Bonded magnet and preparation method and application thereof

Abstract

The invention discloses a bonded magnet and a preparation method and application thereof. The bonded magnet comprises at least three substrates and bonding layers arranged between every two adjacent substrates. The bonding layer comprises an insulating bonding agent and micro-beads; the D50 particle size of the microbeads is 10 [mu] m or more and less than 90 [mu] m; the standard deviation sigma tlt of the glue line width t of different bonding layers; 10. The adhesive seam width consistency of the bonded magnet is good, and the eddy current loss and eddy current heating are low when the bonded magnet is applied to a motor.

Description

Technical Field

[0001] The present invention relates to an adhesive magnet, a preparation method thereof, and an application thereof. Background Art

[0002] Neodymium-iron-boron rare earth permanent magnets are widely used in fields such as new energy vehicles, intelligent communication, and wind power generation. In recent years, neodymium-iron-boron magnets have been continuously improved and have more excellent magnetic properties. Especially due to their strong magnetic field intensity, high coercivity, and high temperature resistance, they are widely used in permanent magnet motors. However, as a permanent magnet material, it still has certain defects.

[0003] In the application of motors, with the increase of motor speed or power, there is an eddy current effect in the neodymium-iron-boron magnet, which will further cause the temperature to rise. In the worst case, it may cause the demagnetization of the neodymium-iron-boron magnet material, thus greatly reducing the performance of the motor. In the prior art, generally, most of the permanent magnets of motors use neodymium-iron-boron materials with high coercivity and remanence. Their conductivity is high and their heat resistance is poor. Compared with copper loss and iron loss, the eddy current loss of the permanent magnet is not large in most cases. However, for high-speed, high-power density motors and motors with a closed structure, the eddy current loss of the neodymium-iron-boron permanent magnet will cause a large temperature rise in the rotor part, and even cause irreversible demagnetization of the permanent magnet in severe cases, which is fatal to permanent magnet motors.

[0004] Therefore, there is a need for a magnet that can effectively reduce eddy current loss without affecting the use of the motor. Summary of the Invention

[0005] In order to overcome the defect that there is serious eddy current loss when the magnet in the prior art is applied to a motor, the present application provides an adhesive magnet, a preparation method thereof, and an application thereof. The adhesive magnet has good consistency in the width of the glue seam, and has low eddy current loss and eddy current heating when applied to a motor.

[0006] The present invention solves the above technical problems through the following technical solutions.

[0007] The present invention provides an adhesive magnet, which includes at least three substrates and adhesive layers respectively disposed between two adjacent substrates;

[0008] The adhesive layer includes an insulating adhesive and microbeads; the D50 particle size of the microbeads is more than 10 μm and less than 90 μm;

[0009] The standard deviation σt of the glue seam width t of different adhesive layers is < 10.

[0010] In the present invention, preferably, the substrate is a neodymium-iron-boron magnet, and the definition of "neodymium-iron-boron" can be conventional in the art, that is, a class of permanent magnet materials that at least include neodymium element, iron element, boron element, and inevitable impurities.

[0011] In the present invention, preferably, the material of the microbeads includes ceramic material and / or glass material.

[0012] Among them, preferably, the ceramic material includes one or more of metal oxides, carbides, nitrides, and borides. Among them, the meaning of carbide is a binary compound formed by carbon and an element (except hydrogen) with an electronegativity smaller than or close to it; the meaning of nitride is a binary compound formed by nitrogen and an element with an electronegativity smaller than it; the meaning of boride is a binary compound formed by boron and a metal or certain non-metals (such as carbon).

[0013] Among them, the metal oxides include, for example, alumina (Al2O3) and / or zirconia (ZrO2).

[0014] Among them, the carbides include, for example, silicon carbide (SiC) and / or boron carbide (B4C).

[0015] Among them, the nitrides include, for example, silicon nitride (Si3N4) and / or aluminum nitride (AlN).

[0016] Among them, the borides include, for example, zirconium boride (ZrB2) and / or silicon hexaboride (SiB6).

[0017] Among them, preferably, the glass material includes one or more of Na2SiO3, CaSiO3, SiO2, Na2O·CaO·6SiO2, K2O, CaO, and B2O3.

[0018] In some preferred embodiments of the present invention, the material of the microbeads is alumina (Al2O3).

[0019] In some preferred embodiments of the present invention, the material of the microbeads is silicon carbide (SiC).

[0020] In some preferred embodiments of the present invention, the material of the microbeads is zirconium boride (ZrB2).

[0021] In the present invention, preferably, the D50 particle size of the microbeads is 20 - 40 μm or 50 - 70 μm.

[0022] In the present invention, preferably, the material of the microbeads is ceramic material, and the density of the microbeads is less than 1.5 g / cm 3 .

[0023] In the present invention, preferably, the material of the microbeads is glass material, and the density of the microbeads is greater than 2.5 g / cm 3 , for example, 1.2 g / cm 3 .

