High comprehensive magnetic property sintered neodymium-iron-boron multi-pole magnetic ring and preparation method thereof

Abstract

The application discloses a kind of high comprehensive magnetic property sintered neodymium iron boron multipolar magnetic ring and preparation method thereof, it is related to permanent magnet material technical field, by following each component is made by weight parts: rare earth alloy A 9-10 parts, rich rare earth alloy B 0.1-1 part, alloy C 0.8-1.2 parts, lubricant 0.01-0.03 parts, aviation gasoline 0.01-0.03 parts;The alloy C includes following component by mass percent: rare earth element 29-32wt%, Ta 0.05-0.2wt%, In 0.1-0.3wt%, Re 0.02-0.08wt%, W 0.08-0.2wt%, Mo 0.1-0.4wt%, Ge 0.1-0.5wt%, B 0.9-1.2wt%, the balance is Fe.The multipolar magnetic ring comprehensive magnetic property is excellent, and cracking rate is low.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of permanent magnet materials, and particularly relates to a high-comprehensive-magnetic-property sintered neodymium-iron-boron multi-pole magnetic ring and a preparation method thereof. BACKGROUND

[0002] In modern industry and technology, the demand for high-performance permanent magnet materials is increasing. Sintered neodymium-iron-boron permanent magnet materials have excellent magnetic properties and are widely used in many fields such as motors, sensors, medical devices, etc. As a special permanent magnet structure, multi-pole magnetic rings have the advantages of high precision, smooth operation and low noise in high-performance permanent magnet motors and sensors, and are the preferred choice for high-speed and high-precision control motors, playing an important role in industrial automation equipment, intelligent equipment, etc.

[0003] Traditional sintered neodymium-iron-boron multi-pole magnetic rings face many challenges in the preparation process. On the one hand, during the powder filling of the mold, due to the diversity of the size of the magnetic ring, especially for small-sized magnetic rings, the powder filling is difficult and has poor dispersibility, resulting in uneven distribution of the magnetic powder, which further affects the overall magnetic properties of the magnetic ring. On the other hand, during the pressing and demolding process, the existing process is prone to cause the pressing blank to be unshaped, resulting in low pressing qualification rate and difficult improvement of production efficiency. The existing sintered neodymium-iron-boron multi-pole magnetic rings also have technical defects such as insufficient surface magnetic strength, uneven magnetic property distribution, and cracking caused by sintering shrinkage anisotropy.

[0004] In order to solve the above problems, a Chinese invention patent with authorization publication number CN112164575B discloses a manufacturing method of small-sized sintered neodymium-iron-boron multi-pole magnetic ring, which adopts a pneumatic pressing device to press and form sintered neodymium-iron-boron powder, then takes out the pressing blank for isostatic pressing treatment, high-temperature sintering, tempering treatment, and hole sleeving and grinding processing to obtain a sintered neodymium-iron-boron multi-pole magnetic ring. The pneumatic pressing device includes an orientation mechanism and a pressing mold, wherein the orientation mechanism is composed of an even number of sintered neodymium-iron-boron magnetic tiles uniformly distributed in the circumferential direction, and the sintered neodymium-iron-boron magnetic tiles form a mold mounting cavity around them, and the pressing mold is correspondingly mounted in the mold mounting cavity. The technical scheme of the present application can effectively manufacture small-sized sintered neodymium-iron-boron multi-pole magnetic rings, the manufacturing process is relatively convenient, the equipment investment cost is relatively low, the multi-stage magnetic ring has good magnetic properties, and the pressing qualification rate and overall efficiency are also improved. However, it only optimizes the magnetic properties from the preparation process and device aspects, and does not study the comprehensive magnetic properties of the multi-stage magnetic ring from the composition formula aspect. In addition, the comprehensive magnetic properties of the sintered neodymium-iron-boron multi-pole magnetic ring made by the patent still need to be further improved.

[0005] It can be seen that the high comprehensive magnetic performance sintered neodymium-iron-boron multi-pole magnetic ring with excellent comprehensive magnetic performance and low cracking rate and the preparation method thereof meet the market demand, have wide market value and application prospect, and have very important significance for promoting the development of the field of permanent magnet materials. SUMMARY

[0006] The main purpose of the present application is to provide a high comprehensive magnetic performance sintered neodymium-iron-boron multi-pole magnetic ring with excellent comprehensive magnetic performance and low cracking rate and a preparation method thereof.

[0007] To achieve the above purpose, the present application provides a high comprehensive magnetic performance sintered neodymium-iron-boron multi-pole magnetic ring, which is made of the following components by weight parts: rare earth alloy A 9-10 parts, rich rare earth alloy B 0.1-1 part, alloy C 0.8-1.2 parts, lubricant 0.01-0.03 parts, aviation gasoline 0.01-0.03 parts; the composition of the rare earth alloy A is (PrNd) a1 (TM) b1 (HM) c1 B d1 Fe 100-a1-b1-1c-d1 , the composition of the rich rare earth alloy B is (PrNd) a2 (TM) b2 (HM) c2 B d2 Fe 100-a2-b2-c2-d2 ; wherein TM is one or more of Al, Cu, Co, Mn, Ga, HM is one or more of Nb, Zr, Hf, Ti, V; a1, b1, c1, d1, a2, b2, c2, d2 all represent the weight percentage content, and 28.5≤a1≤29.5, 0<b1≤2, 0<c1≤0.3, 0.93≤d1≤1.02, 31.5≤a2≤33, 0<b2≤0.5, 0<c2≤0.1, 0.88≤d2≤0.92; the alloy C comprises the following components by mass percentage: rare earth element 29-32wt%, Ta 0.05-0.2wt%, In 0.1-0.3wt%, Re 0.02-0.08wt%, W 0.08-0.2wt%, Mo 0.1-0.4wt%, Ge 0.1-0.5wt%, B 0.9-1.2wt%, and the balance is Fe.

