Preparation method of rare earth iron alloy and nitride thereof

Abstract

The invention provides a rare earth iron alloy and a preparation method of nitride thereof, and belongs to the technical field of rare earth magnetic materials. According to the method, a high-purity phase rare earth-iron compound Yb2Fe17 is obtained by combining a briquetting sealing means with a reduction diffusion technology, the high-purity phase rare earth-iron compound Yb2Fe17 is converted into Yb2Fe17N3-delta through a controllable nitriding technology, redundant CaO is removed through water washing, and high-purity Yb2Fe17N3-delta is obtained through drying. The preparation method of the rare earth iron alloy and the nitride thereof, provided by the invention, has the advantages of simple process, low energy consumption, high purity, small crystal grains and the like, and successfully solves the problem that a pure phase is difficult to successfully prepare by means of electric arc melting and the like due to high volatility of Yb. The method provided by the invention is also suitable for preparing volatile alloy materials containing Sm, Mn and the like. The method has remarkable technical advantages in preparation of materials containing volatile alloys.

Description

Technical Field

[0001] This invention relates to the field of rare earth magnetic materials technology, and in particular to a method for preparing rare earth iron alloys and their nitrides. Background Technology

[0002] Among the 17 rare earth elements, the 4f¹ of the heavy rare earth Yb³⁺ ion... 3 Its electronic configuration endows it with strong spin-orbit coupling and crystal field effects, but Yb has a boiling point of only 1196℃, the lowest among the 17 rare earth elements. It is difficult to successfully synthesize pure-phase Yb₂Fe using methods such as arc melting or rapid quenching. 17 This limitation restricts our understanding of its intrinsic structure and magnetism, thus hindering research into its application areas. To study its properties, researchers often use diffraction patterns of Yb-Fe alloys. For example, Th₂Ni has been observed in the Yb-Fe-Sb system using powder metallurgy. 17 Type hexagonal structure Yb2Fe 17 The existence of Yb2Fe was confirmed in the Yb-Fe-B system using electric arc melting technology. 17 A trend has emerged in the formation of phases in the Yb-Fe-Ga system, where increasing the Ga concentration leads to a change in the material structure from LuFe... 9.5 Transformation into Th2Zn 17 Type. Although studies on these Yb-Fe derivatives have shown some interest in Yb2Fe. 17 While these methods offer some understanding, they still fail to completely overcome the high volatility of Yb, resulting in synthesized samples with insufficient purity or complex compositions. Therefore, in order to further investigate Yb₂Fe 17 To understand the intrinsic physical properties of Yb and promote its applied research, it is urgent to develop a novel experimental method that can effectively suppress Yb volatilization and achieve the preparation of high-purity samples. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing rare earth iron alloys and their nitrides. The method provided by this invention effectively suppresses the high-temperature volatilization of Yb, thereby successfully preparing high-purity Yb₂Fe. 17 and Yb2Fe 17 N 3-δ Magnetic powder was used, and Sm2Fe was prepared using the same method. 17 and Sm2Fe 17 N 3-δ This led to the preparation of high-purity rare earth iron alloys and their nitrides.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a method for preparing rare earth iron alloys and their nitrides, comprising the following steps:

[0006] (1) M2O3, Fe and Ca are mixed evenly and pressed to obtain a shaped block, wherein M in M2O3 is Yb and / or Sm;

[0007] (2) The shaped block obtained in step (1) is subjected to a reduction-diffusion reaction under sealed conditions to obtain M2Fe. 17 Where M is Yb and / or Sm;

[0008] (3) Take the M2Fe obtained in step (2) 17 The alloy was subjected to crushing, nitriding, and post-treatment in sequence to obtain the rare earth iron-nitrogen magnetic material M2Fe. 17 N 3-δ , where M is Yb and / or Sm, 0≤δ≤3.0.

[0009] Preferably, in step (1), the mass ratio of M2O3 to Fe is (0.42~1.0):1; and the mass ratio of Ca to Fe is (0.16~0.5):1.

[0010] Preferably, the pressure applied in step (1) is 1 MPa to 1 GPa.

[0011] Preferably, the reduction diffusion reaction in step (2) is carried out in an H2-Ar or Ar atmosphere.

