Magnetic material and magnet, and method for manufacturing quency cooling alloy

Abstract

The purpose of the present invention is to provide an Sm-Fe-N-based magnetic material having excellent magnetic properties. This Sm-Fe-N magnetic material contains: M1, which is one element selected from the group consisting of Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W; M2, which is one element selected from the group consisting of Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W and is different from the M1; and C.

Description

Technical Field

[0001] This disclosure relates to magnetic materials and magnets, as well as rapidly solidified alloys, and methods for manufacturing magnetic materials and magnets. Background Technology

[0002] Rare-earth magnets possess high magnetic flux density, making them extremely strong permanent magnets suitable for various applications. Among rare-earth magnets, Sm-Fe-N magnets are known. Sm-Fe-N magnets are typically manufactured by nitriding Sm-Fe polycrystalline materials. It is believed that by dissolving nitrogen atoms within the lattice of the Sm-Fe polycrystalline material, lattice distortion occurs, exhibiting uniaxial magnetic anisotropy. The resulting Sm-Fe-N magnetic material can function as a hard magnetic material.

[0003] As a Sm-Fe-N based magnetic material, Patent Document 1 describes the manufacture of a thin-film isotropic Sm-Fe-N based powder magnet material by nitriding a magnetic alloy powder obtained by a roller cooling method, which has a composition of Sm-Fe-N in atomic percent. x Fe 100－x－v N v 、Sm x Fe 100-x-y-v M 1 y N v or Sm x Fe 100-x-z-v M 2 z N v (where M is in the formula) 1 For Hf or Zr. M 2 It consists of one or more of Si, Nb, Ti, Ga, Al, Ta, and C. It has a composition and TbCu type crystal structure with a thickness of 10–30 μm, and the following properties are used: 7≤x≤12, 0.5≤v≤20, 0.1≤y≤1.5, and 0.1≤z≤1.0.

[0004] Patent document 2 describes a Sm-Fe-N based magnetic material, specifying its composition, expressed as an atomic percentage, as consisting of Sm... x R a Fe 100－x－y－z－a M y N z (where R is at least one of Zr and Hf, M is at least one of Co, Ti, Nb, Cr, V, Mo, Si, Ga, Ni, Mn, and Al, x+a is 7% to 10%, a is 0% to 1.5%, y is 0% to 5%, and z is 10% to 14%) represents a rare earth permanent magnet material.

[0005] Prior art literature

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2002-57017

[0008] Patent Document 2: Japanese Patent Application Publication No. 2018-157197 Summary of the Invention

[0009] Patent Document 1 describes the use of one metal element in addition to Sm, Fe, and N in Sm-Fe-N magnetic materials, while Patent Document 2 describes the use of two metal elements in addition to Sm, Fe, and N in Sm-Fe-N magnetic materials. According to the researchers' findings, adding a metal element other than Sm and Fe can improve magnetic properties. However, it can also cause the precipitation of a heterogeneous phase composed of Fe and the added element, which sometimes reduces the magnetic properties of the resulting Sm-Fe-N magnetic material.

[0010] The purpose of this disclosure is to provide a Sm-Fe-N based magnetic material with good magnetic properties, particularly a good rectangularity ratio, and a method for manufacturing the same. Furthermore, the purpose of this disclosure is to provide a magnet comprising the Sm-Fe-N based magnetic material and a method for manufacturing the same.

[0011] The Sm-Fe-N based magnetic materials disclosed herein include:

[0012] M1 is selected from one element among Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W.

[0013] M2 is an element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W that is different from M1 mentioned above, and C.

[0015] According to this disclosure, a Sm-Fe-N based magnetic material with particularly good rectangularity ratio and a method for manufacturing the same can be provided. Additionally, this disclosure can provide a magnet comprising the Sm-Fe-N based magnetic material and a method for manufacturing the same. Attached Figure Description

[0016] Figure 1 The STEM-EDX analysis results of the Sm-Fe-N magnetic material obtained in Example 1 are shown. DF-I is a dark field image, and Fe, Zr, Nb and C are mapping images (elemental distribution images) representing the concentration distribution of each element.

[0017] Figure 2The STEM-EDX analysis results of the Sm-Fe-N magnetic material obtained in Comparative Example 1 are shown. DF-I is the dark field image, and Fe, Zr and C are mapping images (elemental distribution images) representing the concentration distribution of each element.

[0018] Figure 3 The STEM-EDX analysis results of the Sm-Fe-N magnetic material obtained in Comparative Example 2 are shown. DF-I is the dark field image, and Fe, Nb and C are mapping images (elemental distribution images) representing the concentration distribution of each element.

[0019] Figure 4 This is a schematic diagram showing the concentration distribution of Fe, M1, M2 and C in an Sm-Fe-N magnetic material in one embodiment of 1. Detailed Implementation

[0020] (Implementation Method 1: Sm-Fe-N based magnetic materials)

[0021] The following is a detailed description of an embodiment of the Sm-Fe-N magnetic material of the present disclosure, but the present disclosure is not limited to this embodiment.

[0022] The Sm-Fe-N based magnetic materials disclosed herein include:

[0023] M1 is selected from one element among Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W.

[0024] M2 is an element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W that is different from M1 mentioned above, and C.

[0026] The Sm-Fe-N magnetic material disclosed herein has the above-described structure, and therefore exhibits excellent magnetic properties, particularly a good rectangularity ratio. While it should not be limited to a specific theory for explanation, the reason why the Sm-Fe-N magnetic material of this disclosure achieves the above-described effect is believed to be as follows.

