A method for the reduction diffusion of an easy plane alloy magnetic powder

Abstract

本发明涉及一种易基面合金磁性粉末的还原扩散方法，属于磁性材料的技术领域。本发明的易基面合金磁性粉末的还原扩散方法，其包括以下步骤：（1）准备R2O3粉末、纯铁粉末和任选的M粉末，加入氢化钙压制成坯；（2）在真空炉中充入N2，在600~800℃进行还原热处理，然后在1100~1200℃进行中温热扩散反应；（3）停止加热后，继续通入N2，炉冷至室温后开炉得到反应产物块体；（4）在水中分离出CaO和残余的Ca；（5）将R2Fe17‑xMxNy初级粉末进行研磨和筛分，从而得到所述R2Fe17‑xMxNy磁性粉末，R为Sm、Y、Ce、Pr、Nd中的一种。本发明的还原扩散方法以稀土氧化物为原料，不仅降低了成本，磁体粉末磁性能优异且耐热性好，可作为高性能的稀土永磁材料或微波吸收屏蔽粉末材料。

Description

Technical Field

[0001] This invention relates to the technical field of magnetic materials, and more specifically, to a reduction and diffusion method for easy-plane alloy magnetic powder. Background Technology

[0002] In 1990, Hong Sun and Coey et al. synthesized the intermetallic compound R2Fe using a gas-solid phase reaction. 17 N, from which the surface-type rare earth iron-based intermetallic compound R2Fe 17 N has become a research hotspot in the industry.

[0003] In the prior art, R2Fe 17 Rare earth metals (N) can be prepared using methods such as mechanical pulverization and reduction-diffusion. Mechanical pulverization involves vacuum smelting high-purity rare earth metals R and Fe to form a surface-type rare earth iron-based intermetallic compound, R₂Fe. 17 The rare earth elements are mechanically crushed and then ground into fine powder, which is then nitrided to produce Re-Fe-N magnetic powder. The above-mentioned R-Fe-N magnetic powder preparation process involves high melting temperatures, significant volatilization of rare earth elements, difficulty in controlling the chemical composition, and instability in the magnetic properties of the product. The reduction-diffusion method uses rare earth oxides or salts as raw materials, calcium hydride as a reducing agent to extract rare earth metals, and then diffusion between the rare earth metals and Fe forms an easily diffused rare earth iron-based intermetallic compound, R2Fe. 17 R-Fe-N magnetic powder is prepared by nitriding alloy powder, and some element H is also added in the existing technology. f Modification treatments are performed using Zr, Ga, Al, Ta, etc. The aforementioned reduction-diffusion methods involve a long nitriding process, which can easily lead to a decrease in the performance of the magnetic powder. Furthermore, the heat resistance and other properties of R-Fe-N magnetic powder also require improvement. Summary of the Invention

[0004] To address the aforementioned technical problems in the prior art, the present invention aims to provide a reduction and diffusion method for easy-surface alloy magnetic powder.

[0005] The reduction-diffusion method of the free-faceted alloy magnetic powder of the present invention is used to prepare R2Fe 17-x M x N y Magnetic powder, wherein R is one of the rare earth elements Sm, Y, Ce, Pr, and Nd, and the reduction diffusion method includes the following steps: (1) Prepare R2O3 powder, pure iron powder and optional M powder according to the ratio, add calcium hydride mixture to obtain mixed powder, and then press into blank; (2) Fill the vacuum furnace with N2 and maintain the N2 partial pressure at 0.01~0.03MPa. First, perform reduction heat treatment at 600~800℃, and then continue heating to 1100~1200℃ for medium-temperature thermal diffusion reaction; (3) After heating is stopped, N2 is continued to be introduced and the N2 partial pressure is maintained at 0.01~0.03MPa. After the furnace is cooled to room temperature, the furnace is opened to obtain the reaction product block; (4) The reaction product block is immersed in water to break it up, and CaO and residual Ca are separated to obtain R2Fe. 17-x M x N y Primary powder; (5) The R2Fe 17-x M x N y The primary powder is ground and sieved to obtain the R2Fe. 17-x M x N y Magnetic powder.

