Sintered neodymium magnets are the most powerful commercially available magnets in the world . They are made from an alloy of neodymium, iron, and boron, and are produced using a powder metallurgy process .
Sintered neodymium magnets have the highest energy product among all types of permanent magnets. They are known for their high magnetic strength, excellent temperature stability, and good corrosion resistance .
Here are some of the Physical Properties of sintered neodymium magnets:
Br Temperature Coefficient | -0.095~-0.105%/°C | Density | 7.3-7.5g/cm3 | Curie Temperature | 310-340°C |
Coercivity Temperature Coefficient | -0.45~-0.60%/°C | Vickers-hardness | 600HV | Electrical Resistivity | 114μΩ·cm |
Across Transfiguration Coefficient | 0.24 | Break Strength | 8.0Kgf/mm2 | Bending Strength | 25kgf/mm2 |
Thermal Expansion Coefficient | 4×10-6/°C | Specific Heat | 0.12Kcal/Kg | Stiffness | 0.64N/m2 |
The Conduction Coefficient | 7.7kcal/[m.h. °C] | Young’s Modulus | 1.6×1011N/m2 | Compressibility | 9.8×10-12m2/N |
Surface Treatment
Coating | Thickness(μm) | Color | SST(hrs) | PCT/HAST(hrs) | Operation Temperature (°C) | Corrosive Resistance | Application |
Zn | 4-15 | Bright blue | 24 | – | ≤160 | Good | Suitable for working conditions with low corrosive and humidity requirements. |
Ni-Cu-Ni | 5-20 | Bright silver | 48 | 48 | ≤200 | Excellent | Most regular used multi-layer coating. |
Electroless Ni | 5-20 | Dark silver | 72 | 48 | ≤200 | Excellent performance with uniform appearance. | Suitable for working conditions with high corrosive and humidity requirements. |
Ni-Cu-Ni-Au | 5-20 | Golden | 72 | 96 | ≤200 | Good | Suitable for parts that placed into the high reliable electronic equipments or decoration. |
Ni-Cu-Ni-Ag | 5-20 | Silver | 72 | 96 | ≤160 | Good | Suitable for parts that may be welded or placed into the electric equipment. |
Ni-Cu-Ni-Sn | 5-20 | Silver | 72 | 96 | ≤200 | Excellent | Suitable for parts that may be welded or placed into electric equipment. |
Passivation | 1-3 | Dark grey | – | – | ≤200 | Poor | Temporary protection. |
Aluminum | 2-15 | Bright silver | 240 | 168 | ≤400 | Excellent | Suitable for working conditions with very high corrosive and humidity requirements. |
Epoxy resin | 10-30 | Black/Grey | 96 | 24 | ≤160 | Excellent. Superior binding force. | Suitable for parts used to insulate the electric equipments or placed in the high corrosive industrial atmosphere. |
Parylene | 5-20 | Colorless | 168 | – | ≤200 | Excellent | Free of pore. Suitable for biomedical applications. |
Everlube | 10-15 | Golden yellow | 96 | 72 | ≤200 | Excellent | Suitable for working conditions with very high corrosive and humidity requirements. |
Note:1. The SST results differ from coating. In general, Salt Spray Test results, which is coated by grinding (small size magnets), is better than the one, which is coated by hanging up (big size magnets).2. Salt Spray Test (SST) condition: 5% NaCl, 35℃, continuously spray a certain time, test whether there is corrosion on coating surface.3. Pressure Cooking Test (PCT) condition: 2 atm, 95% RH (relative humidity), 121℃ to test the coating adhesion. (Zinc, Passivated, and Epoxy are not suitable for PCT).4. Other test methods for coating: Drop Test, Cross Cut test, Heating and Spilling Test, Constant Temperature and Humidity Test and etc. |
