(Pr, Ce) FeB-PrFeCu alloy ribbon as well as preparation method and application thereof

Abstract

The invention discloses a (Pr, Ce) FeB-PrFeCu alloy ribbon and a preparation method and application thereof.The alloy ribbon takes Pr, Ce, Fe, B and Cu as raw materials, the chemical formula of the alloy ribbon is 70 at.% (Pr0. 3Ce0. 7) 2Fe14B + 30 at.% Pr6Fe13Cu, the addition amount of Pr and Ce is additionally increased by 0.5 at.% on the basis of the theoretical content to serve as loss compensation, a (Pr, Ce) FeB-PrFeCu alloy ingot is obtained through overturning smelting, then vacuum melt-spinning is conducted through a customized quartz tube, and the (Pr, Ce) FeB-PrFeCu alloy ribbon can be obtained. The permanent magnetic (Pr, Ce) FeB-PrFeCu alloy thin strip is prepared, and the permanent magnetic (Pr, Ce) FeB-PrFeCu alloy thin strip is obtained; the main phase component of the (Pr, Ce) FeB-PrFeCu alloy ribbon is (Pr, Ce) 2Fe14B, and the intergranular phase of the (Pr, Ce) FeB-PrFeCu alloy ribbon is Pr6Fe13Cu. The preparation method comprises the following steps: 1, smelting a (Pr, Ce) FeB-PrFeCu gold cast ingot; and 2, preparing the (Pr, Ce) FeB-PrFeCu alloy thin strip. When the material is used as a neodymium iron boron permanent magnet material, the coercive force of the material is 15.7-18.1 kOe, and the residual magnetism of the material is 33.5-49.5 emu / g.

Description

Technical Field

[0001] The present invention relates to an alloy permanent magnet material in the field of permanent magnet materials, and particularly relates to a (Pr, Ce)FeB-PrFeCu alloy ribbon without Nd and with high Ce, and a preparation method and application thereof. Background Art

[0002] Since NdFeB has the characteristics that the Nd sublattice and the Fe sublattice providing magnetocrystalline anisotropy fields are caused by the interaction between the 3d and 4f electron orbital magnetic moments and the lattice field, NdFeB can be used as the base material of permanent magnet materials. For example, the existing literature 1 (Sagawa, Masato, et al. "New material for permanent magnets on a base of Nd and Fe." Journal of Applied Physics 55.6 (1984): 2083-2087.) uses a single alloy method to prepare NdFeB. Specifically, first, an Nd 15 Fe 77 B 8 ingot is prepared by induction melting, then the ingot is crushed by mechanical ball milling, and then ground into NdFeB powder by a nitrogen gas stream mill. Finally, the powder is pressed into shape and sintered at 1370K for 1h and then rapidly cooled. The coercivity of the NdFeB alloy obtained by this technical solution is 11.9 kOe. However, due to the relatively low coercivity value, it cannot meet the applications in technical fields such as aerospace, new energy vehicles, and digital devices, and cannot even meet its operation under high-temperature conditions. Therefore, it is necessary to increase the room-temperature coercivity of the permanent magnet to resist thermal demagnetization.

[0003] To solve the problem of the low coercivity value of NdFeB, by using the fact that the magnetocrystalline anisotropy of the heavy rare earth compound Dy 2 Fe 14 B is higher than that of Nd 2 Fe 14 B, a double alloy preparation method can be used, that is, a heavy rare earth element or its alloy is added to the master alloy during preparation. The existing literature 2 (Liang L, Ma T, Zhang P, et al. Effects of Dy71.5Fe28.5 intergranular addition on the microstructure and the corrosion resistance of Nd–Fe–B sintered magnets[J]. Journal of Magnetism and Magnetic Materials, 2015, 384: 133-137.) by adding different contents of Dy71.5 Fe 28.5 The powder was added to the sintered NdFeB powder as a composite addition to prepare a double-alloy sintered NdFeB magnet. It was found that due to the coupling effect between the main-phase grains in direct contact, the coercivity of the magnet without Dy 71.5 Fe 28.5 addition was very low, only 9.6 kOe. For the magnet with a 3% mass fraction addition, the coercivity was 17 kOe, the remanence decreased from 14.3 kG to 13.6 kG, and the maximum energy product decreased from 48.8 MGOe to 45 MGOe.

[0004] As can be seen from the above-mentioned existing literature 2, doping with the heavy rare-earth element Dy can increase the coercivity, but inevitably leads to a decrease in the remanence and energy product; in addition, the heavy rare-earth elements are scarce in nature and expensive, resulting in an increase in cost and inability to meet the application requirements.

[0005] In recent years, the substantial increase in the production of NdFeB permanent magnets has consumed a large amount of rare-earth resources. In the production process of NdFeB permanent-magnet alloys, Nd in light rare earths is mainly utilized, while the utilization rate of relatively abundant rare earths such as Ce and La (i.e., high-abundance rare-earth elements) is very low, resulting in a large backlog of Ce, La and other rare earths, seriously affecting the balanced utilization of rare-earth resources. Therefore, attempts have been made at home and abroad to partially replace Nd in NdFeB with Ce, La, mixed rare earths (MM), etc. to obtain magnets with lower costs and better magnetic properties.