[0012] Preferably, the temperature of the reduction diffusion reaction in step (2) is 800℃~1200℃, and the time of the reduction diffusion reaction is 0.5~10h.

[0013] Preferably, the M2Fe obtained in step (2) is crushed 17 The average particle size of the alloy particles is 1~100μm.

[0014] Preferably, the nitriding reaction in step (3) is carried out in an atmosphere of N2, NH3 or H2-N2.

[0015] Preferably, the temperature of the nitriding reaction in step (3) is 300~600℃, and the time of the nitriding reaction is 1~48h.

[0016] Preferably, the post-processing in step (3) includes: washing and drying the product of the nitriding reaction sequentially; the number of times the water is washed is 1 to 10.

[0017] Preferably, the drying is carried out under vacuum conditions of <1000Pa, and the drying time is 1~24h.

[0018] This invention provides a simple and controllable method for preparing high-purity rare-earth iron alloys and their nitrides. Its core advantage lies in the liquid-solid reaction pathway under compaction and a closed environment: using M₂O₃ as a precursor, active M atoms are generated in situ under the action of the reducing agent Ca. Under compaction and a closed environment, M cannot escape, thus utilizing the diffusion of M to directly react with Fe powder to generate M₂Fe. 17 An alloy, wherein M is Yb and / or Sm, is then subjected to a nitriding reaction to obtain M2Fe. 17 N 3-δ Magnetic material powder, wherein M is Yb and / or Sm, 0≤δ≤3.0. The close contact between the CaO matrix and powder particles generated in this process constitutes an in-situ confinement environment for M atoms, greatly suppressing their vaporization escape and grain growth. The compression sealing combined with reduction diffusion method used in this invention effectively suppresses the high-temperature volatilization problem of Yb, thus successfully preparing high-purity Yb₂Fe. 17 and Yb2Fe 17 N 3-δ The magnetic powder is then purified through a systematic water washing process to further remove byproducts such as calcium oxide generated during the reaction, ultimately yielding a high-purity single-phase product. Furthermore, this invention is also applicable to the preparation of high-purity (Yb) x Sm y )2Fe 17 and (Yb) x Sm y )2Fe 17 N 3-δ Materials such as x + y = 1. Attached Figure Description

[0019] Figure 1 The powder, compressed block, compressed block & seal, and Yb2Fe in Embodiment 1 of this invention 17 -After washing with water and Yb2Fe 17 N 3-δ - XRD patterns after water washing, where (a)~(c) are powder, compressed block, compressed block & sealed sample respectively, and (d)~(e) are Yb2Fe 17 -After washing with water and Yb2Fe 17 N 3-δ - Sample after water washing;

[0020] Figure 2 The images shown are SEM images and mapping images of the ytterbium-iron alloy and ytterbium-iron nitrogen magnetic powder prepared in Example 1, where (a) and (b) are Yb2Fe 17 The SEM images have scale bars of 10 μm and 1 μm, respectively. (c) shows Yb2Fe 17 N 3-δ SEM images, (d)~(f) are Yb2Fe17 The mapping images are: (f) for Yb2Fe, (g)~(j) for Yb2Fe. 17 N 3-δ The mapping image is shown, where (e) and (h) represent Fe elements, (f) and (i) represent Yb elements, and (j) represents N elements;

[0021] Figure 3 (Yb,Sm)2Fe prepared in Example 2 17 N 3-δ Magnetic powder, and (Yb,Sm)2Fe 17 N 3-δ &CaO and (Yb,Sm)2Fe 17 XRD pattern of CaO. Detailed Implementation

[0022] This invention provides a method for preparing rare earth iron alloys and their nitrides, comprising the following steps:

[0023] (1) M2O3, Fe and Ca are mixed evenly and pressed to obtain a shaped block, wherein M in M2O3 is Yb and / or Sm;

[0024] (2) The shaped block obtained in step (1) is subjected to a reduction-diffusion reaction under sealed conditions to obtain M2Fe. 17 Alloy, wherein M is Yb and / or Sm;

[0025] (3) Take the M2Fe obtained in step (2) 17 The alloy was subjected to crushing, nitriding, and post-treatment in sequence to obtain the rare earth iron-nitrogen magnetic material M2Fe. 17 N 3-δ , where M is Yb and / or Sm, 0≤δ≤3.0.