[0027] That is, it is believed that in Sm-Fe-N magnetic materials, the addition of metallic elements, such as Zr, can promote amorphization during the manufacturing process, resulting in fine and uniform precipitation of the main phase and improved magnetic properties in the final Sm-Fe-N magnetic material. However, it is also believed that the addition of metallic elements such as Zr can lead to the precipitation of a heterogeneous phase, such as Fe-Zr, which reduces magnetic properties, particularly the rectangularity ratio. In this case, a method was investigated to further add C to precipitate a non-magnetic Zr-C phase, thus making it less likely for the Fe-Zr heterogeneous phase to precipitate, but this method could not sufficiently reduce the Fe-Zr heterogeneous phase.

[0028] In contrast, it is believed that if M1, M2 and C are further added, the main phase will precipitate finely and uniformly, and the non-magnetic M1-M2-C phase will precipitate preferentially. As a result, it is believed that the precipitation of Fe-M1 and Fe-M2 heterogeneous phases is suppressed, and Sm-Fe-N magnetic materials with good magnetic properties, especially good rectangularity ratio, can be obtained.

[0029] The aforementioned Sm-Fe-N magnetic materials contain: one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W, namely M1; and one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W but different from M1, namely M2. These elements are metallic elements of groups IVB to VIB, and are all transition metals. The rationale is not yet clear, but by simultaneously including M1 and M2, the M1-M2-C phase can be precipitated, the precipitation of Fe-M1 or Fe-M2 heterogeneous phases is suppressed, and Sm-Fe-N magnetic materials with good magnetic properties, especially good rectangularity ratio, can be obtained.

[0030] In a preferred embodiment, M1 can be one element selected from Zr, Ti, Hf, V, Nb, and Ta, and M2 can be one atom selected from Zr, Ti, Hf, V, Nb, and Ta that is different from M1.

[0031] In a more preferred embodiment, M1 can be an element selected from Zr, Hf, V, Nb, and Ta, and M2 can be an element selected from Zr, Hf, V, Nb, and Ta that is different from M1.

[0032] The ratio of the content of M1 to the content of M2 (M1:M2) is preferably 2:8 to 8:2 on an atomic percentage basis, more preferably 3:7 to 7:3, and even more preferably 4:6 to 6:4. By having the content ratio of M1 to M2 within this range, the precipitation of the Fe-M1-M2 phase can be promoted, and the rectangularity of the Sm-Fe-N magnetic material can be further improved.

[0033] In the Sm-Fe-N magnetic material, the total content of M1 and M2 in 100 atomic percent of the elements is preferably 1.6 atomic percent to 5.0 atomic percent, more preferably 1.8 atomic percent to 4.0 atomic percent, and even more preferably 2.0 atomic percent to 3.5 atomic percent. With the total content of M1 and M2 within this range, the rectangularity of the Sm-Fe-N magnetic material can be further improved.

[0034] The aforementioned Sm-Fe-N magnetic materials contain C. By including C, non-magnetic M1-M2-C phases precipitate, and the magnetic properties, especially the rectangularity ratio, of the Sm-Fe-N magnetic materials can become better.

[0035] In the aforementioned Sm-Fe-N magnetic materials, of the total 100 atomic percent of the elements contained in the Sm-Fe-N magnetic materials, the content of C is preferably greater than 0 atomic percent and less than 2.5 atomic percent, more preferably 0.1 atomic percent to 2.3 atomic percent, and even more preferably 0.1 atomic percent to 2.2 atomic percent. By ensuring that the content of C in the Sm-Fe-N magnetic materials is within the above range, the rectangularity of the Sm-Fe-N magnetic materials can be optimized.

[0036] In the aforementioned Sm-Fe-N magnetic materials, the content of Sm is preferably 7.0 atomic% to 11.0 atomic% of the total 100 atomic% of the elements contained in the Sm-Fe-N magnetic materials, more preferably 7.5 atomic% to 10.5 atomic%, and even more preferably 7.5 atomic% to 10.0 atomic%. By maintaining the Sm content in the Sm-Fe-N magnetic powder within this range, the rectangularity of the Sm-Fe-N magnetic materials can be further improved.

[0037] In Sm-Fe-N based magnetic materials, the Fe content is preferably 69.5 atomic% to 82.0 atomic% of the total 100 atomic% of the elements contained in the Sm-Fe-N based magnetic materials, more preferably 70.0 atomic% to 80.0 atomic%, and even more preferably 71.0 atomic% to 78.0 atomic%. By maintaining the Fe content in the Sm-Fe-N based magnetic powder within this range, the rectangularity of the Sm-Fe-N based magnetic materials can be optimized.

[0038] In Sm-Fe-N based magnetic materials, the ratio of Fe content to Sm content (Fe content / Sm content) is preferably 5 to 10 on an atomic basis, more preferably 7 to 9.5, and even more preferably 8 to 9. By maintaining the Fe content to Sm content ratio within this range, the rectangularity of the Sm-Fe-N based magnetic material can be optimized.

[0039] In the aforementioned Sm-Fe-N magnetic materials, the total content of Sm and Fe in 100 atomic percent of the Sm-Fe-N magnetic powder is preferably 66.5 atomic percent to 96.5 atomic percent, more preferably 68.5 atomic percent to 90.0 atomic percent, and even more preferably 70.0 atomic percent to 86.0 atomic percent. By maintaining the total content of Sm and Fe in the Sm-Fe-N magnetic materials within this range, the rectangularity of the Sm-Fe-N magnetic materials can be optimized.

[0040] In the aforementioned Sm-Fe-N magnetic materials, in a total of 100 atomic% of the ratio of Fe content to Sm content, the N content is preferably 12.0 atomic% to 18.0 atomic%, more preferably 12.5 atomic% to 17.0 atomic%, and even more preferably 13.0 atomic% to 16.5 atomic%. By maintaining the N content within this range, the rectangularity of the Sm-Fe-N magnetic material can be optimized.