[0006] Existing literature 3 (Wang, R.Q., et al. " and TEM studies of the phasecomposition and structure of (Nd 1-x Ce x ) 32.7 Fe 66.22 B 1.08 ribbons." Journal ofMaterials Science 52(2017):7311-7322.) obtained (Nd 1-x Ce x ) 32.7 Fe 66.22After ingot casting of B(x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0), it was induction melted in a quartz tube and sprayed onto the surface of a copper wheel at a speed of 28 - 30 m / s to obtain Nd-Ce-Fe-B series ribbons, and the ribbons were annealed in high-purity argon at 600 °C for 20 min. The results show that the pure NdFeB (x = 0) sample has the highest magnetic properties, Hci = 16.56 kOe and Br = 8.06 kGs. When x = 0.4, (Nd 0.6 Ce 0.4 ) 32.7 Fe 66.22 B 1.08 ribbons have Hcj = 13.6 kOe and Br = 0.695 T. Similarly, the existing literature 4 (Zha L, Liu Z, Chen H, et al. High coercivity Nd-Ce-Fe-B nanostructured ribbons prepared from melt spinning technique[J]. Journal of Rare Earths, 2019, 37(10):1053 - 1058.) obtained (Nd 1-x Ce x ) 12.2 Fe 81.6 B 6.2 alloy ribbons by argon arc melting and annealing. The results show that when x = 0.6, the coercivity decreases by 7.5 kOe.

[0007] The existing literature 5 (Goll D, Boettle M, Buschbeck J, et al. High-Cerium-Content Fe–Ce–Nd–B Sintered Magnets with High Coercivity[J]. physica status solidi (RRL)–Rapid Research Letters, 2024, 18(11): 2400151.) successfully prepared a series of Fe-Ce-Nd-B sintered magnets with high Ce content by replacing 75% (atomic percentage) of Nd with Ce and a small amount of La respectively. First, in an Ar atmosphere, the corresponding pre-alloy was prepared by induction melting of the constituent elements and high-purity (>99.9%) FeB pre-alloy at 1450 °C. Second, the pre-alloy was heat-treated in an Ar atmosphere at 950 °C for 16 h for homogenization. The heat treatment process included (hydrogenation at 100 °C for 1 h first and then partial dehydrogenation at 550 °C for 2.5 h) and ball milling (5 min) for pre-crushing. Then, jet milling (classifying wheel 25,000 rpm) was used in an N2 atmosphere to obtain fine powder (D50 ≤ 4 μm). Next, the powder (1.15 g) was arranged and pressed using rubber isostatic pressing in a magnetic field (2.4 T). The obtained magnet was sintered in a lift furnace at 1000 °C for 2 h. The precise sintering temperature was fine-tuned between 950 and 1030 °C to optimize the magnet performance. Finally, the sintered magnet was subjected to two-step post-annealing in vacuum at 800 and 500 °C for 2 h each. The results showed that for the sintered magnet with such a high Ce content (75% RE fraction), sample Ce 92.5 La 7.5 The obtained coercivity Hcj = 7.4 kOe, Jr = 0.83 T.

[0008] By simply summarizing the above existing literature, it can be seen that when the atomic fraction x of Ce = 0, Hcj = 16.56 kOe; when x = 0.4, Hcj = 13.6 kOe; when x = 0.6, the coercivity is only 7.5 kOe. When the Ce content accounts for 75% of the rare earth ratio, Hcj = 7.4 kOe. Due to Ce 2 Fe 14 The intrinsic magnetic property (Ha = 2070 kA / m) of B is lower than that of Nd 2 Fe 14 B (Ha = 5810 kA / m), there is a problem that the magnetic properties of the permanent magnet decrease with the increase of Ce content, and the obtained coercivity still does not meet the requirements.

[0009] Experiments have shown that the addition of some low-melting-point elements such as Ga and Cu can change the microstructure of the magnet: reduce the melting point of the RE-rich phase, increase the intergranular wetting behavior, thereby demagnetizing the main phase grains and improving the coercive force of the magnet. For example, the existing document 6 (Lin Z, **J, Chen W, et al. Dependences of magnetic performance and microstructure on the PrGa diffusion time for multi-main-phase Nd-La-Ce-Fe-B magnet[J]. Intermetallics, 2023, 157: 107891.) reported the use of PrGa as a diffusion source to perform grain boundary diffusion treatment on Nd-Ce-Fe-B-based magnets. Due to RE 6 Fe 13 The formation of Ga phase and Pr-rich shell improves the coercive force of the magnet. The specific preparation process is as follows: first, the Nd-Ce-Fe-B-based powder is arranged and compacted under a magnetic field of 1.8T and a pressure of 5MPa, and then isostatically pressed at 200MPa. After vacuum sintering at 1040℃ for 3h, the bulk magnet is cut into pieces with a size of 10×5mm. 3 Secondly, Pr and Ga metals with a purity of 99.9% were arc-melted and crushed into powder to prepare a Pr 80 Ga 20 (at%) diffusion alloy. 80 Ga 20 The powder, ethanol and polyvinyl pyrrolidone were mixed in a mass ratio of 1:1:1, and the diffusion slurry was placed on the two electrode surfaces under Ar protection. Subsequently, diffusion was carried out at 890℃ for 4h, 6h and 8h, and finally annealed at 480℃ for 4h. The results show that compared with the untreated magnet (Hcj=5.2kOe, Br=1.29T), the RE 6 Fe 13 The formation of Ga phase and Pr-rich shell, after 6 hours of diffusion, the magnet obtains the best coercivity of 16.1kOe, Br = 1.31T. Longer diffusion time increases the diffusion depth of Pr and Ga, and promotes the non-ferromagnetic RE 6 Fe 13 The formation of Ga continuous grain boundary phase is beneficial to improve the coercivity of the alloy. However, the longer diffusion time also leads to the uniform distribution of rare earth elements in the matrix phase grains, weakening the magnetic hardening effect of the Pr / Nd-rich shell, which is not conducive to magnetic enhancement.

