 150-400 mu m scale-shaped neodymium iron boron alloy sheet, mixing low-melting-point powder, wherein the mixed low-melting-point powder contains CeCu, CeAl and CeGa, the weight percentage of each component is that CeCu is more than or equal to 0% and less than or equal to 3%, CeAl is more than or equal to 0% and less than or equal to 3%, and CeGa is more than or equal to 0% and less than or equal to 3%, then performing high-temperature absorption and dehydrogenation, adhering the low-melting-point powder on the scale-shaped neodymium iron boron alloy sheet, and preparing the neodymium iron boron magnet by means of jet milling, magnetic field orientation molding, sintering and heat treatment;

s3, machining the sintered NdFeB magnet into a required shape, and then coating a diffusion source on the surface of the NdFeB magnet to form a diffusion source film, wherein the diffusion source has a formula R1_xR2_yH_zM_1-x-y-zThe composition is shown in the specification, wherein R1 refers to at least one of Nd and Pr, R2 refers to at least one of Ho and Gd, H refers to at least one of Tb and Dy, M refers to at least one of Al, Cu, Ga, Ti, Co, Mg, Zn and Sn, x, y and z are weight percentages, wherein x is more than 15% and less than 50%, y is more than 0% and less than or equal to 10%, and z is more than or equal to 40% and less than or equal to 70%.

And S4, performing diffusion and aging treatment on the neodymium iron boron magnet coated with the diffusion source film to prepare the low-cost rare earth magnet.

Wherein, the high temperature dehydrogenation process of step S2 includes hydrogen absorption and dehydrogenation processes, the hydrogen absorption temperature is 100-300 ℃, and the dehydrogenation temperature is 400-600 ℃.

Preferably, in the high-temperature hydrogen absorption and dehydrogenation treatment, the hydrogen content is less than 1000ppm, and the oxygen content is less than 500ppm

Wherein the granularity range of the low-melting-point powder in the step S2 is 200nm-4 mu m, and the granularity of the D50 alloy powder is 3-5 mu m by the jet mill.

Wherein, the sintering temperature of the sintering process in the step S2 is 980-1060 ℃, the sintering time is 6-15h, the primary aging temperature is 850 ℃, the primary aging time is 3h, the secondary aging temperature is 450-660 ℃, and the aging time is 3 h.

And in the step S3, the preparation method of the diffusion source is atomizing powder preparation, amorphous melt-spun powder preparation or ingot casting.

Wherein, the diffusion temperature of the neodymium iron boron magnet in the step S4 is 850-.

Wherein, the temperature rising speed of the aging temperature of the neodymium iron boron magnet in the step S4 is 1-5 ℃/min, and the temperature reduction speed is 5-20 ℃/min.

Compared with the prior art, the invention has the advantages that:

1. the crystal boundary is designed to be a low-melting-point magnet, namely, the neodymium iron boron magnet containing Ce at low cost.

2. The low melting point diffusion source is designed, has double functions of low melting point and high temperature resistant elements, and is low in cost.

3. The diffusion source is a low heavy rare earth alloy diffusion source, contains elements Ho and Gd for increasing the high temperature resistance of the magnet, and can greatly increase the diffusion depth of the heavy rare earth to form a double-shell or even three-shell structure of the heavy rare earth Dy, Ho or Gd.

4. The formed double-shell or even three-shell structure and the grain boundary structure of the deeply diffused heavy rare earth Dy, Ho or Gd can have good high-temperature resistance.

5. Under the condition of less heavy rare earth content, the coercive force of the magnet is greatly increased, the Dy diffusion amplitude can be increased by more than 8kOe, the diffusion effect of pure Tb metal is basically achieved, the high-temperature resistance performance is realized, and the production cost of the magnet can be greatly reduced.

6. The invention can well reduce the content of heavy rare earth in the magnet, improve the high temperature resistance, greatly reduce the cost of the magnet, has simple process and can realize mass production.

Detailed Description

For a better understanding and practice, the present invention is described in detail below with reference to the following examples; the examples are given solely for the purpose of illustration; and are not intended to limit the scope of the present invention.

