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Neodymium Magnets
Neodymium iron boron (NdFeB) magnets offer the highest energy product of any material today and are available in a wide range of shapes, sizes and grades. Neodymium magnets can be divided into sintered Neodymium magnets and bonded Neodymium magnets base on the manufacturing process. NdFeB magnets can be found in a variety of applications including high performance motors, brushless DC motors, magnetic separation, magnetic resonance imaging, sensors and loudspeakers. Neodymium magnets have made possible smaller and more advanced electronic devices than ever before.
Sintered Neodymium Magnets
Sintered Neodymium magnets have excellent permanent magnetic properties and high performance price ratio compared with traditional permanent magnets. Sintered Neodymium magnets mainly comprised of iron, neodymium, boron and other trace elements. They are widely used in the fields of transportation, energy, communications, intelligence manufacture, intelligent drive.
Magnetic Properties
1. Typical magnetic properties of sintered neodymium magnets
Magnetic properties of different manufacturers vary slightly. Following data are only for reference when designing and selecting materials.
| Grade | Residual magnetic flux density Br |
Coercive force HcB |
Intrinsic coercive force HcJ |
Maximum energy product (BH)max |
Work Temperature Tw |
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| T | kGs | kA/m | kOe | kA/m | kOe | kJ/ｍ³ | MGOe | ℃ | ||
| Range | Min | Min | Range | Reference Value | ||||||
| N | N30 | 1.08-1.13 | 10.8-11.3 | 796 | 10.0 | 955 | 12 | 223-247 | 28-31 | 80 |
| N33 | 1.13-1.17 | 11.3-11.7 | 836 | 10.5 | 955 | 12 | 247-271 | 31-34 | 80 | |
| N35 | 1.17-1.22 | 11.7-12.2 | 860 | 10.8 | 955 | 12 | 263-287 | 33-36 | 80 | |
| N38 | 1.22-1.25 | 12.2-12.5 | 860 | 10.8 | 955 | 12 | 287-310 | 36-39 | 80 | |
| N40 | 1.25-1.28 | 12.5-12.8 | 860 | 10.8 | 955 | 12 | 302-326 | 38-41 | 80 | |
| N42 | 1.28-1.32 | 12.8-13.2 | 860 | 10.8 | 955 | 12 | 318-342 | 40-43 | 80 | |
| N45 | 1.32-1.38 | 13.2-13.8 | 860 | 10.8 | 955 | 12 | 342-366 | 43-46 | 80 | |
| N48 | 1.38-1.42 | 13.8-14.2 | 860 | 10.8 | 955 | 12 | 366-390 | 46-49 | 80 | |
| N50 | 1.40-1.45 | 14.0-14.5 | 860 | 10.8 | 955 | 12 | 382-406 | 48-51 | 80 | |
| N52 | 1.43-1.48 | 14.3-14.8 | 836 | 10.5 | 955 | 12 | 398-422 | 50-53 | 80 | |
