A method to enhance SmFe 12 Methods for improving the magnetic properties of sintered permanent magnet materials

Abstract

This invention discloses a method for improving SmFe 12 A method for determining the magnetic properties of sintered permanent magnet materials. The method includes: using a low-melting-point rare-earth-rich alloy sheet as a diffusion source to conduct magnetic analysis on SmFe2... 12 The sintered permanent magnet material is sandwiched and heat-treated to achieve SmFe 12 The magnetic properties of sintered permanent magnet materials are improved; wherein the low-melting-point rare-earth-rich metal sheet includes Sm sheet and / or Sm alloy sheet. The modified SmFe prepared by this invention... 12 Sintered permanent magnet materials exhibit continuous grain boundary phases, high coercivity, and high energy product. Room temperature coercivity can be increased by 2000–8000 Oe. This method is simple and effective, and is applicable to SmFe... 12 This provides a new approach to improving the overall magnetic properties of sintered permanent magnet materials.

Description

Technical Field

[0001] This invention belongs to the field of rare earth permanent magnet materials technology, specifically relating to a method for improving SmFe 12 Methods for determining the magnetic properties of sintered permanent magnet materials. Background Technology

[0002] In the field of rare-earth permanent magnet materials, although third-generation rare-earth permanent magnets, represented by neodymium iron boron (NdFeB), possess extremely high theoretical maximum energy product, several key challenges remain. These challenges include a limited operating temperature range, uneven consumption of rare-earth resources, and high production costs. Furthermore, after decades of development and optimization, the performance of NdFeB permanent magnets has gradually approached its theoretical limits, and further breakthroughs face technological bottlenecks. Therefore, developing next-generation rare-earth permanent magnets that can both optimize performance and promote more balanced resource utilization has become an urgent scientific and technological problem to be solved.

[0003] SmFe 12 Sintered permanent magnet materials, as an important branch of rare-earth permanent magnet materials, possess high saturation magnetization, high Curie temperature, and good magnetocrystalline anisotropy, and have broad application prospects in high-end manufacturing fields. However, existing SmFe... 12 Sintered permanent magnet materials suffer from problems such as unstable phase composition, uneven microstructure, and insufficient magnetic properties during the preparation process, which limit their large-scale application. Summary of the Invention

[0004] The main objective of this invention is to provide a method for improving SmFe 12 A method for improving the magnetic properties of sintered permanent magnet materials to overcome the shortcomings of existing technologies.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0006] This invention provides a method for improving SmFe 12 A method for determining the magnetic properties of sintered permanent magnet materials, comprising:

[0007] Provide SmFe 12 Sintered permanent magnet material, wherein SmFe 12 The chemical formula of the sintered permanent magnet material is Sm a (Fe 1- b Co b ) bal Ti c V 16-c M d Where 8≤a≤13, 0≤b≤0.2, 0≤c≤16, 0≤d≤3, and M is selected from Al, Cu or Ga;

[0008] Low-melting-point rare-earth-rich alloy sheets were used as a diffusion source for the SmFe 12 The sintered permanent magnet material is sandwiched and heat-treated to achieve SmFe 12 The magnetic properties of sintered permanent magnet materials are improved; wherein the low-melting-point rare-earth-rich metal sheet includes Sm sheet and / or Sm alloy sheet.

[0009] This invention also provides a modified SmFe 12 Type sintered permanent magnet material, wherein the modified SmFe 12 The sintered permanent magnet material is prepared by the aforementioned method.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention prepares a highly dense magnet by precisely designing the composition and combining a multi-step synergistic process including ingot homogenization heat treatment, sintering and forming and low-temperature heat treatment after sandwiching metal Sm thin sheets, and constructs a non-magnetic grain boundary phase with good magnetic isolation effect, which significantly improves the room temperature coercivity, and finally obtains a bulk permanent magnet with excellent comprehensive performance that has both high coercivity and high maximum magnetic energy product. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 It is Sm9Fe in Embodiment 1 of the present invention bal Ti5V 11 Backscattered scanning electron microscope image of sintered magnet (untreated);

[0013] Figures 2a-2b Sm9Fe in Embodiment 3 of the present invention bal Ti5V 11 Backscattered electron microscope image and elemental distribution map of metal Sm thin film sandwiched and heat-treated at 1060℃ for 1h;

[0014] Figure 3 It is Sm9Fe in Embodiment 16 of the present invention bal Ti5V 11 via Sm 71 Cu 29 Backscattered electron microscope image and elemental distribution map of alloy sheet after heat treatment at 1020℃ for 1 hour. Detailed Implementation

[0015] In view of the shortcomings of the existing technology, SmFe has been further improved. 12 The inventors of this invention, through long-term research and extensive practice, have developed a technical solution for improving the magnetic properties of SmFe2O3 sintered permanent magnet materials. 12 A method for determining the magnetic properties of sintered permanent magnet materials. The technical solution of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0016] Specifically, as one aspect of the technical solution of this invention, it involves an improvement method for SmFe 12 Methods for improving the magnetic properties of sintered permanent magnet materials include:

[0017] Provide SmFe 12 Sintered permanent magnet material, wherein SmFe 12 The chemical formula of the sintered permanent magnet material is Sm a (Fe 1- b Co b ) bal Ti c V 16-c M d Where 8≤a≤13, 0≤b≤0.2, 0≤c≤16, 0≤d≤3, M is selected from Al, Cu or Ga; bal is an abbreviation for balance, which means surplus, referring to the remaining part after adjusting for the content of other components when the sum of atomic percentages is 100%;

[0018] Low-melting-point rare-earth-rich alloy sheets were used as a diffusion source for the SmFe 12 The sintered permanent magnet material is sandwiched and heat-treated to achieve SmFe 12 The magnetic properties of sintered permanent magnet materials are improved; wherein the low-melting-point rare-earth-rich metal sheet includes Sm sheet and / or Sm alloy sheet.

