WO2016158552A1 - R-tm-b系焼結磁石 - Google Patents
R-tm-b系焼結磁石 Download PDFInfo
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- WO2016158552A1 WO2016158552A1 PCT/JP2016/058917 JP2016058917W WO2016158552A1 WO 2016158552 A1 WO2016158552 A1 WO 2016158552A1 JP 2016058917 W JP2016058917 W JP 2016058917W WO 2016158552 A1 WO2016158552 A1 WO 2016158552A1
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- 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
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- 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
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
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- 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
- H01F1/057—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B
- H01F1/0571—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes
- H01F1/0575—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together
- H01F1/0577—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 and IIIa elements, e.g. Nd2Fe14B in the form of particles, e.g. rapid quenched powders or ribbon flakes pressed, sintered or bonded together sintered
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- 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
- H01F1/06—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 in the form of particles, e.g. powder
- H01F1/08—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 in the form of particles, e.g. powder pressed, sintered, or bound together
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- 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
- B22F2009/044—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling by jet milling
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- 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
- the present invention relates to an R-TM-B sintered magnet with improved corrosion resistance and an R-TM-B cylindrical anisotropic sintered magnet with reduced cracking.
- R-TM-B sintered magnets are widely used because of their high magnetic properties.
- the R-TM-B sintered magnet has a problem of being easily corroded because it contains a rare earth element (R element) as a main component. It is known that corrosion starts from a rare earth-rich phase containing a large amount of rare earth elements and proceeds while the main phase drops off.
- R element rare earth element
- the surface of R-TM-B sintered magnets is usually provided with a rust-preventive coating (painting or plating). It is difficult to prevent completely.
- a cylindrical polar anisotropic magnet and a cylindrical radial anisotropic magnet are known as one of the forms of the R-TM-B sintered magnet. These cylindrical magnets are easy to assemble and widely used because they do not need to be attached to the rotor one by one like a bow-shaped magnet when used in a rotating machine.
- Co is known as a metal that improves the corrosion resistance of R-TM-B sintered magnets.
- JP-A-63-38555 describes that Co is taken into the main phase and grain boundaries of an R-TM-B sintered magnet to form an intermetallic compound with a rare earth element that is less susceptible to corrosion than a rare earth-rich phase. is doing.
- the added Co is included not only in the main phase but also in the grain boundary phase, thereby causing a problem of reducing the mechanical strength. For this reason, R-TM-B sintered magnets containing Co are liable to be chipped and cracked during handling after sintering or grinding, which may reduce production efficiency.
- JP 2003-31409 describes the addition of Co and Cu to segregate Co and Cu around the R-rich phase (rare earth element-rich grain boundary phase) to form an intermediate phase, thereby converting the R-rich phase to Co. And a technique of coating with Cu to improve the corrosion resistance of individual R-rich phases.
- Patent Document 2 there is a problem that the mechanical strength of the sintered magnet decreases due to the addition of Co. Therefore, it is desired to develop a technique for improving the corrosion resistance particularly in a magnet having a stress such as a cylindrical magnet. ing.
- Japanese Patent Laid-Open No. 2013-216965 discloses R, which is a rare earth element, T, which is a transition metal essential for Fe, a metallic element M containing one or more metals selected from Al, Ga, and Cu, and B And an alloy for RTB rare earth sintered magnets composed of inevitable impurities.
- T which is a rare earth element
- M metallic element M containing one or more metals selected from Al, Ga, and Cu
- B an alloy for RTB rare earth sintered magnets composed of inevitable impurities.
- an object of the present invention is to provide an R-TM-B based sintered magnet that achieves both high mechanical strength and excellent corrosion resistance without adding Co.
- Another object of the present invention is to provide an R-TM-B cylindrical anisotropic sintered magnet with reduced generation of cracks, chips and cracks.
- R-TM-B based sintered magnets added with Ga or (Ga + Cu) have excellent corrosion resistance even when they contain substantially no Co.
- the present invention finds that the occurrence of cracks, chips, cracks, etc. is reduced even when a cylindrical anisotropic sintered magnet that does not cause a decrease in mechanical strength and is liable to generate residual stress. I came up with it.