[0006] The reduction heat treatment time is 90~180min, and the medium-temperature thermal diffusion reaction time is 15~45min.

[0007] M is one of Mo, Nb, Zr, V, Ti, and Cr.

[0008] Where 0≤x≤0.5, 2.1≤y≤3.5.

[0009] Wherein, the R2Fe 17-x M x N y The average particle size d of the magnetic powder 50 The thickness is 0.3~20μm, preferably 0.5~10μm.

[0010] Wherein, R is Sm, and Sm2Fe 17-x M x N y The magnetic powder is a permanent magnet material, and M is preferably Mo.

[0011] Wherein, the Sm2Fe 17-x M x N y The coercivity Hc of the magnetic powder is ≥11.2kOe, and the saturation magnetization is ≥153emu / g.

[0012] Wherein, R is Y, Y2Fe 17-x M x N y The magnetic powder is a permanent magnet material with a coercivity Hc≥8.9kOe and a saturation magnetization ≥165emu / g.

[0013] Wherein, R is Ce, Ce2Fe 17-x M x N y The magnetic powder is a soft magnetic material with a saturation magnetization of ≥161 emu / g.

[0014] Wherein, R is Pr, Pr2Fe 17-x M x N y The magnetic powder is a soft magnetic material with a saturation magnetization of ≥167 emu / g.

[0015] Wherein, R is Nd, Nd2Fe 17-x M x N y The magnetic powder is a soft magnetic material with a saturation magnetization of ≥178 emu / g.

[0016] Compared with the prior art, the reduction and diffusion method of the easy-surface alloy magnetic powder of the present invention has the following advantages: The reduction-diffusion method of the present invention uses N2 as a protective atmosphere and reactive gas, and rare earth oxides as raw materials to carry out reduction and diffusion treatment at different temperatures. This not only reduces costs but also reduces the volatilization of rare earth elements, and can obtain magnetic powder with excellent heat resistance and high anisotropy, which can be used as high-performance rare earth permanent magnet materials or microwave absorption shielding powder materials. Detailed Implementation

[0017] The reduction and diffusion method of the easy-surface alloy magnetic powder of the present invention will be further described below with reference to specific embodiments, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the technical solution of the present invention. Example 1

[0018] Prepare Sm₂O₃ with an atomic percentage of Sm:Fe of 2.02:17 (with a 1% excess of rare earth element Sm) (average particle size d). 50 (with a particle size of 2.1 μm) and pure iron powder (average particle size d) 50 The average particle size is 0.8 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Sm molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0019] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.02 MPa. The furnace is heated to 720℃ and held for 120 min for reduction heat treatment, and then heated to 1150℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0020] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.02 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up into a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Sm2Fe. 17 N 2.3 Primary powder; the Sm2Fe 17 N 2.3 The primary powder is ground and sieved to obtain an average particle size d. 50 Sm2Fe with a diameter of 3.2 μm 17 N 2.3 Magnetic powder. Example 2

[0021] Prepare Sm₂O₃ with an atomic percentage of Sm:Fe:Mo of 2.02:16.85:0.15 (with a 1% excess of rare earth element Sm) (average particle size d). 50 (2.1 μm), pure iron powder (average particle size d) 50 (0.8 μm) and pure Mo powder (average particle size d) 50 The average particle size is 1.3 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Sm molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0022] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The billet is heated to 750℃ and held for 150 min for reduction heat treatment, and then heated to 1120℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0023] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up into a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Sm2Fe. 16.85 Mo 0.15 N 2.3 Primary powder; the Sm2Fe 16.85 Mo 0.15 N 2.3 The primary powder is ground and sieved to obtain an average particle size d. 50Sm2Fe with a diameter of 3.0 μm 16.85 Mo 0.15 N 2.3 Magnetic powder. Example 3