[0026] Unless otherwise specified, all raw materials used in this invention are commercially available products in the art.

[0027] In this invention, the preferred mass ratio of M₂O₃ to Fe is (0.4~1.0):1, more preferably (0.42~0.9):1, and even more preferably (0.45~0.65):1. In this invention, the preferred mass ratio of Ca to Fe is (0.16~0.40):1, more preferably (0.2~0.4):1. This invention controls the proportions of M₂O₃, Fe, and Ca within the above ranges to ensure an appropriate and sufficient amount of Ca as a reducing agent, and that the contents of Fe and M elements are appropriate, in order to obtain M₂Fe. 17 alloy.

[0028] In this invention, the pressing is preferably carried out in an inert atmosphere, more preferably in an Ar atmosphere. The pressing pressure is 1 MPa to 1 GPa, more preferably 50 MPa to 500 MPa. This invention controls the pressing pressure within the above range to ensure that volatile elements such as Yb and Sm do not easily overflow or volatilize, while also preventing the pressure from being too high, thus making it easier for the compacted mass after reduction and diffusion to break into powder.

[0029] In this embodiment of the invention, the sealing condition specifically refers to a sealed crucible. In this invention, the reduction-diffusion reaction is preferably carried out in an H2-Ar or Ar atmosphere, more preferably in an Ar atmosphere. In this invention, the temperature of the reduction-diffusion reaction is preferably 800℃~1200℃, more preferably 900~1100℃. In this invention, the time of the reduction-diffusion reaction is preferably 0.5~10h, more preferably 2~6h.

[0030] In this invention, the M2Fe obtained by crushing 17 The average particle size of the alloy particles is preferably 1~100μm. This invention obtains magnetic powder materials with excellent magnetic properties through crushing.

[0031] In this invention, the nitriding reaction is preferably carried out in an atmosphere of N2, NH3, or H2-N2, more preferably in an N2 atmosphere. In this invention, the temperature of the nitriding reaction is preferably 300-600°C, more preferably 400-500°C. In this invention, the time of the nitriding reaction is preferably 1-48 hours, more preferably 10-24 hours. This invention controls the temperature and time of the nitriding reaction within the above ranges to ensure that the nitriding reaction proceeds fully and achieves optimal magnetic properties.

[0032] In this invention, the post-treatment preferably includes: sequentially washing and drying the product of the nitriding reaction. In this invention, the number of water washes is preferably 1 to 10, more preferably 2 to 6. This invention removes byproducts such as calcium oxide generated during the reaction by washing with water. In this invention, the drying is preferably carried out under vacuum conditions of <1000 Pa, and the drying time is preferably 1 to 24 hours. This invention avoids prolonged contact between the metal magnetic powder and water, which could lead to oxidation, corrosion, and thus a decrease in magnetic properties.

[0033] The method provided by this invention uses a combination of compression sealing and reduction diffusion technology to obtain high-purity rare earth-iron compound Yb2Fe. 17 It is then converted into Yb2Fe through a controllable nitriding process. 17 N 3-δ Excess CaO was removed by washing with water, and then dried to obtain high-purity Yb2Fe. 17 N 3-δThis invention provides a method for preparing ytterbium-iron alloys and their nitrides, which has the advantages of simple process, low energy consumption, high purity and small grain size, and successfully solves the problem that Yb is difficult to prepare in pure phase by means of electric arc melting due to its high volatility.

[0034] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0035] Unless otherwise specified, all experiments were repeated three times, and the results are expressed as averages.

[0036] Example 1

[0037] A ytterbium-iron alloy Yb2Fe 17 With ytterbium iron nitrogen Yb2Fe 17 N 3-δ The preparation method of magnetic material powder includes the following steps:

[0038] (1) Yb2O3, Fe powder and Ca particles are used as raw materials and are thoroughly mixed in a mass ratio of 0.55:1:0.3 to obtain mixed powder. Then, the mixed powder is pressed into a block sample under an inert atmosphere to obtain a shaped block. The inert atmosphere is Ar gas and the pressing pressure is 100MPa.

