Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/14—Treatment of metallic powder
  • B22F1/142—Thermal or thermo-mechanical treatment
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/10—Sintering only
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C33/00—Making ferrous alloys
  • C22C33/02—Making ferrous alloys by powder metallurgy
  • C22C33/0257—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements
  • C22C33/0278—Making ferrous alloys by powder metallurgy characterised by the range of the alloying elements with at least one alloying element having a minimum content above 5%
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
  • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
  • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
  • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
  • H01F1/032—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials
  • H01F1/04—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of hard-magnetic materials metals or alloys
  • H01F1/047—Alloys characterised by their composition
  • H01F1/053—Alloys characterised by their composition containing rare earth metals
  • H01F1/055—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5
  • H01F1/059—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and Va elements, e.g. Sm2Fe17N2
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/14—Treatment of metallic powder
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/22—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip
  • B22F3/225—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces for producing castings from a slip by injection molding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/02—Making metallic powder or suspensions thereof using physical processes
  • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling

Definitions

• This disclosure relates to magnetic materials and magnets, as well as methods for manufacturing rapidly solidified alloys, magnetic materials, and magnets.
• Rare earth magnets have a high magnetic flux density and can be made into extremely powerful permanent magnets, and are used in a variety of applications.
• One type of rare earth magnet known is the Sm-Fe-N magnet.
• Sm-Fe-N magnets are typically manufactured by nitriding Sm-Fe polycrystals. When N atoms are dissolved in the crystal lattice of Sm-Fe polycrystals, the lattice becomes distorted and uniaxial magnetic anisotropy is expressed. The resulting Sm-Fe-N magnetic material is thought to be capable of functioning as a hard magnetic material.
• Patent Document 1 describes that a flake-shaped isotropic Sm-Fe-N powder magnet material is produced by nitriding a powder of a magnet alloy obtained by a roll quenching method, and that the material has a composition consisting of Sm x Fe 100-x-v N v , Sm x Fe 100-x-y-v M 1 y N v , or Sm x Fe 100-xzv M 2 z N v (wherein M 1 is Hf or Zr, M 2 is one or more selected from Si, Nb, Ti, Ga, Al, Ta and C, 7 ⁇ x ⁇ 12, 0.5 ⁇ v ⁇ 20, 0.1 ⁇ y ⁇ 1.5, and 0.1 ⁇ z ⁇ 1.0) in atomic %, a TbCu type crystal structure, and a flake thickness of 10 to 30 ⁇ m.
• Patent Document 2 describes a rare earth permanent magnet material as an Sm-Fe-N based magnetic material, whose composition, expressed in atomic percent, is represented by Sm x R a Fe 100-x-y-za M y N z (wherein 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%).
• 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 0% to 5%
• z is 10% to 14%).
• Patent Document 1 describes the use of one metal element in addition to Sm, Fe, and N in an Sm-Fe-N magnetic material
• Patent Document 2 describes the use of two metal elements in addition to Sm, Fe, and N in an Sm-Fe-N magnetic material.
• the purpose of this disclosure is to provide an Sm-Fe-N magnetic material with good magnetic properties, particularly squareness ratio, and a method for manufacturing the same.
• the purpose of this disclosure is also to provide a magnet that includes such an Sm-Fe-N magnetic material and a method for manufacturing the same.
• the Sm—Fe—N based magnetic material of the present disclosure is M1 is one element selected from 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, and is one element different from M1; C.
• This disclosure can provide an Sm-Fe-N magnetic material with good magnetic properties, particularly squareness ratio, and a method for manufacturing the same.
• This disclosure can also provide a magnet that includes such an Sm-Fe-N magnetic material and a method for manufacturing the same.
• Example 1 shows the results of STEM-EDX analysis of the Sm—Fe—N based magnetic material obtained in Example 1, in which DF-I is a dark-field image, and Fe, Zr, Nb and C are mapping images (element distribution images) showing the concentration distribution of each element.
• Example 1 shows the results of STEM-EDX analysis of the Sm—Fe—N based magnetic material obtained in Comparative Example 1, in which DF-I is a dark-field image, and Fe, Zr and C are mapping images (element distribution images) showing the concentration distribution of each element.
