Modified high-Ce sintered neodymium-iron-boron magnet and preparation method and application thereof

Abstract

The invention discloses a modified high-Ce sintered neodymium-iron-boron magnet and a preparation method and application thereof, and belongs to the technical field of permanent magnet materials, the modified high-Ce sintered neodymium-iron-boron magnet comprises the following components: (R, Ce) a Fe100-a-b-c Mb Bc, R comprises at least one of Pr, Nd, Ce, Ho and Gd, M comprises at least one of Cu, Al, Zr, Co and Ga, 30.5 wt.% < = a < = 32 wt.%, 0.01 wt.% < = b < = 1.2 wt.%, and 0.8 wt.% < = c < = 1 wt.%. By reasonably optimizing the content of heavy rare earth elements such as Ho and Gd in the formula, the high-temperature coercive force performance of the Ce-containing magnet is accurately adjusted, the development requirements of the sintered neodymium-iron-boron magnet for the electric two-wheeled vehicle with low cost and low demagnetization rate can be met, and the sintered neodymium-iron-boron magnet for the electric two-wheeled vehicle is specifically designed.

Description

Technical Field

[0001] The invention belongs to the technical field of permanent magnetic materials, and in particular relates to a modified high-Ce sintered NdFeB magnet and a preparation method and application thereof. Background Art

[0002] At present, almost all the blanks required for electric two-wheeled vehicle products use Ce-containing magnets, and the content of Ce elements is usually above 5wt.%, which belongs to the high Ce content magnets. However, the high-temperature thermal demagnetization performance of a single high-Ce magnet is poor and cannot meet the requirements of electric two-wheeled vehicle products for magnet performance. Therefore, the existing technology usually adds heavy rare earth elements such as Ho and Gd to Ce-containing magnets to reduce the high-temperature thermal demagnetization rate of the magnet. Heavy rare earth elements such as Ho and Gd are expensive. Unreasonable addition will not only increase the manufacturing cost of the blank, but also make the blank performance excessive, and also cause a waste of heavy rare earth resources. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a modified high-Ce sintered NdFeB magnet and a preparation method thereof, so as to solve the problems of high blank manufacturing cost, excessive or low blank performance, and waste of heavy rare earth resources caused by irrational addition of heavy rare earth elements such as Ho and Gd in existing sintered NdFeB magnets for electric two-wheeled vehicles.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] The present invention provides a modified high-Ce sintered NdFeB magnet, which comprises the following components:

[0006] (R,Ce) a Fe 100-a-b-c M b B c , R includes at least one of Pr, Nd, Ce, Ho, and Gd, M includes at least one of Cu, Al, Zr, Co, and Ga, and 30.5wt.%≤a≤32wt.%, 0.01wt.%≤b≤1.2wt.%, and 0.8wt.%≤c≤1wt.%.

[0007] In the present invention, the content of a is preferably 31.5 wt.%, where wt.% refers to the percentage of the total mass of the modified high-Ce sintered NdFeB magnet.

[0008] In the present invention, the Nd content is preferably 18.5-21.5wt.%, such as 18.5wt.%, 19.5wt.%, 20wt.% or 20.5wt.%, where wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0009] In the present invention, the Ce content is preferably 18.5-10 wt.%, where wt.% refers to the percentage of the total mass of the modified high-Ce sintered NdFeB magnet.

[0010] In the present invention, the modified high-Ce sintered NdFeB magnet further includes RH, and the RH is a heavy rare earth element.

[0011] The content of RH may be conventional in the art, preferably 0.8-3.2 wt.%, such as 1 wt.%, 2 wt.%, 3 wt.% or 1.5 wt.%, where wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0012] The type of RH can be conventional in the art, preferably Ho and / or Gd.