[0041] The aforementioned Sm-Fe-N magnetic material may further contain Co. In the Sm-Fe-N magnetic powder, of the total 100 atomic percent of the elements contained in the main phase, the content of Co is preferably 0.0 atomic percent to 5.0 atomic percent, more preferably 1.0 atomic percent to 5.0 atomic percent, and even more preferably 1.5 atomic percent to 5.0 atomic percent. By ensuring that the Co content in the Sm-Fe-N magnetic material is within the above range, the rectangularity of the Sm-Fe-N magnetic material can be optimized.

[0042] In another embodiment, the Co content in the Sm-Fe-N magnetic material is more preferably 0.0 atomic% to 5 atomic%, and even more preferably 0.0 atomic% to 2.0 atomic%. By ensuring that the Co content in the Sm-Fe-N magnetic material is within the above range, the rectangularity of the Sm-Fe-N magnetic material can be optimized.

[0043] The aforementioned Sm-Fe-N magnetic materials may contain Al, Si, Mn, and O as unavoidable impurities. When the Sm-Fe-N magnetic material contains Al, the Al content in 100 atomic percent of the total elements contained in the Sm-Fe-N magnetic material may, for example, be 10.0 atomic percent or less, and more specifically, 5.0 atomic percent or less. When the Sm-Fe-N magnetic material contains Si, the Si content in 100 atomic percent of the total elements contained in the Sm-Fe-N magnetic material may, for example, be 10.0 atomic percent or less, and more specifically, 5.0 atomic percent or less. When the Sm-Fe-N magnetic material contains Mn, the Mn content in 100 atomic percent of the total elements contained in the Sm-Fe-N magnetic material may, for example, be 10.0 atomic percent or less, and more specifically, 5.0 atomic percent or less. When Sm-Fe-N magnetic materials contain O, the O content in the total 100 atomic percent of the elements contained in the Sm-Fe-N magnetic materials can be, for example, 10.0 atomic percent or less, and more specifically, 5.0 atomic percent or less.

[0044] The total content of all elements in Sm-Fe-N magnetic materials does not exceed 100 atoms. If the total content of all elements that can be contained in Sm-Fe-N magnetic materials is calculated, it is theoretically 100 atoms.

[0045] In this disclosure, the types and contents of elements other than C, N, and O in Sm-Fe-N magnetic materials can be determined by X-ray fluorescence analysis (XRF) or inductively coupled plasma atomic emission analysis (ICP-AES), preferably by X-ray fluorescence analysis (XFR). Furthermore, C can be determined by combustion in an oxygen stream – infrared absorption method, and N and O can be determined by inert gas melting – thermal conductivity method (TCD).

[0046] (Main Aspect)

[0047] The aforementioned main phase is composed of Sm-Fe-N grains. Sm-Fe-N grains have a structure in which N atoms are dissolved in the crystal lattice of the Sm-Fe system. The main phase is the region in Sm-Fe-N magnetic materials that contributes to magnetic properties. Due to the solid solution of N atoms, strain is applied to the crystal lattice, exhibiting uniaxial magnetic anisotropy, and thus it can function as a hard magnetic material.

[0048] The aforementioned main phase preferably includes those selected from Th2Zn. 17 One or more of the following: Sm-Fe-N system crystals exhibiting the TbCu7 type structure and Sm-Fe-N system crystals exhibiting the TbCu7 type structure.

[0049] The main phase mentioned above contains at least Sm, Fe and N.

[0050] In addition, the aforementioned principal phase includes: one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W, namely M1; one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W that is different from the aforementioned M1, namely M2; and C.

[0051] The aforementioned principal phase may further include Co.

[0052] The crystallite diameter of the Sm-Fe-N grains contained in the main phase is preferably 10 nm to 1 μm, more preferably 15 nm to 400 nm, and even more preferably 20 nm to 200 nm. By ensuring the crystallite diameter of the Sm-Fe-N grains is within the above range, the rectangularity of the Sm-Fe-N magnetic material becomes favorable. It should be noted that the Sm-Fe-N grains can typically exist as single crystals. In this disclosure, the crystallite diameter can be directly measured from images obtained by transmission electron microscopy (TEM) or scanning transmission electron microscopy (STEM).

[0053] (Grain boundary phase)

[0054] The aforementioned grain boundary phase exists between multiple Sm-Fe-N grains constituting the main phase. This grain boundary phase can representatively be a layer covering the Sm-Fe-N grains, for example, it can exist as a continuous layer separating multiple Sm-Fe-N grains. The grain boundary phase can representatively be a non-magnetic phase. Because the grain boundary phase is non-magnetic, the magnetic regions of the main phase are divided by the grain boundary phase, thus suppressing magnetic field reversal, increasing remanent magnetization, and consequently increasing the rectangularity ratio.

[0055] The aforementioned grain boundary phase may further contain one or more elements selected from Sm, Fe, Co, Ti, V, Mn, Zr, Nb, Hf, Ta, Si, B, and C.

[0056] In one approach, the aforementioned grain boundary phase can be a region where, in STEM-EDX analysis, the N content of 2 nm or more is higher than that of the Sm-Fe-N crystalline phase. In this approach, the thickness of the grain boundary phase is preferably 2 nm to 8 nm, more preferably 4 nm to 6 nm. By allowing the width of the grain boundary phase to fall within this range, the rectangularity of the Sm-Fe-N crystalline material can be optimized.

[0057] (M1-M2-C phase)

[0058] The Sm-Fe-N magnetic material disclosed herein preferably contains the M1-M2-C phase. By including the M1-M2-C phase, the precipitation of Fe-M1 and Fe-M2 heterogeneous phases can be suppressed, resulting in an Sm-Fe-N magnetic material with good magnetic properties, especially a good rectangularity ratio.

