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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

Poland / China / Germany

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

Manufacturing Tolerance

± 0.1 mm

Magnetic properties of material N38

properties

values

units

coercivity bHc ?

860-915

kA/m

coercivity bHc ?

10.8-11.5

kOe

energy density [Min. - Max.] ?

287-303

BH max KJ/m

energy density [Min. - Max.] ?

36-38

BH max MGOe

remenance Br [Min. - Max.] ?

12.2-12.6

kGs

remenance Br [Min. - Max.] ?

1220-1260

actual internal force iHc

≥ 955

kA/m

actual internal force iHc

≥ 12

kOe

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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Neodymium magnets MP 25x7.5/4.5x5 / N38 in a ring form are regularly used in various industries due to their specific properties. Thanks to a powerful magnetic field of 1.71 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 electric motors, generating systems, audio systems, and numerous other devices that use magnets for producing motion or energy storage. Despite their significant strength, they have a comparatively low weight of 22.38 grams, which makes them more practical compared to bulkier alternatives.

The operation of ring magnets results from their unique 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. Additionally, their resistance to high temperatures and demagnetization makes them indispensable in industry.

They are used in various fields of technology and industry, such as production of electronic devices, such as speakers and electric motors, the automotive industry, e.g., in the construction of electric motors, and medical equipment, e.g., in scanning devices. Thanks to their temperature resistance and precision makes them indispensable in challenging industrial conditions.

Ring magnets stand out high magnetic strength, resistance to high temperatures, precise control of the magnetic field. Their unique ring form allows for application in devices requiring concentrated magnetic fields. Additionally, these magnets are more durable than traditional ferrite magnets, which has made them popular in advanced technologies and industrial applications.

Ring magnets perform excellently across a wide range of temperatures. They do not lose their magnetic properties, until the Curie temperature is exceeded, which for neodymium magnets is around 80°C. They are more resistant to loss of magnetism than traditional ferrite magnets. 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 NdFeB.

Apart from immense power, neodymium magnets have the following advantages:

They do not lose strength over time - after about 10 years, their strength decreases by only ~1% (theoretically),
They protect against demagnetization caused by external magnetic field very well,
By applying a shiny coating of nickel, gold, or silver, the element gains an aesthetic appearance,
They exhibit extremely high magnetic induction on the surface of the magnet,
By using an appropriate combination of materials, they can achieve high thermal resistance, allowing them to operate at temperatures up to 230°C and above...
The ability for precise shaping and customization to specific needs – neodymium magnets can be produced in various forms and dimensions, which enhances their versatility in applications.
Significant importance in the industry of new technologies – are used in HDD drives, electric motors, medical apparatus or various technologically advanced devices.

Disadvantages of neodymium magnets:

They can break when subjected to a strong impact. If the magnets are exposed to impacts, we recommend using magnets in a protective case. The steel housing in the form of a holder protects the magnet from impacts and at the same time increases its overall strength,
They lose power at high temperatures. Most neodymium magnets experience permanent loss of strength when heated above 80°C (depending on the form and height). However, we also offer special magnets with high temperature resistance, up to 230°C,
They rust in a humid environment. For outdoor use, we recommend using waterproof magnets, such as those made of rubber or plastic,
The use of a cover - a magnetic holder is recommended due to the limited production capabilities of creating threads or complex shapes in the magnet
Potential hazard to health from tiny fragments of magnets pose a threat, if swallowed, which is particularly important in the context of children's health. Furthermore, tiny parts of these magnets are able to be problematic in medical diagnosis when they are in the body.

Be Cautious with Neodymium Magnets

Magnets should not be treated as toys. Therefore, it is not recommended for children to have access to them.

Remember that neodymium magnets are not toys. Be cautious and make sure no child plays with them. Small magnets can pose a serious choking hazard. If multiple magnets are swallowed, they can attract to each other through the intestinal walls, causing significant injuries, and even death.

Neodymium magnets are not recommended for people with pacemakers.

Neodymium magnets generate very strong magnetic fields that can interfere with the operation of a pacemaker. This is because many of these devices are equipped with a function that deactivates the device in a magnetic field.

Neodymium magnets can demagnetize at high temperatures.

Under specific conditions, Neodymium magnets can lose their magnetism when subjected to high temperatures.

Neodymium magnetic are extremely delicate, they easily fall apart as well as can become damaged.

Magnets made of neodymium are delicate as well as will break if allowed to collide with each other, even from a distance of a few centimeters. Despite being made of metal as well as coated with a shiny nickel plating, they are not as hard as steel. At the moment of collision between the magnets, tiny sharp metal pieces can be propelled in various directions at high speed. Eye protection is recommended.

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

On our website, you can find information on how to use neodymium magnets. This will help you avoid injuries and prevent damage to the magnets.

Dust and powder from neodymium magnets are highly flammable.

Do not attempt to drill into neodymium magnets. Mechanical processing is also not recommended. Once crushed into fine powder or dust, this material becomes highly flammable.

Neodymium magnets can attract to each other, pinch the skin, and cause significant injuries.

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

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

Magnetic fields can interfere with compasses and magnetometers used in aviation and maritime navigation, as well as internal compasses of smartphones and GPS devices. There are neodymium magnets in every smartphone, for example, in the microphone and speakers.

Make sure not to bring neodymium magnets close to the TV, wallet, and computer HDD.

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

The magnet is coated with nickel - be careful if you have an allergy.

Studies clearly indicate a small percentage of people who suffer from metal allergies such as 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.

Exercise caution!

In order to show why neodymium magnets are so dangerous, read the article - How very dangerous are powerful neodymium magnets?.