[0013] When the RH contains Ho, the content of Ho is preferably 0-3 wt.%, such as 0.5 wt.%, 1 wt.%, 2 wt.% or 3 wt.%, where wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0014] When the RH contains Gd, the content of Gd is preferably 0-3 wt.%, such as 0.5 wt.%, 1 wt.%, 2 wt.% or 3 wt.%, where wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0015] In a preferred embodiment of the present invention, the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 20.5wt.%, Ho 1wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co0.5wt.%, Zr 0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0016] In a preferred embodiment of the present invention, the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 19.5wt.%, Ho 2wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co0.5wt.%, Zr 0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0017] In a preferred embodiment of the present invention, the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 18.5wt.%, Ho 3wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co0.5wt.%, Zr 0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0018] In a preferred embodiment of the present invention, the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 20.5wt.%, Gd 1wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co0.5wt.%, Zr 0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0019] In a preferred embodiment of the present invention, the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 19.5wt.%, Gd 2wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co0.5wt.%, Zr 0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0020] In a preferred embodiment of the present invention, the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 18.5wt.%, Gd 3wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co0.5wt.%, Zr 0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0021] In a preferred embodiment of the present invention, the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 20wt.%, Ho 0.5wt.%, Gd 1wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu0.1wt.%, Co 0.5wt.%, Zr0.3wt.%, B 0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0022] In a preferred embodiment of the present invention, the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 20wt.%, Ho 1wt.%, Gd 0.5wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu0.1wt.%, Co 0.5wt.%, Zr0.3wt.%, B 0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0023] In a preferred embodiment of the present invention, the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 19.5wt.%, Ho 1wt.%, Gd 1wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu0.1wt.%, Co 0.5wt.%, Zr0.3wt.%, B 0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0024] In a preferred embodiment of the present invention, the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 18.5wt.%, Ho 1wt.%, Gd 2wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu0.1wt.%, Co 0.5wt.%, Zr0.3wt.%, B 0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0025] In a preferred embodiment of the present invention, the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 19.5wt.%, Ho 2wt.%, Gd 1wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu0.1wt.%, Co 0.5wt.%, Zr0.3wt.%, B 0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

[0026] The present invention also provides a method for preparing the modified high-Ce sintered NdFeB magnet, the method comprising:

[0027] S1, at 5×10 -2 Pa vacuum environment, melting at a temperature of 1500-1550°C and then rapidly solidifying to prepare high Ce magnet alloy flakes, high Ce Ho-containing alloy flakes and high Ce Gd-containing alloy flakes respectively;

[0028] S2, subjecting the high Ce magnet alloy flakes, high Ce Ho-containing alloy flakes and high Ce Gd-containing alloy flakes in S1 to hydrogen absorption, and then subjecting them to vacuum dehydrogenation treatment at 500-600°C to obtain high Ce magnet alloy coarse powder, high Ce Ho-containing alloy coarse powder and high Ce Gd-containing alloy coarse powder, respectively, with a particle size of 100-125 μm; subjecting them to jet milling in an atmosphere with an oxygen content of less than 10 ppm to obtain high Ce magnet alloy fine powder, high Ce Ho-containing alloy fine powder and high Ce Gd-containing alloy fine powder, respectively, with a particle size of 3.6-4.5 μm;

[0029] S3, mixing the high Ce magnet alloy finely pulverized powder in S2 with at least one of a high Ce Ho-containing alloy finely pulverized powder and a high Ce Gd-containing alloy finely pulverized powder to obtain a modified alloy powder;

[0030] S4. Orient and press the modified alloy powder in S3 in a press with a magnetic field strength of 1.0-2.0T, and then isostatically press at a pressure of 200MPa, and then sinter at a temperature of 1050-1090°C and age at a temperature of 400-800°C to obtain the modified high Ce sintered NdFeB magnet.

[0031] In the present invention, the mass ratio of Ce magnet alloy finely crushed powder, high Ce Ho-containing alloy finely crushed powder and high Ce Gd-containing alloy finely crushed powder is preferably (1-3.3):(0-10):(0-10), for example 3:1:0, 1:1:0, 3.3:10:0, 3:0:1, 1:0:1, 3.3:0:10, 1:5:2, 2:5:1, 2:1:1, 1:1:2 or 2:1:1.

[0032] In a preferred embodiment of the present invention, when the modified alloy powder is mixed with high Ce magnet alloy finely pulverized powder and high Ce Ho-containing alloy finely pulverized powder, the mass ratio is 3:1.

[0033] In a preferred embodiment of the present invention, when the modified alloy powder is mixed with high Ce magnet alloy finely pulverized powder and high Ce Ho-containing alloy finely pulverized powder, the mass ratio is 1:1.

[0034] In a preferred embodiment of the present invention, when the modified alloy powder is mixed with high Ce magnet alloy finely pulverized powder and high Ce Ho-containing alloy finely pulverized powder, the mass ratio is 3.3:10.