- the R-TM-B sintered magnet of the present invention has 24.5 to 34.5% by mass of R (R is at least one selected from rare earth elements including Y), 0.85 to 1.15% by mass of B, 0.1%
- R is at least one selected from rare earth elements including Y
- B 0.85 to 1.15% by mass of B
- the R-TM-B sintered magnet of the present invention has 3 mass% or less of M (M is Zr, Nb, Hf, Ta, W, Mo, Al, Si, V, Cr, Ti, Ag, Mn, Ge , Sn, Bi, Pb and Zn) may be further contained.
- M is Zr, Nb, Hf, Ta, W, Mo, Al, Si, V, Cr, Ti, Ag, Mn, Ge , Sn, Bi, Pb and Zn
- the Ga and Cu contents are Ga (mass%) and Cu (mass%) on the XY plane with the X axis and Y axis, respectively, point A (0.5, 0.0), point B (0.5, 0.4). ), Point C ′ (0.1, 0.4), point D ′ (0.1, 0.1), and point E (0.2, 0.0) are preferably in a region surrounded by a pentagon.
- the R-TM-B sintered magnet is preferably a cylindrical radial anisotropic magnet or a cylindrical polar anisotropic magnet.
- the R-TM-B sintered magnet of the present invention exhibits corrosion resistance by including Ga and Cu in a specific range instead of imparting corrosion resistance by containing Co. It is possible to achieve both excellent corrosion resistance. For this reason, it is possible to provide an R-TM-B sintered magnet with reduced occurrence of cracks, chips, cracks, etc., and cylindrical R-TM-B anisotropic sintering that is liable to generate residual stress.
- the present invention can also be applied to a binding magnet (cylindrical radial anisotropic magnet and cylindrical polar anisotropic magnet). Therefore, the R-TM-B based sintered magnet of the present invention can be preferably used as a magnet for a rotating machine.
- FIG. 6 is a schematic diagram showing a molding apparatus for molding the R-TM-B radial anisotropic ring magnet used in Experimental Example 4.
- 10 is a cross-sectional view schematically showing a molding apparatus for molding the R-TM-B polar anisotropic ring magnet used in Experimental Example 5.
- FIG. FIG. 5 is a cross-sectional view taken along line AA in FIG.
- the R-TM-B sintered magnet of the present invention comprises 24.5 to 34.5% by mass of R (R is at least one selected from rare earth elements including Y), 0.85 to 1.15% by mass of B, An R-TM-B sintered magnet containing less than 0.1 mass% Co, 0.07 to 0.5 mass% Ga, 0 to 0.4 mass% Cu, unavoidable impurities, and the balance Fe, The content of Ga and Cu, Ga amount (mass%) and Cu amount (mass%) on the XY plane with the X axis and the Y axis, respectively, point A (0.5, 0.0), point B (0.5, 0.4 ), Point C (0.07, 0.4), point D (0.07, 0.1), and point E (0.2, 0.0).
- the R-TM-B sintered magnet of the present invention preferably consists essentially of R-TM-B.
- R is at least one of rare earth elements including Y, and preferably necessarily includes at least one of Nd, Dy, and Pr, and TM is at least one of transition metal elements, preferably Fe. .
- B is boron.
- the R-TM-B sintered magnet has R of 24.5-34.5% by mass.
- R the amount of R is less than 24.5% by mass, the residual magnetic flux density Br and the coercive force iHc decrease. If the amount of R exceeds 34.5% by mass, the rare earth-rich phase region inside the sintered body increases, so that the residual magnetic flux density Br decreases and the corrosion resistance decreases.
- the R-TM-B sintered magnet has B of 0.85 to 1.15% by mass.
- B 0.85 to 1.15% by mass.
- B necessary for forming the main phase R 2 Fe 14 B phase is insufficient, and an R 2 Fe 17 phase having soft magnetic properties is generated and the coercive force is reduced.
- the amount of B exceeds 1.15% by mass, the phase rich in B which is a nonmagnetic phase increases and the residual magnetic flux density decreases.
- the R-TM-B sintered magnet contains 0.07 to 0.5 mass% Ga.
