Magnetic member, method of manufacturing the same, and powder for lamination molding

Abstract

To provide a magnetic member with high magnetic characteristics having a non-magnetic part.SOLUTION: The present invention relates to a magnetic member comprising a soft-magnetic part consisting of a first iron-based material, a non-magnetic part consisting of a second iron-based material, and an intermediate part consisting of a third iron-based material and made in one body with the soft-magnetic part and the non-magnetic part. The third iron-based material is different in component composition from the first iron-based material and the second iron-based material. The intermediate part is either one of soft-magnetic and non-magnetic, and preferably consists of a columnar crystal of a ferrite single phase. The intermediate part like this is formed on the soft-magnetic part or the non-magnetic part by a lamination molding method such as a directional energy deposition method or a powder bed molten bonding method. The soft-magnetic part and the non-magnetic part also may be lamination-molded together with the intermediate part. A powder used for lamination molding of the intermediate part, for example, is preferably larger in total quantity of ferrite-stabilizing elements than the first iron-based material and smaller in total quantity of austenite-stabilizing elements than the second iron-based material.SELECTED DRAWING: Figure 2C

Description

Technical Field

[0001] The present invention relates to a magnetic member having a soft magnetic portion and a non-magnetic portion, etc.

Background Art

[0002] By providing a non-magnetic (including weakly magnetic and low magnetic) region (non-magnetic portion) in a part of a magnetic member used in a magnetic field, high performance, low loss, high efficiency, etc. of electromagnetic devices can be achieved.

[0003] For example, in the rotor or stator of a magnet-encapsulated motor (motor, generator), a narrow bridge portion or the like on the outer peripheral side of the slot that houses the permanent magnet (magnetizing source) is demagnetized to reduce ineffective magnetic flux that does not contribute to the rotational torque. Descriptions related to such demagnetization are, for example, in the following patent documents.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Non-Patent Documents

[0005]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Patent Document 1 forms a non-magnetic portion by partially removing the ferromagnetic material on the surface layer side from a multi-layer material in which a non-magnetic material is sandwiched between ferromagnetic materials. Patent Document 2 forms a weakly magnetic portion by locally heating a ferromagnetic martensitic stainless steel obtained by annealing. Patent Document 3 combines austenite formation by heating and work-induced martensite formation by cold working to coexist a non-magnetic portion and a ferromagnetic portion. Patent Document 4 forms a non-magnetic portion by embedding a non-magnetic alloy or stainless steel in a part of an electromagnetic steel sheet.

[0007] Non-Patent Document 1 forms a non-magnetic portion by subjecting a Ni-Cr-Fe-B-based alloy to a melting reaction in a part of an electromagnetic steel sheet. Non-Patent Document 2 forms a non-magnetic portion by reacting Cu in a part of an electromagnetic steel sheet.

[0008] None of the documents describe the magnetic properties, component composition, metal structure, etc. near the boundary between the soft magnetic portion (ferromagnetic portion) and the non-magnetic portion. Also, no document has proposed laminating and forming near the boundary between the soft magnetic portion and the non-magnetic portion.

[0009] The present invention has been made in view of such circumstances, and an object thereof is to provide a new magnetic member having a soft magnetic portion and a non-magnetic portion.

Means for Solving the Problems

[0010] As a result of intensive research, the inventor of the present invention conceived of forming a desired intermediate portion between the soft magnetic portion and the non-magnetic portion and succeeded in obtaining a magnetic member capable of exhibiting high characteristics. By developing this result, the present invention described below has been completed.

[0011] 《Magnetic Member》 The present invention includes a soft magnetic portion made of a first iron base material, a non-magnetic portion made of a second iron base material, and an intermediate portion made of a third iron base material integrated with the soft magnetic portion and the non-magnetic portion. The third iron base material has a different component composition from the first iron base material and the second iron base material, and the intermediate portion is a magnetic member that is either soft magnetic or non-magnetic.

[0012] According to the present invention, there is provided a magnetic member in which deterioration of magnetic properties and reduction of mechanical properties caused by, for example, mixing of a soft magnetic phase and a non-magnetic phase and refinement of crystal grains are suppressed in an intermediate portion between a soft magnetic portion and a non-magnetic portion.

