Classifications

• • 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
  • H01F1/057—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
• • 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
• • 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

Definitions

• the present invention relates to R2M17 (where R represents at least one of rare earth elements including yttrium and M is mainly transition metals) tvpe permanent magnet composition and, more particularly, to the R2M17 type permanent magnet composition whose energy product is improved by increasing its residual magnetic flux density while maintaining its coercive force at a level equal to that obtainable in the prior art.
• the energy product (BH) obtainable with such a permanent magnet composition is only 22.1 MG ⁇ Oe or so at the largest.
• compositions which contains 22 wt% R, 5 to 12 wt% copper, 0.2 to 5 wt% X (which is at least one of niobium, zirconium, vanadium, tantalum, chromium, hafnium), 0.2 to 8 wt% manganese and the balance being cobalt which is substituted by less than 35 wt% iron (Japanese Patent Publication No.
• compositions reduce the copper content but instead call for the addition of such expensive and difficult-to-get elements as tantalum, niobium and hafnium --this inevitably leads to advanced cost of material and hence eventually raises the manufacturing costs of products.
• these compositions are all intended to provide a greater energy product by increasing both of the coercive force and the residual magnetic flux density.
• the coercive force increases while decreasing the residual magnetic flux density and vice versa as referred to above. Accordingly, it is very difficult to determine the particular composition which can raise both of characteristics.
• a permanent magnet composition of the present inventon comprises 22 to 28% R (Where R represents at least one of rare earth elements including yttrium), 5 to 16% iron, 0.2 to 6.5% copper, 0.1 to 6% manganese, 0.5 to 6% A (where A represents at least one of zinc and zirconium), and 0.1 to 2% B (where B represents at least one of aluminum, bismuth and thallium) by weight, with the balance being cobalt.
• the amount of copper, which is requisite to the R2M17 type permanent magnet composition, as well as R, iron and cobalt, is held small, i.e. between 0.2 and 6.5 weight percent.
• manganese, at least one of zinc and zirconium of the group A materials and at least one of aluminum, bismuth and thallium of the group B materials are added.
• the zinc in group A and the aluminum in group B are low-cost and easily available and involves no significant difficulty in handling as is well known.
• the permanent magnet composition of the present invention which substitutes the zinc and aluminum for the afore-­mentioned hafnium, niobium, tantalum etc which are expensive, difficult to obtain and must be handled carefully, the coercive force (iHc) is about the same as that in the prior art compositions but the residual magnetic flux density (Br) is enhanced, providing for increased energy product, as will be seen from examples described later.
• the amount of the group A element should be between 0.5 and 6 weight percent because when its amount is less than 0.5 weight percent the coercive force is low, whereas when the amount exceeds 6.5 weight percent the residual magnetic flux density appreciably decreases and the coercive force also decreases.
• group B element is greater than 2 weight percent, the residual magnetic flux density is not improved and the coercive force becomes lower than in the past. On the other hand, if the element is less than 0.1 weight percent, no effect is produced. Therefore, the amount of group B element must be in the range of 0.1 and 2 weight percent.
• the reason the amount of the R is selected in the range of between 22 and 28 weight percent is that, if its amount is greater than 28 weight percent, the residual magnetic flux density decreases and hence its improvement (which is the object of the invention) cannot be attained, whereas when the amount of the R is less than 22 weight percent, the coercive force does not reach the value obtainable in the prior art compositions.
• the manganese is added in amounts between 0.1 and 6 weight percent because no effect is produced if the manganese is less than 0.1 weight percent, whereas if it is greater than 6 weight percent, the coercive force and the residual magnetic flux density both decrease.
• the copper should be added in amounts between 0.2 and 6.5 weight percent. If the copper is greater than 6.5 weight percent, the residual magnetic flux density lowers. On the other hand, if the copper content is less than 0.2 weight percent, the coercive force does not reach about the same level as in the prior art.
• the iron is present in amounts between 5 and 16 weight percent. When the iron content is greater than 16 weight percent, the coercive force lowers as compared with that in the prior art. Also, if it is less than 5 weight percent, the residual magnetic flux density decreases.
• composition in accordance with the present invention are melted and casted into an ingot, which is finely pulverized into a powder.
• the powder is compression-molded into a desired shape at a pressure of 0.5 to 5 tons/cm2 in a magnetic field having a field intensity between 5 and 16 kOe, thereafter the molding being subjected to the following heat treatment.
• the molding is sintered at 1180 to 1250°C for 1 to 10 hours, solution-treated at 1100 to 1240°C for 0.5 to 10 hours, subjected to a first aging treatment at 400 to 800°C for 0.5 to 5 hours and a second aging treatment at 750 to 950°C for 0.5 to 5 hours, and then cooled down to 600°C or below at a rate of 0.1 to 4°C/min.
• the moldings were sintered at 1180 to 1250°C for 5 hours, solution-treated at 1100 to 1240°C for 5 hours, and subjected to a first aging treatment at 700°C for 2 hours and a second aging treatment at 900°C for 3 hours. Finally, the moldings were cooled down to 400°C at a rate of 0.5°C/min.
• Permanent magnets were produced in exactly the same manner as in Example 1 except that bismuth was used in amounts given in Table 2 in place of the aluminum used in Example 1.
• Permanent magnets were produced in exactly the same manner as in Example 1 except that thallium was used in amounts given in Table 3 in place of the aluminum used in Exmple 1.
• An alloy of 24.1 wt% samarium, 2.9 wt% iron, 3.9 wt% copper, 2.0 wt% manganese, 1.1 wt% zinc, 0.9 wt% zirconium, 0.5 wt% aluminum, 0.1 wt% bismuth, 0.1 wt% thallium and the balance cobalt was prepared and a permanent magnet was produced in exactly the same manner as in Example 1.
• the coercive force (iHc), the residual magnetic flux density (Br) and the maximum energy product (BHmax) of this permanent magnet were 10.51, 11.10 and 29.4, respectively.
• Permanent magnets were produced in exactly the same manner as in Example 5 except that the bismuth or thallium was not added.
• the coercive force (iHc), the residual magnetic flux density (Br) and the maximum energy product (BHmax) of the permanent magnet with no bismuth were 10.49, 11.09 and 29.2, respectively.
• the coercive force (iHc), the residual magnetic flux density (Br) and the maximum energy product (BHmax) of the permanent magnet with no thallium were 10.52, 11.07 and 29.3, respectively.
• the present invention provides permanent magnet compositions having improved energy product by raising the residual magnetic flux density while maintining the coercive force substantially at a level equal to that in the prior art compositions through use of aluminum, zinc and other elements which are low-cost, readily available and easy to handle.
• the present invention can remarkably reduce the manufacturing costs of permanent magnets.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Hard Magnetic Materials (AREA)

Applications Claiming Priority (2)

Publications (3)

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ID=17984471

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• 1988
  • 1988-12-08 JP JP63308720A patent/JPH02156051A/ja active Granted
• 1989
  • 1989-12-07 EP EP19890312748 patent/EP0372948B1/de not_active Expired - Lifetime
  • 1989-12-07 DE DE1989616522 patent/DE68916522T2/de not_active Expired - Fee Related

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