[0035] In a preferred embodiment of the present invention, when the modified alloy powder is mixed with high Ce magnet alloy finely pulverized powder and high Ce Gd-containing alloy finely pulverized powder, the mass ratio is 3:1.

[0036] In a preferred embodiment of the present invention, when the modified alloy powder is mixed with high Ce magnet alloy finely pulverized powder and high Ce Gd-containing alloy finely pulverized powder, the mass ratio is 1:1.

[0037] In a preferred embodiment of the present invention, when the modified alloy powder is mixed with high Ce magnet alloy finely pulverized powder and high Ce Gd-containing alloy finely pulverized powder, the mass ratio is 3.3:10.

[0038] In a preferred embodiment of the present invention, when the modified alloy powder is mixed with high Ce magnet alloy finely pulverized powder, high Ce Ho-containing alloy finely pulverized powder, and high Ce Gd-containing alloy finely pulverized powder, the mass ratio is 1:5:2.

[0039] In a preferred embodiment of the present invention, when the modified alloy powder is mixed with high Ce magnet alloy finely pulverized powder, high Ce Ho-containing alloy finely pulverized powder, and high Ce Gd-containing alloy finely pulverized powder, the mass ratio is 2:5:1.

[0040] In a preferred embodiment of the present invention, when the modified alloy powder is mixed with high Ce magnet alloy finely pulverized powder, high Ce Ho-containing alloy finely pulverized powder, and high Ce Gd-containing alloy finely pulverized powder, the mass ratio is 2:1:1.

[0041] In a preferred embodiment of the present invention, when the modified alloy powder is mixed with high Ce magnet alloy finely pulverized powder, high Ce Ho-containing alloy finely pulverized powder, and high Ce Gd-containing alloy finely pulverized powder, the mass ratio is 1:1:2.

[0042] In a preferred embodiment of the present invention, when the modified alloy powder is mixed with high Ce magnet alloy finely pulverized powder, high Ce Ho-containing alloy finely pulverized powder, and high Ce Gd-containing alloy finely pulverized powder, the mass ratio is 2:1:1.

[0043] The present invention also provides applications of the modified high-Ce sintered NdFeB magnet, such as application in motors.

[0044] The beneficial effects of the present invention are:

[0045] 1. The present invention achieves accurate adjustment of the high-temperature coercivity performance of Ce-containing magnets by reasonably optimizing the content of heavy rare earth elements such as Ho and Gd in the formula, which can meet the development needs of low-cost, low-demagnetization rate sintered NdFeB magnets for electric two-wheeled vehicles, and specifically designs sintered NdFeB magnets for electric two-wheeled vehicles.

[0046] 2. The present invention mixes a high Ce magnet alloy with a high Ce Ho-containing alloy and a high Ce Gd-containing alloy through a dual alloy process, thereby optimizing the performance of a high Ce content NdFeB magnet.

[0047] 3. The present invention combines the Ho and Gd elements to adjust the high temperature magnetic properties (especially the coercive force at 100°C) to achieve a low-cost and low demagnetization rate NdFeB magnet.

[0048] Other advantages, objectives and features of the present invention will be described in the following description and will be apparent to those skilled in the art to some extent, or those skilled in the art may be taught from the practice of the present invention. The objectives and other advantages of the present invention may be realized and obtained through the following description. DETAILED DESCRIPTION

[0049] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0050] In the present invention, (R, Ce) a Fe 100-a-b-c M b B c The 100-abc in the above formula represents 100 wt.%-abc.

[0051] Example 1

[0052] S1. Casting process: raw materials are prepared according to the composition of high Ce magnet alloy and mixed alloy, wherein the mixed alloy is a high Ce Ho-containing alloy;

[0053] High Ce containing Ho alloy composition: (Nd 17.5 H4C 10 ) 31.5 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 ;

[0054] High Ce magnet alloy composition: (Nd 21.5 Ce 10 ) 31.5 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 ;

[0055] The two raw materials were placed in a vacuum melting furnace and heated at about 5 × 10 -2 Pa vacuum environment, melting and rapid solidification were performed at 1550°C to obtain high Ce magnet alloy flakes and Ce containing Ho alloy flakes.