[0019] In some preferred embodiments, the Sm alloy sheet includes any one or more combinations of SmCu sheet, SmAl sheet, and SmGa sheet, and is not limited thereto.

[0020] In some preferred embodiments, the method specifically includes: using a low-melting-point rare-earth-rich alloy sheet as a diffusion source to diffuse the SmFe 12The magnet is sandwiched with sintered permanent magnet material and then heat-treated in a Sm-rich atmosphere at 900~1100℃ for 30~120min. The Sm-rich atmosphere is a protective atmosphere containing a high concentration of samarium vapor, which is specially set to prevent excessive volatilization of Sm during the heat treatment process.

[0021] In some preferred embodiments, the SmFe 12 The sintered permanent magnet material has a porous structure, and the SmFe 12 The pore diameter of the sintered permanent magnet material is 0.5~30μm, and the density is 4~6.5cm³ / g.

[0022] In some preferred embodiments, the thickness of the low-melting-point rare-earth-rich metal sheet is 2-3 mm, and the surface of the low-melting-point rare-earth-rich metal sheet is flat and free of oxide scale.

[0023] In some preferred embodiments, the method further includes: processing the SmFe 12 Before encapsulating the sintered permanent magnet material, first process SmFe 12 The sintered permanent magnet material is polished to remove the surface oxide layer.

[0024] In some preferred embodiments, the SmFe 12 The sintered permanent magnet material is obtained by melting, casting annealing, powder preparation, powder mixing, orientation molding, cold isostatic pressing, and sintering of the target component alloy. The sintering conditions include sintering at 1100~1190℃ in a Sm-rich atmosphere for 30~120 minutes. The Sm-rich atmosphere is a protective atmosphere containing a high concentration of samarium vapor, which is specially set to prevent excessive volatilization of Sm during the high-temperature sintering process of the magnet.

[0025] In some preferred embodiments, the enhancement of SmFe 12 Methods for improving the magnetic properties of sintered permanent magnet materials include:

[0026] Provide SmFe 12 Type Sintered permanent magnet material, with the chemical formula Sm a (Fe 1-b Co b ) bal Ti c V 16-c M d Where 8≤a≤13, 0≤b≤0.2, 0≤c≤16, 0≤d≤3, and M is a wetting element such as Al, Cu, or Ga. The SmFe... 12 The sintered permanent magnet material has a porous structure with a pore diameter of 0.5~30μm and a density of 4~6.5cm³ / g;

[0027] For the porous structure SmFe 12Sintered permanent magnet materials were prepared by using Sm metal sheets and low-melting-point rare-earth-rich alloy sheets such as SmCu, SmAl, and SmGa as diffusion sources. After encapsulation, the materials were heat-treated at 900–1100℃ in a Sm-rich atmosphere for 30–120 min, successfully constructing Sm-rich grain boundary phases in the pores. These phases effectively fill the pores and isolate the exchange coupling between the main phase grains, thereby enhancing the SmFe1 / SmFe2 ... 12 Density and magnetic properties of permanent magnet materials.

[0028] In some more specific implementations, the enhancement of SmFe 12 Methods for improving the magnetic properties of sintered permanent magnet materials include:

[0029] (1) Ingredients: The target ingredient is Sm a (Fe 1-b Co b ) bal Ti c V 16-c M d , where 8≤a≤13, 0≤b≤0.2, 0≤c≤16, 0≤d≤3, and M is a wetting element such as Al, Cu, Ga.

[0030] (2) Melting: Place the target alloy composition prepared in step (1) into a vacuum induction melting furnace. After all the components have melted, refine for 3-5 minutes until the molten steel is uniform. Pour it into a water-cooled copper mold to cool and form the target alloy ingot.

[0031] (3) Ingot annealing treatment: The ingot is placed in a vacuum sintering furnace and subjected to homogenization annealing heat treatment under argon atmosphere protection. The annealing process parameters are 1140℃ and held for 5 hours, and then cooled to room temperature to obtain annealed ingot.

[0032] (4) Powder making: The annealed ingot is subjected to hydrogen breaking and air jet milling processes to obtain alloy powder with an average grain size of 2.0-3.5μm.

[0033] (5) Mixing powder: Mix Sm a (Fe 1-b Co b ) bal Ti c V 16-c M d The powder was uniformly mixed in a powder mixer under a protective argon atmosphere for 180 minutes to obtain a powder with uniform composition.

[0034] (6) Orientation molding and cold isostatic pressing: Sm a (Fe 1-b Co b ) bal Ti c V16-c M d Weigh 17-25g of the uniformly mixed powder and shape it in a magnetic field forming machine with a magnetic field strength of 1.5-2T. Then, perform cold isostatic pressing in a fluid at 160MPa to obtain a green body.

[0035] (7) Sintering: The Sm obtained in step (5) is sintered. a (Fe 1-b Co b ) bal Ti c V 16-c M d The permanent magnet material green blank was sintered at 1100~1190℃ in a Sm-rich atmosphere for 50 minutes, and finally cooled to room temperature with furnace air.

[0036] (8) Heat treatment: The Sm obtained in step (6) is subjected to heat treatment. a (Fe 1-b Co b ) bal Ti c V 16-c M d After the oxide layer on the surface of the sintered magnet is cleaned by grinding, metal Sm thin sheets and low melting point rare earth rich alloy thin sheets such as SmCu, SmAl, and SmGa are used as diffusion sources for encapsulation, and the magnet is heat-treated at 900~1100℃ in an Sm rich atmosphere for 1 hour, and finally cooled to room temperature with furnace air.

[0037] Furthermore, in step (1), the oxide scale on the surface of the prepared raw material is polished clean using a polishing machine.