• FIG. 6 shows the results of STEM-EDX analysis of the Sm—Fe—N based magnetic material obtained in Comparative Example 2, in which DF-I is a dark-field image, and Fe, Nb and C are mapping images (element distribution images) showing the concentration distribution of each element.
• FIG. 2 is a schematic diagram showing the concentration distributions of Fe, M1, M2 and C in a Sm—Fe—N based magnetic material according to one aspect of the first embodiment.
• the Sm—Fe—N based magnetic material of the present disclosure is M1 is one element selected from 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, and is one element different from M1; C.
• the Sm-Fe-N magnetic material disclosed herein has the above-mentioned configuration and therefore has good magnetic properties, particularly the squareness ratio. Although it should not be interpreted as being limited to a specific theory, the reason why the Sm-Fe-N magnetic material disclosed herein exhibits the above-mentioned effects is thought to be as follows.
• a metal element such as Zr when added to an Sm-Fe-N magnetic material, amorphization can be promoted during the manufacturing process of the Sm-Fe-N magnetic material, and it is believed that in the final Sm-Fe-N magnetic material, the main phase precipitates finely and uniformly, improving the magnetic properties.
• a metal element such as Zr when added, for example, a heterogeneous phase of Fe-Zr precipitates, and this heterogeneous phase is thought to reduce the magnetic properties, particularly the squareness ratio.
• the main phase precipitates finely and uniformly, and the non-magnetic M1-M2-C phase precipitates preferentially.
• the precipitation of the Fe-M1 and Fe-M2 phases is suppressed, and it is believed that a Sm-Fe-N magnetic material with good magnetic properties, especially squareness ratio, can be obtained.
• the Sm-Fe-N magnetic material includes M1, which is one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W, and M2, which is one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W and is different from M1.
• M1 and M2 allow the precipitation of the M1-M2-C phase, suppressing the precipitation of the heterogeneous phase of Fe-M1 or Fe-M2, resulting in an Sm-Fe-N magnetic material with good magnetic properties, especially squareness ratio.
• M1 is an element selected from Zr, Ti, Hf, V, Nb, and Ta
• M2 is an element selected from Zr, Ti, Hf, V, Nb, and Ta, and may be an atom different from M1.
• M1 is an element selected from Zr, Hf, V, Nb, and Ta
• M2 is an element selected from Zr, Hf, V, Nb, and Ta, and may be an element different from M1.
• the ratio of the M1 content to the M2 content may be, on an atomic percent basis, preferably 2:8 to 8:2, more preferably 3:7 to 7:3, and even more preferably 4:6 to 6:4.
• the ratio of the M1 and M2 contents is within this range, the precipitation of the Fe-M1-M2 phase can be promoted, and the squareness ratio of the Sm-Fe-N magnetic material can be improved.
• the total content of M1 and M2 in the Sm-Fe-N magnetic material may be, out of a total of 100 atomic percent of the elements contained in the Sm-Fe-N magnetic material, 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.
• the squareness ratio of the Sm-Fe-N magnetic material may be improved.
• the above Sm-Fe-N magnetic material contains C.
• the non-magnetic M1-M2-C phase precipitates, which can improve the magnetic properties of the Sm-Fe-N magnetic material, especially the squareness ratio.
• the C content is preferably more than 0 atomic % and not more than 2.5 atomic %, more preferably 0.1 atomic % to 2.3 atomic %, and even more preferably 0.1 atomic % to 2.2 atomic %, out of a total of 100 atomic % of the elements contained in the Sm-Fe-N magnetic material.
• the C content in the Sm-Fe-N magnetic material is within the above range, the squareness ratio of the Sm-Fe-N magnetic material can be improved.
• the Sm content is preferably 7.0 atomic % or more and 11.0 atomic % or less, more preferably 7.5 atomic % or more and 10.5 atomic % or less, and more preferably 7.5 atomic % or more and 10.0 atomic % or less, based on a total of 100 atomic % of the elements contained in the Sm-Fe-N magnetic material.
• the squareness ratio of the Sm-Fe-N magnetic material can be further improved.
• the Fe content is preferably 69.5 atomic % or more and 82.0 atomic % or less, more preferably 70.0 atomic % or more and 80.0 atomic % or less, and even more preferably 71.0 atomic % or more and 78.0 atomic % or less, out of a total of 100 atomic % of the elements contained in the Sm-Fe-N magnetic material.
