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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

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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 unique properties. Thanks to a powerful magnetic field of 1.71 kg, which can be described as force, they are key in applications that require strong magnetism in a compact space. Usage of MP 25x7.5/4.5x5 / N38 magnets include electric motors, generating systems, sound devices, and numerous other devices that use magnets for producing motion or storing energy. Despite their powerful strength, they have a comparatively low weight of 22.38 grams, which makes them more convenient to use compared to heavier alternatives.

Ring magnets work due to their atomic structure. In the production process, neodymium atoms are arranged appropriately, which allows for the creation of a concentrated magnetic field in a specific direction. This makes them perfect for devices such as stepper motors or industrial robots. Additionally, ring magnets are resistant to demagnetization.

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 medicine, where they are used in precision diagnostic devices. Thanks to their temperature resistance and precision makes them ideal for technologically advanced applications.

Their uniqueness comes from extraordinary pulling power, 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 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. Because of this, they are ideal for applications in the automotive industry, robotics, and devices requiring operation in changing or extreme environmental conditions.

A ring magnet of class N50 and N52 is a strong and powerful metallic component with the shape of a ring, that offers high force and universal application. Very good price, availability, durability and broad range of uses.

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their immense field intensity, neodymium magnets offer the following advantages:

They have unchanged lifting capacity, and over more than ten years their performance decreases symbolically – ~1% (according to theory),
Their ability to resist magnetic interference from external fields is notable,
In other words, due to the glossy nickel coating, the magnet obtains an aesthetic appearance,
They exhibit elevated levels of magnetic induction near the outer area of the magnet,
Thanks to their enhanced temperature resistance, they can operate (depending on the shape) even at temperatures up to 230°C or more,
The ability for accurate shaping or adjustment to custom needs – neodymium magnets can be manufactured in multiple variants of geometries, which amplifies their functionality across industries,
Key role in cutting-edge sectors – they are used in HDDs, electromechanical systems, healthcare devices and sophisticated instruments,
Relatively small size with high magnetic force – neodymium magnets offer strong power in small dimensions, which makes them useful in miniature devices

Disadvantages of rare earth magnets:

They are prone to breaking when subjected to a powerful impact. If the magnets are exposed to shocks, we recommend in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage and reinforces its overall strength,
Magnets lose magnetic efficiency when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible field weakening (influenced by the magnet’s dimensions). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
They rust in a moist environment, especially when used outside, we recommend using waterproof magnets, such as those made of polymer,
The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is risky,
Health risk from tiny pieces may arise, if ingested accidentally, which is crucial in the context of child safety. Furthermore, minuscule fragments from these assemblies may disrupt scanning if inside the body,
Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Exercise Caution with Neodymium Magnets

Do not place neodymium magnets near a computer HDD, TV, and wallet.

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. They can also damage televisions, VCRs, computer monitors, and CRT displays. You should especially avoid placing neodymium magnets near electronic devices.

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 swellings.

If joining of neodymium magnets is not under control, at that time they may crumble and also crack. You can't approach them to each other. At a distance less than 10 cm you should hold them very strongly.

Dust and powder from neodymium magnets are 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 are the strongest magnets ever invented. Their power can shock you.

Make sure to review all the information we have provided. This will help you avoid harm to your body and damage to the magnets.

Neodymium magnets are particularly delicate, which leads to their breakage.

Magnets made of neodymium are extremely delicate, and by joining them in an uncontrolled manner, they will crack. Magnets made of neodymium are made of metal and coated with a shiny nickel, but they are not as durable as steel. At the moment of collision between the magnets, small metal fragments can be dispersed in different directions.

Keep neodymium magnets away from 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.

The magnet coating contains nickel, so be cautious if you have a nickel 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, try wearing gloves or avoid direct contact with nickel-plated neodymium magnets.

It is essential 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 such a situation, surgery is necessary to remove them. In the worst case scenario, it can result in death.

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.

Neodymium magnets can demagnetize at high temperatures.

Although magnets are generally resilient, their ability to maintain their magnetic potency can be influenced by factors like the type of material used, the magnet's shape, and the intended purpose for which it is employed.

Caution!

Please read the article - What danger lies in neodymium magnets? You will learn how to handle them properly.