[0056] S2, hydrogen crushing process: the high Ce magnet alloy flakes and the high Ce Ho-containing alloy flakes in step S1 are subjected to hydrogen absorption, and then subjected to vacuum dehydrogenation treatment at 580° C. to obtain high Ce magnet alloy coarse powder and high Ce Ho-containing alloy coarse powder, respectively, with a particle size of 125 μm;

[0057] S3, fine grinding treatment: the high Ce magnet alloy coarse powder and the high Ce Ho-containing alloy coarse powder in step S2 are finely ground in an atmosphere with an oxygen content of less than 10 ppm in a jet mill to obtain high Ce magnet alloy finely ground powder and high Ce Ho-containing alloy finely ground powder with an average particle size of 4.2 μm, respectively;

[0058] S4, fine powder mixing treatment: the high Ce alloy fine powder prepared in S3 and the high Ce Ho-containing alloy fine powder are mixed in an atmosphere with an oxygen content of less than 10 ppm at a mass ratio of 3:1 to obtain a modified alloy powder;

[0059] S5, molding process: orienting and pressing the modified alloy powder in a press with a magnetic field strength of 2.0T, and then isostatically pressing for 10 seconds at a pressure of 200MPa to obtain a magnet green body;

[0060] S6, sintering process: vacuum sintering the magnet green body at a temperature of 1055°C for 540 minutes, and cooling the temperature to room temperature in an argon air-cooling environment to obtain a sintered body;

[0061] S7, aging treatment: the sintered body in S6 is heated to 700°C, wherein the heating time is 100 minutes and the heat preservation time is 180 minutes; then it is cooled to room temperature and heated to 400°C again, wherein the heating time is 60 minutes and the heat preservation time is 180 minutes; it is cooled to room temperature along with the furnace to obtain a modified high Ce sintered NdFeB magnet;

[0062] In this embodiment, the modified high Ce sintered NdFeB magnet composition is Nd 20.5 Ho1Ce 10 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 .

[0063] Magnetic properties test:

[0064] In this embodiment, the remanence of the modified high Ce sintered NdFeB magnet is 13.12 KGs, and the coercive force is 17.25 KOe.

[0065] Example 2

[0066] The difference between this embodiment and embodiment 1 is that:

[0067] The high Ce magnet alloy finely pulverized powder and the high Ce Ho-containing alloy finely pulverized powder are mixed at a mass ratio of 1:1;

[0068] The composition of modified high Ce sintered NdFeB magnet is: Nd 19.5 Ho2Ce 10 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 .

[0069] Magnetic properties test:

[0070] The modified high-Ce sintered NdFeB magnet in this embodiment has a remanence of 12.89 KGs and a coercive force of 17.72 KOe.

[0071] Example 3

[0072] The difference between this embodiment and embodiment 1 is that:

[0073] The high Ce magnet alloy fine powder and the high Ce Ho alloy fine powder were mixed at a mass ratio of 3.3:10; the modified high Ce sintered NdFeB magnet composition is: Nd 18.5 H3C 10 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 .

[0074] Magnetic properties test:

[0075] The modified high-Ce sintered NdFeB magnet in this embodiment has a remanence of 12.65 KGs and a coercive force of 17.67 KOe.

[0076] Example 4

[0077] The difference between this embodiment and embodiment 1 is that:

[0078] The mixed alloy is a high Ce-containing Gd alloy.

[0079] High Ce-containing Gd alloy composition: (Nd 17.5 G JZ 10 ) 31.5 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 ;

[0080] The high Ce magnet alloy fine powder and the high Ce Gd alloy fine powder are mixed at a mass ratio of 3:1;

[0081] The composition of modified high Ce sintered NdFeB magnet is: Nd 20.5 G JZ 10 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 .

[0082] Magnetic properties test:

[0083] The modified high-Ce sintered NdFeB magnet in this embodiment has a remanence of 13.18 KGs and a coercive force of 16.87 KOe.

[0084] Example 5

[0085] The difference between this embodiment and embodiment 4 is that:

[0086] The high Ce magnet alloy fine powder and the high Ce Gd alloy fine powder are mixed at a mass ratio of 1:1;

[0087] The composition of modified high Ce sintered NdFeB magnet is: Nd 19.5 G JZ 10 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 .

