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| Comparison between Alnico and Ferrite Magnet Properties. |
| Physical Property |
Alnico Magnet |
Ferrite Magnet |
Sm-Co Magnet |
| |
Alnico5 |
SrO·6Fe2O3 |
SmCo5 |
Sm2Co17 |
M
a
g
n
e
t
i
c
P
r
o
p
p
e
r
t
y
|
Residual Flux Br
Density |
(KG) |
12.5~13.5 |
4.3~4.6 |
8.8~9.2 |
11.0~11.6 |
| (T) |
1.25~1.35 |
0.43~0.46 |
0.88~0.92 |
1.10~1.16 |
| Coercive Forece Hcj |
(kOe) |
0.6~0.7 |
3.1~3.4 |
12~20 |
>8 |
| (kA/m) |
47.8~55.7 |
247~271 |
955~1592 |
>637 |
| Muximum Energy Product (BH)max |
(MGOe) |
4.5~5.5 |
4.5~4.8 |
19~21 |
28~32 |
| (kJ/m3) |
36~44 |
36~38 |
151~167 |
223~255 |
Br Tempaerature
Coefficient  Br/Br/T |
(%/ºC) |
-0.021 |
-0.18 |
-0.045 |
-0.030 |
| (%/K) |
-0.021 |
-0.18 |
-0.045 |
-0.030 |
Hcj
Temperature Coefficient | (25~180ºC)
(298~453K)
|
|
(%/ºC) |
~0 |
+40(40ºC~R.T.) |
-0.35 |
-0.15 |
| (%/K) |
~0 |
+40(40ºC~R.T.) |
-0.35 |
-0.15 |
| Curie Temperature Tc |
(ºC) |
850 |
460 |
700~750 |
800~850 |
| (K) |
1123 |
733 |
973~1023 |
1073~1123 |
| Maximum Temperature for Practical Use |
(ºC) |
600 |
300 |
350 |
250 |
| (K) |
873 |
573 |
623 |
523 |
| Magnetizing Field |
(kOe) |
3.0 |
10.0 |
15.0~25.0 |
15.0~25.0 |
| (kA/m) |
239 |
796 |
1194~1990 |
1194~1990 |
| Density |
(g/cm3) |
7.3 |
4.9~5.0 |
8.1~8.3 |
8.3~8.5 |
| (kg/m3) |
7300 |
4900~5000 |
8100~8300 |
8300~8500 |
M
e
c
h
a
n
i
c
a
l |
Fracture Strength |
(kg/mm2) |
- |
5.0~9.0 |
18 |
15 |
| (N/m2) |
- |
49×107~8.8×107 |
18.0×107 |
15.0×107 |
| Compressive Strength |
(kg/mm2) |
- |
>70 |
102 |
82 |
| (N/m2) |
- |
>6.9×107 |
10.0×108 |
8.0×108 |
| Tensile Strlength |
(kg/mm2) |
3.8 |
2.0~5.0 |
4.1 |
3.8 |
| (N/m2) |
3.7×107 |
2.0×107~4.9×107 |
4.0×107 |
3.5×107 |
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