MPL 25x12.5x5 / N38 - lamellar magnet
lamellar magnet
Catalog no 020136
GTIN/EAN: 5906301811428
length
25 mm [±0,1 mm]
Width
12.5 mm [±0,1 mm]
Height
5 mm [±0,1 mm]
Weight
11.72 g
Magnetization Direction
↑ axial
Load capacity
7.72 kg / 75.74 N
Magnetic Induction
299.70 mT / 2997 Gs
Coating
[NiCuNi] Nickel
4.92 ZŁ with VAT / pcs + price for transport
4.00 ZŁ net + 23% VAT / pcs
bulk discounts:
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Technical of the product - MPL 25x12.5x5 / N38 - lamellar magnet
Specification / characteristics - MPL 25x12.5x5 / N38 - lamellar magnet
| properties | values |
|---|---|
| Cat. no. | 020136 |
| GTIN/EAN | 5906301811428 |
| Production/Distribution | Dhit sp. z o.o. |
| Country of origin | Poland / China / Germany |
| Customs code | 85059029 |
| length | 25 mm [±0,1 mm] |
| Width | 12.5 mm [±0,1 mm] |
| Height | 5 mm [±0,1 mm] |
| Weight | 11.72 g |
| Magnetization Direction | ↑ axial |
| Load capacity ~ ? | 7.72 kg / 75.74 N |
| Magnetic Induction ~ ? | 299.70 mT / 2997 Gs |
| Coating | [NiCuNi] Nickel |
| Manufacturing Tolerance | ±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 | mT |
| 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 sintered neodymium magnets Nd2Fe14B at 20°C
| properties | values | units |
|---|---|---|
| Vickers hardness | ≥550 | Hv |
| 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 10-6 | °C-1 |
| Thermal expansion perpendicular (⊥) to orientation (M) | -(1-3) x 10-6 | °C-1 |
| Young's modulus | 1.7 x 104 | kg/mm² |
Technical simulation of the product - technical parameters
Presented data constitute the outcome of a mathematical simulation. Values were calculated on models for the class Nd2Fe14B. Real-world parameters might slightly differ. Please consider these calculations as a supplementary guide when designing systems.
Table 1: Static force (pull vs distance) - power drop
MPL 25x12.5x5 / N38
| Distance (mm) | Induction (Gauss) / mT | Pull Force (kg/lbs/g/N) | Risk Status |
|---|---|---|---|
| 0 mm |
2996 Gs
299.6 mT
|
7.72 kg / 17.02 lbs
7720.0 g / 75.7 N
|
warning |
| 1 mm |
2705 Gs
270.5 mT
|
6.29 kg / 13.87 lbs
6292.6 g / 61.7 N
|
warning |
| 2 mm |
2384 Gs
238.4 mT
|
4.89 kg / 10.77 lbs
4886.6 g / 47.9 N
|
warning |
| 3 mm |
2067 Gs
206.7 mT
|
3.67 kg / 8.10 lbs
3674.4 g / 36.0 N
|
warning |
| 5 mm |
1517 Gs
151.7 mT
|
1.98 kg / 4.36 lbs
1979.6 g / 19.4 N
|
low risk |
| 10 mm |
702 Gs
70.2 mT
|
0.42 kg / 0.93 lbs
424.1 g / 4.2 N
|
low risk |
| 15 mm |
355 Gs
35.5 mT
|
0.11 kg / 0.24 lbs
108.6 g / 1.1 N
|
low risk |
| 20 mm |
198 Gs
19.8 mT
|
0.03 kg / 0.07 lbs
33.6 g / 0.3 N
|
low risk |
| 30 mm |
76 Gs
7.6 mT
|
0.01 kg / 0.01 lbs
5.0 g / 0.0 N
|
low risk |
| 50 mm |
20 Gs
2.0 mT
|
0.00 kg / 0.00 lbs
0.3 g / 0.0 N
|
low risk |
Table 2: Vertical force (vertical surface)
MPL 25x12.5x5 / N38
| Distance (mm) | Friction coefficient | Pull Force (kg/lbs/g/N) |
|---|---|---|
| 0 mm | Stal (~0.2) |
1.54 kg / 3.40 lbs
1544.0 g / 15.1 N
|
| 1 mm | Stal (~0.2) |
1.26 kg / 2.77 lbs
1258.0 g / 12.3 N
|
| 2 mm | Stal (~0.2) |
0.98 kg / 2.16 lbs
978.0 g / 9.6 N
|
| 3 mm | Stal (~0.2) |
0.73 kg / 1.62 lbs
734.0 g / 7.2 N
|
| 5 mm | Stal (~0.2) |
0.40 kg / 0.87 lbs