[0088] Magnetic properties test:

[0089] The modified high-Ce sintered NdFeB magnet in this embodiment has a remanence of 12.85 KGs and a coercive force of 16.85 KOe.

[0090] Embodiment 6:

[0091] The difference between this embodiment and embodiment 4 is that:

[0092] The high Ce magnet alloy fine powder and the high Ce Gd alloy fine powder were mixed at a mass ratio of 3.3:10;

[0093] The composition of modified high Ce sintered NdFeB magnet is: Nd 18.5 G JZ 10 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr0.3 B 0.98 .

[0094] Magnetic properties test:

[0095] The modified high-Ce sintered NdFeB magnet in this embodiment has a remanence of 12.7 KGs and a coercive force of 16.86 KOe.

[0096] Embodiment 7:

[0097] S1. Casting process: raw materials are configured according to the composition of high Ce magnet alloy and the composition of mixed alloy, wherein the mixed alloy includes high Ce Ho-containing alloy and high Ce Gd-containing alloy;

[0098] High Ce containing Ho alloy composition: (Nd 17.5 H4C 10 ) 31.5 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 ;

[0099] High Ce-containing Gd alloy composition: (Nd 17.5 G JZ 10 ) 31.5 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 ;

[0100] High Ce magnet alloy composition: (Nd 21.5 Ce 10 ) 31.5 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 ;

[0101] The three raw materials were placed in a vacuum melting furnace and heated at about 5 × 10 -2 Pa vacuum environment, melting and rapid solidification were performed at 1550°C to obtain high Ce magnet alloy flakes, high Ce Ho-containing alloy flakes and high Ce Gd-containing alloy flakes.

[0102] S2, hydrogen crushing process: the high Ce magnet alloy flakes, high Ce Ho-containing alloy flakes and high Ce Gd-containing alloy flakes in step S1 are subjected to hydrogen absorption, and then subjected to vacuum dehydrogenation treatment at 580° C. to obtain high Ce magnet alloy coarse powder, high Ce Ho-containing alloy coarse powder and high Ce Gd-containing alloy coarse powder, respectively, with a particle size of 125 μm;

[0103] S3, fine grinding treatment: the high Ce magnet alloy coarse powder, high Ce Ho-containing alloy coarse powder and high Ce Gd-containing alloy coarse powder in step S2 are finely ground in an atmosphere with an oxygen content of less than 10 ppm in a jet mill to obtain high Ce magnet alloy finely ground powder, high Ce Ho-containing alloy finely ground powder and high Ce Gd-containing alloy finely ground powder with an average particle size of 4.2 μm respectively;

[0104] S4, fine powder mixing treatment: the high Ce alloy fine powder, the high Ce Ho-containing alloy fine powder and the high Ce Gd-containing alloy fine powder prepared in S3 are mixed in an atmosphere with an oxygen content of less than 10 ppm at a mass ratio of 1:5:2 to obtain a modified alloy powder;

[0105] S5, molding process: orienting and pressing the modified alloy powder in a press with a magnetic field strength of 2.0T, and then isostatically pressing for 10 seconds at a pressure of 200MPa to obtain a magnet green body;

[0106] S6, sintering process: vacuum sintering the magnet green body at a temperature of 1055°C for 540 minutes, and cooling the temperature to room temperature in an argon air-cooling environment to obtain a sintered body;

[0107] S7, aging treatment: the sintered body in S6 is heated to 700°C, wherein the heating time is 100 minutes and the heat preservation time is 180 minutes; then it is cooled to room temperature and heated to 400°C again, wherein the heating time is 60 minutes and the heat preservation time is 180 minutes; it is cooled to room temperature along with the furnace to obtain a modified high Ce sintered NdFeB magnet;

[0108] The modified high Ce sintered NdFeB magnet has a composition of Nd 20 Ho 0.5 G JZ 10 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 .

[0109] Magnetic properties test:

[0110] The modified high-Ce sintered NdFeB magnet in this embodiment has a remanence of 13.07 KGs and a coercive force of 17.17 KOe.

[0111] Embodiment 8:

[0112] The difference between this embodiment and embodiment 7 is that:

[0113] Mix high Ce magnet alloy fine powder, high Ce Ho alloy fine powder, and high Ce Gd alloy fine powder in a mass ratio of 2:5:1;

[0114] The composition of modified high Ce sintered NdFeB magnet is: Nd 20 HkDJ 0.5 Ce 10 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 .