[0024] In the present invention, preferably, the roundness of the microbeads is 0.4 - 1, for example, 0.6. Among them, the roundness can reflect the degree of similarity between the projected area of the microbeads and a circle. Considering the smoothness of the perimeter comprehensively, it is defined as the ratio of the minimum radius to the maximum radius of the microbeads. The minimum radius is the minimum straight-line distance from the centroid of the microbeads to the surface, and the maximum radius is the maximum straight-line distance from the centroid of the microbeads to the surface.

[0025] In the present invention, preferably, the shape of the microbeads is one or more of spherical, polygonal, elliptical, and strip-shaped.

[0026] Among them, the spherical shape can be a regular sphere and / or an irregular sphere.

[0027] Among them, the polygon can be a regular polygon and / or an irregular polygon.

[0028] In the present invention, preferably, the types of the insulating adhesive include one or more of epoxy resin, cyanoacrylate, unsaturated polyester resin, phenolic resin, and polyimide resin.

[0029] In the present invention, preferably, in any one of the bonding layers, the mass percentage of the microbeads in the bonding layer is 0.1 wt% - 5 wt%, for example, 1 wt%.

[0030] In the present invention, preferably, in any one of the bonding layers, the mass percentage of the insulating adhesive in the bonding layer is 95 wt% - 99.9 wt%, for example, 99 wt%.

[0031] In the present invention, the width t of the glue seam of any one of the bonding layers is the thickness of any one of the bonding layers. The meaning of the thickness of the bonding layer is the vertical distance between the two side faces adjacent to the substrate of the bonding layer.

[0032] In the present invention, preferably, in any one of the bonding layers, the glue seam width t is 1 - 3 times the D50 particle size of the microbeads.

[0033] In the present invention, preferably, the glue seam width t is 20 - 100 μm, for example, 30 - 60 μm or 50 - 90 μm.

[0034] In the present invention, preferably, the standard deviation σt of the glue seam widths t of different bonding layers is 5 or less, for example, 3.5, 3.8, 4, 4.1, 4.3, 4.5, 4.6, 4.7, or 4.9.

[0035] In the present invention, preferably, the resistance at both ends of the bonding layer is ≥0.1 MΩ, more preferably >10 MΩ, for example, >20 MΩ. Among them, the meaning of both ends of the bonding layer is the two side faces adjacent to the substrate of the bonding layer.

[0036] In the present invention, preferably, the bonded magnet comprises 3 to 100 substrates.

[0037] The present invention also provides a method for preparing a bonded magnet, which comprises the following steps:

[0038] Apply an insulating adhesive paste between any two adjacent substrates and then perform a curing treatment to form an adhesive layer between the two adjacent substrates;

[0039] Wherein, the insulating adhesive paste comprises an insulating adhesive and microbeads; the D50 particle size of the microbeads is 10 μm or more and less than 90 μm;

[0040] Wherein, the pressure of the curing treatment is 0.5 - 2.5 Mpa.

[0041] In the present invention, preferably, the substrate is a neodymium iron boron magnet.

[0042] In the present invention, preferably, the number of the substrates is 3 to 100.

[0043] In the present invention, preferably, the substrate is a cuboid or a cube.

[0044] In the present invention, the preparation method of the substrate can be a conventional preparation method in the art, for example, comprising the following steps:

[0045] S1. Melting: Put raw materials into a melting furnace according to a formula and perform vacuum melting to obtain an alloy sheet;

[0046] S2. Hydrogen decrepitation: Hydrogenate and dehydrogenate the above alloy sheet in a hydrogen atmosphere in sequence and then cool to obtain coarse powder;

[0047] S3. Jet milling: Jet mill the coarse powder in step S2 in an atmosphere with an oxygen gas content of 200 ppm or less to obtain fine powder;

[0048] S4. Orientation forming: Perform orientation forming on the fine powder in step S3;

[0049] S5. Sintering: Sinter the product after step S4 in a vacuum or inert gas atmosphere to obtain a blank;

[0050] S6. Cutting: Cut the blank in step S5 to obtain an intermediate blank;

[0051] S7. Surface degreasing: Perform phosphating treatment and degreasing on the intermediate blank in step S6 in sequence to obtain the substrate.

[0052] In certain specific embodiments of the present invention, in step S1, the hydrogen decrepitation is carried out using a hydrogen decrepitation furnace.

[0053] Among them, preferably, in step S3, the jet mill pulverization includes jet mill pulverizing the coarse powder and the lubricant in step S2 in an atmosphere with an oxygen gas content of 200 ppm or less to obtain fine powder.

[0054] Among them, the lubricant is, for example, tributyl borate.

[0055] Among them, the mass percentage of the lubricant in the mass of the coarse powder is 0.3% or less, more preferably 0.04% - 0.12%, for example 0.1%.

[0056] Among them, preferably, in step S3, the D50 particle size of the fine powder is 3.9 - 4.4 μm.

[0057] Among them, preferably, in step S4, the magnetic field strength of the orientation forming is 1.5 T or more.

[0058] Among them, preferably, in step S4, it further includes adding an antioxidant to the fine powder and then performing orientation forming.