[0039] (2) The shaped block obtained in step (1) is placed in a sealed crucible and heated to 1000℃ in a pure Ar atmosphere to fully carry out a reduction diffusion reaction for 5 hours to obtain Yb2Fe. 17 ;

[0040] (3) The Yb2Fe obtained in step (2) 17 After being crushed to an average particle size of 50 μm, the sample was nitrided at 500 °C for 15 h in a pure nitrogen atmosphere. The resulting sample was then washed three times with water and dried under a vacuum of <1000 Pa for 12 h to obtain high-purity Yb₂Fe. 17 N 3-δ Magnetic material powder, δ=0.7.

[0041] Performance testing

[0042] The mixed powder (hereinafter referred to as powder), the molded block (hereinafter referred to as briquette), the molded block placed in a sealed crucible (hereinafter referred to as briquette & seal) in Example 1, and the Yb2Fe after water washing 17 Yb2Fe after washing 17 N 3-δThe samples were subjected to XRD analysis to obtain the powder, briquettes, briquettes & seals, and Yb2Fe from Example 1. 17 -After washing with water and Yb2Fe 17 N 3-δ - XRD pattern after washing is shown below Figure 1 As shown, (a)~(c) are powder, compressed block, and compressed block & sealed sample, respectively; (d)~(e) are Yb2Fe after water washing, respectively. 17 Yb2Fe after washing 17 N 3-δ sample.

[0043] XRD testing instrument: PANalytical X'Pert Pro MPD X-ray diffractometer (XRD, CuKα radiation, λ=1.5406 Å);

[0044] Test conditions: Test temperature 20℃, test angle: 25°~55°.

[0045] Depend on Figure 1 It can be seen that under powder conditions, Figure 1 In (a), the α-Fe peak is very high, under compaction conditions. Figure 1 There are a small amount of α-Fe peaks in (b), and through compaction and sealing methods, Figure 1 In sample (c), almost no α-Fe peak is visible. This indicates that, compared to powder samples, compaction and sealing methods can effectively suppress the formation of the α-Fe phase. For the compacted and sealed samples, after washing with water, the prepared Yb₂Fe 17 Master alloy and its nitrided derivative Yb2Fe 17 N 3-δ sample( Figure 1 In (d) to (e), a single Th2Ni is observed. 17 The structure (space group P63 / mmc) confirmed that the product has high phase purity.

[0046] The microstructure of the materials was observed using a Hitachi SU8600 field emission electron microscope. SEM images and mapping diagrams of the ytterbium-iron alloy and ytterbium-iron nitrogen magnetic powder prepared in Example 2 were obtained as follows: Figure 2 As shown, (a) and (b) are Yb2Fe 17 The SEM images have scale bars of 10 μm and 1 μm, respectively. (c) shows Yb2Fe 17 N 3-δ SEM images, (d)~(f) are Yb2Fe 17 The mapping images are: (f) for Yb2Fe, (g)~(j) for Yb2Fe. 17 N 3-δThe mapping image is shown, where (e) and (h) represent Fe elements, (f) and (i) represent Yb elements, and (j) represents N elements.

[0047] from Figure 2 As shown, the method provided by this invention achieves high-fidelity stoichiometry, excellent phase purity, and uniform microstructure, such as... Figure 2 In (a) and (c), Yb2Fe 17 With Yb2Fe 17 N 3-δ The grains are very small, indicating that the compaction seal effectively inhibits grain growth. The mapping image shows that Yb and Fe are evenly distributed, and nitrogen atoms have successfully entered the material interior, forming a high-purity Yb2Fe phase. 17 N 3-δ Magnetic powder.

[0048] Example 2

[0049] A (Yb,Sm)2Fe 17 and (Yb, Sm)2Fe 17 N 3-δ The preparation method of magnetic material powder includes the following steps:

[0050] (1) M2O3, Fe powder and Ca particles are used as raw materials and are thoroughly mixed in a mass ratio of 0.65:1:0.4 to obtain a mixed powder. Then, the mixed powder is pressed into a block sample under an inert atmosphere to obtain a shaped block. The inert atmosphere is Ar gas and the pressing pressure is 100MPa. The M2O3 is composed of Yb2O3 and Sm2O3 in a molar ratio of 1:1.