A low-cost rare earth magnet comprises a neodymium iron boron alloy and a diffusion source film coated on the surface of the neodymium iron boron alloy, wherein the neodymium iron boron alloy is prepared by mixing neodymium iron boron alloy raw materials, low-melting-point powder and other additives, the mixed low-melting-point powder comprises CeCu, CeAl and CeGa, the weight percentage of each component is more than or equal to 0% and less than or equal to 3% of CeCu, more than or equal to 0% and less than or equal to 3% of CeAl, and more than or equal to 0% and less than or equal to 3% of CeGa; the diffusion source has the formula R1_xR2_yH_zM_1-x-y-zThe composition shown, whichWherein R1 is at least one of Nd and Pr, R2 is at least one of Ho and Gd, H is at least one of Tb and Dy, M is at least one of Al, Cu, Ga, Ti, Co, Mg, Zn and Sn, x, y and z are weight percentages, wherein x is more than 15% and less than 50%, y is more than 0% and less than or equal to 10%, and z is more than or equal to 40% and less than or equal to 70%.

The neodymium iron boron alloy comprises the following raw materials, wherein R accounts for 28-30 wt% of rare earth, R refers to at least two of Nd, Pr, Ho and Gd, B accounts for 0.8-1.2 wt% of B, M accounts for 0-3 wt% of M, M refers to at least one of Co, Mg, Ti, Zr, Nb and Mo, and the balance of Fe.

The diffusion source is a low-heavy rare earth alloy diffusion source, and contains elements Ho and Gd capable of increasing the high temperature resistance of the magnet, so that the coercive force of the magnet can be greatly improved, and the magnet can have good high temperature resistance.

Under the condition of less heavy rare earth content, the coercive force of the magnet is greatly increased, the Dy diffusion amplitude can be increased by 8-11.5kOe, the diffusion effect of pure Tb metal is basically achieved, the high-temperature resistance is realized, and the production cost of the magnet can be greatly reduced.

The formed double-shell or even three-shell structure and grain boundary structure of the deep diffusion heavy rare earth Dy, Ho or Gd has good high temperature resistance.

The mixing method of the neodymium iron boron alloy and the low melting point powder can be a method known by those skilled in the art, and can be uniformly mixed in a mixer. Preferably, other additives such as lubricant may be added when mixing the neodymium iron boron alloy powder with the low melting point powder. The lubricant is a general lubricant, and the kind, amount and usage of the lubricant are well known to those skilled in the art, without particular limitation.

According to the preparation method of the application, the neodymium iron boron magnet is prepared, then machined into a magnet with a corresponding size, and then covered with a diffusion source for diffusion and aging, which is specifically referred to as the following.

1. The components of the neodymium iron boron alloy are as follows:

the composition examples are 1-29 examples, the comparative examples are 1-7 examples, wherein 1-29 examples are low melting point alloy powder materials prepared by mixing neodymium iron boron alloy raw materials with different CeCu, CeAl and CeGa composition ratios, and 1-7 examples are Ce component-removed units in weight percentage, namely wt%. As shown in table 1 below:

TABLE 1

Wherein a blank space means that the element is not contained. The components are designed into the above proportions. The preparation method of the neodymium iron boron alloy with the number of the embodiment 1-29 is as follows:

(1) smelting a quick-setting neodymium iron boron alloy raw material sheet without adding low-melting-point powder components, and then mechanically crushing the sheet into a scaly neodymium iron boron alloy sheet with the particle size range of 150-400 mu m;

(2) mixing CeCu, CeAl and CeGa powders with corresponding alloy proportion with the particle size range of 200nm-4 mu m, and adding the mixture into the crushed scaly neodymium iron boron alloy slices;

(3) performing high-temperature absorption and dehydrogenation treatment on the mixed material, wherein the hydrogen absorption temperature is 100-300 ℃, the dehydrogenation temperature is 400-600 ℃, low-melting-point powder is adhered on the sheet, and the jet milling is D50 which is neodymium iron boron alloy powder with the particle size of 3-5 mu m;

(4) and carrying out magnetic field orientation forming and cold isostatic pressing on the neodymium iron boron alloy powder subjected to jet milling to prepare a blank.