[0008] Preferably, the mass percentage content of Pr in PrNd is 60-80wt%.

[0009] Preferably, the aviation gasoline is aviation gasoline No. 75; and the lubricant is zinc stearate.

[0010] Preferably, the rare earth element is a mixture of Nd, Ce and Gd in a mass ratio of (1-3):1:(0.8-1.2).

[0011] Another object of the present application is to provide a preparation method of the sintered Nd-Fe-B multi-pole magnetic ring with high comprehensive magnetic properties.

[0012] Step S1, smelting and flaking: respectively according to the component of the rare earth alloy A, the rare earth alloy B and the alloy C, the smelting, casting, flaking and sieving are sequentially performed to obtain the rare earth alloy A cast sheet, the rare earth alloy B cast sheet and the alloy C cast sheet.

[0013] Step S2, powdering: the sieved rare earth alloy A cast sheet, the rare earth alloy B cast sheet and the alloy C cast sheet are respectively placed in a hydrogen crusher to be crushed into coarse powder; then the airflow milling process is adopted under the protection of nitrogen to obtain the airflow milled fine powder of the rare earth alloy A, the airflow milled fine powder of the rare earth alloy B and the airflow milled fine powder of the alloy C.

[0014] Step S3, powder mixing: the airflow milled fine powder of the rare earth alloy A, the airflow milled fine powder of the rare earth alloy B, the airflow milled fine powder of the alloy C, the lubricant and the aviation gasoline are mixed and stirred uniformly to obtain the mixed powder.

[0015] Step S4, orientation forming and isostatic pressing: the mixed powder is vertically oriented and pressed in a 1.2T magnetic field to form a blank, which is then pressed by the isostatic pressing process.

[0016] Step S5, sintering and aging treatment: the blank prepared by the step S4 is sintered, and then subjected to aging treatment to obtain the sintered Nd-Fe-B multi-pole magnetic ring with high comprehensive magnetic properties.

[0017] Preferably, the smelting temperature of the rare earth alloy A is 1455-1505℃, the casting temperature is 1445-1475℃, and the initial flake thickness of the flake obtained by smelting is 0.15-0.45mm.

[0018] Preferably, the smelting temperature of the rare earth alloy B is 1455-1505℃, the casting temperature is 1400-1445℃, and the initial flake thickness of the flake obtained by smelting is 0.15-0.45mm.

[0019] Preferably, the smelting temperature of the alloy C is 1450-1500℃, the casting temperature is 1420-1450℃, and the initial flake thickness of the flake obtained by smelting is 0.15-0.45mm.

[0020] Preferably, the average particle size of the airflow milled fine powder of the rare earth alloy A is 2.9-3.1μm; the average particle size of the airflow milled fine powder of the rare earth alloy B is 2.6-2.8μm; and the average particle size of the airflow milled fine powder of the alloy C is 2.5-3.0μm.

[0021] Preferably, the isostatic pressing process in step S4 adopts a segmented pressure maintaining process, the first stage pressure is 150-180 Mpa, the pressure maintaining time is 20-40 s, the second stage pressure is 200-220 Mpa, the pressure maintaining time is 40-60 s, then the pressure is released to 100-150 Mpa, the pressure maintaining time is 5-20 s, and finally the pressure is released to zero.

[0022] Preferably, the sintering in step S5 is a multi-stage sintering in a vacuum sintering furnace, the first stage sintering temperature is 150-200 DEG C, the time is 1-2 h, the second stage sintering temperature is 350-550 DEG C, the time is 1-2 h, the third stage sintering temperature is 1000-1050 DEG C, and the sintering time is 6-12 h; the vacuum degree in the sintering furnace is 5*10 -2 Pa or below.

[0023] Preferably, the aging treatment in step S5 adopts a three-stage aging process, the first stage aging treatment temperature is 600-860 DEG C, the time is 2-4 h, the second stage aging treatment temperature is 360-600 DEG C, the time is 2-4 h, and the third stage aging treatment temperature is 450-510 DEG C, the time is 2-4 h.

[0024] Due to the use of the above technical solutions, the application has the following beneficial effects:

[0025] (1) The preparation method of the high-comprehensive-magnetic-property sintered neodymium-iron-boron multi-pole magnetic ring disclosed by the application has simple preparation process, convenient operation control, low dependence on equipment, high preparation efficiency and high finished product qualification rate, is suitable for continuous large-scale production, and has high popularization and application value.

[0026] (2) The high-comprehensive-magnetic-property sintered neodymium-iron-boron multi-pole magnetic ring disclosed by the application is made of the following components in parts by weight: rare earth alloy A 9-10 parts, rich rare earth alloy B 0.1-1 part, alloy C 0.8-1.2 part, lubricant 0.01-0.03 part, and aviation gasoline 0.01-0.03 part; the composition of the rare earth alloy A is (PrNd) a1 (TM) b1 (HM) c1 B d1 Fe 100-a1-b1-1c-d1 , the composition of the rich rare earth alloy B is (PrNd) a2 (TM) b2 (HM) c2 B d2 Fe 100-a2-b2-c2-d2; wherein TM is one or more of Al, Cu, Co, Mn, Ga, and HM is one or more of Nb, Zr, Hf, Ti, V; a1, b1, c1, d1, a2, b2, c2, d2 each represent a weight percentage, and 28.5≤a1≤29.5, 0<b1≤2, 0<c1≤0.3, 0.93≤d1≤1.02, 31.5≤a2≤33, 0<b2≤0.5, 0<c2≤0.1, 0.88≤d2≤0.92; the alloy C comprises the following components in terms of mass percentage: rare earth elements 29-32wt%, Ta 0.05-0.2wt%, In 0.1-0.3wt%, Re 0.02-0.08wt%, W 0.08-0.2wt%, Mo 0.1-0.4wt%, Ge 0.1-0.5wt%, B 0.9-1.2wt%, and the balance being Fe. Through the mutual cooperation between the components and the components, the comprehensive magnetic properties of the prepared multi-pole magnetic ring are excellent, and the cracking rate is low. First, through the mutual matching of the rare earth-rich alloy B and the rare earth-poor alloy A and the alloy C, the uniform distribution of the grain boundary phase in the low-rare earth magnet is realized, thereby solving the contradiction between the remanence and the internal cracking rate of the magnetic ring product. Secondly, through the segmented isostatic pressing and pressure maintaining process, the stress segregation phenomenon caused by the forming orientation anisotropy of the ring-shaped product is slowed down, and the internal cracking rate of the magnetic ring is reduced. In addition, the multi-stage sintering / aging process is adopted to promote the degassing and degreasing of the magnetic ring during the liquid phase densification process, which on the one hand reduces the proportion of internal cracking, and on the other hand optimizes the structure of the grain boundary phase in the magnetic ring, which is helpful to the batch production of high-performance magnetic rings and the improvement of the comprehensive magnetic properties of the magnet.