| N54 | 1.45-1.49 | 14.5-14.9 | 836 | 10.5 | 876 | 11 | 406-438 | 51-55 | 80 | |
| N56 | 1.48-1.52 | 14.8-15.2 | 836 | 10.5 | 876 | 11 | 414-454 | 52-57 | 80 | |
| M | N30M | 1.08-1.13 | 10.8-11.3 | 796 | 10.0 | 1114 | 14 | 223-247 | 28-31 | 100 |
| N33M | 1.13-1.17 | 11.3-11.7 | 836 | 10.5 | 1114 | 14 | 247-271 | 31-34 | 100 | |
| N35M | 1.17-1.22 | 11.7-12.2 | 868 | 10.9 | 1114 | 14 | 263-287 | 33-36 | 100 | |
| N38M | 1.22-1.25 | 12.2-12.5 | 899 | 11.3 | 1114 | 14 | 287-310 | 36-39 | 100 | |
| N40M | 1.25-1.28 | 12.5-12.8 | 923 | 11.6 | 1114 | 14 | 302-326 | 38-41 | 100 | |
| N42M | 1.28-1.32 | 12.8-13.2 | 955 | 12.0 | 1114 | 14 | 318-342 | 40-43 | 100 | |
| N45M | 1.32-1.38 | 13.2-13.8 | 995 | 12.5 | 1114 | 14 | 342-366 | 43-46 | 100 | |
| N48M | 1.38-1.42 | 13.8-14.2 | 1027 | 12.9 | 1114 | 14 | 366-390 | 46-49 | 100 | |
| N50M | 1.40-1.45 | 14.0-14.5 | 1033 | 13.0 | 1114 | 14 | 382-406 | 48-51 | 100 | |
| N52M | 1.43-1.48 | 14.3-14.8 | 1050 | 13.2 | 1114 | 14 | 398-422 | 50-53 | 100 | |
| N54M | 1.45-1.49 | 14.5-14.9 | 1050 | 13.2 | 1114 | 14 | 406-438 | 51-55 | 100 | |
| H | N30H | 1.08-1.13 | 10.8-11.3 | 796 | 10.0 | 1353 | 17 | 223-247 | 28-31 | 120 |
| N33H | 1.13-1.17 | 11.3-11.7 | 836 | 10.5 | 1353 | 17 | 247-271 | 31-34 | 120 | |
| N35H | 1.17-1.22 | 11.7-12.2 | 868 | 10.9 | 1353 | 17 | 263-287 | 33-36 | 120 | |
| N38H | 1.22-1.25 | 12.2-12.5 | 899 | 11.3 | 1353 | 17 | 287-310 | 36-39 | 120 | |
| N40H | 1.25-1.28 | 12.5-12.8 | 923 | 11.6 | 1353 | 17 | 302-326 | 38-41 | 120 | |
| N42H | 1.28-1.32 | 12.8-13.2 | 955 | 12.0 | 1353 | 17 | 318-342 | 40-43 | 120 | |
| N45H | 1.32-1.36 | 13.2-13.6 | 995 | 12.5 | 1353 | 17 | 342-366 | 43-46 | 120 | |
| N48H | 1.38-1.42 | 13.8-14.2 | 1027 | 12.9 | 1353 | 17 | 366-390 | 46-49 | 120 | |
| N50H | 1.40-1.45 | 14.0-14.5 | 1043 | 13.1 | 1353 | 17 | 382-406 | 48-51 | 120 | |
| N52H | 1.43-1.48 | 14.3-14.8 | 1059 | 13.3 | 1353 | 17 | 398-422 | 50-53 | 120 | |
| N54H | 1.45-1.49 | 14.5-14.9 | 1059 | 13.3 | 1273 | 16 | 406-446 | 51-55 | 120 | |
| SH | N30SH | 1.08-1.13 | 10.8-11.3 | 804 | 10.1 | 1592 | 20 | 223-247 | 28-31 | 150 |
| N33SH | 1.13-1.17 | 11.3-11.8 | 844 | 10.6 | 1592 | 20 | 247-271 | 31-34 | 150 | |
| N35SH | 1.17-1.22 | 11.7-12.2 | 876 | 11.0 | 1592 | 20 | 263-287 | 33-36 | 150 | |
| N38SH | 1.22-1.25 | 12.2-12.5 | 907 | 11.4 | 1592 | 20 | 287-310 | 36-39 | 150 | |