• the Fe content in the Sm-Fe-N magnetic powder is within this range, the squareness ratio of the Sm-Fe-N magnetic material can be improved.
• the ratio of the Fe content to the Sm content is, on an atomic basis, preferably 5 to 10, more preferably 7 to 9.5, and even more preferably 8 to 9.
• the ratio of the Fe content to the Sm content in the Sm-Fe-N magnetic material is within this range, the squareness ratio of the Sm-Fe-N magnetic material can be improved.
• the total content of Sm and Fe is, out of a total of 100 atomic percent of the Sm-Fe-N magnetic powder, preferably 66.5 atomic percent or more and 96.5 atomic percent or less, more preferably 68.5 atomic percent or more and 90.0 atomic percent or less, and even more preferably 70.0 atomic percent or more and 86.0 atomic percent or less.
• the total content of Sm and Fe in the Sm-Fe-N magnetic material is within this range, the squareness ratio of the Sm-Fe-N magnetic material can be improved.
• the N content is preferably 12.0 atomic % or more and 18.0 atomic % or less, more preferably 12.5 atomic % or more and 17.0 atomic % or less, and more preferably 13.0 atomic % or more and 16.5 atomic % or less, out of a total of 100 atomic % which is the ratio of the Fe content to the Sm content.
• the N content in the Sm-Fe-N magnetic material is within this range, the squareness ratio of the Sm-Fe-N magnetic material can be improved.
• the Sm-Fe-N magnetic material may further contain Co.
• the Co content is preferably 0.0 atomic % or more and 5.0 atomic % or less, and in one embodiment, more preferably 1.0 atomic % or more and 5.0 atomic % or less, and even more preferably 1.5 atomic % or more and 5.0 atomic % or less, out of a total of 100 atomic % of the elements contained in the main phase.
• the Co content in the Sm-Fe-N magnetic material is within the above range, the squareness ratio of the Sm-Fe-N magnetic material can be improved.
• the Co content in the Sm-Fe-N magnetic material is more preferably 0.0 atomic % or more and 5 atomic % or less, more preferably 0.0 atomic % or more and 2.0 atomic % or less.
• the squareness ratio of the Sm-Fe-N magnetic material can be improved.
• the Sm-Fe-N magnetic material may contain Al, Si, Mn, and O as inevitable impurities.
• the content of Al may be, for example, 10.0 atomic % or less, or even 5.0 atomic % or less, based on the total 100 atomic % of the elements contained in the Sm-Fe-N magnetic material.
• the content of Si may be, for example, 10.0 atomic % or less, or even 5.0 atomic % or less, based on the total 100 atomic % of the elements contained in the Sm-Fe-N magnetic material.
• the content of Mn may be, for example, 10.0 atomic % or less, or even 5.0 atomic % or less, based on the total 100 atomic % of the elements contained in the Sm-Fe-N magnetic material.
• the Sm-Fe-N magnetic material contains O
• the O content may be, for example, 10.0 atomic % or less, or even 5.0 atomic % or less, based on a total of 100 atomic % of the elements contained in the Sm-Fe-N magnetic material.
• the total content of each element in Sm-Fe-N magnetic materials does not exceed 100 atomic %.
• the total content of all elements that can be contained in Sm-Fe-N magnetic materials theoretically equals 100 atomic %.
• the types and contents of elements other than C, N, and O that may be contained in Sm-Fe-N magnetic materials can be measured by X-ray fluorescence analysis (XRF) or inductively coupled plasma atomic emission spectrometry (ICP-AES), and preferably by X-ray fluorescence analysis (XFR).
• XRF X-ray fluorescence analysis
• ICP-AES inductively coupled plasma atomic emission spectrometry
• XFR X-ray fluorescence analysis
• C can be measured by oxygen flow combustion-infrared absorption method
• N and O can be measured by inert gas fusion-thermal conductivity method (TCD).
• the main phase is made of Sm-Fe-N crystal grains.
• the Sm-Fe-N crystal grains have a structure in which N atoms are dissolved in the crystal lattice of Sm-Fe crystals.
• the main phase is a region in the Sm-Fe-N magnetic material that can contribute to the exertion of magnetism, and the solid solution of N atoms applies distortion to the crystal lattice, resulting in the appearance of uniaxial magnetic anisotropy, allowing the material to function as a hard magnetic material.