[0059] Among them, preferably, the antioxidant includes alkanes.

[0060] Among them, preferably, the mass percentage of the antioxidant in the mass of the fine powder is 0.3% or less, more preferably 0.04% - 0.12%, for example 0.1%.

[0061] Among them, preferably, in step S5, the sintering temperature is 1040 - 1100 °C.

[0062] Among them, preferably, in step S5, the sintering time is 4 - 12 h, for example 8 h.

[0063] Among them, preferably, in step S6, the cutting can be performed along the length direction and / or the width direction of the blank. Among them, both the length direction and the width direction are perpendicular to the orientation direction.

[0064] Among them, preferably, in step S6, it is cut into an intermediate blank with a length of 2 - 40 mm and / or a width of 2 - 40 mm, for example an intermediate blank with a length of 2 - 20 mm and / or a width of 2 - 20 mm.

[0065] Among them, preferably, in step S7, the phosphating treatment is to immerse the intermediate blank in a phosphating solution, and the phosphating solution is a composite phosphating solution.

[0066] Among them, preferably, in step S7, the degreasing is to immerse the intermediate blank in a degreasing solution, and the degreasing solution includes degreasing powder.

[0067] In certain specific embodiments of the present invention, the mass content of the degreasing powder in the degreasing solution is 2%.

[0068] In certain specific embodiments of the present invention, the types of the degreasing powder are one or more of sodium carbonate, sodium silicate, sodium bicarbonate, surfactant, and sodium hydroxide.

[0069] In certain specific embodiments of the present invention, in step S7, the degreasing is to soak the intermediate blank in the degreasing solution, and the degreasing solution includes ethanol and isopropanol.

[0070] In the present invention, there is no special limitation on the time of the phosphating treatment and the degreasing in step S7, as long as the surface of the substrate has no rust and grease.

[0071] Those skilled in the art generally understand that in order to achieve curing between two substrates, the direction of the pressure applied in the curing treatment is perpendicular to the bonding layer.

[0072] In the present invention, preferably, the temperature of the curing treatment is 100 - 250 °C.

[0073] In the present invention, preferably, the curing treatment includes a first heating stage and a second heating stage. The temperature of the first heating stage is 100 - 250 °C, and the temperature of the second heating stage is higher than that of the first heating stage.

[0074] Among them, preferably, the pressure of the first heating stage is 0.5 - 2.5 Mpa, for example, 2 Mpa.

[0075] Among them, preferably, the time of the first heating stage is 0.1 - 6 h, for example, 1 h.

[0076] In some specific embodiments of the present invention, the temperature of the first heating stage is 120 °C.

[0077] Among them, preferably, the temperature of the second heating stage is 150 - 250 °C, for example, 160 °C.

[0078] Among them, preferably, the pressure of the second heating stage is 0.5 - 2.5 Mpa, for example, 2 Mpa.

[0079] Among them, preferably, the time of the second heating stage is 0.1 - 6 h, for example, 1 h.

[0080] In certain specific embodiments of the present invention, after the curing treatment, there are also steps of machining and surface treatment.

[0081] Among them, the machining can machine the bonded magnet into a target size.

[0082] Among them, the surface treatment includes, for example, phosphating treatment or spraying epoxy resin.

[0083] In the present invention, preferably, the material of the microbeads includes ceramic material and / or glass material.

[0084] Among them, preferably, the ceramic material includes one or more of metal oxides, carbides, nitrides, and borides. Among them, the meaning of carbide is a binary compound formed by carbon and an element (except hydrogen) with an electronegativity smaller than or close to it; the meaning of nitride is a binary compound formed by nitrogen and an element with an electronegativity smaller than it; the meaning of boride is a binary compound formed by boron and a metal, certain non-metals (such as carbon).

[0085] Among them, the metal oxide includes, for example, alumina (Al2O3) and / or zirconia (ZrO2).

[0086] Among them, the carbide includes, for example, silicon carbide (SiC) and / or boron carbide (B4C).

[0087] Among them, the nitride includes, for example, silicon nitride (Si3N4) and / or aluminum nitride (AlN).

[0088] Among them, the boride includes, for example, zirconium boride (ZrB2) and / or silicon boride (SiB6).

[0089] Among them, preferably, the glass material includes one or more of Na2SiO3, CaSiO3, SiO2, Na2O·CaO·6SiO2, K2O, CaO, and B2O3.

[0090] In some preferred embodiments of the present invention, the material of the microbeads is alumina (Al2O3).

[0091] In some specific embodiments of the present invention, the preparation method of the microbeads is as follows:

[0092] Mix Al2O3 powder, binder, and dispersant, and successively undergo ball milling, heat atomization, screening, sintering, and ball milling to form alumina ceramic microbeads. Among them, the sintering temperature is 1300 - 1500 °C.

[0093] Among them, the binder is, for example, polyvinyl alcohol.

[0094] Among them, the dispersant is, for example, polyacrylic acid.