[0010] Similarly, existing literature 7 ( L, Skokov K, Liu J, et al. Design and qualification of Pr–Fe–Cu–B alloys for the additive manufacturing of permanent magnets[J]. Advanced Functional Materials, 2021, 31(33): 2102148. By taking advantage of the characteristics of a large amount (even excessive) of grain boundary phase existing in RE-Fe-B-based compounds rich in RE, the microstructure of the magnet was designed, and Pr 21 Fe 73.5 Cu 2 B 3.5 and Nd 21 Fe 73.5 Cu 2 B 3.5 two alloys were prepared to improve the coercivity by forming a new microstructure. The specific preparation process includes: under an argon atmosphere, the ingot was subjected to hydrogen explosion (HD process). Then, the obtained ingot alloy was manually ground to less than 60 μm, and the powder was annealed in a dynamic vacuum at 600 °C for 2 hours to remove hydrogen. Secondly, the dehydrogenated powder (less than 3 g) was manually pressed into a rectangular sheet and suction cast into a rectangular block with a thickness of 0.5 mm under a protective argon atmosphere. The subsequent heat treatment included high-temperature annealing at 1000 °C for 5 h and then low-temperature annealing at 500 °C for 3 h. The results showed that the as-cast microstructure consisted of α-Fe grains and large grains of the hard magnetic Nd 2 Fe 14 B and Pr 2 Fe 14 B phases. After two-stage annealing, the microstructure of the two alloys changed significantly. The grains of Nd 2 Fe 14 B and Pr 2 Fe 14 B phases were fine and were separated by the rare-earth-rich Cu phase and the non-magnetic intermetallic compound (Nd, Pr) 6 Fe 13 Cu phase. The Pr 2 Fe 14 B magnet finally obtained a coercivity of 0.75 T. The increase in coercivity can be attributed to the dissolution of the soft magnetic α-Fe phase and the formation of the 6:13:1 phase. The existence of this intergranular phase relieved the ferromagnetic coupling between the grains of the main phase 2:14:1, and the grain size of the alloy after annealing was smaller and more uniform. Compared with the traditional cast Nd-Fe-B-based alloy, the Pr-based magnet has a higher coercivity, and the most obvious difference is the presence of a large number of newly formed intermetallic phases 6:13:1.

[0011] As can be seen from the above existing literature, although the intrinsic magnetic properties of the high-abundance rare-earth compound Ce 2 Fe 14 B are lower than those of Nd 2 Fe 14 B, through reasonable composition design and process optimization, high-abundance rare-earth-based magnets can also obtain a coercivity higher than 15 kOe. However, the problems existing above are that the sintering technology and the preparation process of grain boundary diffusion adopted are complex and cumbersome, and the required heat treatment time is long, which also leads to an increase in time cost and experimental cost. Moreover, the grain boundary diffusion process has relatively strict requirements on the preparation, density, size, etc. of the magnet, and is usually only applicable to the preparation of thin samples (thickness ≤ 6 mm), and is not applicable to bulk magnets without thickness limitations. In addition, in terms of composition design, most studies focus on the research of (Nd,Ce)-Fe-B-based alloys, while the research on (Pr,Ce)-Fe-B is relatively few and not comprehensive. Summary of the Invention

[0012] The object of the present invention is to provide a Nd-free and high-Ce (Pr,Ce)FeB-PrFeCu alloy ribbon and its preparation method and application.

[0013] In order to solve the problems existing in the prior art such as complex preparation process, long preparation cycle, and high preparation cost, based on the phase diagram research results of the present team, a duplex nano-alloy Pr 2 Fe 14 B + Pr 6 Fe 13 Cu is designed according to the Pr-Fe-B and Pr-Fe-Cu ternary alloy phase diagrams; at the same time, based on the high formation temperature of the Pr 2 Fe 14 B phase, while the melting temperature of the Pr 6 Fe 13 Cu phase is low, about 550 °C, that is, the existing objective technical difficulties, and taking advantage of the characteristics of rapid cooling of the melt spinning operation, the technical effect of preparing a duplex alloy is achieved, and finally when preparing a permanent magnet through the technical solution of the present invention, effective simplification of production and reduction of requirements for equipment are obtained, so as to meet the requirements of large-scale industrial production.

[0014] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is as follows:

[0015] A (Pr,Ce)FeB-PrFeCu alloy ribbon, using Pr, Ce, Fe, B and Cu as raw materials, satisfying the chemical formula 70 at.% (Pr 0.3 Ce 0.7 ) 2 Fe 14 B + 30 at.% Pr 6 Fe13 Cu, where the addition amounts of Pr and Ce are increased by an additional 0.5 at.% on the basis of the theoretical content as a compensation for losses. After flipping melting, an (Pr,Ce)FeB-PrFeCu alloy ingot is obtained. Then, by using a customized quartz tube for vacuum strip casting, an (Pr,Ce)FeB-PrFeCu alloy thin strip, that is, a permanent magnetic (Pr,Ce)FeB-PrFeCu alloy, can be obtained.

