480:, and such may be added in small quantities to achieve better heat treatment response. By weight, the alloy will generally contain 25% of samarium. The maximum energy products of these alloys range from 20 to 32 MGOe, what is about 160-260 kJ/m. These alloys have the best reversible temperature coefficient of all rare-earth alloys, typically being -0.03%/°C. The "second generation" materials can also be used at higher temperatures.
568:
456:
fabricating, impurities may be introduced in the magnets, which form nuclei. In this case, because the impurities may have lower anisotropy or misaligned easy axes, their directions of magnetization are easier to spin, which breaks the 180° domain wall configuration. In such materials, the coercivity is controlled by nucleation. To obtain much coercivity, impurity control is critical in the fabrication process.
524:
desired shape, in a magnetic field to orient the magnetic field of the particles. Sintering is applied at a temperature of 1100˚C–1250˚C, followed by solution treatment at 1100˚C–1200˚C and tempering is finally performed on the magnet at about 700˚C–900˚C. It then is ground and further magnetized to increase its magnetic properties. The finished product is tested, inspected and packed.
523:
production. The raw materials are melted in an induction furnace filled with argon gas. The mixture is cast into a mold and cooled with water to form an ingot. The ingot is pulverized and the particles are further milled to further reduce the particle size. The resulting powder is pressed in a die of
384:
In the presence of a moderately strong magnetic field, unmagnetized magnets of this series will try to align their orientation axis to the magnetic field, thus becoming slightly magnetized. This can be an issue if postprocessing requires that the magnet be plated or coated. The slight field that the
507:
Samarium–cobalt alloys are typically machined in the unmagnetized state. Samarium–cobalt should be ground using a wet grinding process (water-based coolants) and a diamond grinding wheel. The same type of process is required if drilling holes or other features that are confined. The grinding waste
455:
are aligned with the easy axis direction. In this case, all of the domain walls are at 180 degrees. When there are no impurities, the reversal process of the bulk magnet is equivalent to lone-domain motes, where coherent rotation is the dominant mechanism. However, due to the imperfection of
394:
drifts with temperature and it is one of the important characteristics of magnet performance. Some applications, such as inertial gyroscopes and travelling wave tubes (TWTs), need to have constant field over a wide temperature range. The reversible temperature coefficient (RTC) of
508:
produced must not be allowed to completely dry as samarium–cobalt has a low ignition point. A small spark, such as that produced with static electricity, can easily initiate combustion. The resulting fire produced can be extremely hot and difficult to control.
472:, or SmCo Series 2:17) are age-hardened with a composition of two atoms of rare-earth samarium per 13–17 atoms of transition metals (TM). The TM content is rich in cobalt, but contains other elements such as iron and copper. Other elements like
381:
of -0.05%/°C. Saturation magnetization can be achieved with a moderate magnetizing field. This series of magnet is easier to calibrate to a specific magnetic field than the SmCo 2:17 series magnets.
101:
Samarium–cobalt magnets have a strong resistance to corrosion and oxidation resistance, usually do not need to be coated and can be widely used in high temperature and poor working conditions.
511:
The reduction/melt method and reduction/diffusion method are used to manufacture samarium–cobalt magnets. The reduction/melt method will be described since it is used for both SmCo
127:, meaning they can only be magnetized in the axis of their magnetic orientation. This is done by aligning the crystal structure of the material during the manufacturing process.
711:
750:"Toshiba : Press Release (16 Aug, 2012): Toshiba develops dysprosium-free samarium–cobalt magnet to replace heat-resistant neodymium magnet in essential applications"
377:. The energy products of these samarium–cobalt alloys range from 16 MG·Oe to 25 MG·Oe, that is, approx. 128–200 kJ/m. These samarium–cobalt magnets generally have a
605:
Samarium-cobalt (SmCo) magnets are used in aerospace and defense due to their exceptional magnetic properties. They are utilized in high-performance motors and
451:(coercive force); that is, they are not easily demagnetized. They are fabricated by packing wide-grain lone-domain magnetic powders. All of the
385:
magnet picks up can attract debris during the plating or coating process, causing coating failure or a mechanically out-of-tolerance condition.
