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As the second generation of
Rare Earth permanent magnet,
SmCo not only has high
energy ranging from 14MGOe
to 28MGOe and reliable
coercive force,but also
exhibits the best
temperature characteristics
in Rare Earth material
family Compared with NdFeB,
SmCo are suitable for
working higher
temperature.SmCo
includes rare earth Sm1Co5
and Sm2Co17 and are referred
to as 1:5 and 2:17 materials
Nd-Fe-B magnets and Sm-Co
magnets are the major
Rare-Earth magnetic
materials of Magnet City.
Although these two magnets
can be substituted by each
other where operating
temperature is less than
80°C, there still exits some
feature differences. The
price of Nd-Fe-B magnets is
relatively lower. The (BH)
max of Nd-Fe-B magnets can
reach up to 48MGOe, which is
higher than that of SmCo
magnets. However, SmCo
magnets have special
advantages also. Besides its
better corrosion & oxidation
resistance, SmCo magnets
have better temperature
stability. SmCo magnets can
be operated at higher
temperature up to 300°C,
while Nd-Fe-B magnets can
not stand temperature over
200°C.
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)
Temperature Effects
SmCo magnets can operate at
temperatures up to 350 C
, depending upon the grade
and permeance coefficient.
Sm2Co17
materials exhibit superior
temperature characteristics
as compared to the Sm1Co5
types.
Common Applications for
Samarium Cobalt Magnets
Holding systems requiring
very high holding forces,
high field yoke magnets,
high performance stepper,
DC, servo, linear, and voice
coil motors, magnetic
bearings, magnetic
couplings, loudspeakers,
Halbach arrays, headphones,
microphones, magnetic
separation, instrumentation,
switches, relays, magnetic
resonance, sputtering,
vacuum deposition, charged
particle beam guidance,
particle Accelerators,
Undulators, Wigglers, and
others.
Comparison of SmCo and
NdFeB Magnets
|
Material
|
Energy
Products(MGOe)
|
Mechanical
Strength
|
Density(lbs/in3-gm/cm3)
|
Corrosion
Resistance
|
Temperature
Stability
|
Cost
|
|
NdFeB
|
10 to 48
|
Medium
|
0.275-7.5
|
Low
|
Low to Medium
|
Lower
|
|
SmCo
|
|
Low
|
0.300-8.3
|
High
|
High
|
Higher
|
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