Neodymium Iron Boron (Nd-Fe-B)Sintered neodymium-iron-boron (Nd-Fe-B) magnets are the most powerful commercialized permanent magnets available today, with maximum energy product ranging from 26 MGOe to 52 MGOe. Nd-Fe-B is the third generation of permanent magnet developed in the 1980s. It has a combination of very high remanence and coercivity, and comes with a wide range of grades, sizes and shapes. With its excellent magnetic characteristics, abundant raw material and relatively low prices, Nd-Fe-B offers more flexibility in designing of new or replace the traditional magnet materials such as ceramic, Alnico and Sm-Co to achieve high efficiency, low cost and more compact devices. A powder metallurgy process is used in producing sintered Nd-Fe-B magnets. Although sintered Nd-Fe-B is mechanically stronger than Sm-Co magnets and less brittle than other magnets, it should not be used as structural component. Selection of Nd-Fe-B is limited by temperature due to its irreversible loss and moderately high reversible temperature coefficient of Br and Hci. The maximum application temperature is 200 °C for high coercivity grades. Nd-Fe-B magnets are more prone to oxidation than any other magnet alloys. If Nd-Fe-B magnet is to be exposed to humidity, chemically aggressive media such as acids, alkaline solutions salts and harmful gases, coating is recommended. It is not recommended in a hydrogen atmosphere. | Grade | Maximum
Energy
Product
BHmax | Residual
Induction
Br | Minimum
Intrinsic
Coercivity
Hci | Coercivity
Hc | Maximum
Operating
Temp
Tmo | Curie Temp
Tc | Coefficient
Induction
20-150 °C]
α | Coefficient
Coercivity
20-150 °C]
β | | MGOe | kG | kOe | kOe | °C | °C | % / °C | % / °C | | N5211 | 52 | 14.5 | 11 | 10.6 | 50 | 310 | -0.12 | -0.65 | | N5011 | 50 | 14.3 | 11 | 10.6 | 50 | 310 | -0.12 | -0.63 | | N4811 | 48 | 13.9 | 11 | 10.6 | 50 | 310 | -0.12 | -0.63 | | N4511 | 45 | 13.6 | 11 | 10.5 | 50 | 310 | -0.12 | -0.63 | | N4812 | 48 | 14.0 | 12 | 11.4 | 80 | 310 | -0.12 | -0.63 | | N4512 | 45 | 13.5 | 12 | 11.3 | 80 | 310 | -0.12 | -0.63 | | N4212 | 42 | 13.5 | 12 | 11.2 | 80 | 310 | -0.12 | -0.63 | | N4012 | 40 | 12.8 | 12 | 11.1 | 80 | 310 | -0.12 | -0.63 | | N3812 | 38 | 12.4 | 12 | 10.9 | 80 | 310 | -0.12 | -0.63 | | N3512 | 35 | 12.0 | 12 | 10.8 | 80 | 310 | -0.12 | -0.63 | | N5014 | 50 | 14.2 | 14 | 12.6 | 80 | 310 | -0.12 | -0.63 | | N4814 | 48 | 13.9 | 14 | 12.4 | 80 | 310 | -0.12 | -0.63 | | N4514 | 45 | 13.6 | 14 | 12.3 | 80 | 310 | -0.12 | -0.63 | | N4214 | 42 | 13.1 | 14 | 12.1 | 80 | 310 | -0.12 | -0.63 | | N4014 | 40 | 12.8 | 14 | 11.8 | 80 | 310 | -0.12 | -0.63 | | N3814 | 38 | 12.4 | 14 | 11.5 | 80 | 310 | -0.12 | -0.63 | | N3514 | 35 | 12.0 | 14 | 11.3 | 80 | 310 | -0.12 | -0.63 | | N3314 | 33 | 11.6 | 14 | 10.9 | 80 | 310 | -0.12 | -0.63 | | N4816 | 48 | 13.8 | 16 | 12.9 | 100 | 320 | -0.11 | -0.61 | | N4516 | 45 | 13.7 | 16 | 12.8 | 100 | 320 | -0.11 | -0.61 | | N4216 | 42 | 13.1 | 16 | 12.4 | 100 | 320 | -0.11 | -0.61 | | N3616 | 36 | 12.2 | 16 | 11.6 | 100 | 320 | -0.11 | -0.61 | | N3216 | 32 | 11.4 | 16 | 10.9 | 100 | 320 | -0.11 | -0.61 | | N4517 | 45 | 13.4 | 17 | 12.7 | 120 | 320 | -0.11 | -0.60 | | N4217 | 42 | 13.0 | 17 | 12.4 | 120 | 320 | -0.11 | -0.60 | | N4017 | 40 | 12.8 | 17 | 12.3 | 120 | 320 | -0.11 | -0.60 | | N3817 | 38 | 12.4 | 17 | 11.9 | 120 | 320 | -0.11 | -0.60 | | N3517 | 35 | 12.0 | 17 | 11.5 | 120 | 320 | -0.11 | -0.60 | | N3317 | 33 | 11.6 | 17 | 11.2 | 120 | 320 | -0.11 | -0.60 | | N3017 | 30 | 11.0 | 17 | 10.6 | 120 | 320 | -0.11 | -0.60 | | N4220 | 42 | 13.0 | 20 | 12.5 | 150 | 330 | -0.11 | -0.58 | | N4020 | 40 | 12.8 | 20 | 12.4 | 150 | 330 | -0.11 | -0.58 | | N3820 | 38 | 12.4 | 20 | 12.0 | 150 | 330 | -0.11 | -0.58 | | N3520 | 35 | 12.0 | 20 | 11.6 | 150 | 330 | -0.11 | -0.58 | | N3320 | 33 | 11.6 | 20 | 11.3 | 150 | 330 | -0.11 | -0.58 | | N3020 | 30 | 11.1 | 20 | 10.8 | 150 | 330 | -0.11 | -0.58 | | N4221 | 42 | 13.0 | 21 | 12.5 | 150 | 330 | -0.11 | -0.55 | | N4021 | 40 | 12.8 | 21 | 12.4 | 150 | 330 | -0.11 | -0.55 | | N3821 | 38 | 12.6 | 21 | 12.3 | 150 | 330 | -0.11 | -0.55 | | N3521 | 35 | 11.9 | 21 | 11.5 | 150 | 330 | -0.11 | -0.55 | | N3021 | 30 | 11.1 | 21 | 10.8 | 150 | 330 | -0.11 | -0.55 | | N3825 | 38 | 12.5 | 25 | 12.2 | 180 | 340 | -0.10 | -0.55 | | N3525 | 35 | 12.0 | 25 | 11.6 | 180 | 340 | -0.10 | -0.55 | | N3325 | 33 | 11.6 | 25 | 11.3 | 180 | 340 | -0.10 | -0.55 | | N3025 | 30 | 11.1 | 25 | 10.8 | 180 | 340 | -0.10 | -0.55 | | N2825 | 28 | 10.6 | 25 | 10.4 | 180 | 340 | -0.10 | -0.55 | | N3830 | 38 | 12.5 | 30 | 12.2 | 200 | 360 | -0.08 | -0.55 | | N3530 | 35 | 12.0 | 30 | 11.7 | 200 | 360 | -0.08 | -0.55 | | N3330 | 33 | 11.6 | 30 | 11.4 | 200 | 360 | -0.08 | -0.55 | | N3030 | 30 | 11.0 | 30 | 10.7 | 200 | 360 | -0.08 | -0.55 | | N2830 | 28 | 10.7 | 30 | 10.5 | 200 | 360 | -0.08 | -0.55 |
| Typical Physical Properties | | Curie Temperature | 320 - 380°C | | *Coefficient of Thermal Expansion - Perpendicular to magnetization orientation | -1.0 - -3.0 x 10-6 °C-1 | | *Coefficient of Thermal Expansion - Parallel to magnetization orientation | +5.0 - +8.0 x 10-6 °C-1 | | Electrical Resistivity | 120 - 160 µΩ·cm | | Density | 7.4 - 7.8 g·cm-3 | | Vicker's Hardness | 550 - 650 HV | | Young's Modulus | 150 - 170 kN·mm-2 | | Bending Strength | 0.18 - 0.29 kN·mm-2 | | Compressive Strength | 0.8 - 1.0 kN·mm-2 |
*Due to magnetostriction, all magnetic materials expand/contract at different rates, depending on magnetic orientation. |