US3891476A - Method of magnetizing a body of M{HD 5{B R at high temperatures - Google Patents
Method of magnetizing a body of M{HD 5{B R at high temperatures Download PDFInfo
- Publication number
- US3891476A US3891476A US418124A US41812473A US3891476A US 3891476 A US3891476 A US 3891476A US 418124 A US418124 A US 418124A US 41812473 A US41812473 A US 41812473A US 3891476 A US3891476 A US 3891476A
- Authority
- US
- United States
- Prior art keywords
- temperature
- field
- magnetization
- strength
- magnetic
- 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.)
- Expired - Lifetime
Links
- 238000000034 method Methods 0.000 title claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 29
- 230000005291 magnetic effect Effects 0.000 claims abstract description 28
- 238000001816 cooling Methods 0.000 claims abstract description 8
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 5
- 150000002910 rare earth metals Chemical class 0.000 claims abstract description 5
- 238000000137 annealing Methods 0.000 claims description 6
- 229910052727 yttrium Inorganic materials 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 2
- 230000005415 magnetization Effects 0.000 abstract description 37
- 238000005245 sintering Methods 0.000 abstract description 3
- 229910017052 cobalt Inorganic materials 0.000 abstract description 2
- 239000010941 cobalt Substances 0.000 abstract description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 abstract description 2
- 238000002474 experimental method Methods 0.000 description 8
- 229910000938 samarium–cobalt magnet Inorganic materials 0.000 description 6
- 229910052802 copper Inorganic materials 0.000 description 2
- 230000005347 demagnetization Effects 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 238000009738 saturating Methods 0.000 description 2
- 101100264195 Caenorhabditis elegans app-1 gene Proteins 0.000 description 1
- 229910052776 Thorium Inorganic materials 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003302 ferromagnetic material Substances 0.000 description 1
- 230000005307 ferromagnetism Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
Images
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
- H01F1/0555—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together
- H01F1/0557—Alloys characterised by their composition containing rare earth metals and magnetic transition metals, e.g. SmCo5 pressed, sintered or bonded together sintered
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F13/00—Apparatus or processes for magnetising or demagnetising
- H01F13/003—Methods and devices for magnetising permanent magnets
Definitions
- Steinhauser 5 7 ABSTRACT A method for the magnetization of a sintered magnetic body mainly consisting of a material of the type M R, in which M may be cobalt and R a rare earth metal.
- the magnetization proceeds most easily when magnetization is carried out consistently in one direction or when magnetization is carried out at a temperature between 200C and the Curie point.
- the body to be magnetized is preferably first annealed at a temperature between the sintering temperature and a temperature which is 300C lower and magnetized during the subsequent cooling.
- the invention relates to a method for the magnetization of a magnetic body principally consisting of a material of the type M R, in which M is Co or a combination of Co with at least one representative of the group consisting of Fe, Ni and Cu, and in which R is at least one representative of the group consisting of Y. Th and the rare earth metals.
- Such a magnetic body is usually magnetized in a very strong magnetic field (two to three times the intrinsic coercive field strength of the material) so as to saturate the material in such mannerthat the hysteresis loop is closed.
- the intrinsic coercive field strength for example, of SmCo is approximately l2,000 Oe and it is usual to use a field of approximately 40,000 Oe for the magnetization.
- SmCo is approximately l2,000 Oe and it is usual to use a field of approximately 40,000 Oe for the magnetization.
- Such a high field is difficult to realize in series production of permanent magnets so that one would have to be satisfied with a final product which does not have the optimum magnetic value. This problem is the more urgent when a magnet of the present type is to be incorporated in an apparatus in the demagnetized state.
- a field strength equal to the intrinsic coercive field strength of the material is sufficient to magnetically saturate a body of M R. provided magnetization is carried out in only one direction. Magnetization with a field equal to the coercive field strength proves to be impossible when magnetization is not consequently carried out in one direction, but, for example, first in a first direction and then in the opposite direction. In that case, a field of at least two to three times the coercive field strength is necessary to magnetize the material to saturation.