[0115] Magnetic properties test:

[0116] The modified high-Ce sintered NdFeB magnet in this embodiment has a remanence of 13.05 KGs and a coercive force of 17.22 KOe.

[0117] Example 9

[0118] The difference between this embodiment and embodiment 7 is that:

[0119] The high Ce magnet alloy finely pulverized powder, the high Ce Ho-containing alloy finely pulverized powder, and the high Ce Gd-containing alloy finely pulverized powder are mixed at a mass ratio of 2:1:1;

[0120] The composition of modified high Ce sintered NdFeB magnet is: Nd 19.5 HkDJ 10 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 .

[0121] Magnetic properties test:

[0122] The modified high-Ce sintered NdFeB magnet in this embodiment has a remanence of 12.96 KGs and a coercive force of 17.32 KOe.

[0123] Example 10

[0124] The difference between this embodiment and embodiment 7 is that:

[0125] Mixing high Ce magnet alloy fine powder, high Ce Ho alloy fine powder, and high Ce Gd alloy fine powder in a mass ratio of 1:1:2;

[0126] The composition of modified high Ce sintered NdFeB magnet is: Nd 18.5 HkDJ 10 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 .

[0127] Magnetic properties test:

[0128] The modified high-Ce sintered NdFeB magnet in this embodiment has a remanence of 12.84 KGs and a coercive force of 16.6 KOe.

[0129] Embodiment 11

[0130] The difference between this embodiment and embodiment 7 is that:

[0131] Mix high Ce magnet alloy fine powder, high Ce Ho alloy fine powder, and high Ce Gd alloy fine powder in a mass ratio of 2:1:1;

[0132] The modified high Ce sintered NdFeB magnet has a composition of Nd 19.5 HkDJ 10 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.98 .

[0133] Magnetic properties test:

[0134] The modified high-Ce sintered NdFeB magnet in this embodiment has a remanence of 12.79 KGs and a coercive force of 18.27 KOe.

[0135] In order to prove the superiority of the present invention, comparative example 1 is set here:

[0136] Comparative Example 1

[0137] S1. Casting process: The raw materials are configured according to the sintered NdFeB magnet alloy. The composition of sintered NdFeB magnet is (Nd 21.5 Ce 10 ) 31.5 Fe 66.72 Al 0.1 Cu 0.1 Co 0.5 Zr 0.3 B 0.9 ;

[0138] The raw materials were placed in a vacuum melting furnace and heated at about 5 × 10-2 Pa vacuum environment, melting and rapid solidification were performed at 1550°C to obtain sintered NdFeB magnet alloy sheets;

[0139] S2, hydrogen crushing process: the sintered NdFeB magnet alloy flakes in step S1 are subjected to hydrogen absorption, and then subjected to vacuum dehydrogenation treatment at 580°C to obtain sintered NdFeB magnet alloy coarse powder with a particle size of 125 μm;

[0140] S3, fine pulverization treatment: finely pulverize the coarse pulverized powder in step S2 in an atmosphere with an oxygen content of less than 10 ppm in a jet mill to obtain a sintered NdFeB magnet fine pulverized powder with an average particle size of 4.2 μm;

[0141] S4, fine powder treatment: mixing the coarsely crushed powder prepared in S3 in an atmosphere with an oxygen content of less than 10 ppm to obtain sintered NdFeB magnet powder;

[0142] S5, molding process: orienting and pressing the modified alloy powder in a press with a magnetic field strength of 2.0T, and then isostatically pressing for 10 seconds at a pressure of 200MPa to obtain a magnet green body;

[0143] S6, sintering process: vacuum sintering the magnet green body at a temperature of 1055°C for 540 minutes, and cooling the temperature to room temperature in an argon air-cooling environment to obtain a sintered body;

[0144] S7, aging treatment: the sintered body in S6 is heated to 700°C, wherein the heating time is 100 minutes and the heat preservation time is 180 minutes; then it is cooled to room temperature and heated to 400°C again, wherein the heating time is 60 minutes and the heat preservation time is 180 minutes; it is cooled to room temperature along with the furnace to obtain a sintered NdFeB magnet.

[0145] Magnetic properties test:

[0146] The remanence of the magnet in this comparative example is 13.32 KGs, and the coercive force is 16.78 KOe.

