MP 25x8x5 / N38 - ring magnet
ring magnet
Catalog no 030196
GTIN: 5906301812135
Diameter [±0,1 mm]
25 mm
internal diameter Ø [±0,1 mm]
8 mm
Height [±0,1 mm]
5 mm
Weight
20.03 g
Magnetization Direction
↑ axial
Load capacity
2.28 kg / 22.36 N
Magnetic Induction
253.21 mT
Coating
[NiCuNi] nickel
5.90 ZŁ with VAT / pcs + price for transport
4.80 ZŁ net + 23% VAT / pcs
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MP 25x8x5 / N38 - ring magnet
Magnetic properties of material N38
Physical properties of NdFeB
Shopping tips
Advantages and disadvantages of neodymium magnets NdFeB.
In addition to their immense magnetic power, neodymium magnets offer the following advantages:
- They have unchanged lifting capacity, and over more than ten years their attraction force decreases symbolically – ~1% (in testing),
- They protect against demagnetization induced by ambient magnetic influence remarkably well,
- The use of a mirror-like nickel surface provides a smooth finish,
- They exhibit elevated levels of magnetic induction near the outer area of the magnet,
- They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
- With the option for tailored forming and precise design, these magnets can be produced in numerous shapes and sizes, greatly improving design adaptation,
- Wide application in new technology industries – they serve a purpose in HDDs, rotating machines, healthcare devices as well as sophisticated instruments,
- Thanks to their efficiency per volume, small magnets offer high magnetic performance, in miniature format,
Disadvantages of magnetic elements:
- They are fragile when subjected to a heavy impact. If the magnets are exposed to shocks, we recommend in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time reinforces its overall robustness,
- They lose strength at increased temperatures. Most neodymium magnets experience permanent degradation in strength when heated above 80°C (depending on the form and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
- They rust in a humid environment. For outdoor use, we recommend using sealed magnets, such as those made of plastic,
- The use of a protective casing or external holder is recommended, since machining fine details in neodymium magnets is risky,
- Possible threat from tiny pieces may arise, if ingested accidentally, which is significant in the context of child safety. It should also be noted that tiny components from these assemblies might disrupt scanning if inside the body,
- High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which increases the cost of large-scale applications
Maximum magnetic pulling force – what contributes to it?
The given holding capacity of the magnet corresponds to the highest holding force, measured in the best circumstances, specifically:
- with the use of low-carbon steel plate acting as a magnetic yoke
- having a thickness of no less than 10 millimeters
- with a refined outer layer
- with no separation
- in a perpendicular direction of force
- in normal thermal conditions
Lifting capacity in real conditions – factors
The lifting capacity of a magnet is determined by in practice the following factors, according to their importance:
- Air gap between the magnet and the plate, as even a very small distance (e.g. 0.5 mm) can cause a drop in lifting force of up to 50%.
- Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
- Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
- Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
- Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
- Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.
* Lifting capacity was assessed using a polished steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, whereas under parallel forces the load capacity is reduced by as much as 5 times. Additionally, even a small distance {between} the magnet and the plate decreases the holding force.
Precautions
Never bring neodymium magnets close to a phone and GPS.
Neodymium magnets generate strong magnetic fields that interfere with magnetometers and compasses used in navigation, as well as internal compasses of smartphones and GPS devices.
The magnet coating is made of nickel, so be cautious 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, try wearing gloves or avoid direct contact with nickel-plated neodymium magnets.
Neodymium magnets should not be near 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.
Magnets will attract to each other, so remember not to allow them to pinch together without control or place your fingers in their path.
If have a finger between or on the path of attracting magnets, there may be a large cut or even a fracture.
Dust and powder from neodymium magnets are 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.
You should maintain neodymium magnets at a safe distance from the wallet, computer, and TV.
Neodymium magnets produce intense magnetic fields that can damage magnetic media such as floppy disks, video tapes, HDDs, credit cards, magnetic ID cards, cassette tapes, or other devices. They can also damage devices like video players, televisions, CRT computer monitors. Do not forget to keep neodymium magnets at a safe distance from these electronic devices.
Neodymium magnets are over 10 times more powerful than ferrite magnets (the ones in speakers), and their power can shock you.
To handle magnets properly, it is best to familiarize yourself with our information beforehand. This will help you avoid significant harm to your body and the magnets themselves.
Neodymium magnets can demagnetize at high temperatures.
Whilst Neodymium magnets can demagnetize at high temperatures, it's important to note that the extent of this effect can vary based on factors such as the magnet's material, shape, and intended application.
Neodymium magnetic are especially delicate, resulting in their breakage.
Neodymium magnets are characterized by significant fragility. Neodymium magnets are made of metal and coated with a shiny nickel, but they are not as durable as steel. In the event of a collision between two magnets, there may be a scattering of fragments in different directions. Protecting your eyes is crucial in such a situation.
Neodymium magnets should not be around youngest children.
Remember that neodymium magnets are not toys. Do not allow children to play with them. In the case of swallowing multiple magnets simultaneously, they can attract to each other through the intestinal walls. In the worst case scenario, this can lead to death.
Be careful!
So you are aware of why neodymium magnets are so dangerous, see the article titled How dangerous are strong neodymium magnets?.