EP0350967A2 - Harzgebundener Magnet und dessen Herstellung - Google Patents

Harzgebundener Magnet und dessen Herstellung Download PDF

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Publication number
EP0350967A2
EP0350967A2 EP89113061A EP89113061A EP0350967A2 EP 0350967 A2 EP0350967 A2 EP 0350967A2 EP 89113061 A EP89113061 A EP 89113061A EP 89113061 A EP89113061 A EP 89113061A EP 0350967 A2 EP0350967 A2 EP 0350967A2
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EP
European Patent Office
Prior art keywords
resin
ihc
atomic
bonded magnet
magnet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP89113061A
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English (en)
French (fr)
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EP0350967A3 (de
Inventor
Fumitoshi Yamashita
Masami Wada
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Publication of EP0350967A2 publication Critical patent/EP0350967A2/de
Publication of EP0350967A3 publication Critical patent/EP0350967A3/de
Withdrawn legal-status Critical Current

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    • 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
    • H01F1/0578—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 bonded together

Definitions

  • the present invention relates to a resin-bonded magnet and its production. More particularly, it relates to a resin-bonded magnet improved in magnetic characteristics and heat stability, which comprises ferromagnetic alloy particles of a rare earth element system, and its produc­tion.
  • Fe83Nd13B4 as a typical example of said resin-bonded Fe-B-R magnet shows the following magnetic characteristics irrespective of the magnet structure or shape or the magnetization direction: Br, 6.1 kG; bHc, 5.3 KOe; iHc, 15 KOe, (BH)max, 8 MGOe; temperature coefficient of Br, -0.19 %/°C; temperature coefficient of iHc, -0.42 %/°C; Curie temperature, 310°C.
  • Br and heat stability such as irreversible demagnetizing factor is desirable in view of a pronounced tendency toward high efficiency, miniaturization and resistance to surroundings of a permanent magnet motor.
  • a resin-bonded magnet which comprises a resinous binder and ferromagnetic alloy particles having a composi­tion of the formula: Fe 100-x-y-z Co x R y B z (I) wherein R is at least one of Nd and Pr, x is an atomic % of not less than 15 and not more than 30, y is an atomic % of not less 10 and not more than 13 and z is an atomic % of not less than 5 and not more than 8 uniformly dispersed therein.
  • the ferromagnetic alloy particles in the magnet is the one produced by the melt quenching process and having a coercive force (iHc) of 8 to 12 KOe.
  • the resinous binder is preferred to comprise a heat-polymeriz­able resin such as an epoxy resin.
  • the magnet of the invention may be produced by forming a granular complex material comprising a heat-­polymerizable resin as a resinous binder and ferromagnetic alloy particles of the formula (I) uniformly dispersed therein in a green body and heating the green body at a temperature for the polymerization of the heat-polymerizable resin.
  • the heat stability as represented by the irreversible demagnetizing factor may be considered to be a function influenced by the iHc level and the temperature (Curie temperature) coefficient of iHc.
  • the level of the coeffi­cient temperature of iHc it is necessary to decrease the level of the coeffi­cient temperature of iHc to at least such an extent as corresponding to the decrease of iHc for decreasing the magnetization energy while assuring the heat stability.
  • the value which affords a serious influence on the level of iHc is y indicating the atomic % of R.
  • the reason why the iHc level is made above 15 KOe or above 8 KOe is due to the fact that the iHc level in both cases is more or less increased with the increase of x indicating the atomic % of Co.
  • Manufacture of said resin-bonded magnet was carried out by forming a granular complex material comprising the ferromagnetic alloy particles and a heat-polymerisable resin as a resin binder into a gree body and subjecting the green body to heat treatment for obtaining a resin-bonded magnet having an outer diameter of 0.5 cm and a permeance coefficient (B/H) of 1, 2, 4 or 7.