| N40SH | 1.25-1.28 | 12.5-12.8 | 939 | 11.8 | 1592 | 20 | 302-326 | 38-41 | 150 | |
| N42SH | 1.28-1.32 | 12.8-13.2 | 955 | 12.0 | 1592 | 20 | 318-342 | 40-43 | 150 | |
| N45SH | 1.32-1.36 | 13.2-13.6 | 995 | 12.5 | 1592 | 20 | 342-366 | 43-46 | 150 | |
| N48SH | 1.38-1.42 | 13.8-14.2 | 1035 | 13.00 | 1592 | 20 | 366-390 | 46-49 | 150 | |
| N50SH | 1.40-1.45 | 14.0-14.5 | 1043 | 13.1 | 1592 | 20 | 382-406 | 48-51 | 150 | |
| UH | N28UH | 1.04-1.08 | 10.4-10.8 | 764 | 9.6 | 1990 | 25 | 207-231 | 26-29 | 180 |
| N30UH | 1.08-1.13 | 10.8-11.3 | 812 | 10.2 | 1990 | 25 | 223-247 | 28-31 | 180 | |
| N33UH | 1.13-1.17 | 11.3-11.7 | 852 | 10.7 | 1990 | 25 | 247-271 | 31-34 | 180 | |
| N35UH | 1.17-1.22 | 11.7-12.2 | 860 | 10.8 | 1990 | 25 | 263-287 | 33-36 | 180 | |
| N38UH | 1.22-1.25 | 12.2-12.5 | 907 | 11.4 | 1990 | 25 | 287-310 | 36-39 | 180 | |
| N40UH | 1.25-1.28 | 12.5-12.8 | 923 | 11.6 | 1990 | 25 | 302-326 | 38-41 | 180 | |
| N42UH | 1.28-1.32 | 12.8-13.2 | 971 | 12.2 | 1990 | 25 | 318-342 | 40-43 | 180 | |
| N45UH | 1.32-1.36 | 13.2-13.6 | 1003 | 12.6 | 1990 | 25 | 342-366 | 43-46 | 180 | |
| N48UH | 1.38-1.42 | 13.8-14.2 | 1031 | 12.9 | 1990 | 25 | 366-390 | 46-49 | 180 | |
| EH | N28EH | 1.04-1.08 | 10.4-10.8 | 780 | 9.8 | 2388 | 30 | 207-231 | 26-29 | 200 |
| N30EH | 1.08-1.13 | 10.8-11.3 | 820 | 10.3 | 2388 | 30 | 223-247 | 28-31 | 200 | |
| N33EH | 1.13-1.17 | 11.3-11.7 | 860 | 10.8 | 2388 | 30 | 247-271 | 31-34 | 200 | |
| N35EH | 1.17-1.22 | 11.7-12.2 | 884 | 11.1 | 2388 | 30 | 263-287 | 33-36 | 200 | |
| N38EH | 1.22-1.25 | 12.2-12.5 | 923 | 11.6 | 2388 | 30 | 287-310 | 36-39 | 200 | |
| N40EH | 1.25-1.28 | 12.5-12.8 | 947 | 11.9 | 2388 | 30 | 302-326 | 38-41 | 200 | |
| N42EH | 1.28-1.32 | 12.8-13.2 | 970 | 12.2 | 2388 | 30 | 318-342 | 40-43 | 200 | |
| N45EH | 1.32-1.36 | 13.2-13.6 | 1003 | 12.6 | 2388 | 30 | 342-366 | 43-46 | 200 | |
| AH/TH | N28AH | 1.04-1.08 | 10.4-10.8 | 787 | 9.9 | 2786 | 35 | 207-231 | 26-29 | 230 |
| N30AH | 1.08-1.13 | 10.8-11.3 | 819 | 10.3 | 2786 | 35 | 223-247 | 28-31 | 230 | |
| N33AH | 1.13-1.17 | 11.3-11.7 | 843 | 10.6 | 2786 | 35 | 247-271 | 31-34 | 230 | |
| N35AH | 1.17-1.22 | 11.7-12.2 | 884 | 11.1 | 2786 | 35 | 263-287 | 33-36 | 230 | |
| N38AH | 1.22-1.25 | 12.2-12.5 | 915 | 11.5 | 2786 | 35 | 287-310 | 36-39 | 230 | |
The above mentioned data of magnetic properties and physical properties are given at room temperature (20℃).