853:
T. Ojima; S. Tomizawa; T. Yoneyama; T. Hori (1977). "Magnetic properties of a new type of rare-earth cobalt magnets Sm2(Co, Cu, Fe, M)17".
947:
715:
378:
889:
418:
To address these requirements, temperature compensated magnets were developed in the late 1970s. For conventional SmCo magnets,
575:
17:
970:
790:
613:, and satellite systems where stability and reliability are essential. They are also used in medical technologies, including
818:
K. Strnat; G. Hoffer; J. Olson; W. Ostertag; J. J. Becker (1967). "A Family of New Cobalt-Base
Permanent Magnet Materials".
492:
624:
In the mid-1980s some expensive headphones such as the Ross RE-278 used samarium–cobalt "Super Magnet" transducers.
1084:
250:
236:
1089:
175:
54:
1033:
583:
595:
579:
1099:
499:
process. To increase the coercivity, impurities are intentionally added during the fabrication process.
116:
to 33 MG·Oe, that is approx. 112 kJ/m to 264 kJ/m; their theoretical limit is 34 MG·Oe, about 272 kJ/m.
658:
587:
1094:
1079:
955:
496:
105:
780:
735:
Research and
Development of Rare Earth Transition Metal Alloys as Permanent Magnet Materials,
862:
827:
749:
278:
58:
8:
922:
642:
528:
934:
866:
831:
98:
They are expensive and subject to price fluctuations (cobalt is market price sensitive).
1049:
655:
Applications in which performance is required to be consistent with temperature change
1029:
925:, New Jersey Department of Health and Senior Services Hazardous Substance Fact Sheet.
786:
691:
688: – Strongest type of permanent magnet from an alloy of neodymium, iron and boron
544:
495:. Impurities inside the magnets impede the domain wall motion and thereby resist the
264:
211:
92:
35:
999:
870:
835:
685:
432:
increases as temperature increases within certain temperature ranges. By combining
306:
292:
104:
They are brittle, and prone to cracking and chipping. Samarium–cobalt magnets have
69:
39:
369:
per five atoms of cobalt. By weight, this magnet alloy will typically contain 36%
805:
452:
978:
679:
637:
632:
113:
874:
1073:
778:
27:
Strong permanent magnet made from an alloy of a rare-earth element and cobalt
53:
They were developed in the early 1960s based on work done by Karl Strnat at
591:
532:
131:
Comparison of physical properties of sintered neodymium and Sm-Co magnets
599:
440:
in the alloy, the temperature coefficient can be reduced to nearly zero.
321:
766:
694: – Strong permanent magnet made from alloys of rare-earth elements
673:
649:
618:
610:
540:
448:
437:
161:
124:
73:
61:. In particular, Strnat and Ray developed the first formulation of SmCo
839:
68:
Samarium–cobalt magnets are generally ranked similarly in strength to
852:
817:
606:
556:
473:
147:
120:
806:
Typical physical and chemical properties of some magnetic materials
663:
Rotary encoders where it performs the function of magnetic actuator
433:
370:
366:
88:
Samarium–cobalt magnets are extremely resistant to demagnetization.
43:
567:
425:
decreases as temperature increases. Conversely, for GdCo magnets,
341:
Samarium–cobalt magnets are available in two "series", namely SmCo
631:
High-end electric motors used in the more competitive classes in
477:
971:"The heart & soul of the new fender american deluxe series"
552:
536:
374:
47:
361:
These samarium–cobalt magnet alloys (generally written as SmCo
682: – Searching in outdoor waters for ferromagnetic objects
95:
from 700 °C (973 K) to 800 °C (1,070 K).
890:"Everything You Need to Know About Samarium Cobalt Magnets"
548:
779:
Juha Pyrhönen; Tapani
Jokinen; Valéria Hrabovcová (2009).
712:"Dayton Contributes to the History of Magnetic Materials"
648:
Applications that will require the system to function at
614:
652:
temperatures or very hot temperatures (over 180 °C)
1023:
571:
1980s vintage headphones using
Samarium Cobalt magnets
543:; the cobalt can be substituted by a portion of other
928:
975:The Story of the Samarium Cobalt Noiseless Pickups
527:Samarium can be substituted by a portion of other
365:, or SmCo Series 1:5) have one atom of rare-earth
767:Corrosion and oxidation resistance of SmCo magnet
72:, but have higher temperature ratings and higher
1071:
91:These magnets have good temperature stability ;
1050:"Neodymium Magnets vs. Samarium Cobalt Magnets"
676: – Trivalent metallic rare-earth elements
491:magnets, the coercivity mechanism is based on
808:, permanent magnets comparison and selection.