[0024] Prepare Sm₂O₃ with an atomic percentage of Sm:Fe:Mo of 2.02:16.7:0.3 (with a 1% excess of rare earth element Sm) (average particle size d). 50 (2.1 μm), pure iron powder (average particle size d) 50 (0.8 μm) and pure Mo powder (average particle size d) 50 The average particle size is 1.3 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Sm molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0025] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The billet is heated to 750℃ and held for 150 min for reduction heat treatment, and then heated to 1120℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0026] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up into a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Sm2Fe. 16.7 Mo 0.3 N 2.5 Primary powder; the Sm2Fe 16.7 Mo 0.3 N 2.5 The primary powder is ground and sieved to obtain an average particle size d. 50 Sm2Fe with a diameter of 2.8 μm 16.7 Mo 0.3 N 2.5 Magnetic powder. Example 4

[0027] Prepare Sm₂O₃ with an atomic percentage of Sm:Fe:Nb of 2.02:16.7:0.3 (with a 1% excess of rare earth element Sm) (average particle size d). 50 (2.1 μm), pure iron powder (average particle size d) 50 (0.8 μm) and pure Nb powder (average particle size d) 50The average particle size is 1.5 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a molar ratio of Ca to Sm of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0028] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The billet is heated to 720℃ and held for 150 min for reduction heat treatment, and then heated to 1150℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0029] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up into a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Sm2Fe. 16.7 Nb 0.3 N 2.4 Primary powder; the Sm2Fe 16.7 Nb 0.3 N 2.4 The primary powder is ground and sieved to obtain an average particle size d. 50 Sm2Fe with a diameter of 2.9 μm 16.7 Nb 0.3 N 2.4 Magnetic powder. Example 5

[0030] Prepare Sm₂O₃ with an atomic percentage of Sm:Fe:Zr of 2.02:16.7:0.3 (with a 1% excess of rare earth element Sm) (average particle size d). 50 (2.1 μm), pure iron powder (average particle size d) 50 (0.8 μm) and pure Zr powder (average particle size d) 50 The average particle size is 1.2 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Sm molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0031] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The billet is heated to 720℃ and held for 150 min for reduction heat treatment, and then heated to 1150℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0032] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up into a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Sm2Fe. 16.7 Zr 0.3 N 2.4 Primary powder; the Sm2Fe 16.7 Zr 0.3 N 2.6 The primary powder is ground and sieved to obtain an average particle size d. 50 Sm2Fe with a diameter of 2.8 μm 16.7 Zr 0.3 N 2.4 Magnetic powder. Example 6

[0033] Prepare Sm₂O₃ with an atomic percentage of Sm:Fe:V of 2.02:16.7:0.3 (with a 1% excess of rare earth element Sm) (average particle size d). 50 (2.1 μm), pure iron powder (average particle size d) 50 (0.8μm) and pure V powder (average particle size d) 50 The average particle size is 1.5 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a molar ratio of Ca to Sm of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0034] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The furnace is heated to 720℃ and held for 150 min for reduction heat treatment, and then heated to 1120℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0035] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up into a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Sm2Fe. 16.7 V 0.3 N 2.5 Primary powder; the Sm2Fe 16.7 V 0.3 N 2.5The primary powder is ground and sieved to obtain an average particle size d. 50 Sm2Fe with a diameter of 2.5 μm 16.7 V 0.3 N 2.5 Magnetic powder. Example 7

[0036] Prepare Sm₂O₃ with an atomic percentage of Sm:Fe:Ti of 2.02:16.7:0.3 (with a 1% excess of rare earth element Sm) (average particle size d). 50 (2.1 μm), pure iron powder (average particle size d) 50 (0.8 μm) and pure Ti powder (average particle size d) 50 The average particle size is 1.5 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a molar ratio of Ca to Sm of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0037] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The furnace is heated to 720℃ and held for 150 min for reduction heat treatment, and then heated to 1120℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0038] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up into a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Sm2Fe. 16.7 Ti 0.3 N 2.5 Primary powder; the Sm2Fe 16.7 Ti 0.3 N 2.5 The primary powder is ground and sieved to obtain an average particle size d. 50 Sm2Fe with a diameter of 2.7 μm 16.7 Ti 0.3 N 2.5 Magnetic powder. Example 8