[0038] Furthermore, step (2) specifically includes: when the vacuum degree is less than 2×10 -2 Under the conditions of Pa and protective gas filling, the target alloy composition prepared in step (1) is placed in a vacuum induction melting furnace. After all the components are melted, it is refined for 3~5 minutes until the molten steel is uniform. It is then poured into a water-cooled copper mold for cooling to form a target alloy ingot.

[0039] Furthermore, step (2) also includes: before melting the raw materials prepared in step (1), first heating them under a vacuum of 5×10⁻⁶. -2 Under conditions of Pa below and temperature of 100-200℃, the water vapor and gas adsorbed on the surface of the prepared raw materials are removed.

[0040] Further, step (4) specifically includes: hydrogen-crushing the annealed alloy ingot obtained in step (3) into alloy particles of 0.1-0.5 mm, and then obtaining alloy powder with an average grain size of 2.0-3.5 μm by air jet milling under protective argon gas conditions.

[0041] Furthermore, step (8) specifically includes: metal Sm thin sheets and low melting point rare earth rich alloy thin sheets such as SmCu, SmAl, and SmGa with a thickness of about 2 mm, and the surface of the thin sheets is flat and free of oxide scale.

[0042] Furthermore, the protective gas includes, but is not limited to, inert gases such as argon.

[0043] Another aspect of the present invention also provides a modified SmFe 12 Type sintered permanent magnet material, wherein the modified SmFe 12 The sintered permanent magnet material is prepared by the aforementioned method.

[0044] In some preferred embodiments, the modified SmFe 12 In sintered permanent magnet materials, a non-magnetic grain boundary phase is formed around the main phase grains.

[0045] In some preferred embodiments, the modified SmFe 12 Sintered permanent magnet materials are superior to SmFe 12 The room temperature coercivity of the sintered permanent magnet material is increased by 2000~8000 Oe.

[0046] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0047] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0048] Example 1

[0049] Porous structure SmFe 12 The nominal composition of the sintered permanent magnet material is: Sm9Fe bal Ti5V 11 Using metallic Sm sheets as a diffusion source to encapsulate porous SmFe structures 12 The permanent magnet material is sintered and then subjected to heat treatment.

[0050] (1) Smelting: The surface of the raw materials is mechanically polished to remove the oxide layer and unnecessary impurities, and then mixed according to the atomic percentage ratio. The prepared raw materials are placed in a crucible and vacuumed to 5×10 -2 Pa, then at around 150℃ to remove adsorbed water vapor and gas from the surface of the raw material, and after the vacuum stabilizes (<5×10 -2Then, high-purity argon gas (99.999%) at 0.08 MPa is introduced. The heating power is gradually increased, and after all components have melted, it is refined for 3-5 minutes until the molten steel is homogeneous. The power is then gradually reduced to 5.5 KW, and the mixture is poured into a water-cooled copper mold to cool, forming the target alloy ingot.

[0051] (2) Ingot annealing treatment: The ingot is placed in a vacuum sintering furnace and subjected to homogenization annealing heat treatment under argon atmosphere protection. The annealing process parameters are 1140℃ and held for 5 hours, and then cooled to room temperature to obtain annealed ingot.

[0052] (3) Powder making: The annealed ingot is subjected to hydrogen breaking and air jet milling processes to obtain alloy powder with an average grain size of 2.0-3.5μm.

[0053] (4) Mixing powder: Mix Sm9Fe bal Ti5V 11 The powder was uniformly mixed in a powder mixer for 180 minutes under a protective argon atmosphere to obtain a powder with uniform composition.

[0054] (5) Orientation molding and cold isostatic pressing: Sm9Fe bal Ti5V 11 17g of the uniformly mixed powder is weighed and oriented in a magnetic field forming machine with a magnetic field strength of 1.5~2T. Then, it is cold isostatically pressed in a fluid at 160MPa to obtain a green body.

[0055] (6) Sintering: The Sm9Fe obtained in step (5) is sintered. bal Ti5V 11 The permanent magnet material green body was sintered at 1160℃ in a Sm-rich atmosphere for 50 min, and finally cooled to room temperature with furnace air to obtain Sm9Fe. bal Ti5V 11 The sintered magnet, its backscattered scanning electron microscope image is as follows: Figure 1 As shown.

[0056] (7) Heat treatment: The Sm9Fe obtained in step (6) is subjected to heat treatment. bal Ti5V 11 After the oxide layer on the surface of the sintered magnet was cleaned by polishing, it was sandwiched with a metal Sm sheet with a thickness of about 2 mm and a smooth surface free of oxide scale. It was then heat-treated at 1100℃ in an Sm-rich atmosphere for 1 hour, and finally cooled to room temperature with furnace air to obtain modified SmFe. 12 Type sintered permanent magnet material.

[0057] Example 2

[0058] In this embodiment, modified SmFe 12The preparation method of the sintered permanent magnet material is basically the same as that in Example 1, except that the heat treatment temperature after sandwiching the metal Sm sheet in Example 2 is 1080℃.

[0059] Example 3

[0060] This embodiment modifies SmFe 12 The preparation method of the modified SmFe sintered permanent magnet material is basically the same as that in Example 1, except that: in Example 3, the heat treatment temperature after sandwiching with metal Sm sheets is 1060℃ to obtain modified SmFe 12 Backscattered electron microscope images and elemental distribution diagrams of the sintered permanent magnet material are shown below. Figures 2a-2b .

[0061] Example 4

[0062] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 1, except that the heat treatment temperature after sandwiching the metal Sm sheet in Example 4 is 1040℃.

[0063] Example 5

[0064] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 1, except that the heat treatment temperature after sandwiching the metal Sm sheet in Example 5 is 1020℃.