[0095] In some preferred embodiments of the present invention, the material of the microbeads is silicon carbide (SiC).

[0096] In some preferred embodiments of the present invention, the material of the microbeads is zirconium boride (ZrB2).

[0097] In the present invention, preferably, the D50 particle size of the microbeads is 20 - 40 μm or 50 - 70 μm.

[0098] In the present invention, preferably, the material of the microbeads is a ceramic material, and the density of the microbeads is less than 1.5 g / cm 3 .

[0099] In the present invention, preferably, the material of the microbeads is a glass material, and the density of the microbeads is greater than 2.5 g / cm 3 , for example, 1.2 g / cm 3 .

[0100] In the present invention, preferably, the roundness of the microbeads is 0.4 - 1, for example, 0.6. Among them, the roundness can reflect the degree of similarity between the projected area of the microbeads and a circle. Considering the smoothness of the perimeter comprehensively, it is defined as the ratio of the minimum radius to the maximum radius of the microbeads. The minimum radius is the minimum straight-line distance from the centroid of the microbeads to the surface, and the maximum radius is the maximum straight-line distance from the centroid of the microbeads to the surface.

[0101] In the present invention, preferably, the shape of the microbeads is one or more of spherical, polygonal, elliptical, and bar-shaped.

[0102] Among them, the spherical shape can be a regular sphere and / or an irregular sphere.

[0103] Among them, the polygon can be a regular polygon and / or an irregular polygon.

[0104] In the present invention, preferably, the types of the insulating adhesive include one or more of epoxy resin, cyanoacrylate, unsaturated polyester resin, phenolic resin, and polyimide resin.

[0105] In the present invention, the mass percentage of each component in the insulating adhesive paste is the same as the mass percentage of each component in the adhesive layer, and the material loss during the curing process can be ignored.

[0106] In the present invention, preferably, the mass percentage of the microbeads in the insulating adhesive paste is 0.1 wt% - 5 wt%, for example, 1 wt%.

[0107] In the present invention, preferably, the mass percentage of the insulating adhesive in the insulating adhesive paste is 95 wt% - 99.9 wt%, for example, 99 wt%.

[0108] In the present invention, preferably, the mass percentage of the insulating adhesive paste in the substrate is less than 2%, for example, 0.15%.

[0109] The present invention also provides an adhesive magnet prepared by the method for preparing the above-mentioned adhesive magnet.

[0110] The present invention also provides an application of the above-mentioned adhesive magnet in an electric motor.

[0111] On the basis of conforming to the common knowledge in the art, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred examples of the present invention.

[0112] The reagents and raw materials used in the present invention are all commercially available.

[0113] The positive and progressive effects of the present invention are as follows:

[0114] The adhesive magnet of the present invention has good consistency in the width of the glue seam. At the same time, the glue seam can withstand a certain pressure, reduce the probability of conduction, improve the insulation performance of the adhesive layer, thereby facilitating the disconnection of the eddy current flow path, and reducing the eddy current loss and eddy current heating of the high-torque and high-speed permanent magnet motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0115] Figure 1 It is a schematic structural diagram of the adhesive magnet of Example 1.

[0116] The reference numerals are as follows:

[0117] 1 - Substrate; 2 - Adhesive layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0118] The present invention will be further described below by way of examples, but the present invention is not limited to the scope of the described examples. The experimental methods without specific conditions in the following examples are carried out according to conventional methods and conditions, or selected according to the product instructions.

[0119] The manufacturers and models of the products used in the following examples and comparative examples are as follows:

[0120] Phosphating solution: The type is a composite phosphating solution, the manufacturer is Aier Chemistry, and the model is AE;

[0121] Insulating adhesive: The type is epoxy resin, the manufacturer is Tianshan, and the model is 9322;

[0122] Lubricant: The type is tributyl borate, the manufacturer is Ningbo Haotian New Materials, and the model is Ningbo 0#;

[0123] Antioxidant: The type is alkane, the manufacturer is Tianjin Yueshengxing New Materials, and the model is Tianjin 3#;

[0124] Degreasing powder: The type is a mixture of sodium carbonate, sodium silicate, sodium bicarbonate, surfactant and sodium hydroxide, the manufacturer is Ensen, and the model is EFC-142T;

[0125] Microbeads: The type is alumina ceramic, produced by Jinlong Rare Earth Co., Ltd. itself, and the shape of the microbeads is spherical.

[0126] Among them, the preparation method of alumina ceramic microbeads is as follows:

[0127] Mix Al2O3 powder, binder (type: polyvinyl alcohol) and dispersant (type: polyacrylic acid), and successively pass through ball milling, heating atomization, screening, sintering, and ball milling to form alumina ceramic microbeads. Among them, the sintering temperature is 1300 - 1500 °C. After sintering, the binder and dispersant are removed.