Magnetic Properties
Series | Grade | Br | Hcb | Hcj | (BH)max | TW | ||||
mT | KGs | KA/m | kOe | kA/m | kOe | kJ/m3 | MGOe | °C | ||
N | N35 | 1170-1220 | 11.7-12.2 | ≥868 | ≥10.9 | ≥955 | ≥12 | 263-287 | 33-36 | ≤80 |
N38 | 1220-1250 | 12.2-12.5 | ≥899 | ≥11.3 | ≥955 | ≥12 | 287-310 | 36-39 | ≤80 | |
N40 | 1250-1280 | 12.5-12.8 | ≥907 | ≥11.4 | ≥955 | ≥12 | 302-326 | 38-41 | ≤80 | |
N42 | 1280-1320 | 12.8-13.2 | ≥915 | ≥11.5 | ≥955 | ≥12 | 318-342 | 40-43 | ≤80 | |
N45 | 1320-1380 | 13.2-13.8 | ≥923 | ≥11.6 | ≥955 | ≥12 | 342-366 | 43-46 | ≤80 | |
N48 | 1380-1420 | 13.8-14.2 | ≥923 | ≥11.6 | ≥955 | ≥12 | 366-390 | 46-49 | ≤80 | |
N50 | 1400-1450 | 14.0-14.5 | ≥860 | ≥10.8 | ≥955 | ≥12 | 382-406 | 48-51 | ≤80 | |
N52 | 1430-1480 | 14.3-14.8 | ≥860 | ≥10.8 | ≥955 | ≥12 | 398-422 | 50-53 | ≤80 | |
N54 | 1460-1500 | 14.6-15.0 | ≥860 | ≥10.8 | ≥955 | ≥12 | 414-438 | 53-57 | ≤80 | |
N56 | 1480-1520 | 14.8-15.2 | ≥836 | ≥10.5 | ≥875 | ≥11 | 422-454 | 53-57 | ≤80 | |
M | 35M | 1170-1220 | 11.7-12.2 | ≥868 | ≥10.9 | ≥1114 | ≥14 | 263-287 | 33-36 | ≤100 |
38M | 1220-1250 | 12.2-12.5 | ≥899 | ≥11.3 | ≥1114 | ≥14 | 287-310 | 36-39 | ≤100 | |
40M | 1250-1280 | 12.5-12.8 | ≥923 | ≥11.6 | ≥1114 | ≥14 | 302-326 | 38-41 | ≤100 | |
42M | 1280-1320 | 12.8-13.2 | ≥955 | ≥12.0 | ≥1114 | ≥14 | 318-342 | 40-43 | ≤100 | |
45M | 1320-1380 | 13.2-13.8 | ≥995 | ≥12.5 | ≥1114 | ≥14 | 342-366 | 43-46 | ≤100 | |
48M | 1360-1430 | 13.6-14.3 | ≥1027 | ≥12.9 | ≥1114 | ≥14 | 366-390 | 46-49 | ≤100 | |
50M | 1400-1450 | 14.0-14.5 | ≥1033 | ≥13.0 | ≥1114 | ≥14 | 382-406 | 48-51 | ≤100 | |
52M | 1420-1480 | 14.2-14.8 | ≥1043 | ≥13.1 | ≥1114 | ≥14 | 398-422 | 50-53 | ≤100 | |
54M | 1450-1500 | 14.5-15.0 | ≥995 | ≥12.5 | ≥1035 | ≥13 | 406-438 | 51-55 | ≤100 | |
H | 35H | 1170-1220 | 11.7-12.2 | ≥868 | ≥10.9 | ≥1353 | ≥17 | 263-287 | 33-36 | ≤120 |
38H | 1220-1250 | 12.2-12.5 | ≥899 | ≥11.3 | ≥1353 | ≥17 | 287-310 | 36-39 | ≤120 | |
40H | 1250-1280 | 12.5-12.8 | ≥923 | ≥11.6 | ≥1353 | ≥17 | 302-326 | 38-41 | ≤120 | |
42H | 1280-1320 | 12.8-13.2 | ≥955 | ≥12.0 | ≥1353 | ≥17 | 318-342 | 40-43 | ≤120 | |
45H | 1300-1360 | 13.0-13.6 | ≥963 | ≥12.1 | ≥1353 | ≥17 | 326-358 | 43-46 | ≤120 | |
48H | 1370-1430 | 13.7-14.3 | ≥995 | ≥12.5 | ≥1353 | ≥17 | 366-390 | 46-49 | ≤120 | |
50H | 1400-1450 | 14.0-14.5 | ≥1003 | ≥12.6 | ≥1353 | ≥17 | 382-406 | 48-51 | ≤120 | |
52H | 1420-1480 | 14.2-14.8 | ≥1035 | ≥13.0 | ≥1353 | ≥17 | 390-422 | 49-53 | ≤120 | |
SH | 33SH | 1130-1170 | 11.3-11.7 | ≥860 | ≥10.6 | ≥1592 | ≥20 | 247-271 | 31-34 | ≤150 |
35SH | 1170-1220 | 11.7-12.2 | ≥876 | ≥11.0 | ≥1592 | ≥20 | 263-287 | 33-36 | ≤150 | |
38SH | 1220-1250 | 12.2-12.5 | ≥907 | ≥11.4 | ≥1592 | ≥20 | 287-310 | 36-39 | ≤150 | |
40SH | 1240-1280 | 12.5-12.8 | ≥939 | ≥11.8 | ≥1592 | ≥20 | 302-326 | 38-41 | ≤150 | |
42SH | 1280-1320 | 12.8-13.2 | ≥963 | ≥12.1 | ≥1592 | ≥20 | 318-342 | 40-43 | ≤150 | |
45SH | 1320-1380 | 13.2-13.8 | ≥979 | ≥12.3 | ≥1592 | ≥20 | 342-366 | 43-46 | ≤150 | |
48SH | 1370-1430 | 13.7-14.3 | ≥1019 | ≥12.8 | ≥1592 | ≥20 | 366-390 | 46-49 | ≤150 | |