[0016] The main component of the (Pr,Ce)FeB-PrFeCu alloy thin strip is (Pr,Ce) 2 Fe 14 B, and the intergranular phase is Pr 6 Fe 13 Cu.

[0017] A method for preparing an (Pr,Ce)FeB-PrFeCu alloy thin strip includes the following steps:

[0018] Step 1, melting of the (Pr,Ce)FeB-PrFeCu alloy ingot: Weigh Pr, Ce, Fe, B, and Cu as raw materials. Under certain conditions, flip-melt the raw materials. After melting is completed, cool it in the furnace to room temperature, and then an (Pr,Ce)FeB-PrFeCu alloy ingot, abbreviated as (Pr,Ce)FeB-PrFeCu-I, can be obtained.

[0019] In the said Step 1, the masses of Pr, Ce, Fe, B, and Cu satisfy the chemical formula 70 at.% (Pr 0.3 Ce 0.7 ) 2 Fe 14 B + 30 at.% Pr 6 Fe 13 Cu, and the addition amounts of Pr and Ce are increased by an additional 0.5 at.% on the basis of the theoretical content as a compensation for losses.

[0020] In the said Step 1, the capacity condition is that under argon gas, the number of melting times is 4 - 5 times.

[0021] Step 2, preparation of the (Pr,Ce)FeB-PrFeCu alloy thin strip: First, place (Pr,Ce)FeB-PrFeCu-I in a customized quartz tube. Then, under certain conditions, heat (Pr,Ce)FeB-PrFeCu to the liquid state. Finally, under certain conditions, perform vacuum strip casting, and then an (Pr,Ce)FeB-PrFeCu alloy thin strip, that is, a permanent magnetic (Pr,Ce)FeB-PrFeCu alloy, abbreviated as (Pr,Ce)FeB-PrFeCu-R, can be obtained.

[0022] In step 2, the condition for heating (Pr,Ce)FeB-PrFeCu to a liquid state is that the heating temperature is 1700 °C;

[0023] In step 2, the conditions for vacuum melt spinning are that under vacuum conditions, the distance between the nozzle of the quartz tube and the copper roller is 13 mm, and the spinning speed is 25 m / s;

[0024] The aperture of the customized quartz tube nozzle is 1 mm, and the other dimensions of the customized quartz tube are: the outer diameter is 17.92 mm, the inner diameter is 13.82 mm, the flanging diameter is 21.34 mm, the length is 95.3 mm, and the bottom arc length is 5 mm.

[0025] When a (Pr,Ce)FeB-PrFeCu alloy ribbon is used as a NdFeB permanent magnetic material, its coercivity is 15.7 - 16.3 kOe, and its remanence is 49.5 - 94.2 emu / g.

[0026] The technical effects of the present invention are detected by experiments, and the specific content is as follows:

[0027] It can be seen from the XRD test that (Pr,Ce)FeB-PrFeCu-R-25m / s contains the characteristic peaks of 2:14:1. However, the characteristic peaks containing Cu are not detected.

[0028] It can be seen from the TEM test that the main phase is (Pr,Ce) 2 Fe 14 B, and the intergranular phase is Pr 6 Fe 13 Cu, that is, the test results are consistent with the XRD test results.

[0029] It can be seen from the VSM test that the coercivity of (Pr,Ce)FeB-PrFeCu-R-25m / s is 15.7 - 18.1 kOe, and its remanence is 33.5 - 49.5 emu / g.

[0030] It can be seen from the PPMS test that the coercivity of (Pr,Ce)FeB-PrFeCu-R-25m / s when the external magnetic field is 5 T is 9.4 - 18.2 kOe, and its remanence is 55.6 - 67.4 emu / g.

[0031] It can be seen from the PPMS test that the remanence temperature coefficient |α| of (Pr,Ce)FeB-PrFeCu-R-25m / s is 0.1921; the coercivity temperature coefficient |β| is 0.5326.

[0032] Therefore, it can be seen from the detection of the present invention that it has the following advantages:

[0033] 1. On the premise of making full use of high-abundance rare earth elements, based on the phase diagram knowledge learned, the experimental composition of the present invention was designed within the two-phase region of PrFeB and PrFeCu to ensure the existence of Pr during the strip casting operation. 2 Fe 14 B phase and Pr 6 Fe 13 Cu phase, and the antiferromagnetic intergranular phase Pr 6 Fe 13 Cu are uniformly distributed around the main-phase grains, enabling the demagnetization coupling of the main-phase grains. Finally, while the performance of the PrFeB permanent magnet is further improved, the cost of the invention is reduced.

[0034] 2. The excellent permanent magnetic material with such properties can be prepared by the method of "argon arc melting and strip casting operation", without the need for heat treatment, with a short production cycle and high efficiency; the preparation method is simple, easy to operate, has few processes, and has good industrial application prospects.