[0059] like Figure 4 As illustrated, in the region containing the M1-M2-C phase, if we compare the distribution concentrations of Fe, M1, M2, and C, the region outside region 1, where Fe has a high distribution concentration, has the same shape as region 2, where M1 has a high distribution concentration, region 3, where M2 has a high distribution concentration, and region 4, where C has a high distribution concentration. Therefore, it can be said that the M1-M2-C phase exists in the region where regions 2, 3, and 4 overlap.

[0060] The presence of the M1-M2-C phase in the Sm-Fe-N magnetic materials disclosed herein can be confirmed using energy-dispersive X-ray analysis (STEM-EDX) with scanning transmission electron microscopy. For example, when observing Sm-Fe-N magnetic materials using STEM, the presence of multiple main phases and grain boundary phases can be confirmed within a field of view (e.g., 522 × 522 nm). 2In this study, elemental distribution images of Fe, M1, M2, and C are obtained using energy-dispersive X-ray diffraction (EDX), and the distributions of each element are compared. The presence of regions with low Fe density and high M1, M2, and C density confirms the existence of the M1-M2-C phase. Samples for STEM-EDX analysis of Sm-Fe-N magnetic materials can be processed, for example, using a focused ion beam (FIB) device.

[0061] The M1-M2-C phase can be distributed throughout the Sm-Fe-N magnetic material. For example, it can exist in the main phase (i.e., the region surrounded by the main phase), the grain boundary phase (i.e., the region surrounded by the grain boundary phase), or any of the main phase and the grain boundary phase.

[0062] The major diameter of the M1-M2-C phase is preferably 1 nm to 30 nm, more preferably 3 nm to 25 nm, and even more preferably 5 nm to 25 nm, but is not limited thereto.

[0063] In the Sm-Fe-N magnetic materials disclosed herein, the major axis of the M1-M2-C phase can be confirmed using energy-dispersive X-ray diffraction (STEM-EDX) analysis with scanning transmission electron microscopy. For example, Sm-Fe-N magnetic materials can be observed using STEM in a field of view (e.g., 522 × 522 nm) containing multiple main phases and grain boundary phases. 2 In this study, elemental distribution images of Fe, M1, M2, and C were obtained by energy dispersive X-ray diffraction (EDX). The major axis of more than 10 regions with low Fe distribution density was determined, and the average value of these regions was taken as the major axis of the M1-M2-C phase.

[0064] In addition, in this disclosure, the major axis of a region refers to the length of the longest line segment among the line segments that pass through the region and are divided by the boundary of the region.

[0065] In addition to the aforementioned main phase, grain boundary phase, and M1-M2-C phase, the Sm-Fe-N magnetic material disclosed herein may also contain other heterogeneous phases. The aforementioned Sm-Fe-N magnetic material may be a material containing the aforementioned main phase and grain boundary phase. Preferably, it is a material containing the aforementioned main phase, grain boundary phase, and M1-M2 phase. More preferably, it is a material containing the aforementioned main phase, grain boundary phase, and M1-M2-C phase, as well as heterogeneous phases that may be included depending on the situation (which may be representatively different from the Fe-M1 and Fe-M2 phases). More preferably, it is a material composed of the aforementioned main phase, grain boundary phase, and M1-M2-C phase, as well as heterogeneous phases that may be included depending on the situation.

[0066] The Sm-Fe-N magnetic materials disclosed herein can be in the form of magnetic powder and magnets, etc.

[0067] (Sm-Fe-N based magnetic powder)

[0068] Sm-Fe-N magnetic materials can be in the form of magnetic powder (i.e., powder). Hereinafter, Sm-Fe-N magnetic materials in powder form will also be referred to as "Sm-Fe-N magnetic powder".

[0069] The aforementioned Sm-Fe-N magnetic powder comprises the aforementioned main phase and the aforementioned grain boundary phase. Preferably, it is a material comprising the aforementioned main phase, grain boundary phase, and M1-M2 phase. More preferably, it is a powder material comprising the aforementioned main phase, grain boundary phase, and M1-M2-C phase, and, depending on the situation, other dissimilar phases. More preferably, it is a powder material composed of the aforementioned main phase, grain boundary phase, and M1-M2-C phase, and, depending on the situation, other dissimilar phases. The aforementioned Sm-Fe-N magnetic powder comprises Sm, Fe, and N.

[0070] The average particle size of the above-mentioned Sm-Fe-N magnetic powder is preferably 10 μm to 300 μm, more preferably 10 μm to 50 μm, and even more preferably 20 μm to 40 μm.

[0071] The average particle size of the above-mentioned Sm-Fe-N magnetic powder can be determined by laser diffraction particle size distribution measurement method.

[0072] (Sm-Fe-N series magnets)

[0073] Sm-Fe-N magnetic materials can be in the form of magnets (i.e., bulk materials). Hereinafter, bulk Sm-Fe-N magnetic materials will also be referred to as "Sm-Fe-N magnets".

[0074] In one embodiment, the Sm-Fe-N magnet preferably comprises the Sm-Fe-N magnetic powder and a binder. The binder acts as a binder for the Sm-FeN magnetic powder and may typically include resin (plastic), rubber, Zn, or other metals.

[0075] In this method, the content of Sm-Fe-N magnetic powder contained in the above-mentioned Sm-FeN magnetic magnet is preferably 90% to 99.5% by mass, and more preferably 95% to 99% by mass.