[0128] Example 1

[0129] The preparation method of the matrix in Example 1 is as follows:

[0130] S1. Melting: Put the raw materials into a melting furnace according to the formula and carry out vacuum melting to obtain an alloy sheet; the formula is listed in Table 1:

[0131] Table 1

[0132]

[0133] S2. Hydrogen crushing: Use a hydrogen crushing furnace to successively absorb hydrogen and dehydrogenate the above alloy sheet in a hydrogen atmosphere and then cool it to obtain coarse powder;

[0134] S3. Jet milling and pulverization: After the coarse powder is stirred and mixed, the coarse powder in step S2 and the lubricant are subjected to jet milling and pulverization in an atmosphere with an oxidation gas content of 200 ppm to obtain fine powder with a D50 particle size of 3.9 - 4.4 μm; the mass percentage of the lubricant in the coarse powder is 0.1%;

[0135] S4. Orientation forming: Add an antioxidant to the fine powder in step S3, mix evenly, and carry out orientation forming under the condition of a magnetic field strength of 1.5 T; the mass percentage of the antioxidant in the fine powder is 0.1%;

[0136] S5. Sintering: Sinter the product after step S4 under vacuum to obtain a blank; the sintering temperature is 1040 - 1100 °C, and the sintering time is 8 h;

[0137] S6. Cutting: Cut the blank in step S5 along the length direction of the blank to obtain an intermediate blank; the size of the intermediate blank is L = 40.0 mm, W = 5.0 mm, T = 37.5 mm; among them, the direction along T is the orientation direction, the direction along L is the length direction, and the direction along W is the width direction.

[0138] S7. Surface degreasing: The intermediate blank obtained in step S6 is subjected to phosphating treatment and degreasing in sequence to obtain a substrate without rust and grease on the surface; the phosphating solution used for phosphating treatment is a composite phosphating solution, and the degreasing solution used for degreasing is a degreasing powder with a mass content of 2%.

[0139] The preparation method of the bonded magnet in Example 1 is as follows:

[0140] S8. Mix an insulating adhesive and microbeads with a D50 particle size of 20 - 40 μm, a density of 1.2 g / cm 3 , and a roundness of 0.6 to form an insulating adhesive paste. Apply the insulating adhesive paste between the L×T surfaces of any adjacent 5 of the above substrates and then carry out a curing treatment to form an adhesive layer between two adjacent substrates; the mass percentage of the microbeads in the adhesive layer is 1 wt%, and the mass percentage of the insulating adhesive in the adhesive layer is 99 wt%; the mass percentage of the insulating adhesive paste in the substrate is 0.15%.

[0141] Among them, the application direction of the pressure during the curing treatment is perpendicular to the direction of the adhesive layer; the above curing treatment includes a first heating section and a second heating section. The temperature of the first heating section is 120 °C, the time is 1 h, the temperature of the second heating section is 160 °C, and the time is 1 h; the pressure of both the first heating section and the second heating section is 2 Mpa.

[0142] After the curing treatment, it is cooled to room temperature to form a bonded magnet with dimensions of L = 40.0 mm, W = 25.2 mm, and T = 37.5 mm. Then, the bonded magnet is cut along the direction perpendicular to the orientation direction to form 5 segments of bonded magnet assemblies with dimensions of L = 40.0 mm, W = 25.2 mm, and T = 2.5 mm, and an optical microscope is used to observe the width of the glue seam (i.e., the thickness of the adhesive layer). Among them, the structural schematic diagram of the bonded magnet is as Figure 1 shown, which includes a substrate 1 and an adhesive layer 2 respectively provided between two adjacent substrates.

[0143] Example 2

[0144] In step S6 of Example 2, an intermediate blank with dimensions of L = 40.0 mm, W = 3.0 mm, and T = 37.5 mm is formed by cutting;

[0145] In step S8, the insulating adhesive paste is applied between the L×T surfaces of any adjacent 10 of the above substrates and then subjected to a curing treatment. After the curing treatment, it is cooled to room temperature, and then the bonded magnet is cut along the direction perpendicular to the orientation direction to form 10 segments of bonded magnet assemblies with dimensions of L = 40.0 mm, W = 30.4 mm, and T = 2.5 mm.

[0146] Other conditions are the same as those in Example 1.

[0147] Example 3

[0148] In step S6 of Example 3, an intermediate blank with dimensions of L = 20.0 mm, W = 5.0 mm, and T = 37.5 mm is cut and formed.

[0149] In step S8, an insulating adhesive paste is applied between the L×T surfaces of any adjacent 5 of the above-mentioned substrates to form an intermediate body, and then the insulating adhesive paste is applied between the W×T surfaces of any adjacent 2 intermediate bodies and then cured. After the curing treatment is completed, the temperature is lowered to room temperature to form an adhesive magnet with 2 segments of bonding in the length direction and 5 segments of bonding in the width direction. Then, the adhesive magnet is cut along a direction perpendicular to the orientation direction to form a 10-segment adhesive magnet assembly with dimensions of L = 40.0 mm, W = 25.2 mm, and T = 2.5 mm.

[0150] Other conditions are the same as those in Example 1.

[0151] Example 4

[0152] In step S6 of Example 4, an intermediate blank with dimensions of L = 20.0 mm, W = 2.5 mm, and T = 37.5 mm is cut and formed.

