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MP 25x7.5/4.5x5 / N38 - ring magnet

ring magnet

Catalog no 030194

GTIN: 5906301812111

Diameter [±0,1 mm]

25 mm

internal diameter Ø [±0,1 mm]

7.5/4.5 mm

Height [±0,1 mm]

5 mm

Weight

22.38 g

Magnetization Direction

↑ axial

Load capacity

1.71 kg / 16.77 N

Magnetic Induction

333.60 mT

Coating

[NiCuNi] nickel

8.00 ZŁ with VAT / pcs + price for transport

6.50 ZŁ net + 23% VAT / pcs

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MP 25x7.5/4.5x5 / N38 - ring magnet

Specification/characteristics MP 25x7.5/4.5x5 / N38 - ring magnet

properties

values

Cat. no.

030194

GTIN

5906301812111

Production/Distribution

Dhit sp. z o.o.

Country of origin

Polska / Chiny / Niemcy

Customs code

85059029

Diameter

25 mm [±0,1 mm]

internal diameter Ø

7.5/4.5 mm [±0,1 mm]

Height

5 mm [±0,1 mm]

Weight

22.38 g [±0,1 mm]

Magnetization Direction

↑ axial

Load capacity ~ ?

1.71 kg / 16.77 N

Magnetic Induction ~ ?

333.60 mT

Coating

[NiCuNi] nickel

tolerancja wykonania

± 0.1 mm

Magnetic properties of material N38

properties

values

units

remenance Br [Min. - Max.] ?

12.2-12.6

kGs

remenance Br [Min. - Max.] ?

1220-1260

coercivity bHc ?

10.8-11.5

kOe

coercivity bHc ?

860-915

kA/m

actual internal force iHc

≥ 12

kOe

actual internal force iHc

≥ 955

kA/m

energy density [Min. - Max.] ?

36-38

BH max MGOe

energy density [Min. - Max.] ?

287-303

BH max KJ/m

max. temperature ?

≤ 80

°C

Physical properties of NdFeB

properties

values

units

Vickers hardness

≥550

Density

≥7.4

g/cm³

Curie Temperature TC

312 - 380

°C

Curie Temperature TF

593 - 716

°F

Specific resistance

150

μΩ⋅Cm

Bending strength

250

Mpa

Compressive strength

1000~1100

Mpa

Thermal expansion parallel (∥) to orientation (M)

(3-4) x 106

°C^-1

Thermal expansion perpendicular (⊥) to orientation (M)

-(1-3) x 10-6

°C^-1

Young's modulus

1.7 x 104

kg/mm²

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Due to unique properties, MP 25x7.5/4.5x5 / N38 in a ring-shaped form finds extensive use in various industries. Thanks to a powerful magnetic field of ${capacity} kg, which can be described as force, they are key in applications that require high magnetic power in a relatively small area. Applications of MP 25x7.5/4.5x5 / N38 magnets include electrical mechanisms, generators, audio systems, and several other devices that use magnets for generating motion or storing energy. Despite their significant strength, they have a comparatively low weight of ${weight} grams, which makes them more practical compared to heavier alternatives.

Ring magnets work due to their atomic structure. Their properties arise from a controlled production process, including sintering and magnetization, which allows for generating a strong and precise magnetic field. This makes them perfect for devices such as stepper motors or industrial robots. Moreover, ring magnets are resistant to demagnetization.

Ring magnets have a wide range of applications in many industries, such as production of electronic devices, such as speakers and electric motors, automotive, where they are used in brushless electric motors, and medicine, where they are used in precision diagnostic devices. Their ability to work in high temperatures and precise magnetic field control makes them ideal for technologically advanced applications.

Their uniqueness comes from high magnetic strength, ability to work in extreme conditions, and precision in generating the magnetic field. Their unique ring form allows for application in devices requiring concentrated magnetic fields. Moreover, these magnets are significantly stronger and more versatile than ferrite counterparts, making them an ideal choice in the automotive, electronics, and medical industries.

Thanks to their resistance to high temperatures, ring magnets operate reliably even in tough conditions. Their magnetic properties remain stable, as long as the temperature does not exceed the Curie point. Compared to other types of magnets, ring magnets show greater resistance to demagnetization. For this reason, they are ideal for applications in the automotive industry, robotics, and devices requiring operation in changing or extreme environmental conditions.