• the main phase preferably contains at least one type selected from Sm-Fe-N crystals exhibiting a Th 2 Zn 17 type structure and Sm-Fe-N crystals exhibiting a TbCu 7 type structure.
• the main phase contains at least Sm, Fe, and N.
• the main phase also includes M1, which is one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W; M2, which is one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W and different from M1; and C.
• the main phase may further contain Co.
• the crystallite diameter of the Sm-Fe-N crystal grains contained in the main phase is preferably 10 nm or more and 1 ⁇ m or less, more preferably 15 nm or more and 400 nm or less, and even more preferably 20 nm or more and 200 nm or less.
• the Sm-Fe-N crystal grains can typically exist as single crystals. In this disclosure, the crystallite diameter can be measured directly from an image of a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM).
• the grain boundary phase exists between a plurality of Sm-Fe-N crystal grains constituting the main phase.
• the grain boundary phase may typically be a layer covering the Sm-Fe-N crystal grains, and may exist as a continuous layer separating the plurality of Sm-Fe-N crystal grains.
• the grain boundary phase may typically be a non-magnetic phase. Since the grain boundary phase is a non-magnetic phase, the magnetic domains of the main phase are separated by the grain boundary phase, so that magnetic field reversal is suppressed and remanent magnetization can be increased, resulting in an increased squareness ratio.
• the 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.
• the grain boundary phase may be a region in which a measured value having a higher N content than the Sm-Fe-N crystal grain phase is measured continuously for 2 nm or more in STEM-EDX analysis.
• the thickness of the grain boundary phase is preferably 2 nm or more and 8 nm or less, and more preferably 4 nm or more and 6 nm or less.
• the Sm-Fe-N magnetic material of the present disclosure preferably contains an M1-M2-C phase.
• M1-M2-C phase By containing the M1-M2-C phase, the precipitation of different phases such as Fe-M1 and Fe-M2 can be suppressed. This can result in a Sm-Fe-N based magnetic material with excellent magnetic properties, particularly squareness ratio.
• the shapes of the regions other than region 1 where the distribution concentration of Fe is high are consistent with those of region 2 where the distribution concentration of M1 is high, region 3 where the distribution concentration of M2 is high and region 4 where the distribution concentration of C is high. From this, it can be said that the M1-M2-C phase exists in the region where regions 2, 3 and 4 overlap.
• the presence of the M1-M2-C phase can be confirmed by energy dispersive X-ray analysis (STEM-EDX) using a scanning transmission electron microscope.
• STEM-EDX energy dispersive X-ray analysis
• the Sm-Fe-N magnetic material is observed with a scanning transmission electron microscope (STEM), and element distribution images of Fe, M1, M2, and C are obtained by energy dispersive X-ray analysis (EDX) in a field of view (e.g., 522 ⁇ 522 nm 2 ) including a plurality of main phases and grain boundary phases, and the distribution of each element is compared.
• EDX energy dispersive X-ray analysis
• a sample for STEM-EDX analysis of the Sm-Fe-N magnetic material may be processed, for example, by a focused ion beam device (FIB).
• FIB focused ion beam device
• the M1-M2-C phase may be distributed throughout the Sm-Fe-N magnetic material, and may be present, for example, in the main phase (i.e., in the region surrounded by the main phase), in the grain boundary phase (i.e., in the region surrounded by the grain boundary phase), or between the main phase and the grain boundary phase.
• the major axis of the M1-M2-C phase is preferably 1 nm or more and 30 nm or less, more preferably 3 nm or more and 25 nm or less, and even more preferably 5 nm or more and 25 nm or less, but is not limited to this.
• the major axis of the M1-M2-C phase can be confirmed by energy dispersive X-ray analysis using a scanning transmission electron microscope (STEM-EDX).
• STEM-EDX scanning transmission electron microscope
• the Sm-Fe-N magnetic material is observed with a scanning transmission electron microscope (STEM), and an element distribution image of Fe, M1, M2, and C is obtained by energy dispersive X-ray analysis (EDX) in a field of view (e.g., 522 ⁇ 522 nm 2 ) including a plurality of main phases and grain boundary phases, and the major axis of the region with low Fe distribution density is measured at 10 or more points, and the average value thereof may be regarded as the major axis of the M1-M2-C phase.