The max working temperature of magnet is changeable due to length-diameter ratio, coating thickness and other environment factors.
Additional grades are available. Please contact us for information.
Grain Boundary Diffusion (GBD)
The max working temperature of magnet is changeable due to length-diameter ratio, coating thickness and other environment factors.
Additional grades are available. Please contact us for information.
“GBD NdFeB” magnets offer a combination of high energy density and temperature stability at moderate cost by reducing the amount of Dysprosium (Dy) (GBDD) and Terbium (Tb) (GBDT) used. This process enhances coercivity while limiting the adverse effects on remanence, when compared to traditional NdFeB manufacturing methods.
If you want to know more about these kinds of products, please feel free to contact us.
2.Temperature coefficients of sintered neodymium magnets
With higher HcJ value, sintered neodymium magnets are stable during high temperature. The following data are reference values in Chinese national standard (GB∕T 13560-2017) .
| Grade | Temperature ℃ |
Temperature Coefficients | Unit | |
|---|---|---|---|---|
| of Br | of HcJ | |||
| N Serie | 20℃~100℃ | -0.090~-0.124 | -0.70~-0.82 | %/℃ |
| M Serie | 20℃~100℃ | -0.090~-0.124 | -0.65~-0.80 | %/℃ |
| H Serie | 20℃~100℃ | -0.090~-0.124 | -0.60~-0.75 | %/℃ |
| SH Serie | 20℃~100℃ | -0.090~-0.122 | -0.55~-0.70 | %/℃ |
| 20℃~150℃ | -0.095~-0.124 | -0.50~-0.65 | %/℃ | |
| UH Serie | 20℃~100℃ | -0.090~-0.120 | -0.53~-0.66 | %/℃ |
| 20℃~180℃ | -0.095~-0.122 | -0.48~-0.61 | %/℃ | |
| EH Serie | 20℃~100℃ | -0.090~-0.120 | -0.50~-0.62 | %/℃ |
| 20℃~200℃ | -0.095~-0.122 | -0.46~-0.58 | %/℃ | |
| TH Serie | 20℃~100℃ | -0.090~-0.120 | -0.47~-0.60 | %/℃ |
| 20℃~200℃ | -0.095~-0.122 | -0.45~-0.56 | %/℃ | |
| Curie Temperture Tc | 583~623 | K | ||
| Recoil Permeability μrac | 1.05 | - | ||
3.Other characteristic physical properties
Following data are only for reference when designing and selecting materials, not as product acceptance standards.
| Item | Value | Unit |
|---|---|---|
| Density | 7.40~7.70 | g/cm3 |
| Vickers Hardness(HV) | 500~700 | HV |
| Compressive Strength | 1000~1100 | MPa |
| Tensile Strength | 80~90 | MPa |
| Bending Strength | 150~400 | MPa |
| Thermal Conductivity | 8~10 | W/(m·K） |
| Young`s Modulus | 150~200 | GPa |
|
Electrical Resistivity (20℃) |
C∥1.4~1.6 | μΩ·m |
| C ⊥1.2~1.4 |
4.Surface treatment
Surface protective treatment is the necessary procedure for the Neodymium magnet, especially sintered Neodymium magnet since Nd-rich phase possesses very strong oxidation tendency. The type and thickness of the coating depends on the prevalent environmental influences in the application.
