SMCO MAGNETS (SAMARIUM COBALT MAGNETS)
Development History of SmCo Magnets
Early in the 1960s, Karl Strnat and colleagues discovered the extraordinary magnetic properties of samarium-cobalt alloys, confirming the great potential of SmCo magnets in terms of magnetic performance and high-temperature stability. This result fundamentally changed industrial applications, especially in sectors needing excellent temperature stability.
Although neodymium magnets, with their higher energy product and magnetic strength, have become one of the most often used strong magnets today, their great advantage is their high-temperature stability allows SmCo magnets to maintain magnetic performance at temperatures up to 300°C or even higher. SmCo magnets are thus crucial in environments calling for high-temperature operation.
Characteristics of SmCo Magnets
One of the great advantages of SmCo magnets is their extraordinary ability to resist demagnetization. They have a nice magnetic characteristic that can resist any change. They can retain the magnetic characteristics of the substance in a strong magnetic field, and they are not easily demagnetized. But at the same time, this also implies that SmCo magnets have a stronger magnetic field to organize the dipole moments into one direction in order to withstand the energy of the magnetization required for the magnet.
SmCo magnets exceed in heat performance at a temperature of 300°C, with some high-level grade magnets capable of handling even higher temperatures. They can be used in demanding applications. They also give high corrosion resistance, so stable magnetic properties are available even in humid and other challenging conditions.
Nevertheless, high production costs for SmCo magnets are due to the very rare Sm and Co and the complexity and laborious production of these magnets.
| Property | Ferrite | NdFeB | SmCo | AlNiCo |
|---|---|---|---|---|
| Remanence (Br) | 0.2-0.42 T | 1.05-1.45 T | 0.8-1.1 T | 0.6-1.15 T |
| Coercivity (Hcj) | 220-260 kA/m | 875-2786 kA/m | 1200-1500 kA/m | 10-96 kA/m |
| Max Energy Product | 0.8-4.1 MGOe | 26-55 MGOe | 15-23 MGOe | 1.2-12 MGOe |
| Temp. Coefficient | -0.2%/℃ | -0.12%/℃ | -0.04%/℃ | -0.02%/℃ |
| Max Operating Temp. | 250℃ | 80-200℃ | 250-350℃ | 450-550℃ |
| Cost | Very Low | High | Very High | Medium |
SmCo5 Magnetic Properties
| Grade | Remanence induction Br |
Coercive force Hcb |
Intrinsic Coercive force Hcj |
maximum Energy product (BH)max |
Density |
||||
|---|---|---|---|---|---|---|---|---|---|
| T | KGs | KA/m | KOe | KA/m | KOe | KJ/m3 | MGOe | g/cm3 | |
| XG16/20 | 0.82±0.03 | 8.2±0.3 | 621 | 7.8 | 1440 | 18 | 120 | 15 | 8.3 |
| 16/25 | 1760 | 22 | |||||||
| XG18/18 | 0.86±0.03 | 8.6±0.3 | 653 | 8.2 | 1280 | 16 | 136 | 17 | 8.3 |
| 18/20 | 1440 | 18 | |||||||
| 18/25 | 1760 | 22 | |||||||
| XG20/18 | 0.90±0.03 | 9.0±0.3 | 677 | 8.5 | 1280 | 16 | 152 | 19 | 8.3 |
| 20/20 | 1440 | 18 | |||||||
| 20/25 | 1760 | 22 | |||||||
| XG22/15 | 0.95±0.03 | 9.5±0.3 | 701 | 8.8 | 1120 | 14 | 168 | 21 | 8.3 |
| 22/18 | 1280 | 16 | |||||||
| 22/20 | 1440 | 18 | |||||||
| XG24/15 | 1.00±0.03 | 10.0±0.3 | 733 | 9.2 | 1040 | 14 | 184 | 23 | 8.3 |
Sm2Co17 Magnetic Properties
| Grade | Remanence Induction Br |
Coercive Force Hcb |
Intrinsic Coercive Force Hcj |