[0035] 3. The present invention prepares a high-abundance permanent magnetic material without key rare earth elements Nd, Dy, and Tb, with high thermal stability and suitable for the operation of magnets at high temperatures; moreover, this type of magnet can fill the performance gap between permanent ferrite magnets and bonded Nd-Fe-B magnets. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is the hysteresis loop of the (Pr,Ce)FeB-PrFeCu-I alloy ingot obtained in Example 1;

[0037] Figure 2 is the XRD pattern of the (Pr,Ce)FeB-PrFeCu-R-25m / s alloy ribbon obtained in Example 1;

[0038] Figure 3 is the TEM image of the (Pr,Ce)FeB-PrFeCu-R-25m / s alloy ribbon obtained in Example 1;

[0039] Figure 4 is the hysteresis loop of the (Pr,Ce)FeB-PrFeCu-R-25m / s alloy ribbon obtained in Example 1 at 5T;

[0040] Figure 5 is the temperature coefficient diagram of the (Pr,Ce)FeB-PrFeCu-R-25m / s alloy ribbon obtained in Example 1;

[0041] Figure 6 is the hysteresis loop of the (Pr,Ce)FeB-PrFeCu-R-25m / s alloy ribbon obtained in Example 1;

[0042] Figure 7The hysteresis loop of the (Pr, Ce)FeB-PrFeCu-R alloy ribbon obtained in Comparative Example 1;

[0043] Figure 8 The hysteresis loops of the (Pr, Ce)FeB-PrFeCu-R alloy ribbons obtained in Comparative Example 2, Comparative Example 3, and Comparative Example 4;

[0044] Figure 9 The hysteresis loops of the (Pr, Ce)FeB-PrFeCu-R alloy ribbons obtained in Comparative Example 5, Comparative Example 6, and Comparative Example 7;

[0045] Figure 10 The hysteresis loops of the (Pr, Ce)FeB-PrFeCu-R alloy ingots obtained in Comparative Example 8 and Comparative Example 9;

[0046] Figure 11 The hysteresis loops of the (Pr, Ce)FeB-PrFeCu-R alloy ribbons obtained in Comparative Example 10 and Comparative Example 11. Detailed implementation manners

[0047] The content of the present invention will be further described in detail with reference to the accompanying drawings of the specification through embodiments, but it is not a limitation to the present invention.

[0048] Embodiment 1

[0049] A preparation method of a (Pr, Ce)FeB-PrFeCu alloy ribbon, comprising the following steps:

[0050] Step 1, melting of the (Pr, Ce)FeB-PrFeCu alloy ingot, with the chemical formula of 70 at.% (Pr 0.3 Ce 0.7 ) 2 Fe 14 B + 30 at.% Pr 6 Fe 13 Cu, weighing Pr, Ce, Fe, B, and Cu as raw materials, wherein the addition amounts of Pr and Ce are additionally increased by 0.5 at.% on the basis of the theoretical content as compensation for losses. Under the condition of argon, with the number of melting times being 4 times, the raw materials are turned over and melted, and after melting, they are cooled to room temperature with the furnace, and then the ingot of 70 at.% (Pr 0.3 Ce 0.7 ) 2 Fe 14 B + 30 at.% Pr 6 Fe 13 Cu alloy, namely the (Pr, Ce)FeB-PrFeCu alloy ingot, abbreviated as (Pr, Ce)FeB-PrFeCu-I.

[0051] To prove the magnetic properties of 70(Pr,Ce)FeB-30PrFeCu-I, VSM tests were carried out. The test results are as Figure 1 shown, and the coercivity is 0.28 kOe.

[0052] Step 2, Preparation of (Pr,Ce)FeB-PrFeCu alloy ribbon. First, place (Pr,Ce)FeB-PrFeCu-I in a customized quartz tube. Then, heat (Pr,Ce)FeB-PrFeCu to a liquid state at a heating temperature of 1700 °C. Finally, under vacuum conditions, with the nozzle aperture of the customized quartz tube being 1 mm, the distance between the nozzle of the quartz tube and the copper roller being 13 mm, and the spinning speed being 25 m / s, perform vacuum spinning to obtain the (Pr,Ce)FeB-PrFeCu alloy ribbon, that is, the permanent magnetic (Pr,Ce)FeB-PrFeCu alloy, simply referred to as (Pr,Ce)FeB-PrFeCu-R, specifically (Pr,Ce)FeB-PrFeCu-R-25m / s obtained in Example 1.

[0053] The other dimensions of the customized quartz tube are as follows: the outer diameter is 17.92 mm, the inner diameter is 13.82 mm, the flanging diameter is 21.34 mm, the length is 95.3 mm, and the bottom arc length is 5 mm.

[0054] To prove the phase composition of (Pr,Ce)FeB-PrFeCu-R-25m / s, XRD tests were carried out. The test results are as Figure 2 shown, (Pr,Ce)FeB-PrFeCu-R-25m / s contains the characteristic peaks of (Pr,Ce) 2 Fe 14 B, however, the characteristic peaks containing Cu were not detected.

[0055] Therefore, to prove the phase composition of (Pr,Ce)FeB-PrFeCu-R-25m / s, that is, to prove the existence state of Cu, TEM tests were carried out. The test results are as Figure 3 shown, the main phase is (Pr,Ce) 2 Fe 14 B, and the intergranular phase is Pr 6 Fe 13 Cu, that is, the test results are consistent with the XRD test results.

[0056] Therefore, through XRD tests and TEM tests, it can be confirmed that the phase composition of (Pr,Ce)FeB-PrFeCu-R-25m / s consists of (Pr,Ce) 2 Fe 14 B and Pr 6 Fe 13Composed of Cu, (Pr,Ce)FeB-PrFeCu was successfully prepared.

[0057] To prove the magnetic properties of PrFeB-PrFeCu-R-25m / s, VSM tests were carried out. The test results are as Figure 4 shown, and the coercivity is 18.1 kOe.