[0076] In this method, the resins mentioned above can be, for example, thermosetting resins such as epoxy resin, phenolic resin, allyl resin, and unsaturated polyester resin; and thermoplastic resins such as polyamide resin, polyphenylene sulfide resin, polyetherketone resin, polyetheretherketone resin, and polyester resin.

[0077] In this method, the Sm-Fe-N magnets mentioned above may contain other additives in addition to Sm-Fe-N magnetic powder and resin.

[0078] In another embodiment, the Sm-Fe-N magnet is preferably a blocky magnet material comprising the main phase, the grain boundary phase, and, depending on the circumstances, a heterogeneous phase. More preferably, it is a blocky magnet material composed of the main phase, the grain boundary phase, and, depending on the circumstances, a heterogeneous phase.

[0079] (Implementation Method 2: Manufacturing Method of Sm-Fe Alloy)

[0080] The method for manufacturing Sm-Fe alloys disclosed herein includes:

[0081] The steps involve melting, quenching, and solidifying a raw material (hereinafter referred to as "metallic raw material") containing Sm, Fe, one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W (M1), one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W but different from M1 (M2), and C, to obtain an Sm-Fe alloy.

[0082] According to the manufacturing method disclosed herein, Sm-Fe alloys with uniform distribution of Sm, M1, M2 and C can be manufactured, and raw materials for the aforementioned Sm-Fe-N magnetic materials can be provided.

[0083] The types and proportions of elements contained in the aforementioned metallic raw materials have the same meaning as the types and proportions of elements constituting the aforementioned Sm-Fe-N system magnetic materials.

[0084] By melting the aforementioned metal raw materials, the elements can be uniformly distributed in the melt. The temperature at which the metal is melted is preferably, for example, 1200°C to 1700°C. The atmosphere at which the metal is melted is preferably, for example, an inert atmosphere free of nitrogen, such as an Ar atmosphere or a He atmosphere. The melting process is not particularly limited, but high-frequency melting is preferred. The aforementioned metal raw materials may be mixed before melting.

[0085] By rapidly cooling the aforementioned melt, the melt can be cooled below its solidification point without crystallization while maintaining a homogeneous composition, thus obtaining an Sm-Fe alloy. This Sm-Fe alloy typically contains an amorphous phase.

[0086] The aforementioned quenching is not particularly limited, but it is preferably performed by roller quenching. In roller quenching, molten material is sprayed onto a rotating metal roller, thereby rapidly cooling the molten material. The conditions for roller quenching are not particularly limited. As a metal roller, a roller made of molybdenum, copper, or an alloy material with these as the main components is preferably used. The circumferential speed of the roller is preferably, for example, 30 m / s to 100 m / s, more preferably 50 m / s to 90 m / s.

[0087] (Implementation Method 3: Manufacturing Method of Sm-Fe-N System Magnetic Materials)

[0088] The method for manufacturing Sm-Fe-N based magnetic materials disclosed herein includes:

[0089] (a) The steps of crystallizing Sm-Fe alloys to obtain Sm-Fe crystalline materials, and

[0090] (b) The step of nitriding the above-mentioned Sm-Fe crystalline material to obtain Sm-Fe-N magnetic material;

[0091] It may further include:

[0092] (c) The step of heat treatment of Sm-Fe-N magnetic materials.

[0093] According to the manufacturing method disclosed herein, Sm-Fe-N based magnetic materials with good magnetic properties, particularly good rectangularity ratio, can be provided.

[0094] (a) Preparation of Sm-Fe crystalline materials

[0095] By crystallizing the above-mentioned Sm-Fe alloy, Sm-Fe crystals precipitate, resulting in Sm-Fe crystalline materials. Crystallization can typically be performed by heating.

[0096] The preferred heating temperature for the Sm-Fe alloy is 690°C to 800°C, more preferably 725°C to 785°C. The heating time for the Sm-Fe alloy is, for example, 5 to 60 minutes, preferably 5 to 30 minutes. The atmosphere for heating the Sm-Fe non-alloy is, for example, a nitrogen-free, inactive atmosphere such as Ar or He. Heating the Sm-Fe alloy under these conditions facilitates more uniform formation of Sm-Fe crystals.

[0097] The aforementioned Sm-Fe crystalline material can be further pulverized. Powdered Sm-Fe crystalline material can be obtained through pulverization. The pulverization method is not particularly limited; for example, a crusher, grinder, or ball mill can be used. Through this pulverization, the Sm-Fe crystalline material is, for example, pulverized to 10–300 μm, preferably 10–150 μm, and more preferably 30–80 μm.

[0098] (b) Nitriding treatment of Sm-Fe crystalline materials

[0099] By nitriding Sm-Fe crystalline materials, N atoms are incorporated into the Sm-Fe crystalline materials to obtain Sm-Fe-N magnetic materials.

[0100] The above-mentioned nitriding treatment can be typically carried out by heat treatment in a nitrogen atmosphere, an ammonia atmosphere, a hydrogen atmosphere, or a mixture thereof.

[0101] In the above nitriding treatment, when using nitrogen gas, the partial pressure of nitrogen is 10 kPa to 100 kPa, preferably 50 kPa to 100 kPa. By using this nitrogen partial pressure, the nitriding reaction proceeds fully.

[0102] In the above nitriding treatment, when using a mixture of ammonia and hydrogen, and setting the total pressure of the mixture to 0.1 MPa, the partial pressure of ammonia is 20 kPa to 40 kPa, preferably 25 kPa to 33 kPa. By using this partial pressure of ammonia, the nitriding reaction proceeds fully.

[0103] In the above nitriding treatment, the heating temperature is preferably 350℃~500℃, more preferably 400℃~500℃. By using this heating temperature, the decomposition of SmN and Fe that may occur when the nitriding reaction is carried out at higher temperatures can be prevented, and the reaction can be carried out more fully compared with the case of nitriding reaction carried out at lower temperatures.