[0039] Prepare Sm₂O₃ with an atomic percentage of Sm:Fe:Cr of 2.02:16.7:0.3 (with a 1% excess of rare earth element Sm) (average particle size d). 50 (2.1 μm), pure iron powder (average particle size d) 50(0.8μm) and pure Cr powder (average particle size d) 50 The average particle size is 1.8 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Sm molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0040] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The furnace is heated to 720℃ and held for 150 min for reduction heat treatment, and then heated to 1120℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0041] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up into a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Sm2Fe. 16.7 Cr 0.3 N 2.4 Primary powder; the Sm2Fe 16.7 Cr 0.3 N 2.4 The primary powder is ground and sieved to obtain an average particle size d. 50 Sm2Fe with a diameter of 2.7 μm 16.7 Cr 0.3 N 2.4 Magnetic powder. Example 9

[0042] Prepare Y₂O₃ with an atomic percentage of Y:Fe of 2.02:17 (with a 1% excess of rare earth Y element) (average particle size d). 50 (with an average particle size of 2.3 μm) and pure iron powder (average particle size d) 50 The particle size is 0.8 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Y molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0043] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.02 MPa. The furnace is heated to 720℃ and held for 120 min for reduction heat treatment, and then heated to 1150℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0044] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.02 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up, resulting in a slurry. After settling, the turbid supernatant in the slurry was drained. Water was added to separate the turbid Ca(OH)2 suspension, thus separating CaO. Ca was then removed using dilute acetic acid. After vacuum drying, Y2Fe was obtained. 17 N 2.7 Primary powder; Y2Fe 17 N 2.7 The primary powder is ground and sieved to obtain an average particle size d. 50 Y2Fe with a diameter of 3.0 μm 17 N 2.7 Magnetic powder. Example 10

[0045] Prepare Y₂O₃ with an atomic percentage of Y, Fe, and Mo of 2.02:16.85:0.15 (with a 1% excess of rare earth element Sm). The average particle size d0 of the Y₂O₃ is as follows: 50 (2.3μm), pure iron powder (average particle size d) 50 (0.8 μm) and pure Mo powder (average particle size d) 50 The average particle size is 1.3 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Y molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0046] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The billet is heated to 750℃ and held for 150 min for reduction heat treatment, and then heated to 1120℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0047] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up, resulting in a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Y2Fe. 16.85 Mo 0.15 N 2.8 Primary powder; Y2Fe 16.85 Mo 0.15 N 2.8 The primary powder is ground and sieved to obtain an average particle size d. 50 Y2Fe with a diameter of 2.8 μm 16.85 Mo0.15 N 2.8 Magnetic powder. Example 11

[0048] Prepare Y₂O₃ with an average particle size d of 2.02:16.7:0.3 atomic percentages of Y, Fe, and Nb (with a 1% excess of rare earth Y). 50 (2.3μm), pure iron powder (average particle size d) 50 (0.8 μm) and pure Nb powder (average particle size d) 50 The average particle size is 1.5 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Y molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0049] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The billet is heated to 720℃ and held for 150 min for reduction heat treatment, and then heated to 1150℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0050] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up, resulting in a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Y2Fe. 16.7 Nb 0.3 N 2.7 Primary powder; Y2Fe 16.7 Nb 0.3 N 2.7 The primary powder is ground and sieved to obtain an average particle size d. 50 Y2Fe with a diameter of 3.0 μm 16.7 Nb 0.3 N 2.7 Magnetic powder. Example 12

[0051] Prepare Y₂O₃ with an average particle size d of 2.02:16.7:0.3 atomic percentages of Y, Fe, and Zr (with a 1% excess of rare earth Y). 50 (2.3μm), pure iron powder (average particle size d) 50 (0.8 μm) and pure Zr powder (average particle size d) 50The average particle size is 1.2 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Y molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0052] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The billet is heated to 720℃ and held for 150 min for reduction heat treatment, and then heated to 1150℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0053] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up, resulting in a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Y2Fe. 16.7 Zr 0.3 N 2.7 Primary powder; Y2Fe 16.7 Zr 0.3 N 2.7 The primary powder is ground and sieved to obtain an average particle size d. 50 Y2Fe with a diameter of 3.2 μm 16.7 Zr 0.3 N 2.7 Magnetic powder. Example 13