[0065] Example 6

[0066] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 1, except that the heat treatment temperature after sandwiching the metal Sm sheet in Example 6 is 1000℃.

[0067] Comparative Example 1

[0068] In this comparative example, SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that of Example 1, except that: Comparative Example 1 is based on Example 1 without the metal Sm sheet encapsulation and heat treatment in step (7).

[0069] The inventors in this case also modified SmFe obtained using Examples 1, 2, 3, 4, 5, 6 and Comparative Example 1. 12 Sintered permanent magnet materials, SmFe 12 The coercivity Hcj, remanence Br, and magnetic energy product (BH)max of the sintered permanent magnet material were measured at room temperature using a permanent magnet material precision measurement system (BH). The magnetic performance parameters are shown in Table 1.

[0070] Table 1. Magnetic properties of permanent magnet materials prepared in Examples 1, 2, 3, 4, 5, 6 and Comparative Example 1

[0071] name Heat treatment temperature for sandwiching Sm metal sheets (°C) <![CDATA[B r kGs]]> <![CDATA[H cj no]]> <![CDATA[(BH) max MGOe]]> Example 1 1100 6.290 4.383 6.943 Example 2 1080 6.356 6.770 8.488 Example 3 1060 6.458 7.223 9.347 Example 4 1040 6.410 7.495 9.185 Example 5 1020 6.142 8.671 8.401 Example 6 1000 5.822 8.673 7.354 Comparative Example 1 -- 2.108 0.592 0.332

[0072] In this invention, through comparison, the coercivity Hcj of the magnet using the 1060℃ metal Sm sheet sandwich heat treatment process can reach 7.223 kOe, the remanence Br can reach 6.458 kGs, and the maximum energy product (BH) can reach 6.458 kGs. max The coercivity of the magnet can reach 9.347 MGOe, which is 6.5 kOe higher than that without heat treatment. The maximum energy product (BH) is also increased. max Increased MGOe by 8.8%. Significantly improved SmFe. 12 The magnetic properties of this type of permanent magnet material provide a solution for providing high-performance and stable sintered magnets, thus this preparation method has broad application prospects.

[0073] As shown in Table 1, in Comparative Example 1, the magnet coercivity was very poor when no Sm sheet sandwiching heat treatment was performed. In this case, the SmFe magnet prepared using normal processes... 12 The density and magnetic properties of the original permanent magnet material failed to meet the requirements. When using a heat treatment process involving sandwiching Sm metal sheets at 1100℃, a significant increase in the coercivity and remanence of the magnet was observed. Lowering the heat treatment temperature to 1080℃ further improved the coercivity and remanence. Further lowering the temperature to 1060℃ resulted in a noticeable increase in the SmFe... 12 When the coercivity and remanence of the permanent magnet material reach optimal values, the overall magnetic properties of the magnet reach their best value. However, when the heat treatment temperature of the Sm metal sheet is further reduced, the overall magnetic properties of the magnet actually decrease.

[0074] Example 7

[0075] Porous structure SmFe 12 The nominal composition of the sintered permanent magnet material is: Sm9(Fe 0.9 Co 0.1 ) bal Ti8V8Al2Cu 0.5 Using metallic Sm sheets as a diffusion source to encapsulate porous SmFe structures 12 The permanent magnet material is sintered and then subjected to heat treatment.

[0076] (1) Smelting: The surface of the raw materials is mechanically polished to remove the oxide layer and unnecessary impurities, and then mixed according to the atomic percentage ratio. The prepared raw materials are placed in a crucible and vacuumed to 5×10 -2 Pa, then at around 150℃ to remove adsorbed water vapor and gas from the surface of the raw material, and after the vacuum stabilizes (<5×10 -2Then, high-purity argon gas (99.999%) at 0.08 MPa is introduced. The heating power is gradually increased, and after all components have melted, it is refined for 3-5 minutes until the molten steel is homogeneous. The power is then gradually reduced to 5.5 KW, and the mixture is poured into a water-cooled copper mold to cool, forming the target alloy ingot.

[0077] (2) Ingot annealing treatment: The ingot is placed in a vacuum sintering furnace and subjected to homogenization annealing heat treatment under argon atmosphere protection. The annealing process parameters are 1140℃ and held for 5 hours, and then cooled to room temperature to obtain annealed ingot.

[0078] (3) Powder making: The annealed ingot is subjected to hydrogen breaking and air jet milling processes to obtain alloy powder with an average grain size of 2.0-3.5μm.

[0079] (4) Mixing powder: Mix Sm9(Fe 0.9 Co 0.1 ) bal Ti8V8Al2Cu 0.5 The powder was uniformly mixed in a powder mixer for 180 minutes under a protective argon atmosphere to obtain a powder with uniform composition.

[0080] (5) Orientation molding and cold isostatic pressing: Sm9(Fe 0.9 Co 0.1 ) bal Ti8V8Al2Cu 0.5 17g of the uniformly mixed powder is weighed and oriented in a magnetic field forming machine with a magnetic field strength of 1.5~2T. Then, it is cold isostatically pressed in a fluid at 160MPa to obtain a green body.

[0081] (6) Sintering: The Sm9(Fe) obtained in step (5) is sintered. 0.9 Co 0.1 ) bal Ti8V8Al2Cu 0.5 The permanent magnet material green body was sintered at 1160℃ in a Sm-rich atmosphere for 50 min, and finally cooled to room temperature with furnace air to obtain Sm9(Fe)2. 0.9 Co 0.1 ) bal Ti8V8Al2Cu 0.5 Sintered permanent magnet materials.

