Bonded Magnets
Due to the difficulty in precision machining of sintered neodymium iron boron into special shapes, as well as the tendency to crack, damage, edge drop, corner drop, and other issues during the machining process, and the difficulty in assembly, its application is limited. To solve these problems, neodymium iron boron magnetic powder is mixed with and bonded together, and pressed into shape in a mold. This is the preparation method of bonded neodymium boron.
Bonded neodymium iron boron is commonly used in the fields of stepper motors and spindle motors, and its products are widely used in various fields such as automobiles, information technology, consumer electronics, energy-saving home appliances, medical devices, office automation, and factory automation equipment. Bonded neodymium iron boron is easy to form, with high accuracy, strong corrosion resistance, high cost-effectiveness, and diverse magnetization methods.
Process flow: ingredients (magnetic powder, binder, coupling agent) → mixing → pressing and forming → heating and curing → spraying
Surface treatment of neodymium iron boron: Common surface treatment methods: 1. Nano 3010 (3010) refers to the film layer containing 3 or more active chelating groups; 2. Electrophoresis; 3. Organic spray molding.
Physical properties of bonded neodymium iron boron
| Category | Parameter | Unit | Reference Value |
| Physical Property | Density | g/cm3 | 5.1～6.0 |
| Specific Heat | J/(g·C) | 0.62～0.85 | |
| Vickers Hardness | HV | 80～120 | |
| Bending Strength | kgf/mm2 | 22～30 | |
| Compressive Strength | kgf/mm2 | 2～5 | |
| Resistivity | MΩ·cm | 26 | |
| Thermal Conductivity | W/(M·C) | 0.029 | |
| Coefficient of thermal expansion parallel | 10-6/K(20～100℃) | 14～15 | |
| Coefficient of thermal expansion parallel | 10-6/K(20～100℃) | 9～10 | |
| Curie temperature | ℃ | 450～460 | |
| Temperature Coefficient of remanence | %℃ | 0.18～0.2 | |
| Intrinsic coercivity temperature coefficient | %℃ | 0.25～0.4 |
Performanece Table of Bonded NefeB Magnet
|
Product Name |
Br(mT) |
Hcb (KA/m) |
Hcj(KA/m) |
BH(MGOe) |
D/try(G/㎥) |
Ɑ(Br)(℃%) |
TW（℃） |
|
BNP-6 |
550~620 |
285~370 |
600~755 |
5.5~7.0 |
5.5~6.2 |
-0.13~-0.07 |
≤100°C |
|
BNP-8L |
600~640 |
360~400 |
715~800 |
7.0~8.0 |
5.5~6.2 |
-0.13~-0.07 |
≤110°C |
|
BNP-8 |
620~690 |
385~445 |
640~800 |
8.0~9.0 |
5.5~6.2 |
-0.13~-0.07 |
≤120°C |
|
BNP-8S |
620~660 |
410~465 |
880~1120 |
8.0~9.0 |
5.5~6.2 |
-0.13~-0.07 |
≤150°C |
|
BNP-8H |
620~650 |
410~455 |
1190~1440 |
8.0~9.0 |
5.5~6.2 |
-0.13~-0.07 |
≤125°C |
|
BNP-9 |
650~700 |
400~440 |
640~800 |
8.8~9.5 |
5.5~6.2 |
-0.13~-0.07 |
≤120°C |
|
BNP-10 |
680~720 |
420~470 |
640~800 |
9.5~10.5 |
5.5~6.2 |
-0.13~-0.11 |
≤120°C |
|
BNP-11 |
700~740 |
445~480 |
680~800 |
10.0~11.0 |
5.5~6.2 |
-0.13~-0.11 |
≤120°C |
|
BNP-11L |
700~740 |
400~440 |
520~640 |
9.8~10.5 |
5.5~6.2 |
-0.13~-0.11 |
≤110°C |
|
BNP-12L |
740~800 |
420~455 |
520~600 |
10.5~11.5 |
5.5~6.2 |
-0.13~-0.08 |
≤110°C |