(5) Vacuum sintering the blank, introducing argon gas for rapid cooling, then performing primary tempering and secondary aging, and taking out the column for testing the performance of the magnet, wherein the specific process is shown in the following table 2;

TABLE 2

(6) Machining the blank, cutting the machined blank into samples with corresponding sizes, preparing a diffusion source into slurry, and coating the slurry on two sides of the sample, which are vertical to a C axis, wherein the weight of metal Dy is increased by 1.0%, the content of Dy in Dy alloy is 1.0%, and the weight is increased by weight percent (wt%);

wherein, taking diffused Dy alloy as an example and diffused metal Dy as a comparative example, the specific process is shown in the following table 3:

TABLE 3

Based on the data, firstly, CeCu, CeAl and CeGa phase powder is added into the grain boundary of the melt-spun sheet to prepare the neodymium iron boron magnet with the low-melting-point grain boundary channel, the low-cost neodymium iron boron magnet is diffused, the diffusion is facilitated, particularly the diffusion of a heavy rare earth alloy diffusion source is facilitated, after the diffusion, the Delta Hcj is more than 8kOe, and the coercive force is obviously increased.

The examples and comparative examples were specifically analyzed as follows:

examples 1, 2, 3, 4 and comparative example 1, where the diffusion PrHoDyCu was performed compared to the pre-diffusion under the same ndfeb magnet composition and dimensions, the same diffusion temperature and aging temperature, except for the Ce content change, examples 1, 2, 3, 4 and comparative example 1, the Br reduction was 0.22, 0.21, 0.23, 0.2, 0.23kGS, and the Hcj increase was 11.61, 11.2, 11.3, 11.2 and 10.21, respectively. From the above, it can be seen that the performance of the magnet increases after Ce replacement, and the performance of example 1 and comparative example 1 only differs by 0.3kOe, the temperature coefficients of Hcj are substantially the same, the temperature coefficient of coercive force of comparative example is β Hcj150 ℃ — -0.520%, and the temperature coefficient of β Hcj150 ℃ — -0.521% is not much different, thus indicating that the low-cost Ce-containing magnet has a more significant cost advantage.

Examples 5, 6, 7, 8 and comparative example 2, in which NdHoDyCu was diffused before diffusion under the same ndfeb magnet composition and size, the same diffusion temperature and aging temperature, and the like except for the Ce content change, examples 5, 6, 7, 8 and comparative example 2, Br was decreased by 0.25, 0.26, 0.25, 0.23, 0.27kGS, and Hcj was increased by 11.5, 11.1, 11.6, 11.3 and 10.11, respectively. From the above, it can be seen that the performance of the magnet increases after Ce replacement, and the performance of example 5 and comparative example 2 only differs by 0.5kOe, the temperature coefficients of Hcj are substantially the same, the coercivity temperature coefficient of comparative example 2 is β Hcj150 ℃ -0.490%, and the temperature coefficient of β Hcj150 ℃ -0.495% is not much different, thus indicating that the low-cost Ce-containing magnet has a more significant cost advantage.

Examples 9, 10, 11, 12 and comparative example 3, where the diffusion PrGdDyCu was performed compared to before diffusion under the same ndfeb magnet composition and size, the same diffusion temperature and aging temperature, and the like except that the Ce content was changed, examples 9, 10, 11, 12 and comparative example 3, Br was decreased by 0.25, 0.24, 0.24, 0.27, 0.26kGS, Hcj was increased by 11.15, 11.3, 11.6, 11.3 and 9.85, respectively. From the above, it can be seen that the performance of the magnet increases after Ce replacement, and the performance of example 5 and comparative example 2 only differ by 0.5kOe, the temperature coefficients of Hcj are substantially the same, the coercivity temperature coefficient of comparative example 3 is β Hcj150 ℃ -0.495%, and the temperature coefficient of example 4 is β Hcj150 ℃ -0.497%, so that the low-cost Ce-containing magnet has a more significant cost advantage.