[0013] In addition, by interposing the intermediate portion, the degrees of freedom in the form and arrangement of the soft magnetic portion and the non-magnetic portion are expanded, and the degree of freedom in the design of the magnetic member and the magnetic circuit is also increased.

[0014] 《Manufacturing method》 The present invention can also be understood as a method for manufacturing a magnetic member. For example, the present invention may be understood as a method for manufacturing a magnetic member in which an intermediate portion is formed on a soft magnetic portion or a non-magnetic portion by a directed energy deposition (DED) method or a powder bed fusion (PBF) method. The soft magnetic portion and / or the non-magnetic portion may also be laminated and formed by DED or PBF.

[0015] 《Powder for additive manufacturing》 The present invention may also be understood as a powder used for such additive manufacturing. Such a powder for additive manufacturing may be a single type of powder or a mixed powder blended to a desired composition.

[0016] 《Others》 (1) The magnetic member may be entirely additively manufactured, or may be combined with a melted member or a sintered member so that only a part thereof is additively manufactured. The additive manufactured objects referred to in this specification include both. In addition, some additive manufacturing includes modification, repair, build-up, etc.

[0017] Additive manufacturing (AM) that repeats lamination includes, in addition to DED and PBF, binder jetting, material jetting, material extrusion, vat photopolymerization, sheet lamination, and others. These methods can also be used as appropriate. However, for the industrial production of magnetic members made of iron-based materials, DED and PBF are suitable.

[0018] Heat sources for melting the powder (powder for additive manufacturing) used in DED and PBF include laser beams, electron beams, plasma arcs, etc. Laser beams are typical and versatile heat sources. In this specification, mainly L-DED (LMD) and L-PBF using laser beams will be taken up and described.

[0019] (2) Unless otherwise specified, "x to y" as used in this specification includes the lower limit value x and the upper limit value y. Any numerical value included in the various numerical values or numerical ranges described in this specification can be used as a new lower limit value or upper limit value to newly establish a range such as "a to b". Also, "x to y μm" as used in this specification means x μm to y μm. The same applies to other unit systems.

Brief Description of Drawings

[0020]

Figure 1A

Figure 1B

Figure 1C

Figure 1D

Figure 2A

Figure 2B

Figure 2C

Figure 2D

Figure 3A

Figure 3B

Figure 3C

Figure 3D

Figure 4A

Figure 4B

Figure 4C

Figure 4D

Figure 5A

Figure 5B

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0021] One or more components arbitrarily selected from this specification can be added to the components of the present invention. The content described in this specification is applicable not only to magnetic members but also to their manufacturing methods (laminated forming methods), powders for laminated forming, etc. as appropriate.

[0022] 《Soft Magnetic Part》 The first iron base material constituting the soft magnetic part may be pure iron or an iron alloy. The first iron base material may contain ferrite stabilizing elements (Si, Al, Cr, Mo, etc.).

[0023] In particular, Si contributes to suppressing the austenite transformation of the iron base material, promoting high orientation of crystal grains, increasing its electrical resistivity (specific resistance), magnetic properties (permeability), etc. However, when the amount of Si becomes excessive, the iron base material becomes brittle and is prone to cracking and the like.

[0024] Therefore, the first iron base material may contain Si in an amount of, for example, about 1 to 6.5% or 2 to 4% with respect to its entirety (100%). Note that the chemical composition (component composition) referred to in this specification is, unless otherwise specified, the mass ratio with respect to the entirety (100% by mass) of the observation target, and is indicated only by “%” or a numerical value. The composition may be specified in a region where the analysis results by energy dispersive X-ray spectroscopy (EDS) or electron probe micro analyzer (EPMA) are stable (the same applies to other parts).

[0025] 《Non-magnetic part》 The second iron base material constituting the non-magnetic part may contain austenite stabilizing elements (Ni, Mn, Cu, C, etc.). The component composition of the non-magnetic part may be, for example, the component composition (Ni equivalent - Cr equivalent) in which the austenite phase is stably obtained on the Schaeffler diagram. Austenitic stainless steel is a typical second iron base material.