Maximum Energy Product (BH)max |
Density |
||||
|---|---|---|---|---|---|---|---|---|---|
| T | KGs | KA/m | KOe | KA/m | KOe | KJ/m3 | MGOe | g/cm3 | |
| XG22/25 | 0.97±0.03 | 9.7±0.3 | 717 | 9.0 | 2000 | 25 | 176 | 22 | 8.4 |
| 22/30 | 2240 | 28 | |||||||
| 22/35 | 2560 | 32 | |||||||
| XG24/25 | 1.03±0.03 | 10.3±0.3 | 733 | 9.2 | 2000 | 25 | 192 | 24 | 8.4 |
| 24/30 | 2240 | 28 | |||||||
| 24/35 | 2560 | 32 | |||||||
| XG26/10 | 1.06±0.03 | 10.6±0.3 | 598 | 7.5 | 800 | 10 | 200 | 25 | 8.4 |
| XG26/16 | 1.08±0.03 | 10.8±0.3 | 677 | 8.5 | 1120 | 14 | 200 | 25 | 8.4 |
| 26/20 | 757 | 9.5 | 1440 | 18 | |||||
| 26/25 | 1760 | 22 | |||||||
| 26/30 | 2080 | 26 | |||||||
| 26/35 | 2560 | 32 | |||||||
| XG28/16 | 1.10±0.03 | 11.0±0.3 | 701 | 8.8 | 1040 | 13 | 216 | 27 | 8.4 |
| 28/20 | 765 | 9.6 | 1440 | 18 | |||||
| 28/25 | 1760 | 22 | |||||||
| 28/30 | 2080 | 26 | |||||||
| 28/35 | 2560 | 32 | |||||||
| XG30/12 | 1.13±0.03 | 11.3±0.3 | 637 | 8.0 | 800 | 10 | 232 | 29 | 8.4 |
| 30/15 | 717 | 9.0 | 1040 | 13 | |||||
| 30/20 | 757 | 9.5 | 1440 | 18 | |||||
| 30/25 | 1760 | 22 | |||||||
| XG32/12 | 1.15±0.03 | 11.5±0.3 | 637 | 8.0 | 800 | 10 | 248 | 31 | 8.4 |
| 32/15 | 717 | 9.0 | 1040 | 13 | |||||
| 32/20 | 765 | 9.6 | 1440 | 18 | |||||
SmCo Magnets: SmCo5 and Sm2Co17 Types
SmCo5 magnets are the earliest form of samarium-cobalt of permanent magnets. Their performance is relatively lower due to the lower cobalt content. They are mainly used in some instances when moderate magnetic energy products are needed.
The price of SmCo5 magnets is relatively lower than that of Sm2Co17 magnets. Sm2Co17 magnets are an advanced version of samarium-cobalt magnets with a higher cobalt content. Thus, they performed very well. They are primarily used in applications needing elevated magnetic energy products.
Applications of SmCo Magnets
One of the significant advantages of SmCo magnets is their corrosion resistance, and they are frequently used in harsh environments, like marine applications and the aerospace industry.
SmCo magnets are the most widely used in automobile technology due to their ability to tolerate high temperatures. These magnets have been used in electric car drivetrains, actuators, and motors.
They are used in various defense and aerospace applications, including satellite systems, missile guidance systems, and magnetic actuators, where small size, excellent performance, and temperature stability are critical.
Price Trends of SmCo Magnets
In total, the price of a SmCo magnet is affected by different things, such as price instability. Besides, SmCo magnets mainly consist of samarium (Sm) and cobalt (Co), of which samarium belongs to rare earth elements. The extraction and the supply of rare earth elements are limited, and this is getting even worse because of the growing demand all over the world. The rareness of samarium leads to changes in raw material prices, which consequently have an impact on production costs and market prices for SmCo magnets.
In addition, the manufacturing process of SmCo magnets is challenging and difficult, as the case may be, especially at the sintering step, where high temperatures and pressures are applied. These manufacturing problems then result in greater production expenses, increasing the desired product’s price.