• a field of view e.g., 522 ⁇ 522 nm 2
• the major axis of the region with low Fe distribution density is measured at 10 or more points, and the average value thereof may be regarded as the major axis of the
• the major axis of a region refers to the length of the longest line segment that passes through the region and is separated by the boundary of the region.
• the Sm-Fe-N magnetic material of the present disclosure may contain other heterogeneous phases in addition to the main phase, grain boundary phase, and M1-M2-C phase.
• the Sm-Fe-N magnetic material may be a material containing the main phase and grain boundary phase, and in a preferred embodiment, a material containing the main phase, grain boundary phase, and M1-M2 phase, preferably a material containing the main phase, grain boundary phase, and M1-M2-C phase, and a heterogeneous phase that may be included (which may typically be different from the Fe-M1 phase and Fe-M2 phase), and more preferably a material consisting of the main phase, grain boundary phase, and M1-M2-C phase, and a heterogeneous phase that may be included.
• the Sm-Fe-N magnetic material disclosed herein can be in the form of magnetic powder, magnets, etc.
• the Sm-Fe-N magnetic material may be in the form of magnetic powder (i.e., powder).
• the Sm-Fe-N magnetic material in the form of powder is also referred to as "Sm-Fe-N magnetic powder.”
• the Sm-Fe-N magnetic powder includes the main phase and the grain boundary phase, and in a preferred embodiment, is a material including the main phase, grain boundary phase, and M1-M2 phase, and is preferably a powder material including the main phase, grain boundary phase, and M1-M2-C phase, and a heterogeneous phase that may be included, and more preferably a material including the main phase, grain boundary phase, and M1-M2-C phase, and a heterogeneous phase that may be included, or a powder material including a heterogeneous phase that may be included.
• the Sm-Fe-N magnetic powder includes Sm, Fe, and N.
• the average particle size of the Sm-Fe-N magnetic powder is preferably 10 ⁇ m or more and 300 ⁇ m or less, more preferably 10 ⁇ m or more and 50 ⁇ m or less, and even more preferably 20 ⁇ m or more and 40 ⁇ m or less.
• the average particle size of the above Sm-Fe-N magnetic powder can be measured using a laser diffraction particle size distribution measurement method.
• the Sm-Fe-N magnetic material may be in the form of a magnet (i.e., bulk).
• the Sm-Fe-N magnetic material in bulk form will also be referred to as an "Sm-Fe-N magnet.”
• the Sm-Fe-N magnet preferably includes the Sm-Fe-N magnetic powder and a binder.
• the binder can act as a binder for the Sm-FeN magnetic powder, and typically includes resin (plastic), rubber, and metals such as Zn.
• the content of Sm-Fe-N magnetic powder contained in the Sm-FeN magnet may be preferably 90% by mass or more and 99.5% by mass or less, and more preferably 95% by mass or more and 99% by mass or less.
• examples of the resin include thermosetting resins such as epoxy resins, phenolic resins, allyl resins, and unsaturated polyester resins; and thermoplastic resins such as polyamide resins, polyphenylene sulfide resins, polyether ketone resins, polyether ether ketone resins, and polyester resins.
• thermosetting resins such as epoxy resins, phenolic resins, allyl resins, and unsaturated polyester resins
• thermoplastic resins such as polyamide resins, polyphenylene sulfide resins, polyether ketone resins, polyether ether ketone resins, and polyester resins.
• the Sm-Fe-N magnet may contain other additives in addition to the Sm-Fe-N magnetic powder and resin.
• the Sm-Fe-N magnet may be a bulk magnet material that preferably includes the main phase and the grain boundary phase, and optionally includes a heterogeneous phase, and preferably includes the main phase and the grain boundary phase, and optionally includes a heterogeneous phase.
• the method for producing a Sm—Fe based alloy according to the present disclosure includes the steps of: The method includes melting a raw material (hereinafter also simply referred to as "metal raw material") containing Sm; Fe; M1 which is one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W; M2 which is one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W and different from M1; and C, followed by rapid cooling and solidification to obtain a Sm-Fe alloy.
• metal raw material hereinafter also simply referred to as "metal raw material”
• M1 which is one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W
• M2 which is one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W and different from M1
• C followed by rapid cooling and solidification to obtain a Sm-Fe alloy.
• the manufacturing method disclosed herein can produce an Sm-Fe alloy in which Sm, M1, M2 and C are uniformly distributed, and can provide the raw material for the Sm-Fe-N magnetic material.