[0026] 《Intermediate part》 The intermediate part is near the boundary between the soft magnetic part and the non-magnetic part and is a region where the component composition is clearly different (changing) from them. The difference (change) in the component composition can be judged, for example, from the analysis results by EDS.

[0027] The intermediate part may exhibit either soft magnetism (ferromagnetism) or non-magnetism (including weak magnetism). By exhibiting one of the characteristics suitable for the specifications of the magnetic member, high performance of the magnetic member can be achieved. In this specification, for the sake of convenience, the intermediate part exhibiting soft magnetism will be mainly described while being exemplified.

[0028] (1) Structure In the case of the soft magnetic intermediate portion, the third iron base material constituting the same may preferably be substantially composed of a ferrite single phase as a whole. At this time, an austenite phase may slightly exist in the vicinity of the interface or in a minute region.

[0029] The intermediate portion (the third iron base material) may preferably be composed of coarse crystal grains (for example, columnar crystals). Although the specific crystal grain size is not limited, for example, the average value of the maximum length of each crystal grain in the visual field may be 200 to 5000 μm.

[0030] Further, each crystal grain may preferably be oriented in the <001> direction of the magnetization easy axis of BCC. It is preferable that such a crystal grain and the metal structure having the orientation are continuous from the soft magnetic portion to the intermediate portion.

[0031] The metal structure is specified based on, for example, an inverse pole figure orientation map (IPF: Inverse Pole Figure) obtained by analysis using an electron backscattered diffraction method (EBSD: Electron Back Scattered Diffraction Pattern). Further, according to EBSD, the metal phase (α phase, γ phase) is also clarified, and it is also possible to know whether the intermediate portion is in a single phase state or a mixed phase state.

[0032] (2) Composition The intermediate portion (the third iron base material) may have any specific component composition as long as it can be distinguished from the soft magnetic portion (the first iron base material) and the non-magnetized portion (the second iron base material). The component composition may be substantially uniform in the intermediate portion, or may change continuously or stepwise (multilayered) between the soft magnetic portion and the non-magnetic portion. The component composition of each portion is specified by obtaining the average value of the concentration change (analysis results of EDS or EPMA) of each element at a plurality of measurement points within the extracted range (section).

[0033] 《Powder for additive manufacturing》 The powder for additive manufacturing of the intermediate portion is not limited by the manufacturing process, particle morphology (shape, size, etc.), etc. The powder may be an atomized powder or a pulverized powder. Further, it may be an alloy powder, a mixed powder, a granulated powder, or the like.

[0034] When laminating and forming a soft magnetic intermediate portion, for example, powder having a total amount of ferrite stabilizing elements larger than that of the first iron base material and a total amount of austenite stabilizing elements smaller than that of the second iron base material may be used. Incidentally, even when using powder with a large amount of ferrite stabilizing elements (such as Si), embrittlement, cracking, etc. are unlikely to occur due to a decrease in the Si concentration by mixing.

[0035] The powder for laminated forming may contain, for example, 1.5 to 8%, 3 to 6% of Si with respect to the whole. It may also contain 0.5 to 3%, 1 to 2% of Al. Further, it may contain modifying elements (for example, Mo, W, Ti, Nb, V) for improving magnetic properties, impurities (C, P, O, N, etc.). The total of such elements is, for example, 2% or less, 1% or less, 0.5% or less, 0.2% or 0.1% or less.

[0036] The powder for laminated forming of the soft magnetic intermediate portion may have its component composition defined using Gibbs free energy. For example, the maximum value (dG BCC ) of the difference (dG = G FCC - G BCC ) between the Gibbs free energy (G FCC ) when it becomes a body-centered cubic lattice (BCC) and the Gibbs free energy (G max ) when it becomes a face-centered cubic lattice (FCC) in the temperature range from the melting point to room temperature is 30 J / mol or less, 20 J / mol or less, 10 J / mol or less, 5 J / mol or less, and further a negative value (less than 0 J / mol), and it is advisable to use powder that can obtain a third iron base material having such a component composition.