[0054] Prepare Y₂O₃ with an average particle size d of 2.02:16.7:0.3 atomic percentages of Y, Fe, and V (with a 1% excess of rare earth Y). 50 (2.3μm), pure iron powder (average particle size d) 50 (0.8μm) and pure V powder (average particle size d) 50 The average particle size is 1.5 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Y molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0055] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The furnace is heated to 720℃ and held for 150 min for reduction heat treatment, and then heated to 1120℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0056] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up, resulting in a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Y2Fe. 16.7 V 0.3 N 2.7 Primary powder; Y2Fe 16.7 V 0.3 N 2.7 The primary powder is ground and sieved to obtain an average particle size d. 50 Y2Fe with a size of 2.7 μm 16.7 V 0.3 N 2.7 Magnetic powder. Example 14

[0057] Prepare Y₂O₃ with an average particle size d of 2.02:16.7:0.3 atomic percentages of Y, Fe, and Ti (with a 1% excess of rare earth Y). 50 (2.3μm), pure iron powder (average particle size d) 50 (0.8 μm) and pure Ti powder (average particle size d) 50 The average particle size is 1.5 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Y molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0058] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The billet is heated to 720℃ and held for 150 min for reduction heat treatment, and then heated to 1150℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0059] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up, resulting in a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Y2Fe. 16.7 Ti 0.3 N 2.8 Primary powder; Y2Fe 16.7 Ti 0.3 N 2.8 The primary powder is ground and sieved to obtain an average particle size d.50 Y2Fe with a diameter of 3.1 μm 16.7 Ti 0.3 N 2.8 Magnetic powder. Example 15

[0060] Prepare Sm₂O₃ with an atomic percentage of Y, Fe, and Cr of 2.02:16.7:0.3 (with a 1% excess of rare earth Y). The average particle size d0 of the Sm₂O₃ is as follows: 50 (2.1 μm), pure iron powder (average particle size d) 50 (0.8μm) and pure Cr powder (average particle size d) 50 The average particle size is 1.8 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Y molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0061] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.03 MPa. The furnace is heated to 720℃ and held for 150 min for reduction heat treatment, and then heated to 1120℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0062] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.03 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up, resulting in a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Y2Fe. 16.7 Cr 0.3 N 2.5 Primary powder; Y2Fe 16.7 Cr 0.3 N 2.5 The primary powder is ground and sieved to obtain an average particle size d. 50 Y2Fe with a diameter of 3.1 μm 16.7 Cr 0.3 N 2.5 Magnetic powder. Example 16

[0063] Prepare Ce₂O₃ with an atomic percentage of Ce:Fe of 2.02:17 (with a 1% excess of rare earth element Ce) (average particle size d). 50 (with an average particle size of 2.5 μm) and pure iron powder (average particle size d) 50The particle size is 0.8 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Ce molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0064] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.02 MPa. The furnace is heated to 720℃ and held for 120 min for reduction heat treatment, and then heated to 1150℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0065] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.02 MPa. The furnace was cooled to room temperature before being opened to obtain a block of reaction product. The block of reaction product was then immersed in water to break it up, resulting in a slurry. After settling, the turbid supernatant in the slurry was drained. Water was added to separate the turbid Ca(OH)2 suspension, thus separating CaO. Ca was then removed using dilute acetic acid. After vacuum drying, Ce2Fe was obtained. 17 N 3.1 Primary powder; Ce2Fe 17 N 3.1 The primary powder is ground and sieved to obtain an average particle size d. 50 Ce2Fe with a diameter of 2.6 μm 17 N 3.1 Soft magnetic powder. Example 17