- Ga has the effect of improving the corrosion resistance in addition to the effect of improving the coercive force. If it is 0.07% by mass or less, the effect of improving the coercive force iHc cannot be obtained. Even if Ga is added in an amount of more than 0.5% by mass, no further effect of improving the coercive force and improving the corrosion resistance cannot be expected.
- the effect of improving corrosion resistance due to the addition of Ga is sufficiently effective if contained in an amount of 0.07% by mass or more, but it is more preferable to contain 0.1% by mass or more. In particular, when Cu is not included, the Ga content is preferably 0.2% by mass or more.
- the R-TM-B sintered magnet contains 0 to 0.4 mass% Cu. Even if it does not contain Cu, the effect of the present invention can be obtained by adjusting the Ga content, but the corrosion resistance is further improved by containing Cu. When the Ga content is 0.07% by mass, it is preferable to contain 0.1% by mass or more of Cu. Even if Cu is added in an amount of more than 0.4% by mass, the effect of further improving the corrosion resistance cannot be obtained.
- the Ga content (Cu) and the Cu content (mass%) should be changed.
- point A 0.5, 0.0
- point B 0.5, 0.4
- point C (0.07, 0.4
- point D (0.07, 0.1
- point E 0.2, 0.0
- substantially not containing is indicated as “substantially” by allowing inclusion as an inevitable impurity.
- the contents of Ga and Cu are point A (0.5, 0.0), point B (0.5, 0.4), point C ′ (0.1, 0.4), point D ′ (0.1, 0.1) and point E. It is preferably within a region surrounded by a pentagon with (0.2, 0.0) as the vertex, and point A (0.5, 0.0), point B (0.5, 0.4), point C "(0.2, 0.4) and point D" ( More preferably, it is in a region surrounded by a quadrangle with the vertices at 0.2, 0.1).
- Part of Fe may be substituted with Co, but if Co is contained in an amount of 0.1% by mass or more, cracking particularly occurs in cylindrical anisotropic sintered magnets, which is undesirable, so the Co content is It is preferably less than 0.1% by mass.
- Co may be used as a material that usually enhances corrosion resistance, but in the present invention, as described above, corrosion resistance can be imparted by Ga or Ga and Cu.
- the use of Co is not mandatory.
- 0.08 mass% or less of Co may be contained as an inevitable impurity of Fe. Although it is desirable that the amount of Co contained as an inevitable impurity is small, it is contained at a certain ratio depending on the purity of raw materials used in the mass production process and the addition of recycled materials. Co contained as an inevitable impurity is more preferably 0.06% by mass or less.
- Ni is one of the impurities that may be mixed into the R-TM-B sintered magnet from the raw material and its manufacturing process. Ni is known to be substituted for a part of Fe and to reduce the magnetic properties of R-TM-B magnets. In addition, inclusion of a certain amount or more of Ni is not desirable because cracks rapidly increase. Ni as an unavoidable impurity contained in the raw material and an impurity which is unintentionally mixed in the manufacturing process is preferably suppressed to less than 0.1% by mass, and more preferably 0.08% by mass or less.
- R-TM-B based sintered magnets are further M (M is Zr, Nb, Hf, Ta, W, Mo, Al, Si, V, Cr, Ti, Ag, Mn, Ge, Sn, Bi, Pb and It may contain at least one selected from Zn.
- M is Zr, Nb, Hf, Ta, W, Mo, Al, Si, V, Cr, Ti, Ag, Mn, Ge, Sn, Bi, Pb and It may contain at least one selected from Zn.
- the trace addition of the metal element M changes the nature of the grain boundary phase, but the coercive force improving effect is obtained, to decrease a large amount of the addition R 2 Fe 14 B phase volume ratio decreases Br, 3 wt% It is preferable to keep it below.
- the R-TM-B sintered magnet of the present invention is preferably cylindrical.
- the cylindrical magnet preferably has radial anisotropy or polar anisotropy as an anisotropic direction.
- the cylindrical magnet having the composition of the R-TM-B sintered magnet of the present invention has not only good corrosion resistance but also a very small amount even if it does not contain Co. There is no occurrence of cracks, chips, cracks, etc. due to it, or even if it occurs, the amount is extremely small.