396.0 g / 3.9 N
|
| 10 mm | Stal (~0.2) |
0.08 kg / 0.19 lbs
84.0 g / 0.8 N
|
| 15 mm | Stal (~0.2) |
0.02 kg / 0.05 lbs
22.0 g / 0.2 N
|
| 20 mm | Stal (~0.2) |
0.01 kg / 0.01 lbs
6.0 g / 0.1 N
|
| 30 mm | Stal (~0.2) |
0.00 kg / 0.00 lbs
2.0 g / 0.0 N
|
| 50 mm | Stal (~0.2) |
0.00 kg / 0.00 lbs
0.0 g / 0.0 N
|
Table 3: Wall mounting (shearing) - behavior on slippery surfaces
MPL 25x12.5x5 / N38
| Surface type | Friction coefficient / % Mocy | Max load (kg/lbs/g/N) |
|---|---|---|
| Raw steel |
µ = 0.3
30% Nominalnej Siły
|
2.32 kg / 5.11 lbs
2316.0 g / 22.7 N
|
| Painted steel (standard) |
µ = 0.2
20% Nominalnej Siły
|
1.54 kg / 3.40 lbs
1544.0 g / 15.1 N
|
| Oily/slippery steel |
µ = 0.1
10% Nominalnej Siły
|
0.77 kg / 1.70 lbs
772.0 g / 7.6 N
|
| Magnet with anti-slip rubber |
µ = 0.5
50% Nominalnej Siły
|
3.86 kg / 8.51 lbs
3860.0 g / 37.9 N
|
Table 4: Material efficiency (substrate influence) - sheet metal selection
MPL 25x12.5x5 / N38
| Steel thickness (mm) | % power | Real pull force (kg/lbs/g/N) |
|---|---|---|
| 0.5 mm |
|
0.77 kg / 1.70 lbs
772.0 g / 7.6 N
|
| 1 mm |
|
1.93 kg / 4.25 lbs
1930.0 g / 18.9 N
|
| 2 mm |
|
3.86 kg / 8.51 lbs
3860.0 g / 37.9 N
|
| 3 mm |
|
5.79 kg / 12.76 lbs
5790.0 g / 56.8 N
|
| 5 mm |
|
7.72 kg / 17.02 lbs
7720.0 g / 75.7 N
|
| 10 mm |
|
7.72 kg / 17.02 lbs
7720.0 g / 75.7 N
|
| 11 mm |
|
7.72 kg / 17.02 lbs
7720.0 g / 75.7 N
|
| 12 mm |
|
7.72 kg / 17.02 lbs
7720.0 g / 75.7 N
|
Table 5: Thermal stability (material behavior) - thermal limit
MPL 25x12.5x5 / N38
| Ambient temp. (°C) | Power loss | Remaining pull (kg/lbs/g/N) | Status |
|---|---|---|---|
| 20 °C | 0.0% |
7.72 kg / 17.02 lbs
7720.0 g / 75.7 N
|
OK |
| 40 °C | -2.2% |
7.55 kg / 16.65 lbs
7550.2 g / 74.1 N
|
OK |
| 60 °C | -4.4% |
7.38 kg / 16.27 lbs
7380.3 g / 72.4 N
|
|
| 80 °C | -6.6% |
7.21 kg / 15.90 lbs
7210.5 g / 70.7 N
|
|
| 100 °C | -28.8% |
5.50 kg / 12.12 lbs
5496.6 g / 53.9 N
|
Table 6: Two magnets (repulsion) - forces in the system
MPL 25x12.5x5 / N38
| Gap (mm) | Attraction (kg/lbs) (N-S) | Shear Strength (kg/lbs/g/N) | Repulsion (kg/lbs) (N-N) |
|---|---|---|---|
| 0 mm |
17.29 kg / 38.13 lbs
4 511 Gs
|
2.59 kg / 5.72 lbs
2594 g / 25.4 N
|
N/A |
| 1 mm |
15.73 kg / 34.68 lbs
5 715 Gs
|
2.36 kg / 5.20 lbs
2360 g / 23.2 N
|
14.16 kg / 31.22 lbs
~0 Gs
|
| 2 mm |
14.10 kg / 31.08 lbs
5 410 Gs
|
2.11 kg / 4.66 lbs
2114 g / 20.7 N
|
12.69 kg / 27.97 lbs
~0 Gs
|
| 3 mm |
12.48 kg / 27.52 lbs
5 091 Gs
|
1.87 kg / 4.13 lbs
1872 g / 18.4 N
|
11.23 kg / 24.77 lbs
~0 Gs
|
| 5 mm |
9.52 kg / 20.99 lbs
4 446 Gs
|
1.43 kg / 3.15 lbs
1428 g / 14.0 N
|
8.57 kg / 18.89 lbs
~0 Gs
|
| 10 mm |
4.43 kg / 9.78 lbs
3 034 Gs
|
0.67 kg / 1.47 lbs
665 g / 6.5 N
|
3.99 kg / 8.80 lbs
~0 Gs
|
| 20 mm |
0.95 kg / 2.09 lbs
1 404 Gs
|
0.14 kg / 0.31 lbs
142 g / 1.4 N
|
0.85 kg / 1.88 lbs
~0 Gs
|
| 50 mm |
0.03 kg / 0.06 lbs
238 Gs
|
0.00 kg / 0.01 lbs
4 g / 0.0 N
|
0.02 kg / 0.05 lbs
~0 Gs
|
| 60 mm |
0.01 kg / 0.02 lbs
153 Gs
|
0.00 kg / 0.00 lbs
2 g / 0.0 N
|
0.01 kg / 0.02 lbs
~0 Gs
|
| 70 mm |
0.01 kg / 0.01 lbs
103 Gs
|
0.00 kg / 0.00 lbs
1 g / 0.0 N
|
0.00 kg / 0.00 lbs
~0 Gs
|
| 80 mm |
0.00 kg / 0.01 lbs
73 Gs
|
0.00 kg / 0.00 lbs
0 g / 0.0 N
|
0.00 kg / 0.00 lbs
