CHEMICAL COMPOSITION OF NEODYMIUM BONDED MAGNET

Bonded NdFeB permanent magnets are permanent magnet products prepared by mixing and molding NdFeB permanent magnet powder and adhesives (including organic adhesives and low melting point metals). The main ingredients are rare earth (RE), iron (Fe), boron (B) and binder.

Among them, the rare earth metal is mainly neodymium (Nd). In order to obtain different properties, some other rare earth metals such as praseodymium (Pr), lanthanum (La), and cerium (Ce) can be substituted. Iron can also be partially replaced by other metals such as cobalt (Co), zirconium (Zr), aluminum (Al), etc.

The content of boron is small, but it does play an important role in forming the tetragonal crystal structure intermetallic compound R2Fe14B, making the compound have high saturation magnetization, high uniaxial anisotropy and high Curie temperature. The binder is usually a polymer resin, such as thermosetting epoxy resin, thermoplastic nylon and polyphenylene sulfide (PPS).

MANUFACTURING PROCESS OF BONDED NDFEB MAGNETS

Bonded NdFeB magnets adopt powder metallurgy technology and composite material technology. The compression molding process usually uses thermosetting resin as the binder.

The process is as follows: first, the smelted alloy is made into magnetic powder through a rapid solidification process. Then mix with adhesive. Then it is shaped by compression method to make a compact. The compact reaches a certain mechanical strength through curing. In order to increase the anti-oxidation ability of the product, it is necessary to carry out surface anti-rust treatment on the product.

The injection molding process uses thermoplastic resin as the adhesive. The magnet does not need to be cured after injection molding.

Moreover, because the resin content is high and a protective film is formed on the surface of the magnet, surface anti-rust treatment is generally not required.

However, for occasions with relatively high anti-rust requirements, surface anti-rust treatment should also be performed, otherwise the requirements cannot be met.

encoder sensor injection molded magnets

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    APPLICATION OF BONDED NEODYMIUM

    Bonded ndfeb magnets have the advantages of good magnetic performance consistency, high dimensional accuracy, no need for post-processing, large degree of shape freedom, and low density. They can be widely used in electronic information, communications, instruments, office automation, and medical care. In the fields of equipment, automobiles, machinery and other fields, the most common ones are computer hard drives, DVD drives, printers, fax machines, air conditioners, speakers, electricity meters, clocks, etc.

    MAGNETIC PROPERTY OF BONDED MAGNET

    Compression Moulding Magnet Grades
    Grade
    Remanence
    Coercive Force
    Intrinsic Coercive Force
    Max. Energy
    Max Working Temp.
    Br
    HcB
    HcJ
    (BH)max.
    Tw.
    mT
    kGs
    (kA/m)
    (kOe)
    (kA/m)
    (kOe)
    kJ/m 3
    MGOe
    °C
    BNP-2
    300-400
    3.0-4.0
    160-240
    2.0-3.0
    440-600
    5.5-7.5
    19-26
    2.4-3.3
    160
    BNP-3
    400-510
    4.0-5.1
    216-280
    2.7-3.5
    504-680
    6.3-8.5
    24-32
    3.0-4.0
    160
    BNP-4
    460-520
    4.6-5.2
    224-288
    2.8-3.6
    504-680
    6.3-8.5
    30-35
    3.8-4.4
    160
    BNP-5
    470-550
    4.7-5.5
    240-360
    3.0-4.5
    520-680
    6.5-8.5
    37-44
    4.7-5.5
    160
    BNP-6
    550-650
    5.5-6.5
    320-376
    4.0-4.7
    600-720
    7.5-9.0
    44-52
    5.5-6.5
    160
    BNP-7
    550-650
    5.5-6.5
    320-408
    4.0-5.1
    560-680
    7.0-8.5
    52-64
    6.5-8.0
    160
    BNP-8
    620-670
    6.2-6.7
    400-456
    5.0-5.7
    640-800
    8.0-10.0
    64-76
    8.0-9.5
    160
    BNP-8A
    620-680
    6.2-6.8
    400-480
    5.0-6.0
    1040-1280
    13.0-16.0
    65-73
    8.2-9.2
    180
    BNP-9L
    670-730
    6.7-7.3
    360-416
    4.5-5.2
    520-640
    6.5-8.0
    68-75
    8.6-9.4
    120
    BNP-9
    650-700
    6.5-7.0
    416-456
    5.2-5.7
    680-800
    8.5-10.0
    68-76
    8.5-9.5
    160
    BNP-9H
    650-700
    6.5-7.0
    432-488
    5.4-6.1
    920-1040
    11.5-13.0
    71-80
    8.9-10.0
    180
    BNP-10H
    650-710
    6.5-7.1
    432-480
    5.4-6.0
    784-960
    9.8-12.0
    74-82
    9.3-10.3
    180
    BNP-10
    670-720
    6.7-7.2
    424-480
    5.3-6.0
    640-800
    8.0-10.0
    76-84
    9.5-10.5
    160
    BNP-11
    680-740
    6.8-7.4
    400-480
    5.0-6.0
    640-800
    8.0-10.0
    80-88
    10.0-11.0
    160
    BNP-12D
    720-770
    7.2-7.7
    440-520
    5.5-6.5
    720-880
    9.0-11.0
    88-96
    11.0-12.0
    160
    BNP-12L
    730-770
    7.3-7.7
    368-432
    4.6-5.4
    520-640
    6.5-8.0
    80-88
    10.0-11.0
    120
    BNP-13L
    780-830
    7.8-8.3
    400-480
    5.0-6.0
    480-640
    6.0-8.0
    88-104
    11.0-13.0
    120
     Injection Moulding Magnet Grades
    Grade
    Remanence
    Coercive Force
    Intrinsic Coercive Force
    Max. Energy
    Max Working Temp.
    Br
    HcB
    HcJ
    (BH)max.
    Tw.
    mT
    kGs
    (kA/m)
    (kOe)
    (kA/m)
    (kOe)
    kJ/m 3
    MGOe
    °C
    BNI-3
    350-450
    3.5-4.5
    200-280
    2.5-3.5
    400-460
    5.0-8.0
    20-28
    2.5-3.5
    120
    BNI-4
    400-500
    4.0-5.0
    240-320
    3.0-4.0
    560-720
    7.0-9.0
    28-36
    3.5-4.5
    120
    BNI-5
    450-550
    4.5-5.5
    304-360
    3.8-4.5
    640-800
    8.0-10.0
    36-44
    4.5-5.5
    120
    BNI-6
    500-600
    5.0-6.0
    328-384
    4.1-4.8
    640-800
    8.0-10.0
    44-52
    5.5-6.5
    120
    BNI-7
    550-650
    5.5-6.5
    344-400
    4.3-5.0
    640-800
    8.0-10.0
    52-60
    6.5-7.5
    120
    BNI-5SR(PPS)
    450-550
    4.5-5.5
    320-400
    4.0-5.0
    880-1120
    11.0-14.0
    36-44
    4.5-5.5
    180
    BNI-6SR(PPS)
    500-600
    5.0-6.0
    320-400
    4.0-5.0
    880-1120
    11.0-14.0
    44-52
    5.5-6.5
    180