799:
916:
200:Temperature coefficient of coercivity (%/K)
937:, Introduction to Samarium Cobalt Magnets.
189:Temperature coefficient of remanence (%/K)
1028:. Jane's Information Group. p. 547.
948:"Fender Vintage Hot Rod '57 Stratocaster"
123:samarium–cobalt magnets exhibit magnetic
84:Some attributes of samarium-cobalts are:
1000:"Samarium Cobalt Magnets (SmCo Magnets)"
566:
887:
253:, normal to magnetizing direction (1/K)
14:
1072:
782:Design of Rotating Electrical Machines
913:Nanocomposite Sm-Co melt spun ribbons
769:, corrosion and oxidation resistance.
785:. John Wiley and Sons. p. 232.
760:
24:
379:reversible temperature coefficient
25:
1111:
968:
888:Marchio, Cathy (June 14, 2024).
739:Alden E. Ray, et al, August 1972
590:in Fender's Vintage Hot Rod '57
1042:
1024:University of Michigan (1993).
1017:
992:
962:
952:Fender Hot Rod '57 Stratocaster
940:
907:
55:Wright-Patterson Air Force Base
881:
855:IEEE Transactions on Magnetics
846:
811:
772:
742:
729:
704:
459:
13:
1:
698:
594:. These pickups were used in
502:
356:
239:, magnetizing direction (1/K)
79:
602:from 2004 until early 2010.
42:made of two basic elements:
7:
667:
464:These alloys (written as Sm
10:
1116:
820:Journal of Applied Physics
659:Benchtop NMR spectrometers
586:series of electric guitar
114:megagauss-oersteds (MG·Oe)
875:10.1109/TMAG.1977.1059703
584:Samarium Cobalt Noiseless
447:magnets have a very high
336:
977:. Fender. Archived from
954:. Fender. Archived from
609:, precision sensors and
1085:Ferromagnetic materials
562:
106:maximum energy products
1090:Loudspeaker technology
1026:Jane's Space Directory
714:. 1998. Archived from
596:American Deluxe Series
572:
497:magnetization reversal
32:samarium–cobalt (SmCo)
18:Samarium-cobalt magnet
935:Sintered SmCo Magnets
621:, and medical pumps.
578:used one of designer
570:
176:Relative permeability
112:) that range from 14
57:and Alden Ray at the
627:Other uses include:
279:Compressive strength
59:University of Dayton
867:1977ITM....13.1317O
832:1967JAP....38.1001S
643:Traveling-wave tube
529:rare-earth elements
493:domain wall pinning
414:) x (1/∆T) × 100%.
132:
1100:Samarium compounds
573:
130:
93:Curie temperatures
34:magnet, a type of
840:10.1063/1.1709459
792:978-0-470-69516-6
754:www.toshiba.co.jp
692:Rare-earth magnet
545:transition metals
373:with the balance
334:
333:
265:Flexural strength
212:Curie temperature
70:neodymium magnets
36:rare-earth magnet
16:(Redirected from
1107:
1065:
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1062:
1060:
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1040:
1039:
1021:
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1004:Stanford Magnets
996:
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959:
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932:
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920:
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905:
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894:Stanford Magnets
885:
879:
878:
850:
844:
843:
826:(3): 1001–1002.
815:
809:
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797:
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776:
770:
764:
758:
757:
746:
740:
733:
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686:Neodymium magnet
453:magnetic domains
307:Vickers hardness
293:Tensile strength
133:
129:
40:permanent magnet
21:
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1095:Magnetic alloys
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430:
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136:Property (unit)
111:
82:
64:
28:
23:
22:
15:
12:
11:
5:
1113:
1103:
1102:
1097:
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1041:
1034:
1016:
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961:
958:on 2012-12-09.