- the R-T-B radial anisotropic ring magnet preferably has a ratio D1 / D2 between the inner diameter (D1) and the outer diameter (D2) of 0.7 or more.
- the number of poles when the R-T-B radial anisotropy ring magnet is multipolarized may be set as appropriate according to the specifications of the motor in which the magnet is used.
- RTB polar anisotropy ring magnet is composed of 4 poles, 6 poles, 8 poles, 10 poles, 12 poles or 14 poles of multi-circular anisotropy and a circular cross section outer peripheral surface You may have.
- the number of poles of the outer peripheral surface is an integral multiple of the number of vertices of the polygon.
- at least one of the intermediate positions of the pole positions of the outer peripheral surface and at least one vertex of a polygon of a cross section constituting the inner peripheral surface coincide with each other in the circumferential direction.
- the number of poles is preferably the same as or twice the number of vertices of the polygon.
- the polygon is preferably a regular polygon.
- yen circumscribing a polygon be an internal diameter.
- Example 1 As shown in Table 1, Nd is 24.80% by mass, Pr is 6.90% by mass, Dy is 1.15% by mass, B is 0.96% by mass, Nb is 0.15% by mass, Al is 0.10% by mass, and Ga and Cu contents are shown in Table 1. Strip casting method of 25 types of alloys containing Fe and unavoidable impurities as the balance, with 0.1, 0.2, 0.3, 0.4, 0.5% by mass and 0.02, 0.1, 0.2, 0.3, 0.4% by mass, respectively. It was produced by. These alloys contained 0.06% by mass of Co as an inevitable impurity. The Cu content is a value containing 0.02% by mass of Cu contained as an inevitable impurity.
- the resulting alloy is crushed by jet mill in nitrogen gas containing 5000 ppm oxygen, compression molded in a magnetic field, sintered and heat-treated, then ground, and R-TM-B sintered.
- Ga or Ga + Cu reduces the corrosion weight loss of the R-TM-B sintered magnet and greatly improves the corrosion resistance.
- Cu was not added (however, when 0.02% by mass of Cu was included as an inevitable impurity), the corrosion weight loss was remarkably large when the Ga content was 0.1% by mass, but when the Ga content was increased, the corrosion weight loss decreased and the corrosion resistance was reduced. Good results were obtained.
- Cu was added at a Ga content of 0.1% by mass, the corrosion weight loss decreased and the corrosion resistance was improved.
- the corrosion weight loss is less than 2 mg / cm 2 when the pressure cooker test is performed under the conditions of 120 ° C. 100% RH, 2 atm and 96 hours in the R-TM-B sintered magnet, It has been confirmed that it can satisfy the standards of corrosion resistance required for automobiles (electric equipment and HV).
- the range of Cu and Ga content that is considered to be able to satisfy the above corrosion resistance standard even when substantially free of Co, Ga amount (mass%) and Cu amount (mass%) are respectively expressed in the X axis and Y direction. As shown in FIG. 1, on the XY plane as the axis, it can be seen that the region is surrounded by a pentagon with the point ABCDE as a vertex.
- Experimental example 2 24.80% by mass of Nd, 6.90% by mass of Pr, 1.15% by mass of Dy, 0.96% by mass of B, 0.15% by mass of Nb, 0.10% by mass of Al, 0.30% by mass of Ga and 0.15% by mass of Cu, Alloy A containing Fe and inevitable impurities as the balance was prepared by strip casting. This alloy A contained 0.06% by mass of Co as an inevitable impurity.
- Alloys B to F were produced in the same manner as Alloy A except that the alloy composition was changed as shown in Table 2. Alloys A to E are included in the composition range of the R-TM-B sintered magnet of the present invention, and Alloy F is not included in the composition range of the R-TM-B sintered magnet of the present invention. Is.
- Co is an inevitable impurity.
- Ga content and Cu content are 0.1% by mass and 0.02% by mass of alloy 1, 0.1% by mass and 0.4% by mass of alloy 2, 0.5% by mass and 0.02% by mass, respectively.