| Coating | Thickness (μm) |
Color | SST (hrs) |
PCT (hrs) |
Characteristics |
|---|---|---|---|---|---|
| White Zn | 4-15 | Bright blue | ≥24 | – | Poor corrosion resistance. |
| Color Zn | 4-15 | Shining color | ≥48 | – | Corrosion resistance is better than white Zn. |
| NiCuNi | 5-20 | Bright silver | ≥48 | ≥48 | Most regular used multi-layer coating. Excellent humidity and salt spray resistance. |
| Aluminum | 2-15 | Bright silver | ≥24 | ≥24 | Noticeable coating. |
| Epoxy | 10-30 | Black/Grey | ≥72 | ≥72 | Excellent humidity and salt spray resistance. Superir binding force. |
| Parylene | 5-20 | Colorless | ≥96 | – | Excellent humidity, salt spray, corrosive vapors, and solvents resistance. Free of pore. |
| Phosphating | 1-3 | Dark grey | – | – | Temporary protection. |
5. Forms of Supply
1. Types of Magnetization
Sintered neodymium magnets are anisotropic materials - they have a preferred direction of magnetization locked into their structure. So the magnets can only be magnetized in one axis - any attempt to magnetize in another axis results in very little performance. Each sintered neodymium magnet has a direction of magnetization.
| Shape | Magnetization Direction | |
|---|---|---|
| Block |  |
Height |
| Cylinder/Disk |  |
Axial |
 |
Diametral | |
| Ring |  |
Axial |
 |
Diametral | |
 |
Radial | |
| Segment |  |
Diametral/Parallel |
 |
Radial | |
2. Dimensional Tolerances
Die-pressed sintered magnets usually need to be ground. The tolerance after grinding is normally ± 0.05 mm; from case to case, values up to ± 0.02 mm are possible. For tighter tolerances we would have to review the shape to inform you of the tolerances could achieve.
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Bonded Neodymium Magnets
Bonded neodymium magnets have high dimensional accuracy, magnetic uniformity and consistency. They can be divided into compression molding NdFeB and injection molding NdFeB according to the processing methods.
Bonded neodymium magnets are usually compact isotropic magnets, they can be magnetized multi-polar and made into complex shapes which are difficult to be realize on sintered neodymiunm magnets and have tight tolerances, no need for further mechanical machining.
Bonded neodymiunm magnets are widely used in computer hard disk drive and optical disk drive, printer / copier motor and magnetic roller, energy saving home appliances, consumer electronics and control components etc.
Magnetic Properties
Typical magnetic properties of bonded neodymium magnets
Bonded magnets can be divided into compression molding NdFeB and injection molding NdFeB according to the processing methods and materials. There are differences in magnetic properties among different manufacturers. Following data are only for reference when designing and selecting materials.
| Grade | Residual magnetic flux density Br |
Intrinsic coercive force HcJ |
Coercive force HcB |
Maximum energy product (BH)max |
Work Temperature Tw |
Average Temperature Coefficients of Br |
|||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| T | KGs | KA/m | KOe | KA/m | KOe | kJ/ｍ³ | MGOe | ℃ | %/℃ | ||
| Compression Molding NdFeB | BNP-2 | 300-400 | 3.0-4.0 | 240-320 | 3.0-4.0 | 480-640 | 6.0-8.0 | 24-32 | 3.0-4.0 | 160 | -0.11 |
| BNP-4 | 400-500 | 4.0-5.0 | 240-320 | 3.0-4.0 | 560-720 | 7.0-9.0 | 32-48 | 4.0-6.0 | 160 | -0.11 | |