[0147] In the present invention, the ratio and result of the specific implementation are shown in Table 1:

[0148] Table 1

[0149]

[0150]

[0151] In the table: Br represents remanence, 20℃-80℃ Hcj / Hcj represents coercivity at different temperatures.

[0152] By analyzing the above table, it can be seen from the comparison between comparative example 1 and examples 2, 3 and 4 that as the Ho content increases, the magnet Br decreases significantly, and the magnet Br decreases by 0.22KGs for every 1wt.% Ho increase; the Hcj increases by 0.31KOe on average for every 1wt.% Ho increase at 20℃; and the Hcj increases by 0.26Koe on average for every 1wt.% Ho increase at 100℃.

[0153] Comparing Comparative Example 1 with Examples 5, 6 and 7, it can be seen that as the Gd content increases, the Br of the magnet decreases significantly, and the Br of the magnet decreases by 0.22KGs for every 1wt.% increase in Gd; the Hcj at 20℃ does not change much for every 1wt.% increase in Gd; the Hcj at 100℃ increases by an average of 0.20Koe for every 1wt.% increase in Gd;

[0154] The difference from Ho element is that the introduction of Gd does not change the 20℃ Hcj of the magnet, but significantly improves the high temperature Hcj of the magnet;

[0155] By comparing Comparative Example 1 with Examples 8, 9, 10 and 11, it can be seen that when heavy rare earth elements such as Ho and Gd are added simultaneously to the high Ce magnet, the action rules thereof are consistent with those when Ho and Gd act alone.

[0156] After comprehensive analysis of the above results, the present invention finds that the Ho element can improve the Hcj at 20°C and 100°C, while the Gd element can improve the Hcj performance at 100°C. Therefore, by using a single or simultaneous combination of Ho and Gd elements, it is possible to meet the requirement that Br is lower than 13.32KGs, and the room temperature and high temperature Hcj of the high Ce magnet can be controllably adjusted, thereby meeting the development needs of low-cost, low demagnetization rate high Ce sintered NdFeB.

[0157] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A modified high Ce sintered NdFeB magnet, characterized in that: The composition of the modified high Ce sintered NdFeB magnet is: (R, Ce) a Fe 100-a-b-c M b B c , Wherein R includes at least one of Pr, Nd, Ce, Ho, and Gd, M includes at least one of Cu, Al, Zr, Co, and Ga, and 30.5wt.%≤a≤32wt.%, 0.01wt.%≤b≤1.2wt.%, and 0.8wt.%≤c≤1wt.%.

2. A modified high Ce sintered NdFeB magnet according to claim 1, characterized in that: The content of a is 30.5wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; And / or, the Nd content is 18.5-21.5wt.%, where wt.% refers to the percentage of the total mass of the modified high-Ce sintered NdFeB magnet; And / or, the Ce content is 10wt.%, where wt.% refers to the percentage of the total mass of the modified high-Ce sintered NdFeB magnet; And / or, the modified high-Ce sintered NdFeB magnet further includes RH, and the RH is a heavy rare earth element.

3. A modified high Ce sintered NdFeB magnet according to claim 1, characterized in that: The content of a is 30.5wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; And / or, the Nd content is 18.5wt.%, 19.5wt.%, 20wt.% or 20.5wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; And / or, the Ce content is 10wt.%, where wt.% refers to the percentage of the total mass of the modified high-Ce sintered NdFeB magnet; And / or, the modified high-Ce sintered NdFeB magnet further comprises RH, and the content of RH is 0.8-3.2wt.%, And / or, the modified high-Ce sintered NdFeB magnet further comprises RH, and the type of RH is Ho and / or Gd.

4. A modified high Ce sintered NdFeB magnet according to claim 3, characterized in that: The content of RH is 1wt.%, 2wt.%, 3wt.% or 1.5wt.%; wt.% refers to the percentage of the total mass of the modified high-Ce sintered NdFeB magnet; And / or, when the RH contains Ho, the content of Ho is 0-3wt.%, where wt.% refers to the percentage of the total mass of the modified high-Ce sintered NdFeB magnet; And / or, when the RH contains Gd, the content of Gd is 0-3 wt.%, where wt.% refers to the percentage of the total mass of the modified high-Ce sintered NdFeB magnet.