- a second embodiment of the method for magnetically saturating a sintered magnetic body consisting principally of a material of the type M R involves carrying out magnetization at a temperature between 200C and the Curie point of the material in a field whose strength is less than two times the intrinsic coercive field strength of the material.
- the use of the method according to the invention results in the advantage that magnetization can be carried out in certain cases in which this is not possible when using the usual method or when the latter would result in undesired complications. This is the case, for example, when the magnetization must be carried out in a place which is difficult to reach for the field to be applied or in manufacturing a multipolar magnet.
- a magnetization field is sufficient whose strength corresponds to or is even smaller than the intrinsic coercive field strength of the material, provided the magnetization is carried out at a sufficiently high temperature, in particular above 400C.
- the magnetizing field When magnetization is carried out at a temperature above 200C, according to a preferred embodiment of the method according to the invention, the magnetizing field, during the subsequent cooling to room temperature, is maintained to a temperature below 200C, and preferably to room temperature. If this is not done, the possibility exists that the magnetized body demagnetizes itself entirely or partly.
- the magnetic body is sintered and subsequently is annealed at a temperature between the sintering temperature and a temperature which is 300C lower before it is introduced into the magnetizing field.
- a magnetic body pretreated in such manner is not only found to be easier to magnetize but in addition the resulting magnet has a higher intrinsic coercive force.
- the magnetic body When the magnetic body is to be magnetized immediately after the annealing treatment, it is preferrable to cause the magnetisation field to influence the body during the cooling from the annealing temperature to room temperature. This makes an additional heating- /cooling phase superfluous.
- FIG. 1 shows the dependence of the intrinsic coer' cive force ,H,. as a function of various magnetization fields H.
- FIG. 2 shows for magnets treated in various manners the dependence of the intrinsic coercive force ,H,. as a function of various magnetizing fields H.
- FIG. 3 shows for various magnetizing fields the dependence of the relative intrinsic coercive force ,H (rel) as a function of various magnetization temperatures T.
- FIG. 4 shows a series of magnetisations with increasing field in one sense for an SmCo -magnet.
- EXPERIMENT l A compressed block consisting of powder particles of the compound SmCo was sintered at 1,100C. The resulting sintered body was magnetized at room temperature in a field of 45,000 Oe. The B-H curve of the thus magnetized body was measured. The intrinsic coercive force ,H proved to be 11,000 Oe. The body was then demagnetized at 500C in an alternating field having a maximum field strength of 2,000 Oe. It was then measured at room temperature to show how the ,H,. depends upon the strength of the magnetizing field (FIG. 1). A magnetizing field of 25,000 Oe proved to be necessary to regain the ,H,. of 1 1,000 Oe, that is to say to reach again the outer loop of the 8-H curve. It is to be noted that the body was not always consistently magnetized in one direction.
- EXPERIMENT III The SmCo magnet used in the preceding experiments was demagnetized at 500C in an alternating field and it was investigated in three different magnetization fields of 5,000 0e, 8,000 Oe and 10,000 Oe, respectively, how the magnetization depends upon the temperature.
- FIG. 3 shows the results of the investigation.
- the relative ,H,., i.e. the ,H of the magnet divided by the ,H, after magnetization at room temperature in a field of 45,000 Oe is plotted on the vertical axis.
- the temperature T at which magnetization was carried out is plotted on the horizontal axis.
- Curve I shows the variation of the relative ,H when using a magnetization field of 5,000 Oe
- curve 11 shows the variation when using a field of 8,000 Oe
- curve 111 shows the variation when using a field of 10,000 Oe.
- magnetization fields may be used which are much weaker than the field to be derived from FIG. 1 (which has a strength of 25,000 Oe), provided that a suitable magnetization temperature is chosen. However, this higher temperature is still far below the Curie temperature which is approximately 730C).
- FIG. 4 shows with reference to a number of B-H curves how in a certain experiment an SmCoS magnetic body was consistently magnetized in one direction.