[0037] 《Magnetic Member》 The magnetic member constitutes, for example, a yoke (armature) or a core (magnetic core). The yoke and the core are, for example, a rotor or a stator of an electric motor (including a generator), a core for a transformer, etc. The electric motor is, for example, a synchronous motor or a DC motor provided with a permanent magnet, an induction motor or a switched reluctance motor (SR motor) not provided with a permanent magnet, etc.

Example

[0038] Samples (laminated objects) made of ferroalloys (iron-based substrates) were fabricated in various ways by LMD (L-DED), and their component compositions, metal structures (crystal grains, metal phases), properties, etc. were evaluated. The present invention will be described in more detail based on such specific examples.

[0039] 《Fabrication of Samples》 (1) Powders for laminated manufacturing Fe-3Si powder (particle size: 45 - 105 μm), SUS316 powder (Fe-18Cr-12Ni-2.5Mo powder / particle size: 45 - 105 μm), Fe-9Si-7Al powder (particle size: 25 - 105 μm), pure Si powder (particle size: -300 μm), and pure Ni powder (particle size: 74 - 104 μm) were prepared. The component compositions of the alloy powders were shown only by numerical values of mass% with respect to the whole powder (the balance: Fe).

[0040] The particle size was defined by classification (screening) using a mesh. The particle size of x - y (μm) means that the particles do not pass through a sieve with a mesh opening of x (μm) and pass through a sieve with a mesh opening of y (μm). The particle size of -y means that the particles are of a size that passes through a sieve with a mesh opening of y (μm).

[0041] As powders for laminated manufacturing, in addition to using the above-mentioned powders alone as they were, mixed powders (rotary mixed at 45 rpm for 1 hour) obtained by appropriately weighing a plurality of powders and blending them into a desired composition were also used.

[0042] (2) Laminated manufacturing The powders for laminated manufacturing (also referred to as raw material powders) placed in the powder feeder (powder box) of an LMD apparatus (laser processing tester manufactured by Ensyu Co., Ltd.) were supplied to the powder nozzle with a carrier gas (Ar).

[0043] Using the LMD device, a cube (10 mm × 10 mm × 10 mm) sample (additive manufactured object) was fabricated on a substrate (SS400 / 100 × 100 × t10 mm) in a room-temperature air atmosphere. Except for the tensile test specimens described later, the entire sample was fabricated by additive manufacturing. At that time, the lower side (substrate side) was made of a non-magnetic part, and the upper side was made of a soft magnetic part. For Samples 1 to 3, an intermediate part with a raw material powder of a different component composition was also additively manufactured between them.

[0044] The irradiation conditions of the laser (YLS-4000CW manufactured by IPG Corporation) were as follows. For the non-magnetic part (SUS316) and the intermediate part, the laser output was 750 W and the scanning speed was 25 mm / s. For the soft magnetic part (Fe-3Si), the laser output was 950 W and the scanning speed was 40 mm / s.

[0045] Also, for each part, the beam diameter (spot diameter) was 2.0 mm (diameter), the powder supply rate was 0.08 g / s, the scanning pitch (x direction) was 0.5 mm, the layer pitch (z direction / building direction) was 0.3 mm, and the carrier gas (Ar) flow rate was 25 L / min (common conditions).

[0046] The non-magnetic part was laminated 17 times in the Z direction using SUS316 powder. The intermediate part was laminated 2 times in the Z direction on the non-magnetic part using the following powder (referred to as "intermediate powder"). The soft magnetic part was laminated 17 times in the Z direction on the intermediate part using Fe-3Si powder. Sample 1: Fe-6.5Si powder Sample 2: Fe-4.5Si-1.2Al powder Sample 3: Fe-10Cr-4.7Ni-1.5Mo powder

[0047] The intermediate powder of Sample 1 had a composition in which Si (a ferrite-stabilizing element) was increased with respect to the powder (Fe-3Si powder) forming the soft magnetic part. The intermediate powder of Sample 2 had a composition in which Si was increased and Al (a ferrite-stabilizing element) was added with respect to the powder (Fe-3Si powder) forming the soft magnetic part. The intermediate powder of Sample 3 had a composition in which Cr and Ni (austenite-stabilizing elements) were decreased and Mo (a ferrite-stabilizing element) was increased with respect to the powder (SUS316 powder) forming the non-magnetic part.