~0 Gs
|
| 90 mm |
0.00 kg / 0.00 lbs
53 Gs
|
0.00 kg / 0.00 lbs
0 g / 0.0 N
|
0.00 kg / 0.00 lbs
~0 Gs
|
| 100 mm |
0.00 kg / 0.00 lbs
40 Gs
|
0.00 kg / 0.00 lbs
0 g / 0.0 N
|
0.00 kg / 0.00 lbs
~0 Gs
|
Table 7: Hazards (electronics) - precautionary measures
MPL 25x12.5x5 / N38
| Object / Device | Limit (Gauss) / mT | Safe distance |
|---|---|---|
| Pacemaker | 5 Gs (0.5 mT) | 8.5 cm |
| Hearing aid | 10 Gs (1.0 mT) | 6.5 cm |
| Timepiece | 20 Gs (2.0 mT) | 5.0 cm |
| Mobile device | 40 Gs (4.0 mT) | 4.0 cm |
| Remote | 50 Gs (5.0 mT) | 4.0 cm |
| Payment card | 400 Gs (40.0 mT) | 1.5 cm |
| HDD hard drive | 600 Gs (60.0 mT) | 1.5 cm |
Table 8: Impact energy (kinetic energy) - collision effects
MPL 25x12.5x5 / N38
| Start from (mm) | Speed (km/h) | Energy (J) | Predicted outcome |
|---|---|---|---|
| 10 mm |
26.76 km/h
(7.43 m/s)
|
0.32 J | |
| 30 mm |
44.85 km/h
(12.46 m/s)
|
0.91 J | |
| 50 mm |
57.88 km/h
(16.08 m/s)
|
1.51 J | |
| 100 mm |
81.85 km/h
(22.74 m/s)
|
3.03 J |
Table 9: Corrosion resistance
MPL 25x12.5x5 / N38
| Technical parameter | Value / Description |
|---|---|
| Coating type | [NiCuNi] Nickel |
| Layer structure | Nickel - Copper - Nickel |
| Layer thickness | 10-20 µm |
| Salt spray test (SST) ? | 24 h |
| Recommended environment | Indoors only (dry) |
Table 10: Construction data (Flux)
MPL 25x12.5x5 / N38
| Parameter | Value | SI Unit / Description |
|---|---|---|
| Magnetic Flux | 9 639 Mx | 96.4 µWb |
| Pc Coefficient | 0.35 | Low (Flat) |
Table 11: Physics of underwater searching
MPL 25x12.5x5 / N38
| Environment | Effective steel pull | Effect |
|---|---|---|
| Air (land) | 7.72 kg | Standard |
| Water (riverbed) |
8.84 kg
(+1.12 kg buoyancy gain)
|
+14.5% |
1. Wall mount (shear)
*Warning: On a vertical surface, the magnet holds only approx. 20-30% of its perpendicular strength.
2. Efficiency vs thickness
*Thin steel (e.g. computer case) significantly weakens the holding force.
3. Power loss vs temp
*For N38 grade, the safety limit is 80°C.
4. Demagnetization curve and operating point (B-H)
chart generated for the permeance coefficient Pc (Permeance Coefficient) = 0.35
This simulation demonstrates the magnetic stability of the selected magnet under specific geometric conditions. The solid red line represents the demagnetization curve (material potential), while the dashed blue line is the load line based on the magnet's geometry. The Pc (Permeance Coefficient), also known as the load line slope, is a dimensionless value that describes the relationship between the magnet's shape and its magnetic stability. The intersection of these two lines (the black dot) is the operating point — it determines the actual magnetic flux density generated by the magnet in this specific configuration. A higher Pc value means the magnet is more 'slender' (tall relative to its area), resulting in a higher operating point and better resistance to irreversible demagnetization caused by external fields or temperature. A value of 0.42 is relatively low (typical for flat magnets), meaning the operating point is closer to the 'knee' of the curve — caution is advised when operating at temperatures near the maximum limit to avoid strength loss.