[0027] (3) The high-comprehensive-magnetic-property sintered neodymium-iron-boron multi-pole magnetic ring disclosed in the application has a (PrNd) content of the rare earth-poor alloy A controlled in 28.5-29.5wt%, which provides a high remanence basis as a main phase; the (PrNd) content of the rare earth-rich alloy B is increased to 31.5-33wt%, and a rare earth-rich phase is formed through grain boundary diffusion, which significantly enhances the coercive force. This double-alloy process not only reduces the amount of heavy rare earth, but also optimizes the magnetic properties through grain boundary phase strengthening. TM elements such as Al, Cu, and Co can reduce the melting point of the grain boundary phase, promote the uniform distribution of the grain boundary liquid phase during sintering, and improve the bonding strength between the magnetic powders; HM elements such as Nb, Zr, and Hf can refine the grain size, inhibit the movement of magnetic domain walls, and improve the intrinsic coercive force.

[0028] (4) The high-comprehensive-magnetic-property sintered neodymium-iron-boron multi-pole magnetic ring disclosed in the application, the multi-element micro-alloying technology of alloy C, breaks through the performance bottleneck; the grain refinement effect of Ta and W, through the formation of TaC and WC nano precipitated phase, pins the grain boundary migration, reduces the average grain size, and improves the coercive force; the grain boundary wettability improvement of In, reduces the grain boundary surface energy, promotes the uniform coating of rare earth-rich phase on the main phase grain, and reduces the magnetic property fluctuation; the corrosion resistance enhancement of Ge, forms a dense oxide layer at the grain boundary, effectively prolongs the service time; the mutual cooperation of each element composition, makes the multi-stage magnetic ring product with excellent comprehensive magnetic property and low cracking rate.

[0029] (5) The high-comprehensive-magnetic-property sintered neodymium-iron-boron multi-pole magnetic ring disclosed in the application, through the reasonable selection of preparation process parameters, the comprehensive magnetic property of the multi-stage magnetic ring is better, the cracking rate is lower, and the service life is longer. DETAILED DESCRIPTION

[0030] The following description is used to disclose the application so that those skilled in the art can implement the application. The preferred embodiments in the following description are only as examples, and other obvious modifications can be thought of by those skilled in the art.

[0031] Embodiment 1: A high-comprehensive-magnetic-property sintered neodymium-iron-boron multi-pole magnetic ring is made of the following components by weight parts: rare earth-poor alloy A 9 parts, rare earth-rich alloy B 0.1 part, alloy C 0.8 part, lubricant 0.01 part, aviation gasoline 0.01 part; the composition of the rare earth-poor alloy A is (PrNd) a1 (TM) b1 (HM) c1 B d1 Fe 100-a1-b1-1c-d1 , the composition of the rare earth-rich alloy B is (PrNd) a2 (TM) b2 (HM) c2 B d2 Fe 100-a2-b2-c2-d2 ; wherein TM is Al, HM is Nb; a1, b1, c1, d1, a2, b2, c2, d2 all represent weight percentage content, and 28.5=a1, b1=0.2, c1=0.1, 0.93=d1, 31.5=a2, b2=0.1, c2=0.03, 0.88=d2; the alloy C includes the following components by mass percentage: rare earth element 29wt%, Ta 0.05wt%, In 0.1wt%, Re 0.02wt%, W 0.08wt%, Mo 0.1wt%, Ge 0.1wt%, B 0.9wt%, and the balance is Fe.

[0032] The mass percentage of Pr in the PrNd is 60wt%; the aviation gasoline is No. 75 aviation gasoline; the lubricant is zinc stearate; and the rare earth element is a mixture of Nd, Ce and Gd in a mass ratio of 1:1:0.8.

[0033] A preparation method of the high-comprehensive-magnetic-property sintered Nd-Fe-B multi-pole magnetic ring, comprising the following steps:

[0034] Step S1, smelting and flaking: respectively according to the component of the rare earth alloy A, the rare earth alloy B and the alloy C, sequentially through smelting, casting, flaking and sieving, the rare earth alloy A cast sheet, the rare earth alloy B cast sheet and the alloy C cast sheet are obtained;

[0035] Step S2, powdering: the sieved rare earth alloy A cast sheet, the rare earth alloy B cast sheet and the alloy C cast sheet are respectively placed in a hydrogen crusher to be crushed into coarse powder; then under the protection of nitrogen, the rare earth alloy A airflow-milled fine powder, the rare earth alloy B airflow-milled fine powder and the alloy C airflow-milled fine powder are respectively obtained by using airflow milling process;

[0036] Step S3, powder mixing: the rare earth alloy A airflow-milled fine powder, the rare earth alloy B airflow-milled fine powder, the alloy C airflow-milled fine powder, the lubricant and the aviation gasoline are mixed and stirred uniformly to obtain a mixed powder;

[0037] Step S4, orientation forming and isostatic pressing: the mixed powder is vertically oriented and pressed in a 1.2T magnetic field to form a blank, and then the blank is pressed by isostatic pressing process;

[0038] Step S5, sintering and aging treatment: the blank obtained by step S4 is sintered, and then subjected to aging treatment to obtain a high-comprehensive-magnetic-property sintered Nd-Fe-B multi-pole magnetic ring.