[0066] Prepare Pr₂O₃ with an atomic percentage of Pr:Fe of 2.02:17 (with a 1% excess of rare earth Pr). The average particle size d0 is d0. 50 (with an average particle size of 2.2 μm) and pure iron powder (average particle size d) 50 The particle size is 0.8 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Pr molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0067] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.02 MPa. The furnace is heated to 720℃ and held for 120 min for reduction heat treatment, and then heated to 1150℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0068] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.02 MPa. The furnace was cooled to room temperature before being opened to obtain a block of the reaction product. The block was then immersed in water to break it up, resulting in a slurry. After settling, the supernatant of the suspension was drained, and water was added to separate the suspended Ca(OH)2 to obtain CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Pr2Fe. 17 N 2.9 Primary powder; the Pr2Fe 17 N 2.9 The primary powder is ground and sieved to obtain an average particle size d. 50 Pr2Fe with a diameter of 3.1 μm 17 N 2.9 Soft magnetic powder. Example 18

[0069] Prepare Nd₂O₃ with an atomic percentage of Nd:Fe of 2.02:17 (with a 1% excess of rare earth Nd). The average particle size is d... 50 (with an average particle size of 2.3 μm) and pure iron powder (average particle size d) 50 The particle size is 0.8 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Nd molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0070] The billet is placed in a stainless steel vacuum tube furnace, then evacuated to below 0.01 Pa, and then N2 is introduced, maintaining the N2 partial pressure at 0.02 MPa. The furnace is heated to 720℃ and held for 120 min for reduction heat treatment, and then heated to 1150℃ and held for 30 min for medium-temperature thermal diffusion reaction.

[0071] After heating was stopped, N2 was continuously introduced to maintain a partial pressure of 0.02 MPa. The furnace was cooled to room temperature before being opened to obtain a block of reaction product. The block of reaction product was then immersed in water to break it up, resulting in a slurry. After settling, the turbid supernatant in the slurry was drained. Water was added to separate the turbid Ca(OH)2 suspension, thus separating CaO. Ca was then removed using dilute acetic acid. After vacuum drying, Nd2Fe was obtained. 17 N 3.4 Primary powder; Nd2Fe 17 N 3.4 The primary powder is ground and sieved to obtain an average particle size d. 50 Nd2Fe with a diameter of 2.9 μm 17 N 3.4 Soft magnetic powder.

[0072] Comparative Example 1

[0073] Prepare Sm₂O₃ with an atomic percentage of Sm:Fe of 2.1:17 (with a 5% excess of rare earth element Sm) (average particle size d). 50 (with an average particle size of 2.1 μm) and pure iron powder (average particle size d) 50 The average particle size is 0.8 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Sm molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0074] The billet was placed in a stainless steel vacuum tube furnace, and then evacuated to below 0.01 Pa. Ar was then introduced, maintaining an Ar partial pressure of 0.1 MPa. The furnace was heated to 1100℃ and held for 180 min to perform reduction diffusion, obtaining a master alloy block. The master alloy block was then immersed in water to break it up. After settling, the turbid supernatant was drained, and water was added to separate the turbid Ca(OH)₂ suspension to separate CaO. Ca was then removed using dilute acetic acid. After vacuum drying, the master alloy powder was obtained. Nitriding was then performed under a 0.1 MPa N₂ atmosphere at 500℃ for 24 hours to obtain Sm₂Fe. 17 N 3.2 Grinding and sieving, average particle size d 50 It is 2.7 μm.

[0075] Comparative Example 2

[0076] Prepare SmCl3 (average particle size d) with an atomic percentage of Sm:Fe of 2.1:17 (5% excess of rare earth element Sm). 50 (3.2 μm, after dehydration) and pure iron powder (average particle size d) 50 The average particle size is 0.8 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Sm molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0077] The billet was placed in a stainless steel vacuum tube furnace, and then evacuated to below 0.01 Pa. Ar was then introduced, maintaining an Ar partial pressure of 0.1 MPa. The furnace was heated to 820℃ and held for 120 min to perform reduction diffusion, obtaining a master alloy block. The master alloy block was then immersed in water to break it up. After settling, the turbid supernatant was drained, and water was added to separate the turbid Ca(OH)₂ suspension to separate CaO. Ca was then removed using dilute acetic acid. After vacuum drying, the master alloy powder was obtained. Nitriding was then performed under an NH₄ atmosphere at 0.1 MPa, at a nitriding temperature of 450℃ for 1 hour to obtain Sm₂Fe. 17 N 2.1The average particle size d after grinding and sieving 50 It is 3.3 μm.