[0153] In step S8, an insulating adhesive paste is applied between the L×T surfaces of any adjacent 10 of the above-mentioned substrates to form an intermediate body, and then the insulating adhesive paste is applied between the W×T surfaces of any adjacent 2 intermediate bodies and then cured. After the curing treatment is completed, the temperature is lowered to room temperature to form an adhesive magnet with 2 segments of bonding in the length direction and 10 segments of bonding in the width direction. Then, the adhesive magnet is cut along a direction perpendicular to the orientation direction to form a 20-segment adhesive magnet assembly with dimensions of L = 40.0 mm, W = 25.4 mm, and T = 2.5 mm.

[0154] Other conditions are the same as those in Example 1.

[0155] Example 5

[0156] In step S6 of Example 5, an intermediate blank with dimensions of L = 10.0 mm, W = 5.0 mm, and T = 37.5 mm is cut and formed.

[0157] In step S8, an insulating adhesive paste is applied between the L×T surfaces of any adjacent 5 of the above-mentioned substrates to form an intermediate body, and then the insulating adhesive paste is applied between the W×T surfaces of any adjacent 4 intermediate bodies and then cured. After the curing treatment is completed, the temperature is lowered to room temperature to form an adhesive magnet with 4 segments of bonding in the length direction and 5 segments of bonding in the width direction. Then, the adhesive magnet is cut along a direction perpendicular to the orientation direction to form a 20-segment adhesive magnet assembly with dimensions of L = 40.1 mm, W = 25.2 mm, and T = 2.5 mm.

[0158] Other conditions are the same as those in Example 1.

[0159] Example 6

[0160] In step S6 of Example 6, an intermediate blank with dimensions of L = 10.0 mm, W = 3.0 mm, and T = 37.5 mm is cut and formed.

[0161] In step S8, the D50 particle size of the microbeads is 50 - 70 μm. After applying the insulating adhesive paste between the L×T surfaces of any adjacent 10 of the above-mentioned substrates to form an intermediate body, and then applying the insulating adhesive paste between the W×T surfaces of any adjacent 4 intermediate bodies and performing a curing treatment, after the curing treatment is completed, the temperature is lowered to room temperature to form an adhesive magnet with 4 segments bonded in the length direction and 10 segments bonded in the width direction. Then, the adhesive magnet is cut along a direction perpendicular to the orientation direction to form a 40-segment adhesive magnet assembly with dimensions of L = 40.0 mm, W = 30.5 mm, and T = 2.5 mm.

[0162] Other conditions are the same as those in Example 1.

[0163] Example 7

[0164] In step S6 of Example 7, an intermediate blank with dimensions of L = 6.0 mm, W = 5.0 mm, and T = 37.5 mm is cut and formed.

[0165] In step S8, the D50 particle size of the microbeads is 50 - 70 μm. In step S8, after applying the insulating adhesive paste between the L×T surfaces of any adjacent 2 of the above-mentioned substrates to form an intermediate body, and then applying the insulating adhesive paste between the W×T surfaces of any adjacent 7 intermediate bodies and performing a curing treatment, after the curing treatment is completed, the temperature is lowered to room temperature to form an adhesive magnet with 7 segments bonded in the length direction and 2 segments bonded in the width direction. Then, the adhesive magnet is cut along a direction perpendicular to the orientation direction to form a 14-segment adhesive magnet assembly with dimensions of L = 42.4 mm, W = 10.1 mm, and T = 2.5 mm.

[0166] Other conditions are the same as those in Example 1.

[0167] Example 8

[0168] In step S6 of Example 8, an intermediate blank with dimensions of L = 6.0 mm, W = 5.0 mm, and T = 37.5 mm is cut and formed.

[0169] In step S8, the D50 particle size of the microbeads is 50 - 70 μm. In step S8, after applying the insulating adhesive paste between the L×T surfaces of any adjacent 5 of the above-mentioned substrates to form an intermediate body, and then applying the insulating adhesive paste between the W×T surfaces of any adjacent 7 intermediate bodies and performing a curing treatment, after the curing treatment is completed, the temperature is lowered to room temperature to form an adhesive magnet with 7 segments bonded in the length direction and 5 segments bonded in the width direction. Then, the adhesive magnet is cut along a direction perpendicular to the orientation direction to form a 35-segment adhesive magnet assembly with dimensions of L = 42.4 mm, W = 25.2 mm, and T = 2.5 mm.

[0170] Other conditions are the same as those in Example 1.

[0171] Example 9

[0172] In step S6 of Example 9, an intermediate blank with dimensions of L = 2.1 mm, W = 10 mm, and T = 37.5 mm is formed by cutting;

[0173] In step S8, the D50 particle size of the microbeads is 50 - 70 μm. In step S8, an insulating adhesive paste is applied between the W×T surfaces of any adjacent 50 of the above substrates and then cured. After the curing treatment is completed, the temperature is reduced to room temperature to form an adhesive magnet with 50 segments bonded in the length direction and no bonding in the width direction. Then, the adhesive magnet is cut along a direction perpendicular to the orientation direction to form 50 segments of an adhesive magnet assembly with dimensions of L = 107.9 mm, W = 10.0 mm, and T = 2.5 mm.

