SmCo Magnet

Samarium cobalt (SmCo) magnet is a type of strong permanent magnet made of samarium, cobalt and few other elements. It is known for its high magnetic strength and good temperature stability. SmCo magnet is usually weaker than Neodymium magnet at room temperature, however, it still performs reliable in extreme temperature when Neodymium magnet is out of work. SmCo is usually unnecessary to be coated for its strong resistance to corrosion and oxidation. Since the samarium cobalt magnet is made by sintering, it is very brittle and may have cracks inside.

SmCo5

The SmCo5 alloy contains one atom of samarium per five atoms of cobalt, it is the first generation of SmCo magnet. The 1:5 SmCo alloy offers (BH)max from 15 MGOe to 25 MGOe and its working temperature is up to 250℃. SmCo5 contains mainly Sm and Co without Iron so it has better resistance to corrosion and demagnetization.

Sm2Co17

Compared with SmCo5, the 2:17 SmCo alloy performs better in magnetic properties. Its (BH)max usually vary from 24 MGOe to 32 MGOe and its working temperature is up to 300℃. The Sm2Co17 contains few other elements like iron, copper as well as samarium and cobalt. The exit of iron in this alloy means it may occur slight corrosion in high humidity environments, so Sm2Co17 magnets are coated with nickel in some cases. 

Application of SmCo Magnet

With excellent magnetic properties, good thermal stability and chemical stability, SmCo magnet is widely used in high-speed motors and generators, military applications, microwave communication technologies, etc. However, cobalt is an expensive and scarce strategic metal element, samarium is a rare earth element, which result in the high price of this magnet. The high price makes it can only be used in limited areas and also limits its development.

Magnetic properties of sintered smco magnet

Grade RemanenceBr CoercivityHcb Intrinsic CoercivityHcj Max. Energy ProductBHmax Max. Working Temperature Density
T kGs kA/m kOe kA/m kOe kJ/m3 MGOe ˚C g/cm3
Sm1Co5-16
0.79-0.84
7.9-8.4
620-660
7.8-8.3
≥1830
≥23
118-135
15-17
≤250
8.3
Sm1Co5-18
0.84-0.89
8.4-8.9
660-700
8.3-8.8
≥1830
≥23
135-151
17-19
≤250
8.3
Sm1Co5-20
0.89-0.93
8.9-9.3
684-732
8.6-9.2
≥1830
≥23
150-167
19-21
≤250
8.3
Sm1Co5-22
0.92-0.96
9.2-9.6
710-756
8.9-9.5
≥1830
≥23
167-183
21-23
≤250
8.3
Sm1Co5-24
0.96-1.00
9.6-10.0
740-788
9.3-9.9
≥1830
≥23
183-199
23-25
≤250
8.3
Sm2Co17-24L
0.95-1.02
9.5-10.2
541-716
6.8-9.0
636-955
8-12
175-191
22-24
≤250
8.4
Sm2Co17-26L
1.02-1.05
10.2-10.5
541-784
6.8-9.4
636-955
8-12
191-207
24-26
≤250
8.4
Sm2Co17-28L
1.03-1.08
10.3-10.8
541-764
6.8-9.6
636-955
8-12
207-220
26-28
≤250
8.4
Sm2Co17-30L
1.08-1.15
10.8-11.5
541-796
6.8-10.0
636-955
8-12
220-240
28-30
≤250
8.4
Sm2Co17-32L
1.10-1.15
11.0-11.5
541-812
6.8-10.2
636-955
8-12
230-255
29-32
≤250
8.4
Sm2Co17-26M
1.02-1.05
10.2-10.5
676-780
8.5-9.8
955-1433
12-18
191-207
24-26
≤300
8.4
Sm2Co17-28M
1.03-1.08
10.3-10.8
676-796
8.5-10.0
955-1433
12-18
207-220
26-28
≤300
8.4
Sm2Co17-30M
1.08-1.1
10.8-11.0
676-835
8.5-10.5
955-1433
12-18
220-240
28-30
≤300
8.4
Sm2Co17-32M
1.10-1.13
11.0-11.3
676-852
8.5-10.7
955-1433
12-18
230-255
29-32
≤300
8.4
Sm2Co17-33M
1.13-1.15
11.3-11.5
820-870
10.3-10.9
955-1433
12-18
246-262
31-32
≤300
8.4
Sm2Co17-22
0.93-0.97
9.3-9.7
676-740
8.5-9.3
≥1433
≥18
160-183
20-23
≤300
8.4
Sm2Co17-24
0.95-1.02
9.5-10.2
692-764
8.7-9.6
≥1433
≥18
175-191
22-24
≤300
8.4
Sm2Co17-26
1.02-1.05
10.2-10.5
748-796
9.4-10.0
≥1433
≥18
191-207
24-26
≤300
8.4
Sm2Co17-28
1.03-1.08
10.3-10.8
756-812
9.5-10.2
≥1433
≥18
207-220
26-28
≤300
8.4
Sm2Co17-30
1.08-1.10
10.8-11.0
788-835
9.9-10.5
≥1433
≥18
220-240
28-30
≤300
8.4
Sm2Co17-32
1.10-1.13
11.0-11.3
812-860
10.2-10.8
≥1433
≥18
230-255
29-32
≤300
8.4
Sm2Co17-33
1.13-1.15
11.3-11.5
820-870
10.3-10.9
≥1433
≥18
246-262
31-32
≤300
8.4
Sm2Co17-24H
0.95-1.02
9.5-10.2
692-764
8.7-9.6
≥1990
≥25
175-191
22-24
≤350
8.4
Sm2Co17-26H
1.02-1.05
10.2-10.5
748-796
9.4-10.0
≥1990
≥25
191-207
24-26
≤350
8.4
Sm2Co17-28H
1.03-1.08
10.3-10.8
756-812
9.5-10.2
≥1990
≥25
207-220
26-28
≤350
8.4
Sm2Co17-30H
1.08-1.10
10.8-11.0
788-835
9.9-10.5
≥1990
≥25
220-240
28-30
≤350
8.4
Sm2Co17-32H
1.10-1.13
11.0-11.3
812-860
10.2-10.8
≥1990
≥25
230-255
29-32
≤350
8.4
Sm2Co17-33H
1.13-1.15
11.3-11.5
830-880
10.4-11
≥1990
≥25
246-262
31-32
≤350
8.4
Sm2Co17-20TR
0.9-0.94
9.0-9.4
661-732
8.3-9.2
≥1592
≥20
143-159
18-20
≤500
8.4
Sm2Co17-16LT
0.81-0.85
8.1-8.5
605-669
7.6-8.4
≥1592
≥20
111-127
14-16
≤300
8.4
Sm2Co17-18LT
0.85-0.9
8.5-9.0
629-708
7.9-8.9
≥1592
≥20
127-143
16-18
≤300
8.4
Sm2Co17-20LT
0.9-0.94
9.0-9.4
661-732
8.3-9.2
≥1592
≥20
143-159
18-20
≤300
8.4
Sm2Co17-22LT
0.94-0.97
9.4-9.7
685-740
8.6-9.3
≥1592
≥20
159-175
20-22
≤300
8.4