Bonded NdFeB Magnets
Bonded
NdFeB magnets are manufactured by binding rapid-quenching NdFeB
powder. The powder is mixed with resin to form a magnet by compression
molding with epoxy or infection molding with nylon. The latter
technique is particular effective in large volume production,
though the magnetic value of products is lower than those made
with compression molding because of their relatively lower density.
Various shapes of high dimensional accuracy can be produced without
further processing. Surface is treated by epoxy coating or nickel-plating
to prevent corrosion
Other
Properties of NdFeB Bonded Magnets
Hybrid
magnets to create different magnetic properties
With
different ratio of additives to NdFeB powder, magnetic properties
of hybrid NdFeB magnets can be tuned in a wide range. Once the
ratio is fixed, magnetic property fluctuation can still be limited
in a narrow bank. Hybrid magnets will meet customers’specified
properties.
Characteristics
for the initial magnetization of NdFeB bonded magnets
Rapidly
quenched NdFeB powder used for bonded magnets is multi grain with
grain size of sub-micron. Powder is isotropic in magnetic properties,
which results in flat increasing of remanence and intrinsic coercivity
with applied field. Magnet can only be magnetized to saturation
in high fields.
Advantages
of Bonded Magnet
*Produced
with high efficiency, stability and repeatability.
*Magnet
and other part may form together in one step.
*Free
choice of magnetizing direction-especially for multi-polar applications
*High
dimensional accuracy-large quantity applications with minimum
post-press machining.
*Thin-wall
ring and complex shape magnets.
*High
resistance to corrosion.
Magnetic properties of bonded
NdFeB Magnets
|
P/N
|
Br
Remanence
|
Hcj
Intrinsic
Coercivity
|
Hcb
Coercive
Force
|
(BH)max.
Maximum
Energy Product
|
|
MT
|
kG
|
kA/m
|
kOe
|
kA/m
|
kOe
|
KJ/m3
|
MGOe
|
|
ndfeb-NB6
|
440-560
|
4.40-5.60
|
560-680
|
7.0-8.5
|
240-320
|
3.0-4.0
|
32-48
|
4.0-6.0
|
|
ndfeb-NB8
|
540-640
|
5.40-6.40
|
640-720
|
8.0-9.0
|
320-400
|
4.0-5.0
|
48-64
|
6.0-8.0
|
|
ndfeb-NB8M
|
540-620
|
5.40-6.20
|
1040-1360
|
13.0-17.0
|
384-464
|
4.8-5.8
|
56-72
|
7.0-9.0
|
|
ndfeb-NB10
|
620-700
|
6.20-7.00
|
608-800
|
7.6-10.0
|
360-456
|
4.5-5.7
|
64-80
|
8.0-10.0
|
|
ndfeb-NB12
|
690-760
|
6.90-7.60
|
640-840
|
8.0-10.5
|
400-480
|
5.0-6.0
|
80-96
|
10.0-12.0
|
Physical
Chracteristics of bonded NdFeB Magnets
|
P/N
|
Recoil
Permeability
|
Hs
Magnetizing
Field
|
Ο
Density
|
Temperature
Coefficient
|
Tc
Curie
Temperature
|
K[2]
Ring
Crushing Strength
|
Coefficient
of Thermal Expansion (25-200℃)
|
|
|
kA/m
|
g/cm3
|
kOe
|
 %/
|
 (Hcj)%/
|
|
kg/mm2
|
10-6/
|
|
ndfeb-NB6
|
1.22
|
 1600
|
5.1-5.6
|
√20
|
-0.14
|
-0.40
|
360
|
5.5
|
4.8
|
|
ndfeb-NB8
|
1.22
|
1600
|
5.4-5.8
|
√20
|
-0.13
|
-0.40
|
360
|
5.5
|
4.8
|
|
ndfeb-NB8M
|
1.18
|
2000
|
5.8-6.0
|
√25
|
-0.12
|
-0.38
|
305
|
5.5
|
4.8
|
|
ndfeb-NB10
|
1.22
|
1600
|
5.8-6.0
|
√20
|
-0.11
|
-0.40
|
360
|
5.5
|
4.8
|
|
ndfeb-NB12
|
1.17
|
1600
|
5.9-6.1
|
√20
|
-0.11
|
-0.41
|
360
|
5.5
|
4.8
|
Note:
[1] The properties given above are typical at room temperature(23)for uncoated samples.
[2] Ring Crushing Strength K is defined as follows, with
the force applying along a diameter of magnet ring and P is the
value at which the first crack appears. K=P(D-T)/LT2
K-Ring Crushing
Strength(kg/mm2) P-Load on magnet ring(kg)
D-Outer diameter(mm)
T-Ring thickness(mm)
L-Height of the ring(mm)
Safety
Notes for the Use and Storage of Bonded Magnets.
*Do
not place magnets near person wearing electrical medical equipment.such
as pacemaker,because the magnet may result in malfunction of the
equipment and endanger person's life.
*Keep
magnets away from magnetic memory media or other magnetic field
sensitive devices such as magnetic cards.tapes,floppy disks,hard
disk drivers,and watches.Otherwise information stored in the media
or the devices may be damaged.
*Big
block of magnet will strongly attract each other or attract iron
steel pieces,which may cause serious injure to person.
*Relatively
weak in strength,bonded magnets may break into pieces when collide
with other materials.Be careful in assembling magnets and prevent
the finy fragments from entering into eyes or cause other injuries.
*Keep
magnets in good condition and avoid following environment in case
that magnets become rust or weaken in mechanical or magnetic strength.
A.
With acid,alkali,organic solvent or electrolytes.
B.
Immersed in water or in oil.
C.
Space filled with hydrogen.
D.
Space filled with corrosive gases such
as Cl2,NH3,Nox,etc.
E.
With radioactive rays.
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