SmCo Magnets

Permanent Samarium Cobalt magnets (SmCo) are composed of samarium, cobalt and iron. These rare earth magnets are extremely strong for their small size, metallic in appearance and found in simple shapes such as rings, blocks and discs.
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Samarium Cobalt MAGNETS

Permanent Samarium Cobalt magnets (SmCo) are composed of samarium, cobalt and iron.
These rare earth magnets are extremely strong for their small size, metallic
in appearance and found in simple shapes such as rings, blocks and discs.

Attributes of Samarium Cobalt

  • High resistance to demagnetization
  • High energy (magnetic strength is strong for its size)
  • Good temperature stability
  • Expensive material (cobalt is market price sensitive)

Applications of Samarium Cobalt

Computer disc drives, sensors, traveling wave tubes, linear actuators,
satellite systems, motors where temporary stability is vital.

Magnetizing and Handling

Samarium Cobalt magnets are very brittle and very strong magnetically. Therefore,
it is crucial to handle these magnets with extreme care to avoid personal
injury and damage to the magnets. Fingers can be severely pinched between
attracting magnets. Magnets can chip if allowed to “jump at” an
attracting object. It is highly recommended that when constructing rare
earth magnetic assemblies, they be magnetized after assembly.

Samarium Cobalt Machining

Since Samarium Cobalt magnet material is prone to chipping and cracking,
it does not lend itself to conventional machining methods. It can, however,
be abrasively ground, but only with the use of liberal amounts of coolant.
The coolant minimizes heat fracturing and the risk of fires caused by
oxidized grinding dust.

Tolerances

For as pressed material, tolerance on the thickness (direction of magnetization) is ± .005. Other dimensions are ± 2.5% or ± .010, whichever is greater.

According to IMA standards, visual imperfections such as hairline cracks, porosity and minor chips are commonly found in sintered metallic magnets. A chipped edge is considered acceptable if no more than 10% of the surface is missing. Cracks are acceptable as long as they do not extend across more than 50% of pole surface.

Typical Magnetic and Physical Properties of Ceramic Magnet Material
Magnetic Materials
Density
Maximum
Energy
Product
BH (max)
Residual
Induction
Br
Coercive
Force
Hc
Intrinsic
Coercive
Force
Hc
Normal
Maximum
Operating
Temp.
Curie
Temp.
lbs/in
g/cm
MGO
Gauss
Oersteds
Iersteds
SmCo 18
0.296
8.2
18.0
8700
8000
20000
482
250
1382
750
SmCo 20
0.296
8.2
20.0
9000
8500
15000
482
250
1382
750
SmCo 24
0.304
8.4
24.0
10200
9200
18000
572
300
1517
825
SmCo 26
0.304
8.4
26.0
10500
9000
11000
572
300
1517
825