- the% alloy 3 and 0.5 wt% and 0.4 wt% of the residual magnetic flux density B r and the coercivity H cJ of alloy 4 were measured. The results are shown in Table 3.
- Alloy A ⁇ E and alloys 2-4 are included in the composition range of R-TM-B based sintered magnet of the present invention, the corrosion weight loss is small, it is found to have a high residual magnetic flux density B r and the coercivity H cJ .
- alloy F the sum of Nd, Pr, and Dy exceeds the rare earth amount specified in the present invention, and as a result, it is presumed that the corrosion resistance has deteriorated.
- Experimental Example 3 About the alloy 1 with Ga content and Cu content of 0.1% by mass and 0.02% by mass obtained in Experimental Example 1, respectively, and the alloy 4 with Ga content and Cu content of 0.5% by mass and 0.4% by mass, respectively.
- a pressure cooker test was conducted under the conditions of 120 ° C., 100% RH, 2 atm and 24 hours, and the state of corrosion after the test was observed by SEM. The result is shown in figure 2.
- Example 4 In order to evaluate the effect of Co content on the mechanical strength of R-TM-B sintered magnets, the following experiment was conducted.
- the obtained alloy was pulverized in a jet mill in a nitrogen gas containing 5000 ppm of oxygen to prepare a fine powder.
- compression molding in a magnetic field (magnetic field strength: 318 kA / m, pressure: 98 MPa) with the molding equipment shown in Fig. 3 gives a compact of an R-TM-B radial anisotropic ring magnet. (Outer diameter 41.8 mm x inner diameter 32.5 mm x height 47.2 mm). Ten compacts were produced for each alloy.
- the molding equipment used to mold the R-TM-B radial anisotropic ring magnet includes cylindrical upper and lower cores 40a and 40b (made by permender), a cylindrical outer mold 30 (made by SK3), and a cylindrical shape.
- the upper core 40a can be detached from the lower core 40b, the upper core 40a and the upper punch 90a can be moved up and down independently, and the upper punch 90a can be detached from the cavity 60.
- a magnetic field can be applied in the radial direction to the cavity 60 along the magnetic field line 70 through the closely contacted upper core 40a and lower core 40b.
- a sintering jig material SUS403 linear expansion coefficient 11.4 ⁇ 10 -6 ) consisting of a cylindrical body with an outer diameter of 29.0 mm into the molded body, and place it on the Mo heat-resistant plate laid in the Mo container. It was sintered for 2 hours at 1080 ° C. in a vacuum. The sintering jig was used after applying Nd 2 O 3 stirred in an organic solvent to the outer peripheral surface. The end surface, outer peripheral surface and inner peripheral surface of the obtained sintered body were ground to produce 13 types of R-TM-B radial anisotropic ring magnets 401 to 413 having different Co contents.
- the results are shown in Table 4.
- the ring magnets 401 to 403 are reference examples in which the Ga content is out of the present invention, but the Co content is less than 0.1% by mass (within the range specified in the present invention), and the ring magnets 404 to 413 are the Co content. Is 0.1% by mass or more (outside the range specified in the present invention).
- Experimental Example 5 Using fine powders of 13 kinds of alloys prepared in the same manner as in Experimental Example 4, compression molding in a magnetic field (pressure: 80 MPa, magnetic field strength was the same under all conditions (pulse Thus, an R-TM-B polar anisotropic ring magnet molded body (outer diameter 31.5 mm ⁇ inner diameter 20.3 mm ⁇ height 27.8 mm) having eight poles on the outer peripheral surface was obtained. Ten compacts were produced for each alloy.
- the forming apparatus 100 in the magnetic field used for forming the R-TM-B polar anisotropic ring magnet has a die 101 made of a magnetic material and a concentric space in the annular space of the die 101. And a core 102 made of a cylindrical non-magnetic material, and the dice 101 are supported by support posts 111 and 112, and the core 102 and the support posts 111 and 112 are both supported by a lower frame 108.
- the upper punch 104 made of a cylindrical non-magnetic material the lower punch 107 made of a cylindrical non-magnetic material is fitted into the molding space 103 between the die 101 and the core 102, respectively.