[0082] (7) Heat treatment: The Sm9(Fe) obtained in step (6) is subjected to heat treatment. 0.9 Co 0.1 ) bal Ti8V8Al2Cu 0.5After the oxide layer on the surface of the sintered permanent magnet material is cleaned by polishing, it is sandwiched with a metal Sm sheet with a thickness of about 2 mm and a smooth surface free of oxide scale. The material is then heat-treated at 1080℃ in a Sm-rich atmosphere for 1 hour, and finally cooled to room temperature with furnace air to obtain modified SmFe. 12 Type sintered permanent magnet material.

[0083] Example 8

[0084] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 7, except that the heat treatment temperature after sandwiching the metal Sm sheet in Example 8 is 1060℃.

[0085] Example 9

[0086] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 7, except that the heat treatment temperature after sandwiching the metal Sm sheet in Example 9 is 1040℃.

[0087] Example 10

[0088] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 7, except that the heat treatment temperature after sandwiching the metal Sm sheet in Example 10 is 1020℃.

[0089] Example 11

[0090] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 7, except that the heat treatment temperature after sandwiching the metal Sm sheet in Example 11 is 1000℃.

[0091] Comparative Example 2

[0092] In this comparative example, SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that of Example 7, except that: Comparative Example 2 is based on Example 7 without the metal Sm sheet sandwiching and heat treatment in step (7).

[0093] The inventors of this case also used a permanent magnet material precision measurement system (BH) to measure the coercivity Hcj, remanence Br, and magnetic energy product (BH)max of the permanent magnet materials obtained in Examples 7, 8, 9, 10, 11 and Comparative Example 2 at room temperature. The magnetic performance parameters are shown in Table 2.

[0094] Table 2 Magnetic properties of permanent magnet materials prepared in Examples 7, 8, 9, 10, 11 and Comparative Example 2

[0095] name Heat treatment temperature for sandwiching Sm metal sheets (°C) <![CDATA[B r kGs]]> <![CDATA[H cj no]]> <![CDATA[(BH) max MGOe]]> Example 7 1080 5.150 6.912 5.319 Example 8 1060 5.744 7.324 6.726 Example 9 1040 5.859 7.924 7.894 Example 10 1020 5.547 8.498 6.391 Example 11 1000 5.452 9.292 6.227 Comparative Example 2 -- 3.225 3.106 3.249

[0096] As shown in Table 2, through comparison, the SmFe produced by using a heat treatment process following the encapsulation of Sm metal sheets in this invention... 12 Coercivity Hcj, remanence Br, and maximum energy product (BH) of permanent magnet materials. max Compared to Comparative Example 2, which did not employ heat treatment, both showed significant improvements, with the coercivity of the magnet increasing by 3-6 kOe and the maximum energy product (BH) increasing. max Increased MGOe by 2.1~4.6. Significantly improved SmFe. 12 Magnetic properties of permanent magnet materials. As the heat treatment temperature decreases, the coercivity Hcj, remanence Br, and maximum energy product (BH) increase. max All of them show a trend of first increasing and then decreasing, and reach the optimal value when the heat treatment temperature is 1040℃, Hcj can reach 7.924kOe, remanence Br can reach 5.859kGs, and the maximum magnetic energy product (BH) can reach 5.859kGs. max It can reach 7.894 MGOe.

[0097] Example 12

[0098] Porous structure SmFe 12 The nominal composition of the sintered permanent magnet material is: Sm9Fe bal Ti5V 11 Using Sm 71 Cu 29 Alloy sheet as diffusion source to encapsulate porous SmFe structure 12 The permanent magnet material is sintered and then subjected to heat treatment.

[0099] (1) Smelting: The surface of the raw materials is mechanically polished to remove the oxide layer and unnecessary impurities, and then mixed according to the atomic percentage ratio. The prepared raw materials are placed in a crucible and vacuumed to 5×10 -2 Pa, then at around 150℃ to remove adsorbed water vapor and gas from the surface of the raw material, and after the vacuum stabilizes (<5×10 -2 Then, high-purity argon gas (99.999%) at 0.08 MPa is introduced. The heating power is gradually increased, and after all components have melted, it is refined for 3-5 minutes until the molten steel is homogeneous. The power is then gradually reduced to 5.5 KW, and the mixture is poured into a water-cooled copper mold to cool, forming the target alloy ingot.

[0100] (2) Ingot annealing treatment: The ingot is placed in a vacuum sintering furnace and subjected to homogenization annealing heat treatment under argon atmosphere protection. The annealing process parameters are 1140℃ and held for 5 hours, and then cooled to room temperature to obtain annealed ingot.

[0101] (3) Powder making: The annealed ingot is subjected to hydrogen breaking and air jet milling processes to obtain alloy powder with an average grain size of 2.0-3.5μm.

[0102] (4) Mixing powder: Mix Sm9Fe bal Ti5V 11 The powder was uniformly mixed in a powder mixer for 180 minutes under a protective argon atmosphere to obtain a powder with uniform composition.

[0103] (5) Orientation molding and cold isostatic pressing: Sm9Fe bal Ti5V 11 17g of the uniformly mixed powder is weighed and oriented in a magnetic field forming machine with a magnetic field strength of 1.5~2T. Then, it is cold isostatically pressed in a fluid at 160MPa to obtain a green body.

[0104] (6) Sintering: The Sm9Fe obtained in step (5) is sintered. bal Ti5V 11 The permanent magnet material green body was sintered at 1160℃ in a Sm-rich atmosphere for 50 min, and finally cooled to room temperature with furnace air to obtain Sm9Fe. bal Ti5V 11 Sintered magnets.

[0105] (7) Heat treatment: The Sm9Fe obtained in step (6) is subjected to heat treatment. bal Ti5V 11 After the oxide layer on the surface of the sintered magnet is cleaned by polishing, a 2mm thick Sm steel with a smooth, oxide-free surface is used. 71 Cu 29 The alloy sheets were sandwiched together and heat-treated at 1100℃ in a Sm-rich atmosphere for 1 hour, and finally cooled to room temperature with furnace air to obtain modified SmFe. 12 Type sintered permanent magnet material.