5. A modified high Ce sintered NdFeB magnet according to claim 4, characterized in that: The Ho content is 0.5wt.%, 1wt.%, 2wt.% or 3wt.%, wt.% refers to the percentage of the total mass of the modified high-Ce sintered NdFeB magnet; And / or, the Gd content is 0.5wt.%, 1wt.%, 2wt.% or 3wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

6. The modified high Ce sintered NdFeB magnet according to claim 1, characterized in that: The modified high Ce sintered NdFeB magnet is composed of the following components: Nd 20.5wt.%, Ho 1wt.%, Ce10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co 0.5wt.%, Zr 0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; Or the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 19.5wt.%, Ho 2wt.%, Ce10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co 0.5wt.%, Zr 0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; Or the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 18.5wt.%, Ho 3wt.%, Ce10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co 0.5wt.%, Zr 0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; Or the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 20.5wt.%, Gd 1wt.%, Ce10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co 0.5wt.%, Zr 0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; Or the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 19.5wt.%, Gd 2wt.%, Ce10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co 0.5wt.%, Zr 0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; Or the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 18.5wt.%, Gd 3wt.%, Ce10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co 0.5wt.%, Zr 0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; Or the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 20wt.%, Ho 0.5wt.%, Gd1wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co 0.5wt.%, Zr0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; Or the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 20wt.%, Ho 1wt.%, Gd0.5wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co 0.5wt.%, Zr0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; Or the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 19.5wt.%, Ho 1wt.%, Gd1wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co 0.5wt.%, Zr0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; Or the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 18.5wt.%, Ho 1wt.%, Gd2wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co 0.5wt.%, Zr0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet; Alternatively, the modified high Ce sintered NdFeB magnet is composed of the following components: Nd 19.5wt.%, Ho 2wt.%, Gd1wt.%, Ce 10wt.%, Fe 66.72wt.%, Al 0.1wt.%, Cu 0.1wt.%, Co 0.5wt.%, Zr0.3wt.%, B0.98wt.%, wt.% refers to the percentage of the total mass of the modified high Ce sintered NdFeB magnet.

7. The method for preparing the modified high-Ce sintered NdFeB magnet according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1, respectively preparing high Ce magnet alloy flakes, high Ce Ho-containing alloy flakes and high Ce Gd-containing alloy flakes; S2, subjecting the high Ce magnet alloy flakes, high Ce Ho-containing alloy flakes and high Ce Gd-containing alloy flakes in S1 to hydrogen crushing and jet milling to obtain high Ce magnet alloy finely pulverized powder, high Ce Ho-containing alloy finely pulverized powder and high Ce Gd-containing alloy finely pulverized powder respectively; S3, mixing the high Ce magnet alloy finely pulverized powder in S2 with at least one of a high Ce Ho-containing alloy finely pulverized powder and a high Ce Gd-containing alloy finely pulverized powder to obtain a modified alloy powder; S4, subjecting the modified alloy powder in S3 to orientation molding, sintering and aging to obtain the modified high-Ce sintered NdFeB magnet.

8. The method for preparing the modified high Ce sintered NdFeB magnet according to claim 7, characterized in that: The mass ratio of the high Ce magnet alloy finely crushed powder, the high Ce Ho-containing alloy finely crushed powder and the high Ce Gd-containing alloy finely crushed powder is (1-3.3):(0-10):(0-10).

9. The method for preparing the modified high Ce sintered NdFeB magnet according to claim 8, characterized in that: When the modified alloy powder is mixed with a high Ce magnet alloy finely pulverized powder and a high Ce Ho-containing alloy finely pulverized powder, the mass ratio is 3:1, 1:1 or 3.3:10; and / or, when the modified alloy powder is a mixture of high Ce magnet alloy finely pulverized powder and high Ce Gd-containing alloy finely pulverized powder, the mass ratio is 3:1, 1:1 or 3.3:10; And / or, when the modified alloy powder is mixed with high Ce magnet alloy finely crushed powder, high Ce Ho-containing alloy finely crushed powder and high Ce Gd-containing alloy finely crushed powder, the mass ratio is 1:5:2, 2:5:1, 2:1:1, 1:1:2 or 2:1:

1.

10. Use of the modified high-Ce sintered NdFeB magnet according to any one of claims 1 to 9 in a motor.

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