- the lower punch 107 is fixed to the substrate 113, while the upper punch 104 is fixed to the upper frame 105.
- the upper frame 105 and the lower frame 108 are connected to the upper cylinder 106 and the lower cylinder 109, respectively.
- Fig. 4 (b) shows the AA cross section of Fig. 4 (a).
- a plurality of grooves 117 are formed on the inner surface of the cylindrical die 101, and a magnetic field generating coil 115 is embedded in each groove 117.
- An annular non-magnetic annular sleeve 116 is provided on the inner surface of the die 101 so as to cover the groove.
- a space 103 between the annular sleeve 116 and the core 102 is formed.
- the magnetic field generating coil 115 in each groove 117 is arranged so that the current flows in a direction perpendicular to the paper surface, and the current direction of the coils adjacent in the circumferential direction is alternately reversed. So connected.
- the obtained molded body was placed on a Mo heat-resistant plate laid in a Mo container and sintered at 1080 ° C. for 2 hours in a vacuum.
- the end surface, outer peripheral surface and inner peripheral surface of the obtained sintered body were ground to produce 13 types of R-TM-B polar anisotropic ring magnets 501 to 513 having different Co contents.
- the obtained R-TM-B polar anisotropic ring magnet was visually checked for cracks.
- the results are shown in Table 5.
- the ring magnets 501 to 503 are reference examples in which the Ga content is out of the present invention but the Co content is less than 0.1% by mass (within the range specified in the present invention), and the ring magnets 504 to 513 are the Co content. Is 0.1% by mass or more (outside the range specified in the present invention).
- Experimental Example 6 A radially anisotropic sintered ring magnet of the present invention example was manufactured in the same manner as in Experimental example 4 except that 25 kinds of fine alloy powders prepared in the same manner as in Experimental example 1 were used. As a result, all of these 25 types of radially anisotropic sintered ring magnets did not crack after grinding.
- Experimental Example 7 A polar anisotropic sintered ring magnet of the example of the present invention was manufactured in the same manner as in Experimental Example 5 except that fine powders of 25 types of alloys prepared in the same manner as in Experimental Example 1 were used. As a result, all of these 25 types of radially anisotropic sintered ring magnets did not crack after grinding.
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Abstract
Description
