NingBo BeiLun Meank Magnetics Co., Ltd
NingBo BeiLun Meank Magnetics Co., Ltd
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Strong Magnets

Strong Magnets

Strong magnets can be made into certain shapes based on different application requirement.

These types of magnets include: disc magnets, square magnets/magnet blocks, ring magnets,  cylinder magnets, countersunk magnets, plastic coated disc magnets, cone magnets and arc magnets. All the shapes above are basic shapes for magnets of which  the material is neodymium, ferrite or SmCo.

We also have wide size range for each type of neodymium permanent magnets for sale.

Strong Neodymium Magnets For Sale

Strong Neodymium Magnets For Sale
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Different Types of Permanent Magnets

NdFeB magnets are divided into sintered and bonded types. Sintered neodymium magnet has the highest magnetic energy product, and known as the strongest permanent magnet.

Strong magnets can be SmCo material which known as rare earth magnets, when the working temperature is above 180℃, its maximum magnetic energy product (BHmax), coercivity, temperature stability and chemical stability are better than those of NdFeB magnets.The maximum energy product (BHmax) of SmCo magnets ranges from 16 MGOe to 32 MGOe, and its theoretical limit is 34 MGOe

The magnetic energy product of ferrite (ceramic) magnet is much lower than that of NdFeB and SmCo, but big ferrite magnets that have powerful magnetism are also called strong magnets.

Besides the above permanent magnetic material for sale, some permanent magnetic assemblies (such as pot magnets, strong fishing magnets, hook magnets) are also called strong magnets.

Here we just introduce some common shapes of neodymium strong magnets, and mainly for sintered neodymium magnets. Because of the high machinability, it can be machined into different shapes and very wide size range is available for each shape. Besides of disc, cylinder, ring and block, neodymium magnets can be machined into some special shapes, for example, countersunk neodymium magnets, sphere neodymium magnets, neodymium cone magnets, neodymium arc & segment magnets, and neodymium convex magnets.

How to Estimate Permanent Strong Magnets Qualified or Not?

Estimate strong magnets qualified or not, mainly decided by these aspects:

Magnetic performance property: magnetic performance of a permanent strong magnet depends on the formulation, which mainly includes remanence, coercivity, and magnetic energy product. Magnetic properties are the most important aspect of magnets and need professional instrument testing.

Tolerance of the magnets: the tolerance accuracy decided by the machineability of a factory. The machining equipment keeps updated as per market needs. Efficient devices and automation trends of industrial processing, not only meet the need of increasing magnets accuracy but also save manpower and cost.

Appearance of the magnets: appearance evaluation firstly depends on whether there are defects in electroplating; secondly, see if there is a lack of angle in the magnets.



Permanent Magnet Application

Neodymium strong magnets are more and more used for fabrics, such as neodymium sew-in magnets which can be sewed in curtains, and also sewed in clothes used as waterproof magnetic buttons.

Some small strong magnets are used for decorating fridges or used on fridges or whiteboards as memo magnets.

Strong neodymium magnets for heavy-duty hanging, the big neodymium hook magnets have hundreds of kilograms holding force and are used as magnetic ceiling hooks and wall hooks.

Strong magnets of neodymium are used for magnet fishing and searching, neodymium search magnets have a strong magnetic force and are used to get out the metal objects that fell to the bottom of the river and wall.

Strong neodymium magnets are widely used for producing motors, by using neodymium magnetic tiles, the performance of motors is more stable.

Strong neodymium magnets are used for making speakers, due to the outstanding magnetic performance, strong neodymium magnets make the size of the speaker the smallest.

Neodymium strong magnets are widely used for magnetic separating, by using magnetic separator of neodymium strong magnets, the metal impurities are filtered more thoroughly from food or grain.