[0051] (2) The shaped block obtained in step (1) is placed in a sealed crucible and heated to 1000℃ in a pure Ar atmosphere to fully carry out a reduction diffusion reaction for 6 hours to obtain (Yb 0.5 Sm 0.5 )2Fe 17 ;

[0052] (3) The (Yb) obtained in step (2) 0.5 Sm 0.5 )2Fe 17 After being crushed to an average particle size of 100 μm, the sample was nitrided at 500 °C for 24 h in a pure nitrogen atmosphere. The resulting sample was then washed three times with water and dried under a vacuum of <1000 Pa for 18 h to obtain high-purity (Yb) 0.5 Sm 0.5 )2Fe 17 N 3-δ Magnetic material powder, δ=0.1.

[0053] (Yb,Sm)2Fe prepared in Example 2 17 N 3-δ Magnetic powder (i.e., Yb) 0.5 Sm 0.5 )2Fe 17 N 3-δ ), and (Yb,Sm)2Fe 17 N 3-δ &CaO and (Yb,Sm)2Fe 17 The XRD pattern of CaO is shown below. Figure 3 As shown. By Figure 3 It can be seen that high-purity (Yb,Sm)₂Fe was successfully prepared. 17 N 3-δ Magnetic powder (i.e., Yb) 0.5 Sm 0.5 )2Fe 17 N 3-δ , δ=0.1).

[0054] Summary: This invention provides high-purity Yb2Fe 17 With Yb2Fe 17 N 3-δ The magnetic powder is prepared through a multi-step strategy involving mixing and briquetting, sealing, reduction diffusion, nitriding, and washing. This method skillfully controls factors such as raw material ratio, pressure, temperature, and time, providing a simple, controllable preparation method with small grain size. Its advantages include high purity, controllable method, reduced cost, and high efficiency, solving the problem that the low boiling point and high vapor pressure of ytterbium make it difficult to synthesize a pure phase using traditional high-temperature melting. Furthermore, the method provided by this invention is also applicable to (Yb x Sm y )2Fe 17 and (Yb) x Sm y )2Fe 17 N 3-δ The material system is such that x + y = 1.

[0055] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing rare earth iron alloys and their nitrides, characterized in that, Includes the following steps: (1) M2O3, Fe and Ca are mixed evenly and pressed to obtain a shaped block, wherein M in M2O3 is Yb and / or Sm; (2) The shaped block obtained in step (1) is subjected to a reduction-diffusion reaction under sealed conditions to obtain M2Fe. 17 Where M is Yb and / or Sm; (3) Take the M2Fe obtained in step (2) 17 The alloy was subjected to crushing, nitriding, and post-treatment in sequence to obtain the rare earth iron-nitrogen magnetic material M2Fe. 17 N 3-δ , where M is Yb and / or Sm, 0≤δ≤3.

0.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of M2O3 to Fe is (0.4~1.0):1; the mass ratio of Ca to Fe is (0.16~0.40):

1.

3. The preparation method according to claim 1, characterized in that, The pressure applied in step (1) is 1 MPa to 1 GPa.

4. The preparation method according to claim 1, characterized in that, In step (2), the reduction diffusion reaction is carried out in an H2-Ar or Ar atmosphere.

5. The preparation method according to claim 1, characterized in that, The temperature of the reduction diffusion reaction in step (2) is 800℃~1200℃, and the time of the reduction diffusion reaction is 0.5~10h.

6. The preparation method according to claim 1, characterized in that, The M2Fe obtained in step (2) is crushed 17 The average particle size of the alloy particles is 1~100μm.

7. The preparation method according to claim 1, characterized in that, In step (3), the nitriding reaction is carried out in an atmosphere of N2, NH3 or H2-N2.

8. The preparation method according to claim 1, characterized in that, The temperature of the nitriding reaction in step (3) is 300~600℃, and the time of the nitriding reaction is 1~48h.

9. The preparation method according to claim 1, characterized in that, The post-processing in step (3) includes: washing and drying the product of the nitriding reaction sequentially; the number of times the water is washed is 1 to 10.

10. The preparation method according to claim 9, characterized in that, The drying is carried out under vacuum conditions of <1000 Pa for 1 to 24 hours.

Images