  • the irreversible demagnetizing factor was determined by pulse magnetizing the resin-bonded magnet with 50 KOe in a longitudinal direction, measuring the magnetic flux (as the initial magnetic flux value) by the use of a Helmholtz coil and a flux meter, heating the resultant magnet at 150°C for 0.5 hour, quenching the heated magnet to room temperature and measuring again the magnetic flux. From Fig. 2, it is apparent that the irreversible demagnetiz­ing factor is controlled by the temperature coefficient of iHc when B/H is constant and the iHc level is the same. Also, the influence of B/H on the irreversible demagnetizing factor is decreased with a smaller temperature coefficient of iHc. As explained in Fig.
  • the temperature coefficient of iHc is controlled by x when the iHc level is the same. Accordingly, it is possible to assure a heat stability equal to that of a high iHc level even in case of a low iHc level insofar as the range of x is specified.
  • Manufacture of said resin-bonded magnet was carried out by forming a granular complex material comprising the ferromagnetic alloy particles and a heat-polymerisable resin as a resin binder into a gree body and subjecting the green body to heat treatment for obtaining a resin-bonded magnet having an outer diameter of 0.5 cm and a permeance coefficient (B/H) of 4.
  • the irreversible demagnetizing factor was determined in the same manner as in Fig. 2 at a temperature of 60 to 220°C. From Fig. 3, it is understood that the heat stability represented by the irreversible demagnetizing factor is substantially equal between the low iHc level and the high iHc level when x is 15 ⁇ 16.
  • the ferromagnetic alloy particles of the composi­tion (I) is preferred to be the one produced by the melt quenching process and have a coercive force (iHc) of 8 to 12 KOe.
  • the melt quenching process as explained, for instance, in U.S. patent 4,689,163 may be applied to production of the ferromagnetic alloy particles usable in this invention, if necessary, with any modification apparent to those skilled in the art.
  • the ferromagnetic alloy particles have usually a particle size of about 50 to 300 micrometers ( ⁇ m). Since they are normally in plates, their specific surface area is from about 0.04 to 0.05 cm2/g even when the particle size distribution is so broad as about 50 to 300 micrometers.
  • the ferromagnetic alloy particles are poor in flow-­ability and therefore may be admixed with a resin binder to make a granular complex material, which can be subjected to powder molding.
  • the resin binder as uable in the invention comprises usually a heat-polymerizable resin, preferably an epoxy resin, as an essential component.
  • a heat-polymerizable resin preferably an epoxy resin
  • it may comprise a curing (or crosslinking) agent for the heat-­polymerizable resin and optionally one or more reactive or non-reactive additives such as a forming acid.
  • the epoxy resin is intended to mean a compound having at least two oxirane rings in the molecule and being representable by the formula: wherein Y is a polyfunctional halohydrin such as a residue formed through a reaction between epichlorohydrin and a polyvalent phenol.
  • Preferred examples of the polyvalent phenol are resorcinol and bisphenols produced by conden­sation of a phenol with an aldehyde or ketone.
  • Specific examples of the bisphenols are 2,2′-bis(p-hydroxyphenyl­propane) (bisphenol A), 4,4′-dihydroxybiphenyl, 4,4′-di­hydroxybiphenylmethane, 2,2′-dihydroxydiphenyl oxide, etc. These may be used independently or as a mixture thereof.
  • glycidyl ether type epoxy resins of the formula: wherein R1 is a hydrogen atom or a methyl group, R2 to R9 are the same or different and each a hydrogen atom, a chlorine atom, a bromine atom or a fluorine atom, A is an alkylene group having 1 to 8 carbon atoms, -S-, -O- or -SO2- and n is an integer of 0 to 10.
  • the curing agent for the epoxy resin there may be used any conventional one.
  • the curing agent are aliphatic polyamines, polyamides, hetero­cyclic diamines, aromatic polyamines, acid anhydrides, aromatic ring-containing aliphatic polyamines, imidazoles, organic dihydrazides, polyisocyanates, etc.
  • the optionally usable additives are monoepoxy compounds, ali­phatic acids and their metal soaps, aliphatic acid amides, aliphatic alcohols, aliphatic esters, carbon-functional silanes, etc.
  • any appropriate means for instance, a substance showing a potential curability to the epoxy resin such as an organic dihydrazide or a polyisocyanate may be incorporated into the epoxy resin.
  • any component usually a heat-polymerizable resin, may be microcapsulated so as to prevent its direct contact to any other reactive component such as a curing agent.
  • one or more polymerizable monomers which will form the film or microcapsules may be subjected to in situ polymerization, for instance, sus­ pension polymerization in the presence of a heat-poly­merizable resin, which is preferred to be in a liquid state at room temperature.