| BNP-6 | 500-600 | 5.0-6.0 | 320-400 | 4.0-5.0 | 560-720 | 7.0-9.0 | 48-60 | 6.0-7.5 | 160 | -0.11 | |
| BNP-8 | 600-680 | 6.0-6.8 | 360-440 | 4.5-5.5 | 640-800 | 8.0-10.0 | 60-72 | 7.5-9.0 | 160 | -0.11 | |
| BNP-8L | 600-680 | 6.0-6.8 | 400-480 | 5.0-6.0 | 640-800 | 8.0-10.0 | 64-72 | 8.0-9.0 | 160 | -0.11 | |
| BNP-8H | 600-660 | 6.0-6.6 | 400-480 | 5.0-6.0 | 1040-1360 | 13.0-17.0 | 64-72 | 8.0-9.0 | 180 | -0.10 | |
| BNP-8SR | 620-680 | 6.2-6.8 | 400-480 | 5.0-6.0 | 800-1120 | 10.0-14.0 | 68-76 | 8.5-9.5 | 180 | -0.10 | |
| BNP-10 | 690-730 | 6.8-7.3 | 400-480 | 5.0-6.0 | 640-800 | 8.0-10.0 | 76-84 | 9.5-10.5 | 160 | -0.10 | |
| BNP-10H | 700-750 | 7.0-7.5 | 440-520 | 5.5-6.5 | 720-840 | 9.0-10.5 | 80-88 | 10.0-11.0 | 160 | -0.10 | |
| BNP-12 | 720-770 | 7.2-7.7 | 440-520 | 5.5-6.5 | 720-800 | 9.0-10.0 | 88-96 | 10.0-12.0 | 160 | -0.10 | |
| BNP-12H | 740-800 | 7.4-8.0 | 440-520 | 5.5-6.5 | 760-880 | 9.5-11.0 | 88-96 | 11.0-12.0 | 160 | -0.10 | |
| BNP-12L | 760-810 | 7.6-8.1 | 400-480 | 5.0-6.0 | 480-640 | 6.0-8.0 | 88-96 | 11.0-12.0 | 150 | -0.12 | |
| BNP-13L | 780-830 | 7.8-8.3 | 400-480 | 5.0-6.0 | 480-640 | 6.0-8.0 | 88-104 | 11.0-13.0 | 150 | -0.12 | |
| Injection Molding NdFeB | BNI-3 | 340-450 | 3.5-4.5 | 200-280 | 2.5-3.5 | 400-600 | 5.0-8.0 | 20-28 | 2.5-3.5 | 120 | -0.11 |
| BNI-4 | 400-500 | 4.0-5.0 | 240-320 | 3.0-4.0 | 560-720 | 7.0-9.0 | 32-48 | 4.0-6.0 | 120 | -0.11 | |
| BNI-5 | 450-550 | 4.5-5.5 | 304-360 | 3.8-4.5 | 640-800 | 8.0-10.0 | 36-44 | 4.5-5.5 | 120 | -0.11 | |
| BNI-6 | 500-600 | 5.0-6.0 | 328-384 | 4.1-4.8 | 640-800 | 8.0-10.0 | 44-52 | 5.5-6.5 | 120 | -0.11 | |
| BNI-7 | 550-650 | 5.5-6.5 | 344-400 | 4.3-5.0 | 640-800 | 8.0-10.0 | 52-60 | 6.5-7.5 | 120 | -0.12 | |
| BNI-5SR | 450-550 | 4.5-5.5 | 320-400 | 4.0-5.0 | 880-1120 | 11.0-14.0 | 36-44 | 4.5-5.5 | 180 | -0.11 | |
| BNI-6SR | 500-600 | 5.0-6.0 | 320-400 | 4.0-5.0 | 800-1120 | 11.0-14.0 | 44-52 | 5.5-6.5 | 180 | -0.11 | |
The above mentioned data of magnetic properties and physical properties are given at room temperature (20℃).
The max working temperature of magnet is changeable due to length-diameter ratio, coating thickness and other environment factors.
Additional grades are available. Please contact us for information.
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Magnetic Assemblies
Magnetic assemblies are permanent magnets which are bonded to other permanent magnets or a different carrier material. Magnetic assemblies are important links to realize the functions of magnetic materials in the form of products or semifinished products made of magnetic materials, metal, nonmetal and other materials, such as motor rotors, sensors, filters, magnetic lifters, magnetic separators and magnetic pumps etc.
MagnetSearcher are not only a supplier of magnets but also your competent partner for the development and manufacture of advanced components and magnet assemblies. To provide you with this service we simply require your initial design sketches and specification profile describing the required function of the magnet assembly, the acceptable dimensions, the thermal and environmental conditions, and the electrical limiting conditions. Or you can simply contact us directly, and we will provide you with expert assistance.