前記Ga及びCuの含有量が、Ga量(質量%)及びCu量(質量%)をそれぞれX軸及びY軸としたXY平面上で、点A(0.5、0.0)、点B(0.5、0.4)、点C(0.07、0.4)、点D(0.07、0.1)及び点E(0.2、0.0)を頂点とする五角形で囲まれる領域内にあることを特徴とする。
本発明のR-TM-B系焼結磁石は、24.5~34.5質量%のR(RはYを含む希土類元素から選ばれる少なくとも1種)と、0.85~1.15質量%のBと、0.1質量%未満のCoと、0.07~0.5質量%のGaと、0~0.4質量%のCuと、不可避不純物と、残部Feとを含有するR-TM-B系焼結磁石であって、
前記Ga及びCuの含有量が、Ga量(質量%)及びCu量(質量%)をそれぞれX軸及びY軸としたXY平面上で、点A(0.5、0.0)、点B(0.5、0.4)、点C(0.07、0.4)、点D(0.07、0.1)及び点E(0.2、0.0)を頂点とする五角形で囲まれる領域内にあることを特徴とする。
本発明のR-TM-B系焼結磁石は円筒状であるのが好ましい。前記円筒状磁石は、異方性方向としてラジアル異方性又は極異方性を有するのが好ましい。円筒状(リング形状)とすることで、回転機として組み立てる際の組立工数を低減することができる。
Ndを24.80質量%、Prを6.90質量%、Dyを1.15質量%、Bを0.96質量%、Nbを0.15質量%、Alを0.10質量%含有し、Ga及びCuの含有量を表1に示すようにそれぞれ0.1、0.2、0.3、0.4、0.5質量%及び0.02、0.1、0.2、0.3、0.4質量%の範囲で変更し、残部としてFe及び不可避不純物を含有する25種類の組成の合金をストリップキャスト法により作製した。これらの合金には、不可避不純物としてCoが0.06質量%含有していた。なお、前記Cu含有量は不可避不純物として含まれる0.02質量%のCuを含んだ値である。
Ndを24.80質量%、Prを6.90質量%、Dyを1.15質量%、Bを0.96質量%、Nbを0.15質量%、Alを0.10質量%、Gaを0.30質量%及びCuを0.15質量%含有し、残部としてFe及び不可避不純物を含有する合金Aをストリップキャスト法により作製した。この合金Aには、不可避不純物としてCoが0.06質量%含有していた。
実験例1で得られた、Ga含有量及びCu含有量がそれぞれ0.1質量%及び0.02質量%の合金1と、Ga含有量及びCu含有量がそれぞれ0.5質量%及び0.4質量%の合金4とについて、120℃100%RH、2気圧及び24時間の条件でプレッシャークッカーテストを行い、テスト後の腐食の様子をSEMで観察した。結果を図2に示す。
Co含有量がR-TM-B系焼結磁石の機械的強度に与える影響を評価するため、以下の実験を行った。
実験例4と同様にして準備した13種類の合金の微粉を用いて、図4に示す成形装置100で磁場中圧縮成形(圧力:80 MPa、磁場強度については全ての条件で同じ磁場強度(パルス磁場)とした。)し、外周面に8極を有するR-TM-B系極異方性リング磁石の成形体(外径31.5 mm×内径20.3 mm×高さ27.8 mm)を得た。各合金について、それぞれ10個の成形体を作製した。
実験例1と同様にして準備した25種類の合金の微粉を用いた以外、実験例4と同様にして本発明例のラジアル異方性焼結リング磁石を製作した。その結果、これらの25種のラジアル異方性焼結リング磁石は、全て研削加工後の割れが発生しなかった。
実験例1と同様にして準備した25種類の合金の微粉を用いた以外、実験例5と同様にして本発明例の極異方性焼結リング磁石を製作した。その結果、これらの25種のラジアル異方性焼結リング磁石は、全て研削加工後の割れが発生しなかった。
Claims (4)
- 24.5~34.5質量%のR(RはYを含む希土類元素から選ばれる少なくとも1種)と、0.85~1.15質量%のBと、0.1質量%未満のCoと、0.07~0.5質量%のGaと、0~0.4質量%のCuと、不可避不純物と、残部Feとを含有するR-TM-B系焼結磁石であって、
前記Ga及びCuの含有量が、Ga量(質量%)及びCu量(質量%)をそれぞれX軸及びY軸としたXY平面上で、点A(0.5、0.0)、点B(0.5、0.4)、点C(0.07、0.4)、点D(0.07、0.1)及び点E(0.2、0.0)を頂点とする五角形で囲まれる領域内にあることを特徴とするR-TM-B系焼結磁石。 - 請求項1に記載のR-TM-B系焼結磁石において、
3質量%以下のM(MはZr、Nb、Hf、Ta、W、Mo、Al、Si、V、Cr、Ti、Ag、Mn、Ge、Sn、Bi、Pb及びZnから選ばれる少なくとも1種)をさらに含有することを特徴とするR-TM-B系焼結磁石。 - 請求項1又は2に記載のR-TM-B系焼結磁石において、
前記Ga及びCuの含有量が、Ga量(質量%)及びCu量(質量%)をそれぞれX軸及びY軸としたXY平面上で、点A(0.5、0.0)、点B(0.5、0.4)、点C'(0.1、0.4)、点D'(0.1、0.1)及び点E(0.2、0.0)を頂点とする五角形で囲まれる領域内にあることを特徴とするR-TM-B系焼結磁石。 - 請求項1~3のいずれかに記載のR-TM-B系焼結磁石において、
前記R-TM-B系焼結磁石が、円筒状ラジアル異方性磁石又は円筒状極異方性磁石であることを特徴とするR-TM-B系焼結磁石。
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JP2017509820A JP6658737B2 (ja) | 2015-03-27 | 2016-03-22 | R−tm−b系焼結磁石 |
DE112016001436.8T DE112016001436T5 (de) | 2015-03-27 | 2016-03-22 | Gesinterter R-TM-B Magnet |
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