[0058] To prove the magnetic properties of PrFeB-PrFeCu-R-25m / s at high temperatures, PPMS tests were carried out. The test results are as Figure 5 shown, and the coercivity is 9.4 - 18.1 kOe. Comparing with PrFeB-PrFeCu-I obtained in Step 1, it can be seen that the strip casting operation can significantly improve the coercivity of the material, and the improvement amplitude is higher than 98%. The reason is that the strip casting operation can achieve uniform distribution of element components and refine grains, avoiding composition segregation during the ingot casting process.

[0059] To prove the thermal stability, i.e., the demagnetization resistance ability of PrFeB-PrFeCu-R-25m / s, PPMS tests were carried out. The test results are as Figure 6 shown, the remanence temperature coefficient |α| is 0.1921; the coercivity temperature coefficient |β| is 0.5326.

[0060] To prove the role of Cu in the technical solution, Comparative Example 1 was provided, which is a (Pr,Ce)FeB alloy thin strip prepared without adding Cu.

[0061] Comparative Example 1

[0062] A preparation method of a (Pr,Ce)FeB alloy thin strip without adding Cu. The steps not specifically described are the same as those in the preparation method of Example 1, except that: the chemical formula in Step 1 is (Pr 0.3 Ce 0.7 )Fe 14 B, that is, the raw materials during weighing do not contain Cu, and the obtained alloy thin strip is named (Pr,Ce)FeB-R.

[0063] The permanent magnetic property test results of (Pr,Ce)FeB are as Figure 7 shown, and the coercivity is 3.6 kOe. Comparing the test results with those of Example 1, it can be seen that adding Cu, that is, forming PrFeCu, can significantly improve the coercivity of the material, and the improvement amplitude is 77.9%. The reason is that PrFeCu formed by introducing the Cu element has antiferromagnetic characteristics, and PrFeCu can act as an intergranular phase of (Pr,Ce)FeB, thus improving the magnetic properties of the (Pr,Ce)FeB permanent magnet.

[0064] To further prove the role of the Cu element, i.e., PrFeCu, in the technical solution, Comparative Example 2 and Comparative Example 3 are provided, which are (Pr,Ce)FeB-PrFeCu alloy thin strips with PrFeCu contents of 10 at.%, 20 at.%, and 40 at.%, respectively.

[0065] Comparative Example 2

[0066] A preparation method of a (Pr,Ce)FeB-PrFeCu alloy thin strip with a (Pr,Ce)FeB content of 10 at.%. The steps not specifically described are the same as those in the preparation method of Example 1. The difference is that: the chemical formula in Step 1 is 90 at.% (Pr 0.3 Ce 0.7 )Fe 14 B + 10 at.% Pr 6 Fe 13 Cu, and the obtained alloy thin strip is named 90(Pr,Ce)FeB-10PrFeCu-R.

[0067] The magnetic property test results of 90(Pr,Ce)FeB-10PrFeCu-R are as Figure 8 shown, and the coercivity is 12.9 kOe.

[0068] Comparative Example 3

[0069] A preparation method of a (Pr,Ce)FeB-PrFeCu alloy thin strip with a (Pr,Ce)FeB content of 20 at.%. The steps not specifically described are the same as those in the preparation method of Example 1. The difference is that: the chemical formula in Step 1 is 80 at.% (Pr 0.3 Ce 0.7 )Fe 14 B + 20 at.% Pr 6 Fe 13 Cu, and the obtained alloy thin strip is named 80(Pr,Ce)FeB-20PrFeCu-R.

[0070] The magnetic property test results of 80(Pr,Ce)FeB-20PrFeCu-R are as Figure 8 shown, and the coercivity is 11.5 kOe.

[0071] Comparative Example 4

[0072] A preparation method of a 60(Pr,Ce)FeB-40PrFeCu alloy thin strip with a PrFeCu content of 40 at.%. The steps not specifically described are the same as those in the preparation method of Example 1. The difference is that: the chemical formula in Step 1 is 60 at.% (Pr 0.3 Ce 0.7 )Fe14 B+40at.%Pr 6 Fe 13 Cu, and the obtained alloy ribbon was named 60(Pr,Ce)FeB-20PrFeCu-R.

[0073] In order to prove the magnetic properties of 60NdFeB-40NdFeCu-R, VSM test was carried out. The test results are as follows Figure 8 As shown, the coercive force is 13.1 kOe.

[0074] By comparing Comparative Examples 2 and 3 with Example 1, it can be seen that increasing the Cu content can increase the coercivity. The reason is that increasing the Cu content can directly increase the antiferromagnetic phase Pr in the grain boundary phase. 6 Fe 13 The Cu content releases the ferromagnetic coupling between the main phase grains and enhances the pinning effect of grain boundaries on magnetic domains, thereby improving the coercive force of the material.

[0075] By comparing Comparative Example 4 with Example 1, it can be seen that when the amount of Cu added is too large, both the coercive force and the remanence decrease. The reason is that the decomposition of the main phase and the formation of the antiferromagnetic phase will lead to a decrease in the remanence; the decrease in coercive force is attributed to the decrease in the volume fraction of the main phase 2:14:1 phase that provides the coercive force, the changes in the phase structure and the magnetic state.

[0076] In order to demonstrate the influence of the general annealing rules on the technical effect, a comparative example is provided.

[0077] The comparative examples include comparative example 5, comparative example 6 and comparative example 7, and the (Pr,Ce)FeB-PrFeCu-R obtained in step 2 of embodiment 1 is subjected to conventional annealing treatment with annealing times of 1 min, 5 min and 10 min, respectively, to obtain annealing rules of the alloy strip.