[0104] The above-mentioned nitriding treatment can typically be carried out at atmospheric pressure, for example, preferably at a pressure of 900 hPa to 1100 hPa, more preferably at a pressure of 950 hPa to 1050 hPa.

[0105] In the above-described nitriding treatment, when using nitrogen gas, the heating time is preferably 2 to 30 hours, more preferably 8 to 25 hours. By using this heating time, grain growth and decomposition into SmN and Fe that may occur with longer heating times can be prevented, and the reaction can proceed more fully compared to cases with longer heating times. By adjusting this heating time, the amount of nitrogen incorporated into the Sm-Fe crystalline material can be controlled.

[0106] In the above nitriding treatment, when using a mixture of ammonia and hydrogen gas, the heating time is preferably 10 to 90 minutes, more preferably 20 to 60 minutes. By using this heating time, grain growth and decomposition into SmN and Fe that may occur with longer heating times can be prevented, and the reaction can proceed more fully compared to shorter heating times. By adjusting this heating time, the amount of nitrogen incorporated into the Sm-Fe crystalline material can be controlled.

[0107] (c) Heat treatment of Sm-Fe-N magnetic materials

[0108] After obtaining Sm-Fe-N magnetic materials through nitriding, further heating can be performed. Typically, the Sm-Fe-N magnetic materials are further heat-treated at 400℃ to 500℃ in an atmosphere where the concentrations of N atoms and O atoms are both below 100 ppm. This allows N atoms to diffuse into the interior of the main phase, resulting in Sm-Fe-N magnetic materials with increased N atom content in the main phase. Hereinafter, the heat treatment of Sm-Fe-N magnetic materials will be referred to as "continuous heat treatment."

[0109] Preferably, the step of cooling the Sm-Fe-N magnetic material is not included between the above-mentioned nitriding treatment and the continuous heat treatment, and it is preferable to perform the continuous heat treatment directly after the nitriding treatment.

[0110] In the aforementioned continuous heat treatment, the atmosphere with a concentration of N atoms and a concentration of O atoms of 100 ppm or less can be exemplified by an H2 gas atmosphere; an Ar atmosphere; a He atmosphere; and a mixed atmosphere of H2 gas and Ar or He.

[0111] In the aforementioned continuous heat treatment, the heating temperature is preferably 350°C to 500°C, more preferably 400°C to 500°C. By using this heating temperature, the decomposition of SmN and Fe that may occur during heat treatment at higher temperatures can be prevented, and compared with heat treatment at lower temperatures, the solid solution of N atoms into the main phase can be fully achieved.

[0112] The aforementioned continuous heat treatment can typically be carried out at atmospheric pressure, for example, preferably at a pressure of 900 hPa to 1100 hPa, more preferably at a pressure of 950 hPa to 1050 hPa.

[0113] In the aforementioned continuous heat treatment, the heating time is preferably 30 minutes to 600 minutes, more preferably 30 minutes to 240 minutes. By using this heating time, grain growth and decomposition into SmN and Fe that may occur with longer heating times can be prevented, and compared with shorter heating times, sufficient solid solution of N atoms into the main phase can be achieved.

[0114] After the above continuous heat treatment, natural cooling can be carried out.

[0115] Through the preparation of (a) Sm-Fe-N crystalline materials, (b) nitriding of Sm-Fe crystalline materials, and (c) heat treatment of Sm-Fe-N magnetic materials as needed, powdered Sm-Fe-N magnetic materials (i.e., Sm-Fe-N magnetic powder) can be typically obtained.

[0116] In one embodiment, the aforementioned Sm-Fe-N magnet can be manufactured by a manufacturing method including the following steps: mixing Sm-Fe-N magnetic powder with a binder raw material to obtain a mixture; and molding the mixture to obtain the Sm-Fe-N magnet. Examples of methods for molding the mixture include compression molding and injection molding. For instance, the resin raw material in the mixture can be heated to melt or dissolved in a solvent to form a liquid, and then subjected to compression molding or injection molding. The liquid mixture can be cured by cooling, crosslinking of the binder raw material, removal of the solvent, etc. Alternatively, the aforementioned Sm-Fe-N magnet can be manufactured by sintering the aforementioned Sm-Fe-N magnetic powder.

[0117] The Sm-Fe-N magnetic materials disclosed herein exhibit excellent magnetic properties, particularly a good rectangularity, making them suitable for various electromagnetic devices such as electromagnetic actuators (motors). In particular, due to their good rectangularity, the Sm-Fe-N magnetic materials of this disclosure suppress demagnetization, which is expected to contribute to the miniaturization and high-output of such electromagnetic devices. Furthermore, because demagnetization is suppressed, the Sm-Fe-N magnetic materials of this disclosure are also suitable for applications requiring reliability in high-temperature environments, such as automotive applications.

[0118] Example

[0119] The present invention is further illustrated by the following embodiments, but the present invention is not limited thereto.

[0120] (Examples 1-10, Comparative Examples 1-5)

[0121] The elements listed in Table 1 were used to prepare a master alloy via high-frequency melting. The resulting master alloy was melted in an Ar atmosphere and sprayed onto a Mo roller rotating at a circumferential speed of 70 m / s to obtain a quenched ribbon (Sm-Fe amorphous material). This quenched ribbon was then heat-treated in an Ar atmosphere at a processing temperature of 755 °C to obtain a Sm-Fe crystalline material, which was then pulverized to pass through a 150 μm sieve. It should be noted that the compositions listed in Table 1 are in atomic percent.

