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Characteristics of Isotropic SmFeN bonded magnets
- Highest (BH)max among isotropic bonded magnets: ~112kJ/m3 (compression molded magnet)
- High corrosion resistance: Does not require coating in typical usage environment
- High thermal stability:
Temperature coefficient of Br, α -0.06 ～ -0.07% /℃ (23 ～ 120℃) - Long-term thermal stability: Superior to Nd-Fe-B bonded magnets
- Injection molding:
Available with PPS (polyphenylene sulfide) which has excellent heat and chemical resistance. - Magnetizability: Requires higher magnetic fields than Nd-Fe-B bonded magnets
- Isotropic → Can be magnetized in any direction, realize flux paths with high permeance.
- Lower supply risk of raw materials (HREE-free, use of surplus rare earth – Sm)
Characteristic field comparison of Isotropic bonded magnets (Daido Steel Group)
Evaluation of long-term thermal stability of isotropic bonded magnets *1
(Sample size: Φ10 mm x t7mm , no coating)
Production process of isotropic SmFeN bonded magnets
Manufacturing and sales of isotropic SmFeN magnet powder, compound (powder with resin), and molded bonded magnets (compression molding and injection molding) by Daido Steel Group.
Compression molded isotoropic SmFeN bonded magnets
Magnetic, physical, and mechanical properties
To meet the increasing demands for high heat resistance, we have been newly introduced the high coercivity type.
We will continue to expand our lineup to meet customers' needs.
| unit | Compression molded isotropic SmFeN bonded magnets | ||
|---|---|---|---|
| High coercivity type SP-12R |
Standard type SP-14 |
||
| Remanence Br |
mT (kG) |
710 ～ 770 (7.1 ～ 7.7) |
750 ～ 820 (7.5 ～ 8.2) |
| Coercivity HcB |
kA/m (kOe) |
470 ～ 530 (5.9 ～ 6.7) |
450 ～ 520 (5.7 ～ 6.5) |
| Intrinsic coercivity HcJ |
kA/m (kOe) |
980 ～ 1,210 (12.3 ～ 15.2) |
670 ～ 800 (8.4 ～ 10.1) |
| Maximum energy product (BH)max |
kJ/m3 (MGOe) |
86 ～ 99 (10.8 ～ 12.4) |
98 ～ 112 (12.3 ～ 14.1) |
| Recoil permeability μrec |
- | 1.10 ～ 1.15 | 1.15 ～ 1.20 |
| Temperature coefficient of Br, α (23 ～ 120 ℃) |
%/℃ | -0.06 | -0.07 |
| Density, ρ | kg/m3 | 5,800 ～ 6,400 | 5,800 ～ 6,400 |
| Thermal Expansion Coefficient | 10-6/℃ (20 ～ 100℃) |
12.6 | 12.6 |
| Flexural Strength | MPa (kgf/mm2) |
52 (5.3) |
52 (5.3) |
| Bending Elastic Modulus | MPa (kgf/mm2) |
10,800 (1,100) |
10,800 (1,100) |
| Ring Crushing Strength | MPa (kgf/mm2) |
54 (5.5) |
54 (5.5) |
※Notes※
- The data in this tabel is obtained from Daido's standard test pieces and are not guaranteed values.
- These values may vary depending on the magnet shape, dimensions, test conditions and equipment. It is recommended that the values be verified in actual products.
- Guaranteed values may be set up for specific shape and sizes by consultation.
- The contents of data are subject to change without prior notice.
Demagnetization curves
Demagnetization curves at elevated temperatures Demagnetization curves (23 ～ 150℃)
Corrosion resistance: High temperature and high humidity test 80 ℃ x 95 % RH x 300 hrs
Appearance of SmFeN magnet (SP-14) shows no change even after exposure to high temperature and high humidity.
SP-14(Compression molded magnets)
(Compression molded magnets)
Corrosion resistance: Immersion test (Rate of change after 1 hour immersed in 70 ℃ water) *2
Injection molded isotropic SmFeN bonded magnets
Magnetic, physical, and mechanical properties
With an optimized PPS (polyphenylene sulfide) resin and kneading conditions, highest (BH)max for isotropic bonded injection molded magnets is achieved: ~ 56 kJ/m3 (7MGOe)
| unit | Injection molded isotropic SmFeN bonded magnets | ||
|---|---|---|---|
| SPI-6LR | SPI-7LR | ||
| Remanence Br |
mT (kG) |
480 ～ 560 (4.8 ～ 5.6) |
540 ～ 620 (5.4 ～ 6.2) |
| Coercivity HcB |
kA/m (kOe) |
302 ～ 366 (3.8 ～ 4.6) |
335 ～ 400 (4.2 ～ 5.0) |
| Intrinsic coercivity HcJ |
kA/m (kOe) |
612 ～ 788 (7.7 ～ 9.9) |
620 ～ 796 (7.8 ～ 10.0) |
| Maximum energy product (BH)max |
kJ/m3 (MGOe) |
38 ～ 50 (4.8 ～ 6.3) |
49 ～ 60 (6.2 ～ 7.5) |
| Recoil permeability μrec |
- | 1.10 ～ 1.20 | 1.10 ～ 1.20 |
| Temperature coefficient of Br, α (23 ～ 120℃) |
% /℃ | -0.07 | -0.08 |
| Density, ρ | kg/m3 | 4,600 ～ 5,100 | 5,000 ～ 5,500 |
| Thermal Expansion Coefficient | 10-6/℃ (30 ～ 100℃) |
MD : 16 TD : 20 |
MD : 16 TD : 20 |
| Flexural Strength | MPa (kgf/mm2) |
60 (6.1) |
47 (4.8) |
| Bending Elastic Modulus | MPa (kgf/mm2) |
24,800 (2,500) |
26,900 (2,700) |
| Ring Crushing Strength | MPa (kgf/mm2) |
84 (8.6) |
60 (6.1) |
| Hardness | HRM | 96 | 95 |
| Tensile Strength | MPa (kgf/mm2) |
38 3.9 |
31 3.2 |
| Tensile Elastic Modulus | MPa (kgf/mm2) |
22,000 2,244 |
24,000 2,448 |
※Notes※
- The data in this tabel is obtained from Daido's standard test pieces and are not guaranteed values.
- These values may vary depending on the magnet shape,dimensions, test conditions and equipment. It is recommended that the values be verified in actual products.
- Guaranteed values may be set up by consultation for specific shape and sizes.
- The contents of data are subject to change without prior notice.
Demagnetization curves