[0106] Example 13

[0107] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 12, except that: in Example 13, Sm 71 Cu 29 The heat treatment temperature after the alloy sheet is sandwiched is 1080℃.

[0108] Example 14

[0109] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 12, except that: in Example 14, Sm 71 Cu 29 The heat treatment temperature after the alloy sheet is sandwiched is 1060℃.

[0110] Example 15

[0111] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 12, except that: in Example 15, Sm 71 Cu 29 The heat treatment temperature after the alloy sheet is sandwiched is 1040℃.

[0112] Example 16

[0113] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 12, except that: in Example 16, Sm 71 Cu 29 The alloy sheet was sandwiched and then heat-treated at 1020℃ to obtain modified SmFe. 12 Backscattered electron microscope images and elemental distribution diagrams of the sintered permanent magnet material are shown below. Figures 2a-2b .

[0114] Example 17

[0115] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 12, except that: in Example 17, Sm 71 Cu 29 The heat treatment temperature after the alloy sheet is sandwiched is 1000℃.

[0116] Example 18

[0117] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 12, except that: in Example 18, Sm 71 Cu 29 The heat treatment temperature after the alloy sheet is sandwiched is 980℃.

[0118] Example 19

[0119] In this embodiment, modified SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 12, except that: in Example 19, Sm 71 Cu 29 The heat treatment temperature after the alloy sheet is sandwiched is 960℃.

[0120] Comparative Example 3

[0121] In this comparative example, SmFe 12The preparation method of the type sintered permanent magnet material is basically the same as that of Example 12, except that: Comparative Example 3 is based on Example 12 without step (7) of Sm 71 Cu 29 Alloy sheet clamping and heat treatment.

[0122] The inventors of this case also used a permanent magnet material precision measurement system (BH) to measure the coercivity Hcj, remanence Br, and magnetic energy product (BH)max of the permanent magnet materials obtained in Examples 12, 13, 14, 15, 16, 17, 18, 19 and Comparative Example 3 at room temperature. The magnetic performance parameters are shown in Table 3.

[0123] Table 3 Magnetic properties of permanent magnet materials prepared in Examples 12, 13, 14, 15, 16, 17, 18, 19 and Comparative Example 3

[0124] name Heat treatment temperature for sandwiching Sm metal sheets (°C) <![CDATA[B r kGs]]> <![CDATA[H cj no]]> <![CDATA[(BH) max MGOe]]> Example 12 1100 4.406 2.742 2.058 Example 13 1080 5.032 6.326 4.527 Example 14 1060 4.993 7.225 4.783 Example 15 1040 5.222 8.420 6.070 Example 16 1020 5.306 8.724 6.218 Example 17 1000 5.370 9.137 6.678 Example 18 980 5.427 9.154 6.748 Example 19 960 5.412 8.633 6.422 Comparative Example 3 -- 2.014 0.624 0.321

[0125] As shown in Table 3, through comparison, Sm is used in this invention. 71 Cu 29 SmFe alloy sheet encapsulation followed by heat treatment 12 Coercivity Hcj, remanence Br, and maximum energy product (BH) of permanent magnet materials. max Compared to Comparative Example 3, which did not employ heat treatment, all samples showed significant improvements, with the coercivity of the magnet increasing by 2-8 kOe and the maximum energy product (BH) increasing. max Increased MGOe by 1.7~6.4. Significantly improved SmFe. 12 Magnetic properties of permanent magnet materials. As the heat treatment temperature decreases, the coercivity Hcj, remanence Br, and maximum energy product (BH) increase. max All of these show an upward trend, reaching their maximum values ​​at a heat treatment temperature of 980℃, with Hcj reaching 9.154 kOe, remanence Br reaching 5.427 kGs, and maximum magnetic energy product (BH). max It can reach 6.748 MGOe. However, when the heat treatment temperature is further reduced, the overall magnetic properties of the magnet actually decrease.

[0126] Example 20

[0127] Porous structure SmFe 12 The nominal composition of the sintered permanent magnet material is: Sm9Fe bal Ti5V 11 Using metallic Sm sheets as a diffusion source to encapsulate porous SmFe structures 12 The permanent magnet material is sintered and then subjected to heat treatment.

[0128] (1) Smelting: The surface of the raw materials is mechanically polished to remove the oxide layer and unnecessary impurities, and then mixed according to the atomic percentage ratio. The prepared raw materials are placed in a crucible and vacuumed to 5×10 -2 Pa, then at around 150℃ to remove adsorbed water vapor and gas from the surface of the raw material, and after the vacuum stabilizes (<5×10 -2 Then, high-purity argon gas (99.999%) at 0.08 MPa is introduced. The heating power is gradually increased, and after all components have melted, it is refined for 3-5 minutes until the molten steel is homogeneous. The power is then gradually reduced to 5.5 KW, and the mixture is poured into a water-cooled copper mold to cool, forming the target alloy ingot.

[0129] (2) Ingot annealing treatment: The ingot is placed in a vacuum sintering furnace and subjected to homogenization annealing heat treatment under argon atmosphere protection. The annealing process parameters are 1140℃ and held for 5 hours, and then cooled to room temperature to obtain annealed ingot.

[0130] (3) Powder making: The annealed ingot is subjected to hydrogen breaking and air jet milling processes to obtain alloy powder with an average grain size of 2.0-3.5μm.

[0131] (4) Mixing powder: Mix Sm9Fe bal Ti5V 11 The powder was uniformly mixed in a powder mixer for 180 minutes under a protective argon atmosphere to obtain a powder with uniform composition.