- the body was first introduced into a small field, said field was caused to decrease and then to grow in the original direction to a larger value than the initial value, caused to decrease again, and so on.
- inner loops in the direction of the outer loop of the 8-H characteristic. It may be established from this experiment that the ,H,. values of the successive inner loops are always much larger than the required magnetization fields. It is still to be noted that the direction of magnetization does not depend upon the material, but only upon the direction with which has been started.
- a method of magnetizing a body consisting principally of a material of the composition M R, M consisting of an element selected from the group consisting of Co and Co in combination with one of the elements Fe, Ni, and Cu, and R being an element selected from the group consisting of Y, Th, and the rare earth metals comprising the steps of, subjecting said body to a magnetic field having a strength sufficient to magnetically saturate the material and less than twice the intrinsic coercive field strength of the material at a temperature between 200C and 0.5 times the Kelvin temperature of the Curie point of said material.
- the magnetic body is formed by compressing the material into a body which is heated at about l,l00C and subsequently said body is annealed at a temperature between said temperature and a temperature which is 300C lower before it is subjected to the magnetic field.
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Hard Magnetic Materials (AREA)
- Powder Metallurgy (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL7217051A NL7217051A (ja) | 1972-12-15 | 1972-12-15 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3891476A true US3891476A (en) | 1975-06-24 |
Family
ID=19817550
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US418124A Expired - Lifetime US3891476A (en) | 1972-12-15 | 1973-11-21 | Method of magnetizing a body of M{HD 5{B R at high temperatures |
Country Status (7)
Country | Link |
---|---|
US (1) | US3891476A (ja) |
JP (1) | JPS5344679B2 (ja) |
CH (1) | CH568643A5 (ja) |
DE (1) | DE2358595C3 (ja) |
FR (1) | FR2327615A1 (ja) |
GB (1) | GB1449687A (ja) |
NL (1) | NL7217051A (ja) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4156623A (en) * | 1974-11-29 | 1979-05-29 | General Electric Company | Method for increasing the effectiveness of a magnetic field for magnetizing cobalt-rare earth alloy |
US4347201A (en) * | 1978-11-04 | 1982-08-31 | Fujitsu Limited | Process and apparatus for producing a temperature sensitive element |
US20080172861A1 (en) * | 2007-01-23 | 2008-07-24 | Holmes Alan G | Methods for manufacturing motor core parts with magnetic orientation |
CN110610789A (zh) * | 2018-06-14 | 2019-12-24 | 中国科学院宁波材料技术与工程研究所 | 永磁材料的稳磁处理方法 |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH604342A5 (ja) * | 1976-10-04 | 1978-09-15 | Bbc Brown Boveri & Cie | |
US4114532A (en) * | 1976-10-12 | 1978-09-19 | Dataproducts Corporation | Impact printer magnet assembly |
JPS6021325U (ja) * | 1983-07-18 | 1985-02-14 | 株式会社東洋クオリティワン | 樹脂廃棄物の溶解装置 |
HU190975B (en) * | 1984-09-28 | 1986-12-28 | Elzett Muevek,Hu | Magnetizing device for magnetizing key-magnets and rotor magnets of magnetic system safety lock |
DE3609530C2 (de) * | 1986-03-21 | 1995-08-31 | Erich Dr Ing Steingroever | Verfahren zum automatischen Einstellen des Arbeitspunktes von Dauermagneten |
JPH0346205A (ja) * | 1989-07-01 | 1991-02-27 | Jionkoo Kantee Guufun Yousenkonsuu | 交流ないしパルス電流による磁化特性改善方法 |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3138494A (en) * | 1961-05-01 | 1964-06-23 | Allegheny Ludlum Steel | Method of annealing magnetic materials |