• the types and proportions of elements contained in the metal raw materials are the same as the types and proportions of elements constituting the Sm-Fe-N magnetic material.
• each element By melting the metal raw materials, each element can be uniformly distributed in the melt.
• the temperature when melting the metal is preferably, for example, 1,200°C or higher and 1,700°C or lower.
• the atmosphere when melting the metal is preferably, for example, an inert atmosphere that does not contain nitrogen, such as an Ar atmosphere or a He atmosphere. Such melting is not particularly limited, but is preferably performed by high-frequency melting.
• the metal raw materials may be mixed before melting.
• the melt By rapidly cooling the melt, the melt can be cooled below the freezing point without crystallizing and while maintaining the uniformity of its composition, resulting in a Sm-Fe alloy.
• a Sm-Fe alloy typically contains an amorphous phase.
• the above quenching is not particularly limited, but is preferably performed by roll quenching.
• roll quenching the molten material is quenched by spraying it onto a rotating metal roll.
• the conditions for roll quenching are not particularly limited.
• the metal roll it is preferable to use a roll made of, for example, molybdenum, copper, or an alloy material having these as its main components.
• the peripheral speed of the roll can be, for example, preferably 30 m/s or more and 100 m/s or less, more preferably 50 m/s or more and 90 m/s or less.
• the method for producing the Sm—Fe—N based magnetic material includes the steps of: (a) crystallizing a Sm—Fe based alloy to obtain a Sm—Fe based crystalline material; and (b) nitriding the Sm—Fe-based crystalline material to obtain a Sm—Fe—N-based magnetic material; The method may further include (c) heat treating the Sm-Fe-N based magnetic material.
• the manufacturing method disclosed herein can provide Sm-Fe-N magnetic materials with good magnetic properties, particularly squareness ratio.
• the temperature when the Sm-Fe alloy is heated may be, for example, preferably 690°C or higher and 800°C or lower, more preferably 725°C or higher and 785°C or lower.
• the heating time when the Sm-Fe alloy is heated may be, for example, 5 minutes or higher and 60 minutes or lower, preferably 5 minutes or higher and 30 minutes or lower.
• the atmosphere when the Sm-Fe non-alloy is heated may be, for example, an inert atmosphere that does not contain nitrogen, such as an Ar atmosphere or a He atmosphere.
• the Sm-Fe crystalline material may be further pulverized.
• pulverization By pulverization, a powdered Sm-Fe crystalline material is obtained.
• the pulverization method is not particularly limited, but it can be performed, for example, by a crusher, a stamp mill, a ball mill, etc.
• the Sm-Fe crystalline material is pulverized, for example, to 10 to 300 ⁇ m, preferably 10 to 150 ⁇ m, and more preferably 30 to 80 ⁇ m.
• the nitriding process can typically be carried out by heat treatment in a nitrogen atmosphere, an ammonia atmosphere, a hydrogen atmosphere, or a mixture of these.
• the partial pressure of nitrogen is 10 kPa or more and 100 kPa or less, preferably 50 kPa or more and 100 kPa or less.
• the partial pressure of ammonia is 20 kPa or more and 40 kPa or less, preferably 25 kPa or more and 33 kPa or less, when the total pressure of the mixed gas is 0.1 MPa.
• the heating temperature is preferably 350°C or higher and 500°C or lower, and more preferably 400°C or higher and 500°C or lower. By using this heating temperature, it is possible to prevent decomposition into SmN and Fe that may occur when the nitriding reaction is performed at a higher temperature, and the reaction can proceed more sufficiently compared to when the nitriding reaction is performed at a lower temperature.
• the above nitriding process is typically carried out under atmospheric pressure, for example, preferably at a pressure of 900 hPa or more and 1,100 hPa or less, more preferably at a pressure of 950 hPa or more and 1,050 hPa or less.
• the heating time is preferably 2 hours or more and 30 hours or less, more preferably 8 hours or more and 25 hours or less.
• this heating time it is possible to prevent grain growth and decomposition into SmN and Fe that may occur when the heating time is longer, and the reaction can proceed more fully than when the heating time is shorter.
• this heating time it is possible to adjust the amount of nitrogen incorporated into the Sm-Fe crystalline material.