[0132] (5) Orientation molding and cold isostatic pressing: Sm9Fe bal Ti5V 11 17g of the uniformly mixed powder is weighed and oriented in a magnetic field forming machine with a magnetic field strength of 1.5~2T. Then, it is cold isostatically pressed in a fluid at 160MPa to obtain a green body.

[0133] (6) Sintering: The Sm9Fe obtained in step (5) is sintered. bal Ti5V 11 The permanent magnet material green body was sintered at 1160℃ in a Sm-rich atmosphere for 50 min, and finally cooled to room temperature with furnace air to obtain Sm9Fe. bal Ti5V 11 Sintered magnets.

[0134] (7) Heat treatment: The Sm9Fe obtained in step (6) is subjected to heat treatment. bal Ti5V 11 After the oxide layer on the surface of the sintered magnet was cleaned by polishing, it was sandwiched with a metal Sm sheet with a thickness of about 2 mm and a smooth surface free of oxide scale. It was then heat-treated at 1060℃ in an Sm-rich atmosphere for 1 hour, and finally cooled to room temperature with furnace air to obtain modified SmFe. 12 Type sintered permanent magnet material.

[0135] Comparative Example 4

[0136] In this comparative example, SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that of Example 20, except that the heat treatment temperature after sandwiching the metal Sm sheet in Comparative Example 4 is 700℃.

[0137] Comparative Example 5

[0138] In this comparative example, SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 20, except that the heat treatment temperature after sandwiching the metal Sm sheet in Comparative Example 5 is 800℃.

[0139] Comparative Example 6

[0140] In this comparative example, SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that of Example 20, except that the heat treatment temperature after sandwiching the metal Sm sheet in Comparative Example 6 is 1200℃.

[0141] The inventors in this case also modified SmFe obtained using Example 20 and Comparative Examples 4, 5, and 6. 12 Sintered permanent magnet materials, SmFe 12 The coercivity Hcj, remanence Br, and magnetic energy product (BH)max of the sintered permanent magnet material were measured at room temperature using a permanent magnet material precision measurement system (BH). The magnetic performance parameters are shown in Table 4.

[0142] Table 4. Magnetic properties of permanent magnet materials prepared in Example 20 and Comparative Examples 4, 5, and 6

[0143] name Heat treatment temperature for sandwiching Sm metal sheets (°C) <![CDATA[B r kGs]]> <![CDATA[H cj no]]> <![CDATA[(BH) max MGOe]]> Example 20 1060 6.425 7.327 9.316 Comparative Example 4 700 4.329 3.135 4.126 Comparative Example 5 800 5.121 5.213 6.223 Comparative Example 6 1200 6.037 3.694 5.362

[0144] In this invention, through comparison, as shown in Table 4, SmFe produced by using different heat treatment temperatures and Sm sheet-encasing heat treatment processes is compared. 12 Coercivity Hcj, remanence Br, and maximum energy product (BH) of permanent magnet materials. max Compared with Example 20, which used a heat treatment process at 1060℃, all showed significant deterioration. When the heat treatment temperature was further reduced or increased, the overall magnetic properties of the magnet decreased.

[0145] Example 21

[0146] Porous structure SmFe 12 The nominal composition of the sintered permanent magnet material is: Sm9Fe bal Ti5V 11 Using metallic Sm sheets as a diffusion source to encapsulate porous SmFe structures 12 The permanent magnet material is sintered and then subjected to heat treatment.

[0147] (1) Smelting: The surface of the raw materials is mechanically polished to remove the oxide layer and unnecessary impurities, and then mixed according to the atomic percentage ratio. The prepared raw materials are placed in a crucible and vacuumed to 5×10 -2 Pa, then at around 150℃ to remove adsorbed water vapor and gas from the surface of the raw material, and after the vacuum stabilizes (<5×10 -2 Then, high-purity argon gas (99.999%) at 0.08 MPa is introduced. The heating power is gradually increased, and after all components have melted, it is refined for 3-5 minutes until the molten steel is homogeneous. The power is then gradually reduced to 5.5 KW, and the mixture is poured into a water-cooled copper mold to cool, forming the target alloy ingot.

[0148] (2) Ingot annealing treatment: The ingot is placed in a vacuum sintering furnace and subjected to homogenization annealing heat treatment under argon atmosphere protection. The annealing process parameters are 1140℃ and held for 5 hours, and then cooled to room temperature to obtain annealed ingot.

[0149] (3) Powder making: The annealed ingot is subjected to hydrogen breaking and air jet milling processes to obtain alloy powder with an average grain size of 2.0-3.5μm.

[0150] (4) Mixing powder: Mix Sm9Fe bal Ti5V 11 The powder was uniformly mixed in a powder mixer for 180 minutes under a protective argon atmosphere to obtain a powder with uniform composition.

[0151] (5) Orientation molding and cold isostatic pressing: Sm9Fe bal Ti5V 11 17g of the uniformly mixed powder is weighed and oriented in a magnetic field forming machine with a magnetic field strength of 1.5~2T. Then, it is cold isostatically pressed in a fluid at 160MPa to obtain a green body.

[0152] (6) Sintering: The Sm9Fe obtained in step (5) is sintered. bal Ti5V 11 The permanent magnet material green body was sintered at 1160℃ in a Sm-rich atmosphere for 50 min, and finally cooled to room temperature with furnace air to obtain Sm9Fe. bal Ti5V 11 Sintered magnets.

[0153] (7) Heat treatment: The Sm9Fe obtained in step (6) is subjected to heat treatment. bal Ti5V 11 After the oxide layer on the surface of the sintered magnet was cleaned by polishing, it was sandwiched with a metal Sm sheet with a thickness of about 2 mm and a smooth surface free of oxide scale. It was then heat-treated at 1060℃ in an Sm-rich atmosphere for 1 hour, and finally cooled to room temperature with furnace air to obtain modified SmFe. 12Type sintered permanent magnet material.