[0078] Comparative Example 5

[0079] A method for preparing a (Pr, Ce)FeB-PrFeCu-R alloy strip with an annealing time of 1 min: the (Pr, Ce)FeB-PrFeCu-R obtained in step 2 of Example 1 is subjected to conventional annealing treatment with an annealing time of 1 min, and the obtained alloy strip is named (Pr, Ce)FeB-PrFeCu-R-1min.

[0080] In order to prove the magnetic properties of (Pr,Ce)FeB-PrFeCu-R-1min, VSM test was carried out. The test results are as follows Figure 9 As shown, the coercive force is 10.4 kOe.

[0081] Comparative Example 6

[0082] Preparation method of (Pr,Ce)FeB-PrFeCu-R alloy ribbon with annealing time of 5 min: The (Pr,Ce)FeB-PrFeCu-R obtained in step 2 of Example 1 was subjected to conventional annealing treatment with an annealing time of 5 min, and the obtained alloy ribbon was named (Pr,Ce)FeB-PrFeCu-R-5min.

[0083] To prove the magnetic properties of (Pr,Ce)FeB-PrFeCu-R-5min, VSM tests were carried out. The test results are as Figure 9 shown, and the coercivity is 8.3 kOe.

[0084] Comparative Example 7

[0085] Preparation method of (Pr,Ce)FeB-PrFeCu alloy ribbon with annealing time of 10 min: The (Pr,Ce)FeB-PrFeCu-R obtained in step 2 of Example 1 was subjected to conventional annealing treatment with an annealing time of 10 min, and the obtained alloy ribbon was named (Pr,Ce)FeB-PrFeCu-R-10min.

[0086] To prove the magnetic properties of (Pr,Ce)FeB-PrFeCu-R-10min, VSM tests were carried out. The test results are as Figure 9 shown, and the coercivity is 7.8 kOe.

[0087] By comparing Comparative Example 5, Comparative Example 6 and Comparative Example 7, it can be seen that when annealing the alloy ribbon, the influence on the coercivity can be ignored.

[0088] Further comparing Comparative Example 5, Comparative Example 6, Comparative Example 7 and Example 1, it can be seen that annealing treatment significantly reduces the coercivity. The reasons are as follows:

[0089] 1. The grain size after annealing is significantly increased compared with that of the alloy ribbon, thus significantly reducing the coercivity;

[0090] 2. The obvious decrease in the waist peak of the hysteresis loop after passing through the Y-axis indicates that the intergranular phase Pr 6 Fe 13 Cu is easily decomposed, resulting in a decrease in content.

[0091] To prove the influence of the spinning parameters on the technical effect, two groups of comparative examples are provided.

[0092] The first group of comparative examples includes Comparative Example 8 and Comparative Example 9, which are (Pr,Ce)FeB-PrFeCu-R permanent magnetic materials prepared at spinning speeds of 30 m / s and 20 m / s respectively, to prove the influence of the spinning speed on the technical effect;

[0093] The second group of comparative examples includes Comparative Example 10 and Comparative Example 11, which are (Pr, Ce)FeB-PrFeCu-R permanent magnetic materials prepared with a quartz tube nozzle distance of 3 mm and a nozzle aperture of 0.5 mm respectively, to prove the influence of the customized quartz tube on the technical effect;

[0094] Among them, in order to adjust the quartz tube nozzle distance to 3 mm, the quartz tube used is a customized quartz tube with a length of 105.3 mm;

[0095] In order to adjust the quartz tube nozzle aperture to 0.5 mm, the quartz tube used is a customized quartz tube with a nozzle aperture of 0.5 mm.

[0096] Comparative Example 8

[0097] A preparation method of (Pr, Ce)FeB-PrFeCu-R permanent magnetic material prepared at a spinning speed of 30 m / s. The steps not specifically described are the same as those in the preparation method of Example 1. The difference is that: the spinning speed in Step 2 is 30 m / s, and the obtained material is abbreviated as (Pr, Ce)FeB-PrFeCu-R-30 m / s according to the spinning speed.

[0098] To prove the magnetic properties of (Pr, Ce)FeB-PrFeCu-R-30 m / s, a VSM test was carried out. The test results are as Figure 10 shown, and the coercivity is 4.7 kOe.

[0099] Comparative Example 9

[0100] A preparation method of (Pr, Ce)FeB-PrFeCu-R-20 permanent magnetic material prepared at a spinning speed of 20 m / s. The steps not specifically described are the same as those in the preparation method of Example 1. The difference is that: the spinning speed in Step 2 is 20 m / s, and the obtained material is abbreviated as (Pr, Ce)FeB-PrFeCu-R-20 m / s according to the spinning speed.

[0101] To prove the magnetic properties of (Pr, Ce)FeB-PrFeCu-R-20 m / s, a VSM test was carried out. The test results are as Figure 10 shown, and the coercivity is 11.4 kOe.

