Daido has developed a unique hot extrusion process to produce radially oriented anisotropic Nd-Fe-B ring magnets, NEOQUENCH-DR.
- Unlike sintering, this process does not rely on a magnetic field for radial orientation.
- Our process starts with raw material powders manufactured by rapid quenching of the prescribed alloys into nanocrystalline flakes.
- These flakes are hot pressed to the theoretical density and then hot extruded to ring-shaped magnets.
During this advanced hot extrusion process, randomly oriented crystal grains go through preferential grain growth and rotation.
This results in the full-density, nanocrystalline structure with the highest level of radial orientation.
Although the basic magnetic properties (Br, Hc, and (BH)max) are similar to sintered Nd-Fe-B, our unique process gives rise to several remarkable features listed below.
Features of NEOQUENCH-DR
- Highest energy product of 240 ～ 400 kJ/m3 (30 ～ 40 MGOe) in truly radial direction.
- Full rings with a wide range of diameters (min. OD 6 mm -) and lengths (max. 80 mm) for easy assembly.
- Various magnetization patterns possible (multi-pole to uni-pole, various skew angles) by the design of magnetizing fixtures.
- Precise magnetization waveform control (such as rectangular, trapezoidal, sinusoidal) for high power or low cogging.
- High heat resistant grades (up to 180 deg.C) available.
- Inherently better corrosion resistance due to the absence of internal porosity.
Applications of NEOQUENCH-DR
– EPS (Electric Power Steering) motors: Combined with controlled magnetization waveforms, NEOQUENCH-DR can realize quiet and smooth rotation, giving rise to a natural feeling of steering an automobile.
Servomotors: High power and low cogging, quiet and smooth rotation, ideal for AC/DC servomotors used in industrial robots requiring quick and accurate movements.
Electrical power steering motor
AC servo-motor
Manufacturing process of NEOQUENCH-DR
Realizing close theoritical density and high radial orientation ratio by hot extrusion technology keeping miro structure of grain size.
Feature of NEOQUENCH-DR & detail data
Material properties of radially oriented, anisotropic Nd-Fe-B ring magnets (NEOQUENCH-DR)
Magnetic properties
| ND-31HR | ND-31SHR | ND-35HR | ||
|---|---|---|---|---|
| Remanence, Br | (T) | 1.14 ～ 1.22 | 1.08 ～ 1.18 | 1.22 ～ 1.28 |
| (kG) | (11.4 ～ 12.2) | (10.8 ～ 11.8) | (12.2 ～ 12.8) | |
| Coercivity,HCB | (kA/m) | 830 ～ 890 | 810 ～ 880 | 870 ～ 940 |
| (kOe) | (10.4 ～ 11.2) | (10.2 ～ 11.1) | (10.9 ～ 11.8) | |
| Coercivity,HCJ | (kA/m) | 1110 ～ 1430 | 1590 ～ 1990 | 1110 ～ 1430 |
| (kOe) | (14.0 ～ 18.0) | (20.0 ～ 25.0) | (14.0 ～ 18.0) | |
| Maximum energy product, (BH)max | (kJ/m3) | 240 ～ 270 | 230 ～ 260 | 270 ～ 300 |
| (MGOe) | (30.0 ～ 34.0) | (29.0 ～ 33.0) | (34.0 ～ 38.0) | |
| Recoil permeability | 1.05 | 1.05 | 1.05 | |
| Required magnetizing magnetic field | (kA/m) | ≧1990 | ≧2390 | ≧1990 |
| (kOe) | (≧25) | (≧30) | (≧25) | |
| density | (Mg/m3) | 7.6 | 7.7 | 7.6 |
| (g/cm3) | ||||
| ND-35SHR | ND-39R | ND-39HR | ND-43R | ||
|---|---|---|---|---|---|
| Remanence, Br | (T) | 1.22 ～ 1.28 | 1.28 ～ 1.32 | 1.28～1.32 | 1.30 ～ 1.36 |
| (kG) | (12.2 ～ 12.8) | (12.8 ～ 13.2) | (12.8～13.2) | (13.0 ～ 13.6) | |
| Coercivity,HCB | (kA/m) | 880 ～ 950 | 880 ～ 960 | 928～960 | 840 ～ 960 |
| (kOe) | (11.1 ～ 11.9) | (11.1 ～ 12.1) | (11.6～12.1) | (10.5 ～ 12.1) | |
| Coercivity,HCJ | (kA/m) | 1430 ～ 1800 | 1040 ～ 1280 | 1110～1430 | 900 ～ 1160 |
| (kOe) | (18.0 ～ 22.6) | (13.0 ～ 16.0) | (14.0～18.0) | (11.3 ～ 14.6) | |
| Maximum energy product, (BH)max | (kJ/m3) | 270 ～ 300 | 300 ～ 330 | 300～330 | 320 ～ 360 |
| (MGOe) | (34.0 ～ 38.0) | (38.0 ～ 42.0) | (38.0～42.0) | (40.0 ～ 45.0) | |
| Recoil permeability | 1.05 | 1.05 | 1.05 | 1.05 | |
| Required magnetizing magnetic field | (kA/m) | ≧1990 | ≧1990 | ≧1990 | ≧1990 |
| (kOe) | (≧30) | (≧25) | (25) | (≧25) | |
| density | (Mg/m3) | 7.6 | 7.6 | 7.6 | 7.6 |
| (g/cm3) | |||||
※The above properties are not guaranteed for magnets with thick walls. Please consult with us for details.