Advantages and disadvantages of neodymium magnets

Neodymium magnets, also known as NdFeB magnets, are currently the strongest permanent magnets available on the market. Their exceptional magnetic properties make them suitable for various industries, technologies, and everyday life. Below are the key advantages:

Immense attractive force: Even small neodymium magnets generate a very strong magnetic field.
High coercivity: They are resistant to demagnetization by external magnetic fields.
Wide operating temperature range: Standard neodymium magnets operate up to 80°C, with special versions up to 230°C.
Variety of shapes and sizes: Available in many forms, making them easy to adapt to specific applications.
Relatively low price compared to strength: They offer the best strength-to-price ratio among all magnets.
Longevity: With proper use, they retain their magnetic properties for many years.
Versatility of applications: From electric motors to speakers, separators, toys, and jewelry.

Despite numerous advantages, neodymium magnets also have certain disadvantages to consider:

Brittleness: They are hard but brittle and prone to cracking or chipping upon impact.
Susceptibility to corrosion: They require a protective coating (e.g., nickel, zinc) to prevent rusting.
Limited operating temperature for standard versions: Above the Curie temperature, they lose their magnetic properties.
Strong magnetic field can be dangerous: They can damage electronics, magnetic cards, and pose a risk of attracting metal objects with great force.
Difficulties in mechanical processing: Due to their hardness and brittleness, processing them is complex.

Exercise Caution with Neodymium Magnets

If you have a nickel allergy, avoid contact with neodymium magnets.

Studies show a small percentage of people have allergies to certain metals, including nickel. An allergic reaction often manifests as skin redness and rash. If you have a nickel allergy, you can try wearing gloves or simply avoid direct contact with nickel-plated neodymium magnets.

Neodymium magnets can become demagnetized at high temperatures.

Although magnets have shown to retain their effectiveness up to 80°C or 175°F, this temperature may vary depending on the type of material, shape, and intended use of the magnet.

Neodymium magnets can attract to each other due to their immense internal force, causing the skin and other body parts to get pinched and resulting in significant injuries.

If have a finger between or alternatively on the path of attracting magnets, there may be a serious cut or a fracture.

Comparing neodymium magnets to ferrite magnets (found in speakers), they are 10 times more powerful, and their strength can shock you.

Read the information on our website on how to properly utilize neodymium magnets and avoid significant harm to your body and unintentional damage to the magnets.

Keep neodymium magnets away from TV, wallet, and computer HDD.

Strong fields generated by neodymium magnets can damage magnetic storage media such as floppy disks, credit cards, magnetic ID cards, cassette tapes, video tapes, or other similar devices. In addition, they can damage televisions, VCRs, computer monitors, and CRT displays. You should especially avoid placing neodymium magnets near electronic devices.

Neodymium magnets are particularly delicate, which leads to damage.

Neodymium magnets are fragile as well as will shatter if allowed to collide with each other, even from a distance of a few centimeters. They are coated with a shiny nickel plating similar to steel, but they are not as hard. In the case of a collision between two magnets, there can be a scattering of small sharp metal fragments in different directions. Protecting your eyes is essential.

It is important to maintain neodymium magnets out of reach from youngest children.

Neodymium magnets are not toys. You cannot allow them to become toys for children. In the case of small magnets, they can be swallowed and cause choking. In such cases, the only solution is to undergo surgery to remove the magnets, and otherwise, it can even lead to death.

Keep neodymium magnets as far away as possible from GPS and smartphones.

Neodymium magnets are a source of intense magnetic fields that cause interference with magnetometers and compasses used in navigation, as well as internal compasses of smartphones and GPS devices.

Dust and powder from neodymium magnets are highly flammable.

Avoid drilling or mechanical processing of neodymium magnets. If the magnet is crushed into fine powder or dust, it becomes highly flammable.

Neodymium magnets should not be near people with pacemakers.

Neodymium magnets generate strong magnetic fields. As a result, they interfere with the operation of a pacemaker. This happens because such devices have a function to deactivate them in a magnetic field.

To raise awareness of why neodymium magnets are so dangerous, read the article titled How dangerous are powerful neodymium magnets?.