[0048] Different from Samples 1 to 3 in which the intermediate part was separately shaped, Sample C was also fabricated in which the soft magnetic part (number of laminations 17) was directly laminated after the non-magnetic part (number of laminations 17). That is, in Sample C, the laminated shaping using the intermediate powder was not performed.

[0049] 《Observation, Measurement, Analysis》 Observation, measurement, and analysis were performed in the vicinity of the intermediate part (near the intermediate part) between the non-magnetic part and the soft magnetic part. The results for Samples 1 to 3 and C are shown in FIGS. 1A to 4D (Sample 1: FIG. 1, Sample 2: FIG. 2, Sample 3: FIG. 3, Sample C: FIG. 4), respectively. Specifically, it is as follows.

[0050] (1) Observation Observation images (SEM images) obtained by a scanning electron microscope are shown in FIGS. 1A, 2A, 3A, and 4A, respectively.

[0051] (2) Component Composition Using an energy dispersive X-ray analyzer (EDS), the vicinity (substantially the center) of the intermediate part of each sample was linearly measured. The component compositions of each sample are shown in FIGS. 1B, 2B, 3B, and 4B, respectively. The component compositions of representative regions in the intermediate part of each sample are exemplified in Table 1. In Table 1, the measurement location m is a region on the soft magnetic part side, and the measurement location n is a region on the non-magnetic part side.

[0052] (3) Metallic Structure (Grains) The microstructure (crystalline grains) of each part was analyzed using an electron backscatter diffraction device (EBSD: MSC-2200 manufactured by TSL Solutions Co., Ltd.). The inverse pole figure orientation maps (IPF) of each sample are shown in FIGS. 1C, 2C, 3C, and 4C, respectively. Also, based on the IPF, the morphology of the crystalline grains at the measurement locations m and n in the middle part described above was specified. The results are also shown in Table 1.

[0053] (4) Crystal structure The crystal structure (phase) of each part was analyzed by EBSD. The phase distribution maps of each sample are shown in FIGS. 1D, 2D, 3D, and 4D, respectively.

[0054] 《Properties》 (1) Magnetic domain For Sample 2 and Sample C, the magnetic domains on the surface near the middle part were observed with a Kerr effect microscope. The obtained magnetic domain images are shown in FIGS. 5A and 6, respectively. Also, the magnetic domain image of the soft magnetic part of Sample 2 observed in the same way is shown in FIG. 5B. Along with each magnetic domain image, the IPF and phase distribution map are also shown.

[0055] The magnetic domain image obtained by the Kerr effect microscope shows the change of the magnetic domain by shading (magnetic domain contrast). The more the dark regions are, the faster the change of the magnetic domain with respect to the magnetic field change, and the better the soft magnetic property. Also, considering the presence or absence of the <001> orientation understood from the IPF, the soft magnetic characteristics of the middle part can also be evaluated.

[0056] (2) Hardness For Sample 2 and Sample C, the Vickers hardness at multiple locations around the middle part was measured. The hardness distribution obtained thereby is also shown in FIG. 7.

[0057] (3) Tensile strength The influence on the strength by LMD was investigated as follows. As shown in FIG. 8, a test piece in which a non-magnetic part (SUS316) of substantially the same shape was laminated and formed by LMD on a soft magnetic part (Fe-3Si-0.6Al / φ12 mm × 40 mm) made of a round bar (melted material) was subjected to a tensile test, and the tensile strength of the whole and each part was measured.

[0058] The yield strength (0.2%) of the round bar itself was 419 MPa, and that of the shaped part was 314 MPa. The overall tensile strength was 528 MPa, and its elongation at break was 25%. Fracture (breakage) occurred on the round bar (base material) side. From this, it was confirmed that even when a non-magnetic part was formed by laminated molding on the soft magnetic part, sufficiently high tensile strength and bonding strength could be ensured.