Other properties
| Temperature coefficient of Br, alpha | %/℃ | -0.10 |
|---|---|---|
| Temperature Coefficient of HCJ, beta | %/℃ | -0.50 |
| Curie temperature | ℃ | 360 |
| Specific heat | J/kg℃ | 550 |
| Thermal conductivity | W/m℃ | 4.80 |
| Thermal expansion coefficient (20 ~ 200℃) | ×10-6/℃ | 1 ～ 2(Radial direction) |
| -1 ～ 0(Axial direction) | ||
| Electric resistivity | ×10-8Ωm | 135 |
| Ring crushing strength | MPa | 150 |
| Young’s modulus | MPa | 152000 |
| Bending strength | MPa | 200 |
| Vickers hardness | Hv | 750 |
Product dimemsions
Magnetic properties of radially oriented, anisotropic Nd-Fe-B ring magnets (NEOQUENCH-DR)
Temperature dependence of demagnetization curves
ND-31HR
ND-31SHR
ND-35HR
ND-35SHR
ND-39R
ND-43R
Irreversible flux loss after an exposure to high temperatures
Heating temperature 150℃
Heating temperature 180℃
Temperature dependence of irreversible flux loss
ND-31HR
ND-31SHR
ND-35HR
ND-35SHR
ND-39R
ND-43R
Magnetization properties of radially oriented, anisotropic Nd-Fe-B ring magnets (NEOQUENCH-DR)
Magnetic properties vs magnetizing field
ND-31HR
ND-31SHR
Magnetization patterns and application examples
Examples of magnetized waveforms
1. Multi-pole magnetization
2. North pole on OD and south pole on ID
Examples of controlled waveforms
Surface coatings for radially oriented, anisotropic Nd-Fe-B ring magnets (NEOQUENCH-DR)
Due to the lack of porosity and lower Nd content, NEOQUENCH-DR has higher corrosion resistance than sintered Nd.
These magnets are rust free for a long time in dry air. However, in a humid environment, an appropriate surface protection (coating) is necessary. Daido Electronics Co., Ltd. provides two types of coatings.
| Conditions | Epoxy electrodeposition coating 20 ～ 35 µm |
Ni plating 15 ～ 30 µm |
|---|---|---|
| Humidity test 80 ℃ × 95%RH × 1000 hrs |
B | B |
| Water resistance * 1 Distilled water 40℃ × 96 hrs |
B | B |
| Salt spray test * 2 5% NaCl (pH 6.5 ～ 8) |
B (300hr) | - - - |
| Oil resistance * 1 Gear oil 20℃ × 24 hrs |
B | B |
| Gasoline resistance * 1 Gasoline 20℃ × 24 hrs |
B | B |
| Acid resistance * 1 10% H2SO4 20℃ × 8 hrs |
B | B |
| Alkali resistance * 1 5% Na2CO3 40℃ × 6 hrs |
B | B |
| Heat resistance * 1 Air 100℃ × 1 hr |
B | B |
| Cycle crack test * 3 | B | B |
※1: JIS D0202
※2: JIS Z2371
※3: Five cycles of the pattern below (JIS D0202)
※4: Please consult with us about your preferred locations of electrode marks.
Note for using NEOQUENCH-DR
1. Thermal expansion considerations
NEOQUENCH-DR has lower CTE (coefficient of thermal expansion) than most metallic materials.
Proper clearance between the magnet and shaft is advised.
2. Mechanical Strength
NEOQUENCH-DR can eliminate the banding depending on the magnet OD, wall thickness, and rpm.
This diagram is for your reference purpose only.
3. Other
- Magnets are fragile and easy to break. Please protect your eyes and other parts of your body from the debris.These magnets are extremely strong.Please take extreme caution to avoid being pinched.
- If magnets are damaged, it will lead to lower performance and deterioration.Magnets can also be damaged from high speed rotation. Please design your devise so that the debris would be contained in case of magnet breakage.
- Please be advised that magnets can attract small magnetic substances even when they are not magnetized.For precision motor assemblies, it is advised to perform a cleaning process after assemblying.
- Magnets may erase the records on magnetic media.Please keep magnets away from magnetic cards, tapes, and prepaid cards, etc.
- Electronic devises may be affected byt magnetic fields.Please keep magnets away from these devises to avoid malfunction or accidents.
- Never place magnets near the person who has medical electronic devises such as a pacemaker.These devises may not work properly near magnets.
- Please avoid the use or storage of magnets in the following environment where corrosion or deterioraion may occur.It is advisable to consult with us as to the corrosion resistance of the magnets and protective coating techniques.
- Corrosive gas (Cl2, NH3, SOx, NOx, etc.)
- High electrical conductivity (aquaes solution with electrolytes)
- Hydrogen gas (H2)
- Acids, alkalis, organic solvents, etc.
- Water, oil, etc.
- In general, rare-earth magnets require surface coating to prevent oxidation or corrosion.Please use the magnets with a coating appropriate for the environment.
- Rare-earth magnet powders are classified as a dangerous goods (flammable solid) in the Japanese Fire Services Act.Please do not use these magnets where fine particles can be created from friction, etc. as these particles can easily catch fire.
- Do not swallow magnets.If swallowed by mistake, consult your doctor immediately.
- Keep out of reach of children.
- People with metal alergies may develop skin irritation and redness when in contact with magnets.In such cases, avoid touching the magnets directly.