[0122] Next, the heat-treated powder (powdered Sm-Fe alloy) was nitrided at the atmosphere and temperature specified in Table 1 for the time specified in Table 1 to obtain Sm-Fe-N magnetic material. After nitriding, continuous heat treatment was performed at the atmosphere, temperature, and time specified in Table 1.

[0123] [Table 1]

[0124]

[0125] (STEM-EDX Analysis)

[0126] The materials obtained in the above embodiments and comparative examples were processed using a focused ion beam (FIB) apparatus and an Ar milling apparatus to obtain observation images (dark-field images) based on a transmission electron microscope (accelerating voltage 200 kV) manufactured by Nippon Electron Ltd., and elemental distribution maps based on energy dispersive X-ray analysis (EDX). It should be noted that the field of view of each image is 522 nm × 522 nm, and the number of pixels when the EDX data was acquired was 512 × 512 pixels.

[0127] Figure 1 The analytical results of the Sm-Fe-N magnetic material obtained in Example 1 are shown. Figure 2 The analytical results of the material obtained in Comparative Example 1 are shown. Figure 3 The analytical results of the material obtained in Comparative Example 2 are shown. Figure 1 , Figure 2 and Figure 3 In the diagram, the image shown by DF-I represents a dark-field image based on STEM, while the images shown for Fe, Zr, Nb, and C represent the elemental distribution images for each element.

[0128] exist Figure 2 In the material of Comparative Example 1 shown, when comparing the STEM dark-field image and the elemental distribution images of each element, it was confirmed that there were regions with low Fe concentration and high Zr and C concentrations. Figure 2 (The area indicated by the white arrow in the middle). This confirmed the precipitation of the Zr-C phase as a non-magnetic phase in the material of Comparative Example 1. However, it was also confirmed that regions with high Fe concentrations and the presence of Fe were present in the material of Comparative Example 1. Figure 2 (The area surrounded by a white circle). This confirms that a Fe-Zr phase, as a heterogeneous phase, also precipitated in the material of Comparative Example 1.

[0129] exist Figure 3 In the material of Comparative Example 2 shown, when comparing the STEM dark-field image and the elemental distribution images of each element, it was confirmed that there were regions with low Fe concentration and high Nb and C concentrations. Figure 3 (The area indicated by the white arrow in the middle). This confirmed the precipitation of the Nb-C phase as a non-magnetic phase in the material of Comparative Example 2. However, it was also confirmed that regions with high Nb concentrations and the presence of Fe were also present in the material of Comparative Example 2. Figure 3 (The area surrounded by a white circle). This confirms that a Fe-Nb phase, as a heterogeneous phase, also precipitated in the material of Comparative Example 2.

[0130] In contrast, Figure 1In the material of Example 1, comparison of the STEM dark-field image and the elemental distribution images of each element confirmed the existence of regions with low Fe concentrations and high Zr, Nb, and C concentrations. This confirmed the precipitation of the Zr-Nb-C phase as a non-magnetic phase in the Sm-Fe-N magnetic material of Example 1. Furthermore, the presence of Fe-Zr and Fe-Nb phases was not confirmed in the Sm-Fe-N magnetic material of Example 1.

[0131] (Magnetic measurement)

[0132] Magnetic measurements were performed using a VSM (Vibrating Sample Type Magnetometer). The demagnetizing field Hk is the size of the magnetic field when the magnetic flux density is 90% of the residual magnetic flux density. The ratio obtained by dividing it by the coercivity Hcj is called the rectangularity ratio (Hk / Hcj). The larger the rectangularity ratio, the higher the expected performance as a magnetic material.

[0133] [Table 2]

[0134]

[0135] It was confirmed that the Sm-Fe-N magnetic material of the examples had a rectangularity ratio (Hk / Hcj) of 0.12 or higher than that of the comparative example, showing a good rectangularity ratio. This is believed to be because in the Sm-Fe-N magnetic material of the examples, the precipitation of the M1-M2-C phase, which is a non-magnetic phase, and the precipitation of the Fe-M1 and Fe-M2 phases, which are heterogeneous phases, were suppressed.

[0136] In addition, it was specifically confirmed that in the Sm-Fe-N materials of Examples 1 to 6, 8 and 10, the ratio of the contents of M1 to M2 was 5:5 on an atomic % basis, and the rectangularity ratio was 0.21 to 0.28, showing a further good rectangularity ratio.

[0137] On the other hand, the materials of Comparative Examples 1 to 5 each contain one of Zr, Nb, Hf, Ta, or V, and the rectangularity ratio (Hk / Hcj) is not sufficiently satisfactory. This is believed to be because, in the materials of Comparative Examples 1 to 5, if the metal contained in each is designated as M, although the M-C phase, which is a non-magnetic phase, precipitates, the precipitation of the Fe-M phase, which is a heterogeneous phase, is not sufficiently suppressed.

[0138] Thus, in the embodiments and comparative examples, although the constituent elements and composition of the materials are similar, the magnetic properties, especially the rectangularity ratio, may vary greatly.

[0139] This disclosure provides the following methods. [1]

[0141] A Sm-Fe-N based magnetic material comprising:

[0142] M1 is selected from one element among Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W.

[0143] M2 is an element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W that is different from M1 mentioned above, and C. [2]

[0146] According to the Sm-Fe-N magnetic material described in [1], M1 is an element selected from Zr, Ti, Hf, V, Nb and Ta, and M2 is an element selected from Zr, Ti, Hf, V, Nb and Ta that is different from M1. [3]

[0148] According to the Sm-Fe-N magnetic material described in [1] or [2], the ratio of the content of M1 to the content of M2 is 2:8 to 8:2 in atomic percent. [4]

[0150] The Sm-Fe-N magnetic material according to any one of [1] to [3] contains an M1-M2-C phase. [5]

[0152] The Sm-Fe-N magnetic material according to any one of [1] to [4], wherein the major axis of the M1-M2-C phase is less than 30 nm. [6]

[0154] According to any one of [1] to [5], the Sm-Fe-N magnetic material, wherein,

[0155] The content of Sm is 7.0 atomic% to 11.0 atomic%.