[0039] The smelting temperature of the rare earth alloy A is 1455℃, the casting temperature is 1445℃, and the initial flake thickness of the flake obtained by smelting is 0.45mm; the smelting temperature of the rare earth alloy B is 1455℃, the casting temperature is 1400℃, and the initial flake thickness of the flake obtained by smelting is 0.45mm; the smelting temperature of the alloy C is 1450℃, the casting temperature is 1420℃, and the initial flake thickness of the flake obtained by smelting is 0.45mm.

[0040] The average particle size of the rare earth alloy A airflow-milled fine powder is 2.9μm; the average particle size of the rare earth alloy B airflow-milled fine powder is 2.6μm; and the average particle size of the alloy C airflow-milled fine powder is 2.5μm.

[0041] The isostatic pressing process in step S4 adopts a segmented pressure maintaining process, the first stage pressure is 150 MPa, the pressure maintaining time is 20 s, the second stage pressure is 200 MPa, the pressure maintaining time is 40 s, then the pressure is released to 100 MPa, the pressure maintaining time is 5 s, and finally the pressure is released to zero.

[0042] The sintering in step S5 is a multi-stage sintering in a vacuum sintering furnace, the first stage sintering temperature is 150℃, the time is 1h, the second stage sintering temperature is 350℃, the time is 1h, the third stage sintering temperature is 1000℃, and the sintering time is 6h; the vacuum degree in the sintering furnace is 5×10 -2 Pa below; the aging treatment in step S5 adopts a three-stage aging process, the first stage aging treatment temperature is 600℃, the time is 2h, the second stage aging treatment temperature is 360℃, the time is 2h, and the third stage aging treatment temperature is 450℃, the time is 2h.

[0043] Embodiment 2: A sintered neodymium-iron-boron multi-pole magnetic ring with high comprehensive magnetic properties is made of the following components by weight parts: rare earth alloy A 9.3 parts, rare earth alloy B 0.3 parts, alloy C 0.9 parts, lubricant 0.015 parts, aviation gasoline 0.015 parts; the composition of the rare earth alloy A is (PrNd) a1 (TM) b1 (HM) c1 B d1 Fe 100-a1-b1-1c-d1 , the composition of the rare earth alloy B is (PrNd) a2 (TM) b2 (HM) c2 B d2 Fe 100-a2-b2-c2-d2 ; wherein, TM is Cu, HM is Zr; a1, b1, c1, d1, a2, b2, c2, d2 all represent the weight percentage content, and 28.9=a1, b1=0.5, c1=0.15, 0.95=d1, 32=a2, b2=0.2, c2=0.03, 0.89=d2; the alloy C includes the following components by mass percentage: rare earth element 30wt%, Ta 0.09wt%, In 0.15wt%, Re 0.04wt%, W 0.12wt%, Mo 0.2wt%, Ge 0.2wt%, B 1wt%, and the balance is Fe.

[0044] The mass percentage content of Pr in the PrNd is 65wt%; the aviation gasoline is aviation gasoline No. 75; the lubricant is zinc stearate; the rare earth element is a mixture of Nd, Ce, and Gd in a mass ratio of 1.5:1:0.9.

[0045] A preparation method of the high comprehensive magnetic performance sintered neodymium-iron-boron multi-pole magnetic ring, comprising the following steps:

[0046] Step S1, smelting and flaking: respectively according to the component of the rare earth alloy A, the rare earth alloy B and the alloy C, sequentially through smelting, casting, flaking and sieving, the rare earth alloy A cast sheet, the rare earth alloy B cast sheet and the alloy C cast sheet are obtained;

[0047] Step S2, powdering: the sieved rare earth alloy A cast sheet, the rare earth alloy B cast sheet and the alloy C cast sheet are respectively placed in a hydrogen crusher to be hydrogen crushed into coarse powder; then the airflow grinding process is adopted under nitrogen protection to obtain the airflow ground fine powder of the rare earth alloy A, the airflow ground fine powder of the rare earth alloy B and the airflow ground fine powder of the alloy C;

[0048] Step S3, powder mixing: the airflow ground fine powder of the rare earth alloy A, the airflow ground fine powder of the rare earth alloy B, the airflow ground fine powder of the alloy C, a lubricant and aviation gasoline are mixed and stirred uniformly to obtain a mixed powder;

[0049] Step S4, orientation forming and isostatic pressing: the mixed powder is vertically oriented and pressed in a 1.2T magnetic field to form a blank, and then the isostatic pressing process is adopted to press the blank;

[0050] Step S5, sintering and aging treatment: the blank prepared in step S4 is sintered, and then subjected to aging treatment to obtain a high comprehensive magnetic performance sintered neodymium-iron-boron multi-pole magnetic ring.

[0051] The smelting temperature of the rare earth alloy A is 1470℃, the casting temperature is 1455℃, and the initial flake thickness of the flake obtained by smelting is 0.35mm; the smelting temperature of the rare earth alloy B is 1475℃, the casting temperature is 1420℃, and the initial flake thickness of the flake obtained by smelting is 0.35mm; the smelting temperature of the alloy C is 1470℃, the casting temperature is 1430℃, and the initial flake thickness of the flake obtained by smelting is 0.35mm.

[0052] The average particle size of the airflow ground fine powder of the rare earth alloy A is 3.0μm; the average particle size of the airflow ground fine powder of the rare earth alloy B is 2.7μm; the average particle size of the airflow ground fine powder of the alloy C is 2.6μm; the isostatic pressing process in step S4 adopts a segmented pressure maintaining process, the first stage pressure is 160Mpa, the pressure maintaining time is 25s, the second stage pressure is 205Mpa, the pressure maintaining time is 45s, then the pressure is released to 110Mpa, the pressure maintaining time is 8s, and finally the pressure is released to zero.