Chemical composition
| iron (Fe) | 64% – 68% |
| neodymium (Nd) | 29% – 32% |
| boron (B) | 1.1% – 1.2% |
| dysprosium (Dy) | 0.5% – 2.0% |
| coating (Ni-Cu-Ni) | < 0.05% |
Sustainability
| recyclability (EoL) | 100% |
| recycled raw materials | ~10% (pre-cons) |
| carbon footprint | low / zredukowany |
| waste code (EWC) | 16 02 16 |
Other products
Pros and cons of rare earth magnets.
Pros
- They have constant strength, and over around 10 years their attraction force decreases symbolically – ~1% (in testing),
- They have excellent resistance to magnetic field loss when exposed to external magnetic sources,
- Thanks to the shiny finish, the surface of Ni-Cu-Ni, gold-plated, or silver gives an visually attractive appearance,
- Magnets possess maximum magnetic induction on the active area,
- Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
- Thanks to modularity in constructing and the capacity to adapt to unusual requirements,
- Huge importance in electronics industry – they are commonly used in mass storage devices, electric drive systems, medical devices, as well as industrial machines.
- Compactness – despite small sizes they provide effective action, making them ideal for precision applications
Disadvantages
- To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
- NdFeB magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
- They rust in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
- Limited ability of creating threads in the magnet and complex shapes - recommended is a housing - magnet mounting.
- Possible danger related to microscopic parts of magnets can be dangerous, if swallowed, which gains importance in the aspect of protecting the youngest. Additionally, small elements of these devices are able to be problematic in diagnostics medical when they are in the body.
- High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which hinders application in large quantities
Holding force characteristics
Maximum holding power of the magnet – what affects it?
- using a plate made of low-carbon steel, functioning as a circuit closing element
- with a thickness minimum 10 mm
- with an polished contact surface
- under conditions of ideal adhesion (metal-to-metal)
- for force acting at a right angle (in the magnet axis)
- at temperature approx. 20 degrees Celsius
Determinants of lifting force in real conditions
- Air gap (between the magnet and the metal), because even a tiny distance (e.g. 0.5 mm) leads to a decrease in force by up to 50% (this also applies to paint, corrosion or dirt).
- Angle of force application – highest force is available only during pulling at a 90° angle. The force required to slide of the magnet along the plate is typically many times lower (approx. 1/5 of the lifting capacity).
- Steel thickness – insufficiently thick steel causes magnetic saturation, causing part of the power to be wasted into the air.
- Metal type – not every steel reacts the same. High carbon content weaken the attraction effect.
- Surface finish – ideal contact is obtained only on polished steel. Any scratches and bumps reduce the real contact area, reducing force.
- Thermal environment – temperature increase results in weakening of induction. Check the thermal limit for a given model.
Lifting capacity was determined by applying a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, however under shearing force the lifting capacity is smaller. Additionally, even a slight gap between the magnet’s surface and the plate reduces the lifting capacity.
Safe handling of neodymium magnets
Dust is flammable
Fire warning: Neodymium dust is highly flammable. Do not process magnets in home conditions as this risks ignition.
Nickel coating and allergies
Certain individuals experience a contact allergy to Ni, which is the typical protective layer for neodymium magnets. Extended handling might lead to an allergic reaction. We strongly advise wear safety gloves.
Danger to the youngest
Product intended for adults. Tiny parts can be swallowed, causing intestinal necrosis. Store out of reach of children and animals.
ICD Warning
For implant holders: Strong magnetic fields affect medical devices. Maintain minimum 30 cm distance or ask another person to handle the magnets.
Physical harm
Large magnets can break fingers instantly. Under no circumstances place your hand betwixt two attracting surfaces.
Eye protection
NdFeB magnets are ceramic materials, meaning they are fragile like glass. Impact of two magnets leads to them shattering into small pieces.
Safe operation
Be careful. Neodymium magnets attract from a distance and connect with huge force, often quicker than you can react.
Phone sensors
Be aware: rare earth magnets generate a field that interferes with sensitive sensors. Maintain a separation from your mobile, device, and navigation systems.
Heat warning
Standard neodymium magnets (N-type) lose power when the temperature goes above 80°C. This process is irreversible.
Data carriers
Data protection: Neodymium magnets can ruin payment cards and delicate electronics (pacemakers, medical aids, timepieces).