[0154] Comparative Example 7

[0155] In this comparative example, SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that of Example 21, except that the thickness of the metal Sm sheet used in step (7) of Comparative Example 7 is about 0.5 mm.

[0156] Comparative Example 8

[0157] In this comparative example, SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 21, except that the thickness of the metal Sm sheet used in step (7) of Comparative Example 8 is about 1 mm.

[0158] Comparative Example 9

[0159] In this comparative example, SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 21, except that the thickness of the metal Sm sheet used in step (7) of Comparative Example 9 is about 4 mm.

[0160] Comparative Example 10

[0161] In this comparative example, SmFe 12 The preparation method of the sintered permanent magnet material is basically the same as that in Example 21, except that the thickness of the metal Sm sheet used in step (7) of Comparative Example 10 is about 5 mm.

[0162] The inventors of this case also used a permanent magnet material precision measurement system (BH) to measure the coercivity Hcj, remanence Br, and magnetic energy product (BH)max of the permanent magnet materials obtained by Example 21 and Comparative Examples 7, 8, 9, and 10 at room temperature. The magnetic performance parameters are shown in Table 3.

[0163] Table 5 Magnetic properties of permanent magnet materials prepared in Example 21 and Comparative Examples 7, 8, 9, and 10

[0164] name Thickness (mm) of Sm metal sheet <![CDATA[B r kGs]]> <![CDATA[H cj no]]> <![CDATA[(BH) max MGOe]]> Example 21 2 6.445 7.298 9.353 Comparative Example 7 0.5 5.846 6.367 6.981 Comparative Example 8 1 6.264 6.825 8.615 Comparative Example 9 4 6.377 7.166 9.147 Comparative Example 10 5 6.325 7.197 9.064

[0165] In this invention, through comparison, as shown in Table 5, SmFe using Sm sheet sandwiching heat treatment processes of different thicknesses of metal Sm sheets is compared. 12 Coercivity Hcj, remanence Br, and maximum energy product (BH) of permanent magnet materials. max Compared to Example 21, which uses a 2mm Sm metal sheet sandwiched in a heat treatment process, the overall magnetic properties of the magnet show a significant decrease when the thickness of the Sm metal sheet becomes thinner. When the thickness of the Sm metal sheet is further increased, the overall magnetic properties of the magnet decrease slightly.

[0166] In summary, this invention achieves its goal by pre-preparing SmFe 12 A type of sintered permanent magnet material is prepared by sandwiching metal Sm thin sheets and low-melting-point rare earth-rich alloy thin sheets such as SmCu, SmAl, and SmGa as diffusion sources, and then heat-treating it at 900~1100℃ in an Sm-rich atmosphere for 1 hour. This process effectively enhances the coercivity of the magnet due to the presence of continuous non-ferromagnetic grain boundary phases, thereby obtaining a magnet with excellent comprehensive magnetic properties.

[0167] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0168] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A method for enhancing SmFe 12 A method for determining the magnetic properties of sintered permanent magnet materials, characterized in that... include: Provide SmFe 12 Sintered permanent magnet material, wherein SmFe 12 The chemical formula of the sintered permanent magnet material is Sm a (Fe 1-b Co b ) bal Ti c V 16-c M d Where 8≤a≤13, 0≤b≤0.2, 0≤c≤16, 0≤d≤3, and M is selected from Al, Cu or Ga; Low-melting-point rare-earth-rich alloy sheets were used as a diffusion source for the SmFe 12 The sintered permanent magnet material is sandwiched and heat-treated to achieve SmFe 12 The magnetic properties of sintered permanent magnet materials are improved; wherein the low-melting-point rare-earth-rich metal sheet includes Sm sheet and / or Sm alloy sheet.

2. The method according to claim 1, characterized in that: The Sm alloy sheet includes any one or more combinations of SmCu sheet, SmAl sheet, and SmGa sheet.

3. The method according to claim 1, characterized in that, Specifically, it includes: Low-melting-point rare-earth-rich alloy sheets were used as a diffusion source for the SmFe 12 The permanent magnet material is sandwiched in a sintered shape and then heat-treated in an Sm-rich atmosphere at 900~1100℃ for 30~120min.

4. The method according to claim 1, characterized in that: The SmFe 12 The sintered permanent magnet material has a porous structure, and the SmFe 12 The pore diameter of the sintered permanent magnet material is 0.5~30μm, and the density is 4~6.5cm³ / g.

5. The method according to claim 1, characterized in that: The thickness of the low-melting-point rare-earth-rich metal sheet is 2-3 mm.

6. The method according to claim 1, characterized in that, It also includes: the SmFe 12 Before encapsulating the sintered permanent magnet material, first process SmFe 12 The sintered permanent magnet material is polished to remove the surface oxide layer.

7. The method according to claim 1, characterized in that: The SmFe 12 The sintered permanent magnet material is obtained by melting, casting annealing, powder preparation, powder mixing, orientation forming, cold isostatic pressing, and sintering of the target composition alloy; wherein, the sintering conditions include sintering at 1100~1190℃ in a Sm-rich atmosphere for 30~120min.

8. A modified SmFe 12 Type sintered permanent magnet material, characterized in that: The modified SmFe 12 The sintered permanent magnet material is prepared by the method described in any one of claims 1-7.

9. The modified SmFe according to claim 8 12 Type sintered permanent magnet material, characterized in that: The modified SmFe 12 In sintered permanent magnet materials, a non-magnetic grain boundary phase is formed around the main phase grains.

10. The modified SmFe according to claim 8 12 Type sintered permanent magnet material, characterized in that: The modified SmFe 12 Sintered permanent magnet materials are superior to SmFe 12 The room temperature coercivity of the sintered permanent magnet material is increased by 2000~8000 Oe.

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