[0053] The sintering in step S5 is multi-stage sintering in a vacuum sintering furnace, the first stage sintering temperature is 160℃, the time is 1.2h, the second stage sintering temperature is 400℃, the time is 1.2h, the third stage sintering temperature is 1015℃, and the sintering time is 7h; the vacuum degree in the sintering furnace is 5×10 -2 The aging treatment in step S5 adopts a three-stage aging process, the first stage aging treatment temperature is 700℃, the time is 2.5h, the second stage aging treatment temperature is 450℃, the time is 2.5h, and the third stage aging treatment temperature is 470℃, the time is 2.5h.

[0054] Example 3: A high-comprehensive-magnetic-property sintered neodymium-iron-boron multi-pole magnetic ring is made of the following components by weight parts: rare earth alloy A 9.5 parts, rare earth alloy B 0.6 parts, alloy C 1 part, lubricant 0.02 part, aviation gasoline 0.02 part; the composition of the rare earth alloy A is (PrNd) a1 (TM) b1 (HM) c1 B d1 Fe 100-a1-b1-1c-d1 , the composition of the rare earth alloy B is (PrNd) a2 (TM) b2 (HM) c2 B d2 Fe 100-a2-b2-c2-d2 ; wherein, TM is Co, HM is Hf; a1, b1, c1, d1, a2, b2, c2, d2 all represent the weight percentage content, and 29=a1, b1=1, c1=0.15, 0.98=d1, 32.2=a2, b2=0.35, c2=0.05, 0.9=d2; the alloy C includes the following components by mass percentage: rare earth element 31wt%, Ta 0.13wt%, In 0.15wt%, Re 0.05wt%, W 0.13wt%, Mo 0.25wt%, Ge 0.3wt%, B 1wt%, and the balance is Fe.

[0055] The mass percentage content of Pr in the PrNd is 70wt%; the aviation gasoline is aviation gasoline No. 75; the lubricant is zinc stearate; and the rare earth element is a mixture of Nd, Ce, and Gd in a mass ratio of 2:1:1.

[0056] A preparation method of the high-comprehensive-magnetic-property sintered neodymium-iron-boron multi-pole magnetic ring includes the following steps:

[0057] Step S1, smelting and flaking: respectively according to the component of the rare earth alloy A, the rare earth alloy B, and the alloy C, the components are proportioned, and then sequentially subjected to smelting, casting, flaking, and sieving to obtain the rare earth alloy A cast piece, the rare earth alloy B cast piece, and the alloy C cast piece.

[0058] Step S2, powdering: the sieved lean rare earth alloy A cast piece, the rich rare earth alloy B cast piece and the alloy C cast piece are respectively placed in a hydrogen crusher to be hydrogen-crushed into coarse powder; then the lean rare earth alloy A airflow-milled fine powder, the rich rare earth alloy B airflow-milled fine powder and the alloy C airflow-milled fine powder are respectively obtained by using an airflow mill process under nitrogen protection;

[0059] Step S3, powder mixing: the lean rare earth alloy A airflow-milled fine powder, the rich rare earth alloy B airflow-milled fine powder, the alloy C airflow-milled fine powder, a lubricant and aviation gasoline are mixed, and after being stirred uniformly, a mixed powder is obtained;

[0060] Step S4, orientation forming and isostatic pressing: the mixed powder is vertically oriented and pressed in a 1.2T magnetic field to form a blank, and then the blank is pressed by an isostatic pressing process;

[0061] Step S5, sintering and aging treatment: the blank formed by Step S4 is sintered, and then subjected to aging treatment to obtain a high-comprehensive-magnetic-property sintered neodymium-iron-boron multi-pole magnetic ring.

[0062] The melting temperature of the lean rare earth alloy A is 1480℃, the casting temperature is 1460℃, and the initial thickness of the cast piece obtained by melting is 0.3mm; the melting temperature of the rich rare earth alloy B is 1480℃, the casting temperature is 1425℃, and the initial thickness of the cast piece obtained by melting is 0.3mm; the melting temperature of the alloy C is 1475℃, the casting temperature is 1435℃, and the initial thickness of the cast piece obtained by melting is 0.3mm; the average particle size of the airflow-milled fine powder of the lean rare earth alloy A is 3μm; the average particle size of the airflow-milled fine powder of the rich rare earth alloy B is 2.7μm; and the average particle size of the airflow-milled fine powder of the alloy C is 2.8μm.

[0063] The isostatic pressing process in Step S4 adopts a segmented pressure maintaining process, the first stage pressure is 165Mpa, the pressure maintaining time is 30s, the second stage pressure is 210Mpa, the pressure maintaining time is 50s, then the pressure is released to 130Mpa, the pressure maintaining time is 13s, and finally the pressure is released to zero.

[0064] The sintering in Step S5 is a multi-stage sintering process in a vacuum sintering furnace, the first stage sintering temperature is 180℃, the time is 1.5h, the second stage sintering temperature is 450℃, the time is 1.5h, the third stage sintering temperature is 1030℃, and the sintering time is 9h; the vacuum degree in the sintering furnace is 5×10 -2 Pa or below; the aging treatment in Step S5 adopts a three-stage aging process, the first stage aging treatment temperature is 740℃, the time is 3h, the second stage aging treatment temperature is 460℃, the time is 3h, and the third stage aging treatment temperature is 480℃, the time is 3h.