• the heating time is preferably 10 minutes or more and 90 minutes or less, more preferably 20 minutes or more and 60 minutes or less.
• this heating time it is possible to prevent grain growth and decomposition into SmN and Fe that may occur with a longer heating time, and the reaction can proceed more fully than with a shorter heating time.
• this heating time it is possible to adjust the amount of nitrogen incorporated into the Sm-Fe crystalline material.
• (c) Heat Treatment of Sm-Fe-N Magnetic Material After obtaining the Sm-Fe-N magnetic material by the nitriding treatment, it may be further heated. Typically, the Sm-Fe-N magnetic material is further heat-treated at 400° C. or more and 500° C. or less in an atmosphere in which the concentration of N atoms and the concentration of O atoms are each 100 ppm or less, so that the N atoms can diffuse into the inside of the main phase, and a Sm-Fe-N magnetic material with an increased content of N atoms in the main phase can be obtained.
• the heat treatment of the Sm-Fe-N magnetic material is also referred to as "continuous heat treatment”.
• examples of the atmosphere in which the N atom concentration and the O atom concentration are each 100 ppm or less include an H2 gas atmosphere; an Ar atmosphere; a He atmosphere; and a mixed atmosphere of H2 gas and Ar or He.
• the heating temperature is preferably 350°C or higher and 500°C or lower, and more preferably 400°C or higher and 500°C or lower.
• this heating temperature it is possible to prevent decomposition into SmN and Fe that may occur when heat treatment is performed at a higher temperature, and it is possible to sufficiently advance the solid solution of N atoms into the main phase compared to when heat treatment is performed at a lower temperature.
• the continuous heat treatment is typically carried out under atmospheric pressure, for example, preferably at a pressure of 900 hPa or more and 1,100 hPa or less, more preferably at a pressure of 950 hPa or more and 1,050 hPa or less.
• the heating time is preferably 30 minutes or more and 600 minutes or less, more preferably 30 minutes or more and 240 minutes or less.
• the product may be allowed to cool naturally.
• the Sm-Fe-N magnet can be manufactured by a manufacturing method that includes mixing Sm-Fe-N magnetic powder and binder raw materials to obtain a mixture, and molding the mixture to obtain an Sm-Fe-N magnet.
• Methods for molding the mixture include compression molding and injection molding.
• the resin raw material in the mixture can be heated and melted or dissolved in a solvent to make it liquid, and the liquid mixture can be subjected to compression molding or injection molding.
• the liquid mixture can be hardened by cooling, crosslinking of the binder raw materials, removal of the solvent, etc.
• the Sm-Fe-N magnet can also be manufactured by sintering the Sm-Fe-N magnetic powder.
• the Sm-Fe-N magnetic material disclosed herein has good magnetic properties, particularly the squareness ratio, and can be suitably used in various electromagnetic devices such as electromagnetic actuators (motors).
• electromagnetic actuators motors
• the Sm-Fe-N magnetic material disclosed herein has a good squareness ratio, demagnetization can be suppressed, and it is expected that this will contribute to the miniaturization and high output of such electromagnetic devices.
• demagnetization is suppressed in the Sm-Fe-N magnetic material disclosed herein, it can be suitably used in applications that require reliability in high-temperature environments, such as in-vehicle applications.
• Examples 1 to 10, Comparative Examples 1 to 5 The elements of the composition shown in Table 1 were charged, and a master alloy was produced by high-frequency melting. The obtained master alloy was melted in an Ar atmosphere, and sprayed onto a Mo roll rotating at a peripheral speed of 70 m/s to obtain a quenched ribbon (Sm-Fe-based amorphous material). This quenched ribbon was heat-treated at a processing temperature of 755°C in an Ar gas atmosphere to obtain a Sm-Fe-based crystalline material, which was then pulverized until it passed through a 150 ⁇ m mesh.
• the composition shown in Table 1 is based on atomic %.
• the heat-treated powder (powdered Sm-Fe alloy) was nitrided in the atmosphere, at the temperature, and for the time shown in Table 1 to obtain an Sm-Fe-N magnetic material.
• a continuous heat treatment was performed in the atmosphere, at the temperature, and for the time shown in Table 1.
• Figure 1 shows the analysis results of the Sm-Fe-N magnetic material obtained in Example 1
• Figure 2 shows the analysis results of the material obtained in Comparative Example 1
• Figure 3 shows the analysis results of the material obtained in Comparative Example 2.
