Manufacture process:
Pressing and sintering involves pressing very fine ferrite powder in a die, and then sintering this pressed magnet. All fully dense Ferrite magnets are produced this way. Ferrite magnets can be wet pressed or dry pressed. Wet pressing yields better magnetic properties, but poorer physical tolerances. Generally, the powder is dry for grade 1 or 5 materials, and wet for grade 8 and higher materials. Sintering involves subjecting the material to high temperatures to fuse the pressed powder together, thus creating a solid material. Magnets produced through this process usually need to have some finish machining, otherwise surface finishes and tolerances are not acceptable. Some manufacturers extrude instead of press wet powder slurry and then sinter the material. This is sometimes done for arc segment shapes, where the arc cross-section is extruded in long lengths, sintered, and then cut to length.
Mostly Used National standard - SJ285-77 Permanent Ferrite Magnet standard
|
Grade |
Value(min/typical in our factory) |
|
Br |
Hcb(BHC) |
Hcj(IHC) |
(BH)max |
|
MT |
KG |
KA/m |
Koe |
KA/m |
KOe |
Kj/m 3 |
MGOe |
|
Y10T(=C1) |
200/218 |
2.00/2.18 |
125/145 |
1.57/1.82 |
210/250 |
2.64/3.14 |
6.5/8.0 |
0.8/1.0 |
|
Y25 |
360/370 |
3.60/3.70 |
135/150 |
1.70/1.88 |
140/170 |
1.76/2.14 |
22.5/25.3 |
2.8/3.2 |
|
Y30(=C5) |
380/385 |
3.80/3.85 |
191/210 |
2.40/2.64 |
199/220 |
2.50/2.51 |
26.0/28 |
3.4/3.7 |
|
Y30BH |
380/390 |
3.80/3.90 |
223/235 |
2.80/2.95 |
231/245 |
2.90/3.08 |
27.0/30.0 |
3.4/3.7 |
|
Y33 |
410/420 |
4.10/4.20 |
220/235 |
2.77/2.95 |
225/240 |
2.83/3.01 |
31.5/33.0 |
4.0/4.2 |
|
Y35 |
400/410 |
4.00/4.10 |
175/195 |
2.20/2.45 |
180/200 |
2.26/2.51 |
30.0/32.0 |
3.8/4.0 |
|
C8(=C8A) |
385/390 |
3.85/3.90 |
235/255 |
2.95/3.20 |
242/265 |
3.05/3.33 |
27.8/30.0 |
3.5/3.7 |
|
C10 |
400/410 |
4.00/4.10 |
288/300 |
3.62/3.77 |
280/287 |
3.51/3.60 |
30.4/31.9 |
3.8/4.0 |
Chinese standard -sj/T 10410 2000 Permanent Ferrite magnet standard
| Grade |
(Br) |
(HcB) |
(HcJ) |
(BH)max |
| mT |
KGauss |
KA/m |
KOe |
KA/m |
KOe |
KJ/m3 |
MGOe |
| Y8T |
200~235 |
2.0~2.35 |
125-160 |
1.57-2.01 |
210-280 |
2.64-3.51 |
6.5-9.5 |
0.8-1.2 |
| Y22H |
310~360 |
3.10~3.60 |
220-250 |
2.76-3.14 |
280-320 |
3.51-4.02 |
20.0-24.0 |
2.5-3.0 |
| Y25 |
360~400 |
3.60~4.00 |
135-170 |
1.70-2.14 |
140-200 |
1.76-2.51 |
22.5-28.0 |
2.8-3.5 |
| Y26H-1 |
360~390 |
3.60~3.90 |
200-250 |
2.51-3.14 |
225-255 |
2.83-3.20 |
23.0-28.0 |
2.9-3.5 |
| Y26H-2 |
360~380 |
3.60~3.80 |
263-288 |
3.30-3.62 |
318-350 |
3.99-4.40 |
24.0-28.0 |
3.0-3.5 |
| Y27H |
350~380 |
3.50~3.80 |
225-240 |
2.83-3.01 |
235-260 |
2.95-3.27 |
25.0-29.0 |
3.1-3.6 |
| Y28 |
370~400 |
3.70~4.00 |
175-210 |
2.20-3.64 |
180-220 |
2.26-2.76 |
26.0-30.0 |
3.3-3.8 |
| Y28H-1 |
380~400 |
3.80~4.00 |
240-260 |
3.01-3.27 |
250-280 |
3.14-3.52 |
27.0-30.0 |
3.4-3.8 |
| Y28H-2 |
360~380 |
3.60~3.80 |
271-295 |
3.40-3.70 |
382-405 |
4.80-5.08 |
26.0-30.0 |
3.3-3.8 |
| Y30H-1 |
380~400 |
3.80~4.00 |
230-275 |
2.89-3.46 |
235-290 |
2.95-3.64 |
27.0-32.5 |
3.4-4.1 |
| Y30H-2 |
395~415 |
3.95~4.15 |
275-300 |
3.45-3.77 |
310-335 |
3.89-4.20 |
27.0-32.0 |
3.4-4.0 |
| Y32 |
400~420 |
4.00~4.20 |
160-190 |
2.01-2.39 |
165-195 |
2.07-2.45 |
30.0-33.5 |
3.8-4.2 |
| Y32H-1 |
400~420 |
4.00~4.20 |
190-230 |
2.39-2.89 |
230-250 |
2.89-3.14 |
31.5-35.0 |
3.9-4.4 |
| Y32H-2 |
400~440 |
4.00~4.40 |
224-240 |
2.81-3.01 |
230-250 |
2.89-3.14 |
31.0-34.0 |
3.9-4.3 |
| Y33 |
410~430 |
4.10~4.30 |
220-250 |
2.76-3.14 |
225-255 |
2.83-3.20 |
31.5-35.0 |
3.9-4.4 |
| Y33H |
410~430 |
4.10~4.30 |
250-270 |
3.14-3.39 |
250-275 |
3.14-3.45 |
31.5-35.0 |
3.9-4.4 |
| Y34 |
420~440 |
4.20~4.40 |
200-230 |
2.51-2.89 |
205-235 |
2.57-2.95 |
32.5-36.0 |
4.1-4.4 |
| Y35 |
430~450 |
4.30~4.50 |
215-239 |
2.70-3.00 |
217-241 |
2.73-3.03 |
33.1-38.2 |
4.1-4.8 |
| Y36 |
430~450 |
4.30~4.50 |
247-271 |
3.10-3.40 |
250-274 |
3.14-3.44 |
35.1-38.3 |
4.4-4.8 |
| Y38 |
440~460 |
4.40~4.60 |
285-305 |
3.58-3.83 |
294-310 |
3.69-3.89 |
36.6-40.6 |
4.6-5.1 |
| Y40 |
440~460 |
4.40~4.60 |
330-354 |
4.15-4.45 |
340-360 |
4.27-4.52 |
37.6-41.8 |
4.7-5.2 |
Physical property of hard ferrite mangets
|
Parameters |
Mark |
Unit |
Value |
|
Recoil Permeability |
Urce |
- |
1.05-1.3 |
|
Curie temperture |
Tc |
0 C |
460 |
|
The temperature of Br |
αBr |
0 C -1 |
-0.2% |
|
The temperature of Hcj |
αHcj |
0 C -1 |
0.2-0.5% |
|
Density |
D |
g/cm 3 |
4.5-5.1 |
|
Resistivity |
P |
Ω.cm |
≥10000 |
|
Hardness |
HV |
- |
480-580 |
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