[0065] Example 4: A high-comprehensive magnetic performance sintered neodymium-iron-boron multi-pole magnetic ring is made of the following components by weight parts: lean rare earth alloy A 9.9 parts, rich rare earth alloy B 0.9 parts, alloy C 1.1 parts, lubricant 0.025 parts, aviation gasoline 0.025 parts; the composition of the lean rare earth alloy A is (PrNd) a1 (TM) b1 (HM) c1 B d1 Fe 100-a1-b1-1c-d1 , the composition of the rich rare earth alloy B is (PrNd) a2 (TM) b2 (HM) c2 B d2 Fe 100-a2-b2-c2-d2 ; wherein TM is a mixture of Al, Cu, Co, Mn, Ga in a mass ratio of 1:2:1:1:0.2, and HM is a mixture of Nb, Zr, Hf, Ti, V in a mass ratio of 0.8:1:1.2:1:2; a1, b1, c1, d1, a2, b2, c2, d2 all represent weight percentage contents, and a1=29.3, b1=1.7, c1=0.25, d1=1, a2=32.5, b2=0.4, c2=0.08, d2=0.91; the alloy C includes the following components by mass percentage: rare earth elements 31wt%, Ta 0.18wt%, In 0.25wt%, Re 0.07wt%, W 0.18wt%, Mo 0.35wt%, Ge 0.4wt%, B 1.1wt%, and the balance is Fe.

[0066] The mass percentage content of Pr in the PrNd is 75wt%; the aviation gasoline is aviation gasoline No. 75; the lubricant is zinc stearate; and the rare earth elements are a mixture of Nd, Ce, Gd in a mass ratio of 2.5:1:1.1.

[0067] A preparation method of the high-comprehensive magnetic performance sintered neodymium-iron-boron multi-pole magnetic ring, comprising the following steps:

[0068] Step S1, smelting and flaking: respectively according to the composition of the lean rare earth alloy A, the rich rare earth alloy B, and the alloy C, the components are proportioned, and then sequentially subjected to smelting, casting, flaking, and sieving to obtain lean rare earth alloy A cast pieces, rich rare earth alloy B cast pieces, and alloy C cast pieces;

[0069] Step S2, powdering: the sieved lean rare earth alloy A cast pieces, the rich rare earth alloy B cast pieces, and the alloy C cast pieces are respectively placed in a hydrogen crusher to be hydrogen-crushed into coarse powders; and then under nitrogen protection, airflow milling process is adopted to obtain lean rare earth alloy A airflow milled fine powder, rich rare earth alloy B airflow milled fine powder, and alloy C airflow milled fine powder, respectively;

[0070] Step S3, mixing powder: mix the air-jet-milled fine powder of the rare-earth-lean alloy A, the air-jet-milled fine powder of the rare-earth-rich alloy B, the air-jet-milled fine powder of the alloy C, the lubricant and the aviation gasoline, and obtain the mixed powder after stirring uniformly;

[0071] Step S4, orientation forming and isostatic pressing: vertically orient and press the mixed powder in a 1.2T magnetic field to form a blank, and then press the blank by isostatic pressing process;

[0072] Step S5, sintering and aging treatment: sinter the blank formed in Step S4, and then perform aging treatment to obtain the sintered Nd-Fe-B multi-pole magnetic ring with high comprehensive magnetic performance.

[0073] The melting temperature of the rare-earth-lean alloy A is 1500℃, the casting temperature is 1470℃, and the initial thickness of the spun sheet obtained by melting is 0.2mm; the melting temperature of the rare-earth-rich alloy B is 1500℃, the casting temperature is 1440℃, and the initial thickness of the spun sheet obtained by melting is 0.2mm; the melting temperature of the alloy C is 1490℃, the casting temperature is 1445℃, and the initial thickness of the spun sheet obtained by melting is 0.2mm.

[0074] The average particle size of the air-jet-milled fine powder of the rare-earth-lean alloy A is 3.1μm; the average particle size of the air-jet-milled fine powder of the rare-earth-rich alloy B is 2.8μm; and the average particle size of the air-jet-milled fine powder of the alloy C is 2.9μm.

[0075] The isostatic pressing process in Step S4 adopts a segmented pressure maintaining process, the first stage pressure is 175Mpa, the pressure maintaining time is 35s, the second stage pressure is 215Mpa, the pressure maintaining time is 55s, then the pressure is released to 140Mpa, the pressure maintaining time is 18s, and finally the pressure is released to zero; the sintering in Step S5 is a multi-stage sintering process in a vacuum sintering furnace, the first stage sintering temperature is 190℃, the time is 1.8h, the second stage sintering temperature is 530℃, the time is 1.8h, the third stage sintering temperature is 1040℃, and the sintering time is 11h; the vacuum degree in the sintering furnace is 5×10 -2 Pa or below.

[0076] The aging treatment in Step S5 adopts a three-stage aging process, the first stage aging treatment temperature is 840℃, the time is 3.5h, the second stage aging treatment temperature is 580℃, the time is 3.5h, and the third stage aging treatment temperature is 500℃, the time is 3.5h.

[0077] Example 5: a sintered Nd-Fe-B multi-pole magnetic ring with high comprehensive magnetic performance is made from the following components by weight parts: rare-earth-lean alloy A 10 parts, rare-earth-rich alloy B 1 part, alloy C 1.2 parts, lubricant 0.03 parts, aviation gasoline 0.03 parts; the composition of the rare-earth-lean alloy A is (PrNd)a1 (TM) b1 (HM) c1 B d1 Fe 100-a1-b1-1c-d1 , the composition of the rare earth-rich alloy B is (PrNd) a2 (TM) b2 (HM) c2 B d2 Fe 100-a2-b2-c2-d2 ; wherein TM is Ga, HM is Ti; a1, b1, c1, d1, a2, b2, c2, d2 all represent the weight percentage content, and a1=29.5, b1=2, c1=0.3, d1=1.02, a2=33, b2=0.5, c2=0.1, d2=0.92; the alloy C comprises the following components in percentage by mass: rare earth elements 32wt%, Ta 0.2wt%, In 0.3wt%, Re 0.08wt%, W 0.2wt%, Mo 0.4wt%, Ge 0.5wt%, B 1.2wt%, and the balance is Fe.