• the images shown as DF-I show dark-field images taken by STEM, and the images shown as Fe, Zr, Nb, and C show element distribution images of each element.
• Example 1 when the STEM dark field image is compared with the element distribution image of each element, it is confirmed that there are regions where the distribution concentration of Fe is low and the distribution concentrations of Zr, Nb, and C are high. This confirms that the non-magnetic phase Zr-Nb-C phase is precipitated in the Sm-Fe-N magnetic material of Example 1. Furthermore, the presence of Fe-Zr phase and Fe-Nb phase was not confirmed in the Sm-Fe-N magnetic material of Example 1.
• Magnetic Measurement Magnetic measurements were performed using a VSM (vibrating sample magnetometer).
• the demagnetizing field Hk is the magnitude of the magnetic field when the magnetic flux density is 90% of the residual magnetic flux density
• the squareness ratio (Hk/Hcj) is the ratio obtained by dividing this by the magnitude of the coercive force Hcj. The higher the squareness ratio, the higher the performance of the magnetic material is expected to be.
• the Sm-Fe-N magnetic material of the example had a squareness ratio (Hk/Hcj) of 0.12 or more, and was confirmed to exhibit a good squareness ratio. This is believed to be because in the Sm-Fe-N magnetic material of the example, the non-magnetic phase M1-M2-C phase precipitates, suppressing the precipitation of the heterogeneous phases Fe-M1 and Fe-M2.
• the Sm-Fe-N materials of Examples 1 to 6, 8, and 10 in particular had an M1 to M2 content ratio of 5:5 on an atomic percent basis, and a squareness ratio of 0.21 to 0.28, demonstrating an even better squareness ratio.
• the materials of Comparative Examples 1 to 5 contained one type each of Zr, Nb, Hf, Ta, or V, and did not have a fully satisfactory squareness ratio (Hk/Hcj). This is thought to be because, in the materials of Comparative Examples 1 to 5, where the metal contained in each is M, the non-magnetic M-C phase precipitated, but the precipitation of the heterogeneous Fe-M phase was not sufficiently suppressed.
• a Sm—Fe—N based magnetic material M1 is one element selected from 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, and is one element different from M1; and a Sm-Fe-N based magnetic material comprising C.
• M1 is one element selected from Zr, Ti, Hf, V, Nb and Ta
• M2 is one element selected from Zr, Ti, Hf, V, Nb and Ta, and different from M1.
• the Sm content is 7.0 atomic % or more and 11.0 atomic % or less
• the Fe content is 69.5 atomic % or more and 82.0 atomic % or less
• the content of Co is 0 atomic % or more and 5 atomic % or less
• the content of N is 11.0 atomic % or more and 19.5 atomic % or less
• the total content of M1 and M2 is 1.6 atomic % or more and 5.0 atomic % or less
• the Sm-Fe-N based magnetic material according to any one of [1] to [5], wherein the C content is more than 0 atomic % and 2.5 atomic % or less.
• [8] [8]
• a Sm-Fe-N based magnet comprising the Sm-Fe-N based magnetic material according to any one of [1] to [7] and a binder.
• a method for producing a Sm-Fe alloy comprising melting raw materials containing Sm; Fe; M1 which is one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W; M2 which is one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W and is different from M1; and C, followed by quenching and solidifying the raw materials to obtain a Sm-Fe alloy.
• a raw material containing Sm, Fe, Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W, M1, which is one element selected from Zr, Ti, Hf, V, Nb, Ta, Cr, Mo, and W, and M2, which is one element different from M1, and C, is melted and quenched to obtain a Sm-Fe based rapidly solidified alloy; crystallizing the Sm—Fe-based rapidly solidified alloy to obtain a Sm—Fe-based crystalline material; The Sm-Fe-based crystalline material is nitrided to obtain Sm-Fe-N-based magnetic powder; Mixing the Sm-Fe-N magnetic powder with a binder raw material to obtain a mixture; and and forming the mixture into a Sm-Fe-N magnet.
• the Sm-Fe-N magnetic material disclosed herein has good magnetic properties, particularly the squareness ratio, and can be used effectively in a variety of applications.

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• 2023
  • 2023-11-27 CN CN202380095463.8A patent/CN120858417A/zh active Pending
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