Bonded NdFeB magnets, i.e. bonded neodymium iron boron magnets, are those permanent magnetic materials made of rapid quenched NdFeB magnetic powders combined with resin binders (epoxy, Nylon/polyamide (PA), polyphenylene sulfide (PPS), etc). They are manufactured through a bonded process (compression, injection, extrusion or calendaring molding), so it is available to obtain complex geometries with high dimensional precision. Controlling the performance and proportion of NdFeB magnetic powders, it is able to adjust the magnets’ magnetic properties in a continuous range. Due to their complex geometries availability, high dimensional precision, uniform magnetic properties, diverse magnetization patterns, good corrosion resistance and mechanic properties, bonded NdFeB magnets are widely applied in spindle motors, micro motors, direct current (DC) motors, synchronous motors, power tools, magnetic rollers, Hall effect sensors, etc.
Bonded NdFeB Magnets’ Grades and Their Magnetic Properties
| Grade | Br | Hcb | Hcj | (BH)max | Tw | ||||
| kGs | T | kOe | kA/m | kOe | kA/m | MGOe | kJ/m3 | °C | |
| HGT-12 | 7.0-7.6 | 0.70-0.76 | 5.5-6.5 | 438-517 | 8-11 | 637-875 | 10.0-11.0 | 80-88 | ≤160 |
| HGT-11 | 6.7-7.3 | 0.67-0.73 | 5.3-6.0 | 422-478 | 8-11 | 637-875 | 9.8-10.5 | 78-84 | ≤160 |
| HGT-10H | 6.2-6.8 | 0.62-0.68 | 5.4-6.0 | 430-478 | 11-14 | 875-1115 | 8.8-9.5 | 70-76 | ≤180 |
| HGT-10 | 6.5-7.1 | 0.65-0.71 | 5.2-6.0 | 414-478 | 8-10 | 637-796 | 9.0-9.7 | 72-77 | ≤160 |
| HGT-9 | 6.3-6.9 | 0.63-0.69 | 5.0-5.8 | 398-462 | 8-10 | 637-796 | 8.6-9.3 | 68-74 | ≤160 |
| HGT-8H | 6.0-6.6 | 0.60-0.66 | 4.8-5.8 | 382-462 | 10-13 | 796-1035 | 7.5-8.5 | 60-68 | ≤180 |
| HGT-8 | 6.2-6.8 | 0.62-0.68 | 5.0-5.8 | 398-462 | 8-10 | 637-796 | 7.8-8.8 | 62-70 | ≤160 |
| HGT-7 | 5.8-6.5 | 0.58-0.65 | 4.4-5.2 | 350-414 | 6-9 | 478-716 | 7.0-8.0 | 56-64 | ≤160 |
| HGT-6 | 5.3-6.0 | 0.53-0.60 | 3.7-4.6 | 295-366 | 6-9 | 478-716 | 5.9-6.8 | 47-54 | ≤160 |
| HGT-5 | 4.8-5.5 | 0.48-0.55 | 3.2-4.0 | 255-318 | 5-8 | 398-637 | 4.8-5.5 | 38-44 | ≤160 |
| HGT-4 | 4.2-5.0 | 0.42-0.50 | 2.8-3.6 | 223-287 | 5-8 | 398-637 | 3.5-4.5 | 28-36 | ≤160 |
| HGT-3 | 3.5-4.3 | 0.35-0.43 | 2.4-3.3 | 191-263 | 5-8 | 398-637 | 2.6-3.6 | 21-29 | ≤160 |
| HGT-2 | 3.0-3.8 | 0.30-0.38 | 2.0-3.2 | 159-255 | 5-8 | 398-637 | 1.9-3.0 | 15-24 | ≤160 |
Note:
∗ The data in the above table were samples’ results tested at the temperature of 20 °C.
∗ The temperature coefficients of Br and Hcj are α(Br): -0.10~-0.12 %/ºC and β(Hcj): -0.40~-0.60 %/ºC, respectively.
∗ The above data are only for reference, magnets can be tailored according to customers’ personalized requirements.
Ring Magnets
Abnormal Shape Magnets
Magnetic Assemblies with Metal
Rotor Assemblies
Arc/Segment Magnets
Block/Rectangular Magnets
Bonded NdFeB magnets’ most common coating is epoxy. In addition, Teflon and Parylene coating types are also available.
Some Physical Properties of Bonded NdFeB Magnets
| Parameter | Unit | Value |
|---|---|---|
| Density (ρ) | g/cm3 | 4.5-6.5 |
| Curie Temperature (Tc) | ºC | 300-350 |
| Recoil Permeability (μrec) | - | 1.20 |
| Rockwell Hardness (HR) | MPa | 35-45 |
| Compressive Strenght (σbc) | MPa | 800-1000 |
| Tensile Strength (σb) | MPa | 200 |
| Thermal Expansivity (α) | 10-6/ºC | 1-2 |
Note:
∗ The above data are only for reference, specific magnets maybe have different values.