[0078] The mass percentage content of Pr in the PrNd is 80wt%; the aviation gasoline is aviation gasoline No. 75; the lubricant is zinc stearate; and the rare earth element is a mixture of Nd, Ce and Gd in a mass ratio of 3:1:1.2.

[0079] A preparation method of the high-comprehensive-magnetic-property sintered neodymium-iron-boron multi-pole magnetic ring, comprising the following steps:

[0080] Step S1, smelting and flaking: respectively according to the component of the rare earth-poor alloy A, the rare earth-rich alloy B and the alloy C, sequentially through smelting, casting, flaking and sieving, the rare earth-poor alloy A cast piece, the rare earth-rich alloy B cast piece and the alloy C cast piece are obtained;

[0081] Step S2, powdering: the sieved rare earth-poor alloy A cast piece, the rare earth-rich alloy B cast piece and the alloy C cast piece are respectively placed in a hydrogen crusher to be hydrogen-crushed into coarse powder; then under nitrogen protection, the rare earth-poor alloy A airflow-milled fine powder, the rare earth-rich alloy B airflow-milled fine powder and the alloy C airflow-milled fine powder are respectively obtained by using airflow milling process;

[0082] Step S3, powder mixing: the rare earth-poor alloy A airflow-milled fine powder, the rare earth-rich alloy B airflow-milled fine powder, the alloy C airflow-milled fine powder, the lubricant and the aviation gasoline are mixed, and after uniform stirring, the mixed powder is obtained;

[0083] Step S4, orientation forming and isostatic pressing: the mixed powder is vertically oriented and pressed in a 1.2T magnetic field to form a blank, and then the blank is pressed by isostatic pressing process;

[0084] Step S5, sintering, aging treatment: the blank made in step S4 is sintered, and then aged to obtain a sintered Nd-Fe-B multi-pole magnetic ring with high comprehensive magnetic properties.

[0085] The melting temperature of the rare earth lean alloy A is 1505℃, the casting temperature is 1475℃, and the initial thickness of the spun sheet obtained by melting is 0.15mm; the melting temperature of the rare earth rich alloy B is 1505℃, the casting temperature is 1445℃, and the initial thickness of the spun sheet obtained by melting is 0.15mm; the melting temperature of the alloy C is 1500℃, the casting temperature is 1450℃, and the initial thickness of the spun sheet obtained by melting is 0.15mm.

[0086] The average particle size of the air-milling fine powder of the rare earth lean alloy A is 3.1μm; the average particle size of the air-milling fine powder of the rare earth rich alloy B is 2.8μm; the average particle size of the air-milling fine powder of the alloy C is 3.0μm; the isostatic pressing process in step S4 adopts a segmented pressure maintaining process, the first stage pressure is 180Mpa, the pressure maintaining time is 40s, the second stage pressure is 220Mpa, the pressure maintaining time is 60s, then the pressure is released to 150Mpa, the pressure maintaining time is 20s, and finally the pressure is released to zero.

[0087] The sintering in step S5 is multi-stage sintering in a vacuum sintering furnace, the first stage sintering temperature is 200℃, the time is 2h, the second stage sintering temperature is 550℃, the time is 2h, the third stage sintering temperature is 1050℃, and the sintering time is 12h; the vacuum degree in the sintering furnace is 5×10 -2 Pa or below.

[0088] The aging treatment in step S5 adopts a three-stage aging process, the first stage aging treatment temperature is 860℃, the time is 4h, the second stage aging treatment temperature is 600℃, the time is 4h, and the third stage aging treatment temperature is 510℃, the time is 4h.

[0089] Comparative Example 1

[0090] A sintered Nd-Fe-B multi-pole magnetic ring with high comprehensive magnetic properties and a preparation method thereof, which are basically the same as those of Example 1, except that an equal amount of rare earth rich alloy B is used instead of alloy C.

[0091] Comparative Example 2

[0092] A sintered Nd-Fe-B multi-pole magnetic ring with high comprehensive magnetic properties and a preparation method thereof, which are basically the same as those of Example 1, except that an equal amount of alloy C is used instead of rare earth rich alloy B.

[0093] In order to further illustrate the beneficial technical effects of the high-comprehensive-magnetic-property sintered Nd-Fe-B multi-pole magnetic ring involved in the embodiments of the present application, the high-comprehensive-magnetic-property sintered Nd-Fe-B multi-pole magnetic rings involved in Examples 1-5 and Comparative Examples 1-2 are subjected to relevant performance tests, and the test results are shown in Table 1, and the test methods are as follows: the magnetic properties of the multi-pole magnetic rings are detected according to GB / T 3217-2013; in the continuous production process, the forming conditions of 1000 magnetic rings are counted, the number of the qualified magnetic rings is calculated, and the ratio of the qualified magnetic rings in the total production number is obtained to obtain the pressing qualification rate, and the test results are shown in Table 1.

[0094] Table 1 Performance test results of high-comprehensive-magnetic-property sintered Nd-Fe-B multi-pole magnetic rings

[0095] Item Remanence of magnetic ring Br Coercivity Hcj Pressing yield rate Unit kGs KOe % Example 1 14.03 25.63 99 Example 2 14.10 25.07 99 Example 3 14.31 24.75 100 Example 4 14.50 24.24 100 Example 5 14.74 24.08 100 Comparative Example 1 12.80 21.32 93 Comparative Example 2 13.00 20.45 90

[0096] As shown in Table 1, the high-comprehensive-magnetic-property sintered Nd-Fe-B multi-pole magnetic rings disclosed in the embodiments of the present application have more excellent comprehensive magnetic properties and higher pressing qualification rate than the products of the comparative examples; the combination use of the rare earth-rich alloy B and the alloy C is beneficial to improving the above-mentioned properties.

[0097] The above shows and describes the basic principles, main features and advantages of the present application. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection claimed by the present application is defined by the appended claims and their equivalents.