[0156] The Fe content is 69.5 atomic% to 82.0 atomic%.

[0157] The content of Cο is 0 atomic% to 5 atomic%.

[0158] The nitrogen content is 11.0 atomic% to 19.5 atomic%.

[0159] The combined content of M1 and M2 is 1.6 atomic% to 5.0 atomic%.

[0160] The content of C is greater than 0 atomic% and less than 2.5 atomic%. [7]

[0162] The Sm-Fe-N magnetic material according to any one of [1] to [6] is in the form of magnetic powder or a magnet. [8]

[0164] A Sm-Fe-N magnet comprising any one of [1] to [7] Sm-Fe-N magnetic material and adhesive. [9]

[0166] A method for manufacturing an Sm-Fe alloy includes: melting, quenching and solidifying a raw material comprising Sm, Fe, M1 (selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo and W), M2 (selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo and W but different from M1), and C to obtain an Sm-Fe alloy.

[10]

[0168] A method for manufacturing Sm-Fe-N based magnetic materials includes:

[0169] The steps of crystallizing the Sm-Fe alloy manufactured by the manufacturing method described in [9] to obtain Sm-Fe crystalline materials, and

[0170] The step of nitriding the above-mentioned Sm-Fe crystalline material to obtain Sm-Fe-N magnetic material.

[11]

[0172] A method for manufacturing an Sm-Fe-N magnet, comprising:

[0173] The process of obtaining an Sm-Fe quenched solidification alloy involves melting raw materials containing Sm, Fe, one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W (M1), one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W but different from M1 (M2), and C, followed by quenching.

[0174] The step of performing crystallization treatment on the above-mentioned Sm-Fe rapidly solidified alloy to obtain Sm-Fe crystalline materials is as follows:

[0175] The step of nitriding the above-mentioned Sm-Fe crystalline material to obtain Sm-Fe-N magnetic powder is as follows:

[0176] The steps of mixing the above-mentioned Sm-Fe-N magnetic powder with the binder raw materials to obtain the mixture, and

[0177] The above mixture is shaped to obtain Sm-Fe-N magnets.

[0178] Industrial availability

[0179] The magnetic properties of the Sm-Fe-N magnetic materials disclosed herein, especially their good rectangularity, make them suitable for a variety of applications.

[0180] Symbol Explanation

[0181] 1. Regions with high Fe concentration

[0182] 2. Areas with high M1 concentrations

[0183] 3. Areas with high M2 concentrations

[0184] 4. Areas with high C concentrations

Claims

1. A Sm-Fe-N based magnetic material, comprising: M1 is selected from one element among Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W. M2 is an element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W that is different from M1. C。 2. The Sm-Fe-N magnetic material according to claim 1, wherein, M1 is an element selected from Zr, Ti, Hf, V, Nb, and Ta, and M2 is an element selected from Zr, Ti, Hf, V, Nb, and Ta that is different from M1.

3. The Sm-Fe-N magnetic material according to claim 1 or 2, wherein, The ratio of the content of M1 to the content of M2, expressed in atomic percent, is 2:8 to 8:

2.

4. The Sm-Fe-N magnetic material according to any one of claims 1 to 3, wherein, It includes phases M1-M2-C.

5. The Sm-Fe-N magnetic material according to any one of claims 1 to 4, wherein, The major axis of the M1-M2-C phase is less than 30 nm.

6. The Sm-Fe-N magnetic material according to any one of claims 1 to 5, wherein, The content of Sm is 7.0 atomic% to 11.0 atomic%. The Fe content is 69.5 atomic% to 82.0 atomic%. The content of CO is 0 atomic% to 5 atomic%. The nitrogen content is 11.0 atomic% to 19.5 atomic%. The combined content of M1 and M2 is 1.6 atomic% to 5.0 atomic%. The content of C is greater than 0 atomic percent and less than 2.5 atomic percent.

7. The Sm-Fe-N magnetic material according to any one of claims 1 to 6, wherein it is in the form of magnetic powder or a magnet.

8. A Sm-Fe-N magnet comprising the Sm-Fe-N magnetic material and adhesive as described in any one of claims 1 to 7.

9. A method for manufacturing an Sm-Fe alloy, comprising: The steps involve melting, quenching, and solidifying a raw material containing Sm, Fe, one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W (M1), one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W but different from M1 (M2), and C, to obtain an Sm-Fe alloy.

10. A method for manufacturing an Sm-Fe-N based magnetic material, comprising: The step of crystallizing the Sm-Fe alloy manufactured by the manufacturing method of claim 9 to obtain Sm-Fe crystalline material, and The step of nitriding the Sm-Fe crystalline material to obtain the Sm-Fe-N magnetic material.

11. A method for manufacturing an Sm-Fe-N magnet, comprising: The process of obtaining an Sm-Fe quenched solidification alloy involves melting a raw material containing Sm, Fe, one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W (M1), one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W but different from M1 (M2), and C, followed by quenching. The step of performing crystallization treatment on the Sm-Fe rapidly solidified alloy to obtain Sm-Fe crystalline materials is as follows: The step of nitriding the Sm-Fe crystalline material to obtain Sm-Fe-N magnetic powder is as follows: The steps of mixing the Sm-Fe-N magnetic powder with the binder raw materials to obtain the mixture, and... The step of molding the mixture to obtain Sm-Fe-N magnets.

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