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810:
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741:
728:
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680:Magnet fishing
677:
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638:Turbomachinery
635:
633:slotcar racing
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402:is defined as
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345:magnets and Sm
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225:Density (g/cm)
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62:
38:, is a strong
26:
9:
6:
4:
3:
2:
1112:
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1088:
1086:
1083:
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1080:Cobalt alloys
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1075:
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1051:
1045:
1037:
1031:
1027:
1020:
1005:
1001:
995:
981:on 2012-10-02
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957:
953:
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931:
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802:
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788:
784:
783:
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768:
763:
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751:
745:
738:
732:
718:on 2013-05-27
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645:field magnets
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580:Bill Lawrence
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210:
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206:−0.15..–0.30
205:
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195:−0.03..–0.05
194:
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33:
19:
1057:. Retrieved
1053:
1044:
1025:
1019:
1007:. Retrieved
1003:
994:
983:. Retrieved
979:the original
974:
969:Smith, Dan.
964:
956:the original
951:
942:
930:
918:
909:
897:. Retrieved
893:
883:
858:
854:
848:
823:
819:
813:
801:
781:
774:
762:
753:
744:
736:
731:
720:. Retrieved
716:the original
706:
626:
623:
604:
598:Guitars and
592:Stratocaster
574:
533:praseodymium
526:
510:
506:
482:
463:
442:
426:
419:
417:
396:
388:
387:
383:
360:
340:
327:(110–170)×10
203:−0.40..–0.65
192:–0.09..–0.12
119:
83:
67:
52:
31:
29:
923:Cobalt HSFS
861:(5): 1317.
460:Series 2:17
330:(50–90)×10
322:resistivity
320:Electrical
259:(10–13)×10
170:0.493–2.79
1074:Categories
1054:JDA Magnet
1035:0710610750
985:2012-08-16
737:AD-750 746
722:2017-01-10
699:References
674:Lanthanide
619:pacemakers
617:machines,
611:gyroscopes
547:including
541:gadolinium
531:including
503:Production
449:coercivity
438:gadolinium
357:Series 1:5
167:0.875–2.79
162:Coercivity
125:anisotropy
80:Attributes
74:coercivity
650:cryogenic
607:actuators
557:zirconium
474:zirconium
353:magnets.
287:800–1000
284:1000–1100
245:(5–9)×10
184:1.05–1.1
156:0.8–1.16
148:Remanence
139:Neodymium
668:See also
434:samarium
371:samarium
367:samarium
315:400–650
273:150–180
256:(1–3)×10
242:(3–4)×10
231:8.2–8.5
220:700–850
121:Sintered
44:samarium
1059:Aug 10,
1009:Aug 10,
899:Aug 29,
863:Bibcode
828:Bibcode
588:pickups
478:hafnium
312:500–650
270:200–400
228:7.3–7.7
217:310–370
1032:
789:
600:Basses
576:Fender
555:, and
553:copper
539:, and
537:cerium
515:and Sm
375:cobalt
337:Series
324:(Ω·cm)
301:35–40
295:(N/mm)
281:(N/mm)
267:(N/mm)
164:(MA/m)
142:Sm-Co
48:cobalt
483:In Sm
298:80–90
153:1–1.5
1061:2024
1030:ISBN
1011:2024
901:2024
787:ISBN
563:Uses
549:iron
443:SmCo
436:and
309:(HV)
214:(°C)
181:1.05
46:and
871:doi
836:doi
615:MRI
582:'s
406:(∆B
251:CTE
237:CTE
178:(–)
150:(T)
110:max
108:(BH
1076::
1052:.
1002:.
973:.
950:.
892:.
869:.
859:13
857:.
834:.
824:38
822:.
752:.
559:.
551:,
535:,
521:17
519:Co
489:17
487:Co
476:,
470:17
468:Co
410:/B
351:17
349:Co
76:.
65:.
50:.
30:A
1063:.
1038:.
1013:.
988:.
903:.
877:.
873::
865::
842:.
838::
830::
795:.
756:.
725:.
517:2
513:5
485:2
466:2
445:5
429:r
427:B
422:r
420:B
412:r
408:r
399:r
397:B
391:r
389:B
363:5
347:2
343:5
63:5
20:)
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