[0078] Comparative Example 3

[0079] Prepare Sm₂O₃ with an atomic percentage of Sm:Fe of 2.02:17 (with a 1% excess of rare earth element Sm) (average particle size d). 50 (with an average particle size of 2.1 μm) and pure iron powder (average particle size d) 50 The particle size is 0.8 μm. Then, an excess of granular CaH2 (with an average particle size of 3 mm, prepared according to a Ca to Sm molar ratio of 2:1) is added and placed in a mixer and mixed at a speed of 30 r / min for 2 hours to obtain a mixed powder. The mixed powder is then pressed into a blank.

[0080] The billet was loaded into a stainless steel vacuum tube furnace, and then evacuated to below 0.01 Pa. N2 was then introduced, maintaining a partial pressure of 0.02 MPa, and the furnace was heated to 720°C and held for 180 min to carry out a reduction-diffusion reaction. After heating was stopped, N2 was continued to be introduced, maintaining a partial pressure of 0.02 MPa. The furnace was cooled to room temperature, and then opened to obtain a block of the reaction product. The block of the reaction product was immersed in water to break it up, resulting in a slurry. After settling, the turbid supernatant in the slurry was drained, and water was added to separate the turbid Ca(OH)2 suspension to separate CaO. Ca was then removed using dilute acetic acid, and the product was vacuum dried to obtain Sm2Fe. 17 N 2.1 Primary powder; the Sm2Fe 17 N 2.1 The primary powder is ground and sieved to obtain an average particle size d. 50 Sm2Fe with a diameter of 2.9 μm 17 N 2.1 Magnetic powder.

[0081] TEM observation confirmed that the powders were all R2Fe. 17 N-type crystal structure. Average particle size, saturation magnetization Ms, and coercivity H of each magnet powder. c The magnetic powders of Examples 1-15 were heated to 300°C in air, held at that temperature for 1 hour, and then cooled before measuring the coercivity H after heating. ch The results are summarized in Table 1.

[0082] Table 1 Example 1 3.2 159 11.5 9.0 78 Example 2 3.0 157 15.3 13.8 90 Example 3 2.8 155 14.9 13.8 93 Example 4 2.9 162 13.4 10.2 76 Example 5 2.8 159 13.6 10.2 75 Example 6 2.5 166 12.2 9.3 76 Example 7 2.7 154 13.8 11.0 80 Example 8 2.7 159 13.5 9.9 73 Example 9 3.0 176 9.5 7.5 79 Example 10 2.8 173 11.8 9.7 82 Example 11 3.0 185 9.8 7.6 78 Example 12 3.2 172 10.5 8.0 76 Example 13 2.7 185 10.4 7.8 75 Example 14 3.1 181 10.6 8.4 79 Example 15 3.1 178 10.8 7.8 72 Example 16 2.6 161 / / / Example 17 3.1 167 / / / Example 18 2.9 178 / / / Comparative Example 1 2.7 149 9.6 5.3 55 Comparative Example 2 3.3 137 8.0 4.5 56 Comparative Example 3 2.9 139 7.2 4.3 60 Note: Examples 16-18 are soft magnetic materials with very small Hc values, which are not included in the calculation and are represented by " / ".