Permanent Magnet Specification

Parameter

International Unit

Standard Data

Curie Temperature(Tc)

310-380

Maximum Operating Temperature(Tw)

80-230

Hardness

Hv

620

Electrical Resistivity (ᵨ)

Ω.cm

1.8x10⁻⁴  ~2.0x10⁻⁴

Density(D)

g/m³

7.45~-7.65

Recoil Permeability(µ rec)


1.05

Magnetization Field Strength(Hs)

kA/m

≧2400

kOe

≧30

Bending Strength

Mpa

295-345

Temp. Coefficient of Br

%℃

-0.11~-0.12

Temp.Coefficient of Hcj

%℃

-0.5~-0.7



Surface Treatments for Neodymium Magnets

Surface

Coating

Thickness (Microns)

Color

Resistance

Passivation


1

Silver Grey

Temporary Protection

Nickel

Ni+Ni

10-20

Bright Silver

Excellent Against Humidity

Ni+Cu+Ni

Zinc

Zn

8-20

Bright Blue

Good Against Salt Spray

C-Zn

Shinny Color

Excellent Against Salt Spray

Tin

Ni+Cu+Sn

15-20

Silver

Superior Against Humidity

Silver

Ni+Cu+Ag

10-20

Silver

Superior Against Humidity

Gold

Ni+Cu+Au

10-20

Gold

Superior Against Humidity

Copper

Ni+Cu

10-20

Gold

Temporary Protection

Epoxy

Epoxy

15-25

Black,Red,Grey

Excellent Against Humidity&Salt Spray

Ni+Cu+Epoxy

Zn+Epoxy

Parylene

Parylene

5-20

Grey

Excellent Against Humidity,Salt Spray,Superior Against Solvents,Gases, Fungi and Bacteria,FDA Approved

Chemical

Ni

10-20

Silver Grey

Excellent Against Humidity


Best Temperatures to the Use of Permanent Magnet

Every grade of neodymium magnet has a specific maximum working temperature as the below list,the best temperature should not exceed the maximum of the neodymium magnets.


Neodymium Magnet Material Grade

Maximum Working Temp.

Curie Temp.

N

176°F (80°C)

590°F (310°C)

NM

212°F (100°C)

644°F (340°C)

NH

248°F (120°C)

644°F (340°C)

NSH

302°F (150°C)

644°F (340°C)

NUH

356°F (180°C)

662°F (350°C)

NEH

392°F (200°C)

662°F (350°C)

NAH

428°F (220°C)

662°F (350°C)


The maximum working temperature listed above are values just associated with each grade of permanent magnet materials.  Actual values in your application may vary depend other factors, including the shape of the magnet, the performance coefficient or load line, and how it is used in a magnetic circuit.

Strong Magnets

Common Machining Methods of Strong Permanent Magnet

Grinding machining: for sintered NdFeB magnets, grinding machine needed for the surface of rough delivered magnets. Common used grinding machine methods for block NdFeB magnets are plane grinding, two end face grinding, inner circle grinding, out circle grinding.  Cylinder NdFeB magnets adopt coreless grinding and two end plane grinding. Irregular magnets (arc magnets and segment magnets) adopt multi-station grinding.


Drilling machining: processing cylinder magnets and block magnets into round tube magnets and block magnet tubes.


Cutting machining: processing round magnet rod and magnet blocks into round magnet discs and square magnet discs.

Profile machining: processing rod magnets and rectangle magnets into arc magnets, segment magnets, cone magnets, countersunk magnets, convex magnets, ball magnets and other complex shape magnets.

FAQs about neodymium strong magnets:

FAQs about neodymium strong magnets:
  • Q.
    What is the safety distance between super neodymium magnet and other items?
    A.

    The safety distance is just demanded for ferromagnetic objects and electronics. Ferromagnetic objects and electronics should be placed outside the magnetic field of the neodymium magnets.

  • Q.
    How long do neodymium magnets last?
    A.
    As long as the working environment and preservation methods are appropriate, the magnetic force of neodymium magnets can be maintained permanently. That's why they are called as neodymium permanent magnets.
  • Q.
    What is the strongest magnet on earth?
    A.

    The strongest magnet on earth is the strong neodymium magnet which has the highest magnetic energy.

  • Q.
    What is the material used in permanent magnet?
    A.
    Permanent magnets are usually made from ferromagnetic material, which includes iron, nickel, cobalt, and minerals such as lodestone.
  • Q.
    Why are neodymium magnets so strong?
    A.
    Neodymium magnets are so strong because they are highly resistant to demagnetisation. Due to its strong saturation, we can use smaller sized neodymium magnet to generate the same magnetic fields.
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