  • Preferred examples of the polymeriz­able monomers are vinyl chloride, vinylidene chloride, acrylonitrile, styrene, vinyl acetate, alkyl acrylates, alkyl methacrylates, etc.
  • the suspension polymerization may be effected by a per se conventional procedure in the presence of a polymerization catalyst.
  • microcapsules are preferably in a single nuclear spherical form and have a particle size of several to several ten micrometers.
  • said ferromagnetic alloy particles of the composition (I) are mixed with the resin binder, preferably microcapsulated as above, to make a granular complex material.
  • the granular complex material is optionally admixed with the resin binder, preferably microcapsulated as above and shaped by powder molding in a non-magnetic field into a green body, which is subjected to heat treatment for curing of the heat-polymerizable resin to give a resin-­bonded magnet.
  • the resin-bonded magnet thus obtained is decreased in magnetization energy and improved in Br while assuring a good heat stability represented by an irreversible demagne­tizing factor.
  • the resin-bonded magnet may be incorporated into a permanent magnet motor, for instance, of rotor type or of field system type so that the resultant motor can produce excellent performances with high efficiency. In addition, it may have high resistance to surroundings.
  • fine particles of Fe 65.2 Co 16.2 Nd 12.2 B 6.3 (iHc, 11KOe; particle size, 53 to 350 micrometers) or Fe 81.0 Nd14B 5.0 (iHc, 15KOe; particle size, 53 to 350 micro­meters) manufactured by the melt quenching process (96 parts by weight) were admixed with a 50 % acetone solution of a glycidyl ether type epoxy resin having a melting point of 65 to 75°C (“Durran's”) (3 parts by weight). After evaporation of the solvent, the resulting material was pulverized and shieved to make granules having a particle size of 53 to 500 micrometers.
  • the resultant granules were admixed with the microcapsules (2 parts by weight), fine particles of 1,3-bis(hydrazinocarboethyl)-5-isopropylhydantoin of the formula: having a particle size of 5 to 10 micrometers (0.45 part by weight) and calcium stearate (0.2 part by weight) to give a granular complex material, which is non-sticky and non-­polymerizable at room temperature and has powder flow­ability.
  • a layered core consisting of 22 annular electro­magnetic steel plates each having an outer diameter of 47.9 mm, an inner diameter of 8 mm and a thickness of 0.5 mm was charged in a metal mold to make an annular cavity of 50.1 mm in diameter around said layered core.
  • said granular complex material was introduced and compressed under a load of 12 ton to make a ring-form green body.
  • the green body was taken out from the metal mold and subjected to heat treatment at 120°C for 1 hour so that the heat-polymerizable resin was cured.
  • the microphotograph showing the section of the essential part of the resin-bonded magnet and the layered electromagnetic steel plate is given in Fig. 4 of the accompanying drawings, wherein 1 is the resin-bonded magnet and 2 is the layered electromagnetic steel plate.
  • the resin-bonded magnet had a density of 5.7 g/cm2.
  • the resin-bonded magnet of Fe 65.2 Co 16.2 Nd 12.2 B 6.3 (iHc, 11.0 KOe) according to the invention is presumed to have the following magnetic characteristics: Br, 6.8 kG; bHc, 5.8 KOe; (BH) max , 9.8 MGOe.
  • the resin-bonded magnet of Fe 81.0 Nd14B 5.0 (iHc, 15 KOe) for comparison is presumed to have the following magnetic characteristics: Br, 6.1 kG; bHc, 5.2 KOe; (BH) max , 7.9 MGOe.
  • a shaft was inserted into the center bore of the layered electromagnetic steel plate, and magnetization was made to the ring-form resin-bonded magnet with 4 pole puls at the outer circumference to make a permanent magnet motar.
  • the relationship between the torque on the fan load (1420 rpm, 20°C) and the magnetized current wave height is shown in Table 1 (the winding number of the exciting coil per each pole being 22).
  • the motor according to the invention can decrease the magnetization energy in 20 - 30 % with torque elevation in approximately 10 % in comparison with a conventional motor.
  • this invention can produce decrease of the magnetization energy and improvement of Br while assuring a heat stability represented by an irreversible demagnetizing factor.
  • a permanent magnet motor can be made with high efficiency and miniturization by this invention.
  • a permanent magnet and any other part material or article can be manufactured in an integral body.