50SH | 1400-1450 | 14.0-14.5 | ≥1019 | ≥12.8 | ≥1592 | ≥20 | 374-406 | 47-51 | ≤150 | |
52SH | 1420-1480 | 14.2-14.8 | ≥1035 | ≥13.0 | ≥1512 | ≥19 | 390-422 | 49-53 | ≤150 | |
UH | 28UH | 1020-1080 | 10.2-10.8 | ≥764 | ≥9.6 | ≥1990 | ≥25 | 207-231 | 26-29 | ≤180 |
30UH | 1080-1130 | 10.8-11.3 | ≥812 | ≥10.2 | ≥1990 | ≥25 | 223-247 | 28-31 | ≤180 | |
33UH | 1130-1170 | 11.3-11.7 | ≥852 | ≥10.7 | ≥1990 | ≥25 | 247-271 | 31-34 | ≤180 | |
35UH | 1180-1220 | 11.8-12.2 | ≥860 | ≥10.8 | ≥1990 | ≥25 | 263-287 | 33-36 | ≤180 | |
38UH | 1220-1250 | 12.2-12.5 | ≥899 | ≥11.0 | ≥1990 | ≥25 | 287-310 | 36-39 | ≤180 | |
40UH | 1250-1280 | 12.5-12.8 | ≥939 | ≥11.3 | ≥1990 | ≥25 | 302-326 | 38-41 | ≤180 | |
42UH | 1280-1320 | 12.8-13.2 | ≥963 | ≥12.1 | ≥1990 | ≥25 | 318-342 | 40-43 | ≤180 | |
45UH | 1320-1380 | 13.2-13.8 | ≥979 | ≥12.3 | ≥1990 | ≥25 | 342-366 | 43-46 | ≤180 | |
48UH | 1380-1420 | 13.8-14.2 | ≥1019 | ≥12.8 | ≥1910 | ≥24 | 366-390 | 46-49 | ≤180 | |
EH | 28EH | 1040-1090 | 10.4-10.9 | ≥780 | ≥9.8 | ≥2388 | ≥30 | 207-231 | 26-29 | ≤200 |
30EH | 1080-1130 | 10.8-11.3 | ≥812 | ≥10.2 | ≥2388 | ≥30 | 223-247 | 28-31 | ≤200 | |
33EH | 1130-1170 | 11.3-11.7 | ≥836 | ≥10.5 | ≥2388 | ≥30 | 247-271 | 31-34 | ≤200 | |
35EH | 1170-1220 | 11.7-12.2 | ≥876 | ≥11.0 | ≥2388 | ≥30 | 263-287 | 33-36 | ≤200 | |
38EH | 1220-1250 | 12.2-12.5 | ≥899 | ≥11.3 | ≥2388 | ≥30 | 287-310 | 36-39 | ≤200 | |
40EH | 1250-1280 | 12.5-12.8 | ≥923 | ≥11.6 | ≥2388 | ≥30 | 302-326 | 38-41 | ≤200 | |
42EH | 1280-1320 | 12.8-13.2 | ≥931 | ≥11.7 | ≥2388 | ≥30 | 318-342 | 40-43 | ≤200 | |
45EH | 1330-1380 | 13.3-13.8 | ≥995 | ≥12.5 | ≥2308 | ≥29 | 342-366 | 43-46 | ≤200 | |
AH | 28AH | 1040-1090 | 10.4-10.9 | ≥787 | ≥9.9 | ≥2624 | ≥33 | 207-231 | 26-29 | ≤230 |
30AH | 1080-1130 | 10.8-11.3 | ≥819 | ≥10.3 | ≥2624 | ≥33 | 223-247 | 28-31 | ≤230 | |
33AH | 1130-1170 | 11.3-11.7 | ≥843 | ≥10.6 | ≥2624 | ≥33 | 247-271 | 31-34 | ≤230 | |
35AH | 1170-1220 | 11.7-12.2 | ≥876 | ≥11.0 | ≥2624 | ≥33 | 263-287 | 33-36 | ≤230 | |
38AH | 1220-1250 | 12.2-12.5 | ≥899 | ≥11.3 | ≥2624 | ≥33 | 287-310 | 36-39 | ≤230 | |
40AH | 1250-1280 | 12.5-12.8 | ≥923 | ≥11.6 | ≥2624 | ≥33 | 302-326 | 38-41 | ≤230 | |
42AH | 1290-1330 | 12.9-13.3 | ≥955 | ≥12.0 | ≥2624 | ≥33 | 318-342 | 40-43 | ≤230 |
Temperature Characteristics
Low grade Neodymium magnet may lose strength if heated above 80°C. High grade Neo magnets have been developed to function at temperatures up to 220°C with little irreversible loss. The need for low temperature coefficient in neodymium magnet applications has triggered several grades to be developed to meet specific operating requirements.
Application
The utility of Sintered NdFeB magnet extends across a wide spectrum of industries, including to electronics (such as mobile phones and hard drives), automotive engineering (in motors and sensors), medical technology (in MRI machines), and the energy transportation sector. As technology development, Sintered NdFeB magnet is poised for significant growth in emerging areas such as electric vehicles, wind power generation, and energy-efficient household appliances. This material has redefined the boundaries of what is achievable in the field of magnetic materials, making it a cornerstone of modern engineering.