[0174] Other conditions are the same as those in Example 1.

[0175] Example 10

[0176] In step S6 of Example 10, an intermediate blank with dimensions of L = 2.1 mm, W = 10.0 mm, and T = 37.5 mm is formed by cutting;

[0177] In step S8, the D50 particle size of the microbeads is 50 - 70 μm. In step S8, an insulating adhesive paste is applied between the L×T surfaces of any adjacent 3 of the above substrates to form an intermediate body, and then the insulating adhesive paste is applied between the W×T surfaces of any adjacent 50 intermediate bodies and then cured. After the curing treatment is completed, the temperature is reduced to room temperature to form an adhesive magnet with 50 segments bonded in the length direction and 3 segments bonded in the width direction. Then, the adhesive magnet is cut along a direction perpendicular to the orientation direction to form 150 segments of an adhesive magnet assembly with dimensions of L = 107.9 mm, W = 30 mm, and T = 2.5 mm.

[0178] Other conditions are the same as those in Example 1.

[0179] Comparative Example 1

[0180] In step S8, the insulating adhesive paste does not contain microbeads and only contains an insulating adhesive.

[0181] The remaining conditions are the same as those in Example 1.

[0182] Comparative Example 2

[0183] In step S8, the D50 particle size of the microbeads is 90 - 110 μm.

[0184] The remaining conditions are the same as those in Example 1.

[0185] Comparative Example 3

[0186] In step S8, the pressures of the first heating section and the second heating section are both 0.1 Mpa.

[0187] Other conditions are the same as those in Example 1.

[0188] Comparative Example 4

[0189] In step S8, first coat the insulating adhesive between the L×T surfaces of any adjacent 5 of the above-mentioned substrates, then cover with microbeads, and perform a curing treatment after covering the microbeads.

[0190] Other conditions are the same as those in Example 1.

[0191] Effect Example 1

[0192] 1. The width t of the glue joint and its standard deviation: Use an optical microscope to measure the width of the glue joint of the bonded magnet assemblies prepared in Examples 1-10 and Comparative Examples 1-4, and calculate the standard deviation σt of each glue joint width according to the standard deviation calculation formula.

[0193] 2. The resistance at both ends of the bonding layer: Test with a multimeter.

[0194] 3. The volume resistivity of the bonding layer: Test according to the national standard "GB / T 1410".

[0195] The above test results are listed in Table 2:

[0196] Table 2

[0197]

[0198] According to the data in Table 2, the standard deviation σt of the glue joint width of the bonded magnets prepared in Examples 1-10 of the present invention is <5, indicating that the glue joint widths of the bonded magnets have good consistency.

[0199] The resistance at both ends of the bonding layer of the bonded magnets prepared in Examples 1-10 of the present invention can reach more than 20 MΩ, and the volume resistivity of the bonding layer can reach more than 1.0*10 15 Ω·cm, indicating that the bonding layer of the bonded magnets prepared in Examples 1-10 of the present invention has good insulation performance, which is beneficial to disconnect the eddy current flow path and reduce the eddy current loss and eddy current heating of high-torque and high-speed permanent magnet motors.

Claims

1. An adhesive magnet, characterized in that, It includes at least three substrates and adhesive layers respectively disposed between two adjacent substrates; The adhesive layer includes an insulating adhesive and microbeads; the D50 particle size of the microbeads is 10 μm or more and less than 90 μm; The standard deviation σt of the adhesive joint width t of different adhesive layers < 10.

2. The bonded magnet according to claim 1, characterized in that, The material of the microbeads includes ceramic materials and / or glass materials; Among them, preferably, the ceramic materials include one or more of metal oxides, carbides, nitrides, and borides; Among them, the metal oxides include, for example, alumina and / or zirconia; Among them, the carbides include, for example, silicon carbide and / or boron carbide; Among them, the nitrides include, for example, silicon nitride and / or aluminum nitride; Among them, the borides include, for example, zirconium boride and / or silicon boride; Among them, preferably, the glass materials include one or more of Na2SiO3, CaSiO3, SiO2, Na2O·CaO·6SiO2, K2O, CaO, and B2O3.

3. The bonded magnet according to claim 1, characterized in that, The D50 particle size of the microbeads is 20 - 40 μm or 50 - 70 μm; And / or, the material of the microbeads is a ceramic material, and the density of the microbeads is less than 1.5 g / cm 3 ; And / or, the material of the microbeads is a glass material, and the density of the microbeads is greater than 2.5 g / cm 3 , for example, 1.2 g / cm 3 ; And / or, the roundness of the microbeads is 0.4 - 1, for example, 0.6; And / or, the shape of the microbeads is one or more of spherical, polygonal, elliptical, and bar-shaped; among them, the spherical shape is, for example, a regular sphere and / or an irregular sphere; among them, the polygon is, for example, a regular polygon and / or an irregular polygon; And / or, the types of the insulating adhesive include one or more of epoxy resin, cyanoacrylate, unsaturated polyester resin, phenolic resin, and polyimide resin.