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  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Hard Magnetic Materials (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)
EP19890113061 1988-07-15 1989-07-17 Harzgebundener Magnet und dessen Herstellung Withdrawn EP0350967A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP63177809A JP2839264B2 (ja) 1988-07-15 1988-07-15 永久磁石
JP177809/88 1988-07-15

Publications (2)

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EP0350967A2 true EP0350967A2 (de) 1990-01-17
EP0350967A3 EP0350967A3 (de) 1991-01-02

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Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006100560A (ja) * 2004-09-29 2006-04-13 Neomax Co Ltd 希土類系ボンド磁石およびその製造方法
JP4806983B2 (ja) * 2005-07-11 2011-11-02 日立金属株式会社 希土類系ボンド磁石の製造方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61129802A (ja) * 1984-11-28 1986-06-17 Hitachi Metals Ltd 鉄−希土類−ホウ素系永久磁石の熱処理方法
EP0239031A1 (de) * 1986-03-20 1987-09-30 Hitachi Metals, Ltd. Verfahren zur herstellung von magnetpulver fuer einen megnetisch anisotropen gebundenen magneten
JPS63111603A (ja) * 1986-10-30 1988-05-16 Santoku Kinzoku Kogyo Kk ボンド磁石
EP0284033A1 (de) * 1987-03-23 1988-09-28 Tokin Corporation Verfahren zur Herstellung eines anisotropen seltene Erden-Eisen-Bor-Verbundmagneten mit Hilfe von bandähnlichen Spänen aus einer seltene Erden-Eisen-Bor-Legierung

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61129802A (ja) * 1984-11-28 1986-06-17 Hitachi Metals Ltd 鉄−希土類−ホウ素系永久磁石の熱処理方法
EP0239031A1 (de) * 1986-03-20 1987-09-30 Hitachi Metals, Ltd. Verfahren zur herstellung von magnetpulver fuer einen megnetisch anisotropen gebundenen magneten
JPS63111603A (ja) * 1986-10-30 1988-05-16 Santoku Kinzoku Kogyo Kk ボンド磁石
EP0284033A1 (de) * 1987-03-23 1988-09-28 Tokin Corporation Verfahren zur Herstellung eines anisotropen seltene Erden-Eisen-Bor-Verbundmagneten mit Hilfe von bandähnlichen Spänen aus einer seltene Erden-Eisen-Bor-Legierung

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 10, no. 319 (E-450)(2375) 30 October 86, & JP-A-61 129802 (HITACHI METALS LTD) 17 June 86, *
PATENT ABSTRACTS OF JAPAN vol. 12, no. 355 (E-661)(3202) 22 September 88, & JP-A-63 111603 (SANTOKU KINZOKU KOGYO K.K) 16 May 88, *

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Publication number Publication date
JPH0232737A (ja) 1990-02-02
EP0350967A3 (de) 1991-01-02
JP2839264B2 (ja) 1998-12-16

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