[0102] By comparing Example 1, Comparative Example 8 and Comparative Example 9, it can be seen that when the spinning speed is too fast, the coercivity decreases by 71.2%, and when the spinning speed is too slow, the coercivity decreases by 30.1%; that is, whether the spinning speed is too fast or too slow, the coercivity decreases significantly. The reason is that the phase of 6:13:1 cannot be formed, thus significantly affecting the permanent magnetic properties. Excessively high spinning speed will introduce amorphous soft magnetic phase in the rapidly quenched strip, thereby reducing the coercivity of the rapidly quenched strip. This phase will reverse under the action of a relatively low reverse field, so it shows a shoulder collapse phenomenon in the demagnetization curve. The rapidly quenched strip with a speed of 20 m / s has obvious grain growth and uneven size in the rapidly quenched strip due to its too slow roll speed and too low melt cooling speed, which is not conducive to the improvement of coercivity.

[0103] Comparative Example 10

[0104] A preparation method of (Pr,Ce)FeB-PrFeCu-R alloy thin strip material prepared with a nozzle distance of 3 mm. The steps not specifically described are the same as those in the preparation method of Example 1. The difference is that in step 2, the nozzle distance is 3 mm, and the obtained material is abbreviated as (Pr,Ce)FeB-PrFeCu-R-3mm according to the nozzle distance.

[0105] To prove the magnetic properties of (Pr,Ce)FeB-PrFeCu-R-3mm, VSM test was carried out. The test results are as Figure 11 shown, and the coercivity is 0.3 kOe. The test results show that the nozzle distance has a significant impact on the permanent magnetic properties.

[0106] Comparative Example 11

[0107] A preparation method of (Pr,Ce)FeB-PrFeCu-R alloy thin strip material with an aperture of 0.5 mm. The steps not specifically described are the same as those in the preparation method of Example 1. The difference is that in step 2, the aperture of the quartz tube is 0.5 mm, and the obtained material is abbreviated as (Pr,Ce)FeB-PrFeCu-R-0.5mm according to the aperture.

[0108] To prove the magnetic properties of (Pr,Ce)FeB-PrFeCu-R-0.5mm, VSM test was carried out. The test results are as Figure 11 shown, and the coercivity is 7.7 kOe. The test results show that the aperture of the quartz tube has a significant impact on the permanent magnetic properties.

Claims

1. A (Pr, Ce)FeB-PrFeCu alloy strip, characterized in that: Pr, Ce, Fe, B and Cu are used as raw materials, satisfying the chemical formula of 70at.% (Pr 0.3 Ce 0.7 )2Fe 14 B+30at.%Pr6Fe 13 Cu, wherein the addition amount of Pr and Ce is increased by 0.5at.% on the basis of the theoretical content as compensation, and the (Pr, Ce)FeB-PrFeCu alloy ingot is obtained by tumbling smelting, and then vacuum spinning is carried out with a customized quartz tube to obtain the (Pr, Ce)FeB-PrFeCu alloy strip, that is, the permanent magnetic (Pr, Ce)FeB-PrFeCu alloy.

2. The (Pr, Ce)FeB-PrFeCu alloy strip according to claim 1, characterized in that: The main phase composition of the (Pr, Ce)FeB-PrFeCu alloy ribbon is (Pr, Ce)2Fe 14 B, intergranular phase is Pr6Fe 13 Cu, obtained directly by belt throwing.

3. A method for preparing a (Pr, Ce)FeB-PrFeCu alloy strip, characterized in that: The following steps are involved: Step 1, smelting of (Pr, Ce)FeB-PrFeCu alloy ingot, weighing Pr, Ce, Fe, B and Cu as raw materials, and turning the raw materials over and smelting them under certain conditions, and cooling them to room temperature with the furnace after smelting to obtain a (Pr, Ce)FeB-PrFeCu alloy ingot, referred to as (Pr, Ce)FeB-PrFeCu-I; Step 2, preparation of (Pr,Ce)FeB-PrFeCu alloy ribbon, first, place (Pr,Ce)FeB-PrFeCu-I in a customized quartz tube; then, under certain conditions, heat (Pr,Ce)FeB-PrFeCu-I to liquid; finally, vacuum spin under certain conditions to obtain (Pr,Ce)FeB-PrFeCu alloy ribbon, that is, permanent magnetic (Pr,Ce)FeB-PrFeCu alloy, abbreviated as (Pr,Ce)FeB-PrFeCu-R. The aperture of the customized quartz tube nozzle is 1 mm, the outer diameter of the customized quartz tube is 17.92 mm, the inner diameter is 13.82 mm, the flange diameter is 21.34 mm, the length is 95.3 mm, and the bottom arc length is 5 mm.

4. The preparation method according to claim 3, characterized in that: In step 1, the mass of Pr, Ce, Fe, B and Cu satisfies the chemical formula of 70 at.% (Pr 0.3 Ce 0.7 )2Fe 14 B+30at.%Pr6Fe 13 The addition amount of Cu, Pr and Ce is increased by 0.5at.% on the basis of the theoretical content as compensation; In the step 1, the smelting condition is that the smelting times are 4-5 times under argon gas condition.

5. The preparation method according to claim 3, characterized in that: In the step 2, the condition for heating (Pr,Ce)FeB-PrFeCu to liquid state is that the heating temperature is 1700°C; In step 2, the vacuum belt spinning condition is that under vacuum conditions, the distance between the nozzle of the quartz tube and the copper roller is 13 mm, and the belt spinning speed is 25 m / s.

6. A use of the (Pr, Ce)FeB-PrFeCu alloy ribbon as claimed in claim 1 as a NdFeB permanent magnet material, characterized in that: When used as NdFeB permanent magnet material, its coercive force is 15.7-18.1 kOe and its remanence is 33.5-49.5 emu / g.

Images