4. The bonded magnet according to claim 1, characterized in that, In any one of the adhesive layers, the mass percentage of the microbeads in the adhesive layer is 0.1 wt% - 5 wt%, for example, 1 wt%; And / or, in any one of the adhesive layers, the mass percentage of the insulating adhesive in the adhesive layer is 95 wt% - 99.9 wt%, for example, 99 wt%; And / or, in any one of the adhesive layers, the adhesive joint width t is 1 - 3 times the D50 particle size of the microbeads; And / or, the adhesive joint width t is 20 - 100 μm, for example, 30 - 60 μm or 50 - 90 μm; And / or, the standard deviation σt of the adhesive joint width t of different adhesive layers is 5 or less, for example, 3.5, 3.8, 4, 4.1, 4.3, 4.5, 4.6, 4.7, or 4.9; And / or, the resistance at both ends of the adhesive layer ≥ 0.1 MΩ, for example, > 10 MΩ, where the meaning of both ends of the adhesive layer is the two side surfaces adjacent to the substrate of the adhesive layer; And / or, the adhesive magnet includes 3 - 100 substrates.

5. A method for preparing an adhesive magnet, characterized in that, It includes the following steps: Apply insulating adhesive slurry between any two adjacent substrates and then perform curing treatment to form an adhesive layer between the two adjacent substrates; Among them, the insulating adhesive slurry includes an insulating adhesive and microbeads; the D50 particle size of the microbeads is 10 μm or more and less than 90 μm; Among them, the pressure of the curing treatment is 0.5 - 2.5 Mpa.

6. The method for preparing an adhesive magnet according to claim 5, characterized in that, The number of the substrates is 3 - 100; And / or, the substrate is a neodymium iron boron magnet; And / or, the temperature of the curing treatment is 100 - 250 °C; And / or, the curing treatment includes a first heating section and a second heating section. The temperature of the first heating section is 100 - 250 °C, and the temperature of the second heating section is higher than that of the first heating section; Wherein, preferably, the pressure of the first heating section is 0.5 - 2.5 Mpa, for example, 2 Mpa; Wherein, preferably, the time of the first heating section is 0.1 - 6 h, for example, 1 h; Wherein, preferably, the temperature of the first heating section is 120 °C; Wherein, preferably, the temperature of the second heating section is 150 - 250 °C, for example, 160 °C; Wherein, preferably, the pressure of the second heating section is 0.5 - 2.5 Mpa, for example, 2 Mpa; Wherein, preferably, the time of the second heating section is 0.1 - 6 h, for example, 1 h.

7. The method for preparing an adhesive magnet according to claim 5, characterized in that, The material of the microbeads includes ceramic material and / or glass material; Wherein, preferably, the ceramic material includes one or more of metal oxides, carbides, nitrides, and borides; Wherein, the metal oxides, for example, include alumina and / or zirconia; Wherein, the carbides, for example, include silicon carbide and / or boron carbide; Wherein, the nitrides, for example, include silicon nitride and / or aluminum nitride; Wherein, the borides, for example, include zirconium boride and / or silicon boride; Wherein, preferably, the glass material includes one or more of Na2SiO3, CaSiO3, SiO2, Na2O·CaO·6SiO2, K2O, CaO, and B2O3; And / or, the D50 particle size of the microbeads is 20 - 40 μm or 50 - 70 μm; And / or, the material of the microbeads is a ceramic material, and the density of the microbeads is less than 1.5 g / cm 3 ; And / or, the material of the microbeads is glass material, and the density of the microbeads is greater than 2.5 g / cm 3 , for example, 1.2 g / cm 3 ; And / or, the roundness of the microbeads is 0.4 - 1, for example, 0.6; And / or, the shape of the microbeads is one or more of spherical, polygonal, elliptical, and bar-shaped; wherein, the spherical shape, for example, includes regular spherical and / or irregular spherical; wherein, the polygonal shape, for example, includes regular polygon and / or irregular polygon; And / or, the types of the insulating adhesive include one or more of epoxy resin, cyanoacrylate, unsaturated polyester resin, phenolic resin, and polyimide resin.

8. The method for preparing an adhesive magnet according to claim 5, characterized in that, The mass percentage of the microbeads in the insulating adhesive paste is 0.1 wt% - 5 wt%, for example, 1 wt%; And / or, the mass percentage of the insulating adhesive in the insulating adhesive paste is 95 wt% - 99.9 wt%, for example, 99 wt%; And / or, the mass percentage of the insulating adhesive paste in the substrate is less than 2%, for example, 0.15%.

9. A bonded magnet prepared by the method for preparing a bonded magnet according to any one of claims 5 - 8.

10. An application of a bonded magnet according to any one of claims 1 - 4 and 9 in an electric motor.

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