[0059] 《Gibbs Free Energy》 Based on the component compositions shown in Table 1, the Gibbs free energy (G) of the crystal structures (BCC, FCC) at the measurement points m and n in the intermediate part was calculated using other-element system thermodynamics analysis software (Thermo-Calc, database TCFE7). The free energy was calculated and evaluated in the temperature range from the melting point to room temperature (especially 1500 °C (immediately below the melting point) to 900 °C). Specifically, it is as follows.

[0060] At each temperature, the free energy (G BCC ) when it becomes BCC (ferrite phase / α phase) and the free energy (G FCC ) when it becomes FCC (austenite phase / γ phase) were calculated. The maximum value (dG max ) of the difference (dG) between them was obtained. The obtained results were shown together with Table 1. The smaller dG max (and the more negative it is), the more the phase transformation (ferrite phase ⇔ austenite phase) is suppressed, and the ferrite phase (BCC) becomes stable.

[0061] 《Evaluation》 From the above-described content, the following was found regarding the intermediate part between the soft magnetic part and the non-magnetic part.

[0062] (1) Component composition As can be seen from FIGS. 1B, 2B, 3B, and 4B, regardless of the presence or absence of laminated molding using the intermediate powder, an intermediate part having a component composition different from those of the soft magnetic part and the non-magnetic part was formed between the soft magnetic part and the non-magnetic part. Here, the intermediate part is a region where the component composition (especially the amounts of Fe, Si, Ni, and Cr) clearly changes with respect to the soft magnetic part and the non-magnetic part, based on the analysis results by EDS.

[0063] In the middle part, the component composition was not uniform overall but changed in multiple stages (layers). Specifically, the component composition of the middle part changed stepwise to such an extent that it could be divided into 3 layers for Sample 1, 2 layers for Sample 2, 7 layers for Sample 3, and 4 layers for Sample C. Note that when observed for each layer (within one layer), the component composition was stable.

[0064] From these, it was found that in the case of laminated manufacturing (metal 3D printing) involving melting and solidification of raw material powder, it is difficult to form a region (middle part, boundary layer) with a substantially constant component composition between the soft magnetic part and the non-magnetic part.

[0065] (2) Crystal grains As can be seen from FIGS. 1C, 2C, 3C, and 4C, a region of crystal grain refinement was observed in the middle parts of Samples 1, 3, and C, but not in the middle part of Sample 2. The middle part of Sample 2 was composed of overall coarse columnar crystals and had the same metal structure as the soft magnetic part. Also, there was no substantial boundary between the metal structure of Sample 2's soft magnetic part and its middle part, and the metal structures of both were smoothly continuous. Thus, it was found that it is possible to form a middle part composed of the same metal structure (crystal grains) as the soft magnetic part.

[0066] Note that the crystal grain refinement region mainly consisted of equiaxed crystals, had a larger coercive force (smaller magnetic permeability) than the soft magnetic part composed of coarse columnar crystals, and reduced or deteriorated the magnetic properties (soft magnetism). Incidentally, the crystal grain refinement regions of Sample 3 and Sample C were in a two-layer state, while the crystal grain refinement region of Sample 1 was in a relatively thin single-layer state.

[0067] (3) Crystal structure (metal phase) As can be seen from FIGS. 1D, 2D, 3D, and 4D, a mixed-phase structure in which BCC (ferrite (α) phase / soft magnetic phase) and FCC (austenite (γ) phase / non-magnetic phase) coexist was observed in the middle portions of Sample 3 and Sample C. On the other hand, such a mixed-phase structure was not observed in the middle portions of Samples 1 and 2, and at the boundary between the middle portion and the non-magnetic portion, BCC and FCC changed clearly. Thus, it was found that it is possible to form a middle portion having the same crystal structure (BCC) as the soft magnetic portion.

[0068] From the above, it was found that even if a compositional boundary (layer) cannot be formed between the soft magnetic portion and the non-magnetic portion, a boundary (layer) in which the metal structure (crystal grains, phases) and thus the magnetic properties change clearly can be formed in the laminated molded object.