US3639182A (en) * | 1969-03-27 | 1972-02-01 | Gen Electric | Method for improving the effectiveness of a magnetic field for magnetizing permanent magnets |
US3660175A (en) * | 1969-09-18 | 1972-05-02 | Philips Corp | Method of manufacturing a magnetically anisotropic magnet body |
US3684593A (en) * | 1970-11-02 | 1972-08-15 | Gen Electric | Heat-aged sintered cobalt-rare earth intermetallic product and process |
US3723197A (en) * | 1969-09-20 | 1973-03-27 | K Buschow | Method of manufacturing a body having anisotropic, permanent magneticproperties |
US3802935A (en) * | 1972-05-25 | 1974-04-09 | Geeral Electric Co | Demagnetization of cobalt-rare earth magnets |
-
1972
- 1972-12-15 NL NL7217051A patent/NL7217051A/xx unknown
-
1973
- 1973-11-21 US US418124A patent/US3891476A/en not_active Expired - Lifetime
- 1973-11-24 DE DE2358595A patent/DE2358595C3/de not_active Expired
- 1973-12-12 GB GB5748173A patent/GB1449687A/en not_active Expired
- 1973-12-12 JP JP13784873A patent/JPS5344679B2/ja not_active Expired
- 1973-12-12 CH CH1737373A patent/CH568643A5/xx not_active IP Right Cessation
- 1973-12-13 FR FR7344567A patent/FR2327615A1/fr active Granted
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3138494A (en) * | 1961-05-01 | 1964-06-23 | Allegheny Ludlum Steel | Method of annealing magnetic materials |
US3639182A (en) * | 1969-03-27 | 1972-02-01 | Gen Electric | Method for improving the effectiveness of a magnetic field for magnetizing permanent magnets |
US3660175A (en) * | 1969-09-18 | 1972-05-02 | Philips Corp | Method of manufacturing a magnetically anisotropic magnet body |
US3723197A (en) * | 1969-09-20 | 1973-03-27 | K Buschow | Method of manufacturing a body having anisotropic, permanent magneticproperties |
US3684593A (en) * | 1970-11-02 | 1972-08-15 | Gen Electric | Heat-aged sintered cobalt-rare earth intermetallic product and process |
US3802935A (en) * | 1972-05-25 | 1974-04-09 | Geeral Electric Co | Demagnetization of cobalt-rare earth magnets |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4156623A (en) * | 1974-11-29 | 1979-05-29 | General Electric Company | Method for increasing the effectiveness of a magnetic field for magnetizing cobalt-rare earth alloy |
US4347201A (en) * | 1978-11-04 | 1982-08-31 | Fujitsu Limited | Process and apparatus for producing a temperature sensitive element |
US4459248A (en) * | 1978-11-04 | 1984-07-10 | Fujitsu Limited | Process and apparatus for producing a temperature sensitive element |
US20080172861A1 (en) * | 2007-01-23 | 2008-07-24 | Holmes Alan G | Methods for manufacturing motor core parts with magnetic orientation |
CN110610789A (zh) * | 2018-06-14 | 2019-12-24 | 中国科学院宁波材料技术与工程研究所 | 永磁材料的稳磁处理方法 |
EP3660873A4 (en) * | 2018-06-14 | 2020-09-30 | Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences | MAGNETIZATION STABILIZATION TREATMENT PROCESS FOR PERMANENT MAGNETIZATION MATERIAL |
US11538611B2 (en) | 2018-06-14 | 2022-12-27 | Ningbo Institute Of Materials Technology And Engineering, Chinese Academy Of Sciences | Magnetization stabilizing treatment method for permanently magnetizable material |
Also Published As
Publication number | Publication date |
---|---|
NL7217051A (ja) | 1974-06-18 |
GB1449687A (en) | 1976-09-15 |
DE2358595A1 (de) | 1974-06-20 |
JPS5344679B2 (ja) | 1978-11-30 |
CH568643A5 (ja) | 1975-10-31 |
FR2327615A1 (fr) | 1977-05-06 |
DE2358595B2 (de) | 1979-03-08 |
JPS4989199A (ja) | 1974-08-26 |
DE2358595C3 (de) | 1979-11-08 |
FR2327615B1 (ja) | 1978-04-21 |
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