Claims

1. A sintered neodymium-iron-boron multipole magnetic ring with high overall magnetic properties, characterized in that The following components are used by weight parts: rare earth alloy A 9-10 parts, rare earth alloy B 0.1-1 parts, alloy C 0.8-1.2 parts, lubricant 0.01-0.03 parts, aviation gasoline 0.01-0.03 parts; the composition of the rare earth alloy A is (PrNd) a1 (TM) b1 (HM) c1 B d1 Fe 100-a1-b1-1c-d1 The composition of the rare earth alloy B is (PrNd) a2 (TM) b2 (HM) c2 B d2 Fe 100-a2-b2-c2-d2 ; wherein TM is one or more of Al, Cu, Co, Mn, Ga, and HM is one or more of Nb, Zr, Hf, Ti, V; a1, b1, c1, d1, a2, b2, c2, d2 all represent weight percentage contents, and 28.5≤a1≤29.5, 0 The alloy C includes the following components by mass percentage: rare earth elements 29-32 wt%, Ta 0.05-0.2 wt%, In 0.1-0.3 wt%, Re 0.02-0.08 wt%, W 0.08-0.2 wt%, Mo 0.1-0.4 wt%, Ge 0.1-0.5 wt%, B 0.9-1.2 wt%, and the balance is Fe.

2. The high-comprehensive-magnetic-property sintered neodymium-iron-boron multipole ring according to claim 1, characterized in that, The mass percentage of Pr in the PrNd is 60-80wt%; the aviation gasoline is aviation gasoline No.75; and the lubricant is zinc stearate.

3. The high comprehensive magnetic property sintered neodymium-iron-boron multipole ring of claim 1, wherein, The rare earth elements are Nd, Ce and Gd mixed in a mass ratio of (1-3):1:(0.8-1.2).

4. A method for producing a sintered neodymium-iron-boron multipole magnetic ring having high overall magnetic properties according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: Step S1, smelting and flaking: the components of the lean rare earth alloy A, the rich rare earth alloy B and the alloy C are respectively charged, and then sequentially subjected to smelting, casting, flaking and sieving to obtain the lean rare earth alloy A cast sheet, the rich rare earth alloy B cast sheet and the alloy C cast sheet; Step S2, powdering: the sieved lean rare earth alloy A cast sheet, the sieved rich rare earth alloy B cast sheet and the sieved alloy C cast sheet are respectively placed in a hydrogen crusher to be hydrogen-crushed into coarse powder; and then the lean rare earth alloy A gas jet mill fine powder, the rich rare earth alloy B gas jet mill fine powder and the alloy C gas jet mill fine powder are respectively obtained by using a gas jet mill process under nitrogen protection; Step S3, powder mixing: the lean rare earth alloy A gas jet mill fine powder, the rich rare earth alloy B gas jet mill fine powder, the alloy C gas jet mill fine powder, the lubricant and the aviation gasoline are mixed and stirred uniformly to obtain a mixed powder; Step S4, orientation forming and isostatic pressing: the mixed powder is vertically oriented and pressed in a 1.2T magnetic field to form a blank, and then the blank is subjected to isostatic pressing; Step S5, sintering and aging treatment: the blank obtained in step S4 is sintered, and then subjected to aging treatment to obtain a high-comprehensive-magnetic-property sintered Nd-Fe-B multi-pole magnetic ring.

5. The method of producing high comprehensive magnetic property sintered neodymium-iron-boron multipole magnetic ring according to claim 4, characterized in that, The smelting temperature of the lean rare earth alloy A is 1455-1505℃, the casting temperature is 1445-1475℃, and the initial flake thickness of the flake obtained by smelting is 0.15-0.45mm; the smelting temperature of the rich rare earth alloy B is 1455-1505℃, the casting temperature is 1400-1445℃, and the initial flake thickness of the flake obtained by smelting is 0.15-0.45mm.

6. The method of producing high comprehensive magnetic property sintered neodymium-iron-boron multipole magnetic ring according to claim 4, characterized in that, The smelting temperature of the alloy C is 1450-1500℃, the casting temperature is 1420-1450℃, and the initial flake thickness of the flake obtained by smelting is 0.15-0.45mm.

7. The method of producing high comprehensive magnetic property sintered neodymium-iron-boron multipole magnetic ring according to claim 4, characterized in that, The average particle size of the lean rare earth alloy A gas jet mill fine powder is 2.9-3.1μm; the average particle size of the rich rare earth alloy B gas jet mill fine powder is 2.6-2.8μm; and the average particle size of the alloy C gas jet mill fine powder is 2.5-3.0μm.

8. The method of producing high comprehensive magnetic property sintered neodymium-iron-boron multipole magnetic ring according to claim 4, characterized in that, The isostatic pressing process in step S4 adopts a segmented pressure maintaining process, the first stage pressure is 150-180Mpa, the pressure maintaining time is 20-40s, the second stage pressure is 200-220Mpa, the pressure maintaining time is 40-60s, then the pressure is released to 100-150Mpa, the pressure maintaining time is 5-20s, and finally the pressure is released to zero.

9. The method of producing high comprehensive magnetic property sintered neodymium-iron-boron multipole magnetic ring according to claim 4, characterized in that, The sintering in step S5 is a multi-stage sintering process in a vacuum sintering furnace, the first stage sintering temperature is 150-200℃, the time is 1-2h, the second stage sintering temperature is 350-550℃, the time is 1-2h, the third stage sintering temperature is 1000-1050℃, and the sintering time is 6-12h; the vacuum degree in the sintering furnace is below 5×10-2Pa.

10. The method of producing high comprehensive magnetic property sintered neodymium-iron-boron multipole magnetic ring according to claim 4, characterized in that, The aging treatment in step S5 adopts a three-stage aging process, the first stage aging treatment temperature is 600-860 ℃, the time is 2-4 h, the second stage aging treatment temperature is 360-600 ℃, the time is 2-4 h, and the third stage aging treatment temperature is 450-510 ℃, the time is 2-4 h.