[0069] (4) Magnetic domain The following can be understood from FIGS. 5A, 5B, and 6. As is clear from FIG. 5A, in the middle portion of Sample 2, there were many dark regions (for example, Region C) in the magnetic domain image. These are regions where the magnetic domain change progresses rapidly.

[0070] It was also found from the EBSD analysis results (phase distribution, IPF) that such regions are composed of coarse columnar crystals oriented in <001> in the BCC single phase. As can also be seen from the comparison between FIGS. 5A and 5B, such a middle portion is similar to the soft magnetic portion (Region D, especially Region E) and exhibits high soft magnetic properties.

[0071] As is clear from FIG. 6, in the middle portion of Sample C, there was also a portion composed of coarse columnar crystals (BCC single phase) oriented in <001>, similar to the soft magnetic portion. However, in the middle portion of Sample C, there were also many regions (for example, Region B) where the magnetic domain change was slow and fine. Such regions are composed of very fine crystal grains having a random orientation although they are composed of BCC, and have poor soft magnetic properties. Therefore, Sample C cannot exhibit high magnetic properties like Sample 2.

[0072] Therefore, it was found that by interposing an appropriate middle portion, a boundary (layer) where the magnetic properties (soft magnetism and non-magnetism) change abruptly can also be formed in the laminated molded object.

[0073] (5) Hardness As is clear from FIG. 7, the hardnesses of the soft magnetic portion, the intermediate portion, and the non-magnetic portion were at the same level. That is, no abrupt change in hardness was observed between the respective portions.

[0074] (6) Gibbs free energy As can be seen from Table 1, in the intermediate portion where the Gibbs free energy difference (dG max ) is small, the ferrite phase is stabilized and the phase transformation to the austenite phase is suppressed, so it was columnar crystal (BCC). Conversely, when such an intermediate portion is laminated and formed, an intermediate powder with a small dG max can be used.

[0075] From the above, it was confirmed that a magnetic member exhibiting excellent soft magnetism as a whole can be obtained by laminating and forming an appropriate intermediate portion between the soft magnetic portion and the non-magnetic portion.

[0076]

Table 1

Claims

1. A soft magnetic part made of a first iron base material, a non-magnetic part made of a second iron base material, and an intermediate part made of a third iron base material and integrated with the soft magnetic part and the non-magnetic part, wherein the third iron base material has a different component composition from the first iron base material and the second iron base material, and the intermediate part is a magnetic member that is either soft magnetic or non-magnetic.

2. The magnetic member according to claim 1, wherein the intermediate part is composed of a ferrite single phase.

3. The magnetic member according to claim 2, wherein the intermediate part is composed of columnar crystals.

4. The magnetic member according to claim 1, wherein the intermediate part is a laminated molded article.

5. The third iron-based substrate has a maximum value (dG BCC ), in a temperature range from the melting point to room temperature, of the difference (dG = G FCC −G BCC ) between the Gibbs free energy (G FCC ) when it becomes a body-centered cubic lattice (BCC) and the Gibbs free energy (G max ) when it becomes a face-centered cubic lattice (FCC) of 30 J / mol or less, and the magnetic member according to any one of claims 1 to 4 having a component composition.

6. A method for manufacturing the magnetic member according to claim 1, wherein the intermediate part is a method for manufacturing a magnetic member formed on the soft magnetic part or the non-magnetic part by a directed energy deposition method or a powder bed fusion bonding method.

7. In the method for manufacturing a magnetic member according to claim 6, a powder for laminated molding used for laminated molding of the intermediate part.

8. The powder for laminated molding according to claim 7, having a composition in which the total amount of ferrite stabilizing elements is larger than that of the first iron base material and the total amount of austenite stabilizing elements is smaller than that of the second iron base material.

9. The powder for laminated molding according to claim 7 or 8, containing 1.5 to 8% by mass of Si with respect to the entire powder.

10. The powder for laminated molding according to claim 7 or 8, containing 0.5 to 3% by mass of Al with respect to the entire powder.

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