Examples 13, 14, 15, 16 and comparative example 4, under the same neodymium-iron-boron magnet composition and size, the same diffusion temperature and aging temperature, and the like except for the variation of Ce content, the diffusion PrGdDyCuGa was performed compared to before the diffusion, examples 13, 14, 15, 16 and comparative example 4, Br was decreased by 0.25, 0.27, 0.26, 0.24, 0.25kGS, Hcj was increased by 9.2, 9.4, 9.5, 9.0 and 7.9, respectively. From the above, it can be seen that, after Ce substitution, the performance of the magnet increases and the performance of example 13 and comparative example 4 only differs by 0.4kOe, the temperature coefficients of Hcj are substantially the same, the coercive force temperature coefficient of comparative example 4 is β Hcj150 ℃ -0.485%, and the temperature coefficient of example 13 is β Hcj150 ℃ -0.486%, so that the cost advantage of the low-cost Ce-containing magnet is more obvious.

Examples 17, 18, 19, 20 and comparative example 5, where the diffusion PrHoDyCuGa was performed compared to the pre-diffusion under the same ndfeb magnet composition and dimensions, the same diffusion temperature and aging temperature, except that the Ce content was varied, examples 17, 18, 19, 20 and comparative example 5, Br was decreased by 0.25, 0.25, 0.27, 0.25, 0.27kGS, Hcj was increased by 10.8, 10.7, 10.5, 10 and 9.48, respectively. From the above, it can be seen that the performance of the magnet increases after Ce replacement, and the performance of example 17 and comparative example 5 only differ by 0.5kOe, the temperature coefficients of Hcj are substantially the same, the coercivity temperature coefficient of comparative example 4 is β Hcj150 ℃ -0.495%, and the temperature coefficient of example 13 is β Hcj150 ℃ -0.496%, which are not much different, thus indicating that the low-cost magnet containing Ce has a more significant cost advantage.

Examples 21, 22, 23, 24 and comparative example 6, under the same ndfeb magnet composition and size, the same diffusion temperature and aging temperature, and the like except for the variation of Ce content, compared to the case before diffusion, were subjected to diffusion PrHoDyCuAl, examples 21, 22, 23, 24 and comparative example 6, the Br reduction was 0.2, 0.23, 0.23, 0.2, 0.2kGS, and the Hcj increase was 10, 9.7, 9.5, 9.3 and 8.77, respectively. From the above, it can be seen that, after Ce substitution, the performance of the magnet increases and the performance of example 21 and comparative example 6 only differs by 0.5kOe, the temperature coefficients of Hcj are substantially the same, the coercive force temperature coefficient of comparative example 6 is β Hcj150 ℃ -0.505%, and the temperature coefficient of example 21 is β Hcj150 ℃ -0.509%, which are not much different, thus indicating that the low-cost Ce-containing magnet has a more significant cost advantage.

Examples 26, 27, 28, 29 and comparative example 7, where the diffusion PrGdDyCu was performed compared to before diffusion under the same ndfeb magnet composition and size, the same diffusion temperature and aging temperature, and the like except that the Ce content was changed, the Br was decreased by 0.22, 0.21, 0.2, 0.22, 0.21kGS, and the Hcj was increased by 9.57, 9.8, 9.15, 8.87 and 8.17, respectively. From the above, it can be seen that, after Ce substitution, the performance of the magnet increases and the performance of example 26 and comparative example 7 only differ by 0.3kOe, the temperature coefficients of Hcj are substantially the same, the coercivity temperature coefficient of comparative example 6 is β Hcj150 ℃ -0.560%, and the temperature coefficient of example 21 is β Hcj150 ℃ -0.565% which are not much different, thus indicating that the low-cost Ce-containing magnet has a more significant cost advantage.

With reference to the above examples, experiments were conducted with other raw materials and conditions, etc. listed in the present specification, and the low-cost rare earth magnet of the present invention was also produced.

Compared with the conventional magnet, the heavy rare earth alloy diffusion Ce-containing magnet obtained by the analysis has obvious cost advantage, and the increase amplitude of the coercive force is obviously larger than that of the conventional magnet. The Ce-containing magnet can meet the use of a plurality of magnet grades through the comprehensive action of the diffusion source and the Ce-containing magnet, and has obvious cost advantage.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.