[0083] As can be seen from the above embodiments, the reduction-diffusion method of the present invention not only eliminates the need for rare earth gases as protective gases, but also uses only N2 as a protective atmosphere and nitrogen atmosphere, providing an H2 atmosphere through an excess of reducing agent, and conducting reduction and diffusion treatments under different temperature conditions. This not only ensures the reduction of rare earth oxides, but also produces R2Fe. 17- x M x N y It possesses excellent magnetic properties, particularly for Sm2Fe. 17-x M x N y and Y2Fe 17-x M x N y Magnetic powder, a permanent magnet material, not only possesses high saturation magnetization but also high coercivity, maintaining high coercivity even under heating conditions, demonstrating high thermal stability. It can be used in high-temperature environments while maintaining good performance. Furthermore, the substitution elements, especially Sm₂Fe, are beneficial for permanent magnet materials. 17-x M x N y The introduction of Mo significantly affects the saturation magnetization and coercivity of Ce₂Fe₃, and can significantly improve its coercivity and heat resistance (it can still maintain high coercivity after heating). The prepared Ce₂Fe₃... 17-x M x N y Pr2Fe 17-x M x N y and Nd2Fe 17- x M x N y It is a soft magnetic material with high saturation magnetization and low cost, and can be used in microwave absorption and soft magnetic cores for filtering inductors.

[0084] For those skilled in the art, the specific embodiments are merely illustrative descriptions of the present invention. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the technical solutions of the present invention are within the protection scope of the present invention.

Claims

1. A reduction-diffusion method for easily oriented alloy magnetic powder, used to prepare R2Fe 17-x M x N y Magnetic powder, wherein R is one of the rare earth elements Sm, Y, Ce, Pr, and Nd, characterized in that... Includes the following steps: (1) Prepare R2O3 powder, pure iron powder and optional M powder according to the ratio, add calcium hydride mixture to obtain mixed powder, and then press into blank; M is one of Mo, Nb, Zr, V, Ti and Cr; and 0≤x≤0.5, 2.1≤y≤3.5; (2) Fill the vacuum furnace with N2 and maintain the N2 partial pressure at 0.01~0.03MPa. First, perform reduction heat treatment at 600~800℃, and then continue heating to 1100~1200℃ for medium-temperature thermal diffusion reaction; (3) After heating is stopped, N2 is continued to be introduced and the N2 partial pressure is maintained at 0.01~0.03MPa. After the furnace is cooled to room temperature, the furnace is opened to obtain the reaction product block. (4) The reaction product block is immersed in water to break it up, and CaO and residual Ca are separated to obtain R2Fe. 17-x M x N y Primary powder; (5) The R2Fe 17-x M x N y The primary powder is ground and sieved to obtain the R2Fe. 17-x M x N y Magnetic powder.

2. The reduction and diffusion method for easy-surface alloy magnetic powder according to claim 1, characterized in that: The R2Fe 17-x M x N y The average particle size d of the magnetic powder 50 The range is 0.3~20μm.

3. The reduction and diffusion method for easy-surface alloy magnetic powder according to claim 1, characterized in that: R is Sm, and Sm2Fe 17-x M x N y The magnetic powder is a permanent magnet material.

4. The reduction and diffusion method for easy-surface alloy magnetic powder according to claim 3, characterized in that: The M is Mo.

5. The reduction and diffusion method for easy-surface alloy magnetic powder according to claim 3, characterized in that: The Sm2Fe 17-x M x N y The coercivity Hc of the magnetic powder is ≥11.2 kOe, and the saturation magnetization is ≥153 emu / g.

6. The reduction and diffusion method for easy-surface alloy magnetic powder according to claim 1, characterized in that: R is Y, Y2Fe 17-x M x N y The magnetic powder is a permanent magnet material with a coercivity Hc≥8.9kOe and a saturation magnetization ≥165emu / g.

7. The reduction and diffusion method for easy-surface alloy magnetic powder according to claim 1, characterized in that: R is Ce, Ce2Fe 17-x M x N y The magnetic powder is a soft magnetic material with a saturation magnetization of ≥161 emu / g.

8. The reduction and diffusion method for easy-surface alloy magnetic powder according to claim 1, characterized in that: R is Pr, Pr2Fe 17-x M x N y The magnetic powder is a soft magnetic material with a saturation magnetization of ≥167 emu / g.

9. The reduction and diffusion method for easy-surface alloy magnetic powder according to claim 1, characterized in that: R is Nd, Nd2Fe 17-x M x N y The magnetic powder is a soft magnetic material with a saturation magnetization of ≥178 emu / g.