Samarium Cobalt (Sm-Co)The first commercially viable rare earth permanent magnet material, samarium-cobalt (Sm-Co), is considered to still be the premium material for many high performance applications. Formulated in the 1960s, it came as a revolutionary product, initially tripling the energy product of other materials available at the time. Sm-Co materials come in energy products from 16 MGOe up to 33 MGOe. Their high resistance to demagnetizing influences and excellent thermal stability has ensured Sm-Co as the premium choice for the most demanding motor applications. In addition, the corrosion resistance is significantly higher than, for example, Nd-Fe-B. However, we would still recommend coating the magnet in acidic conditions. Its corrosion resistance has also offered a high degree of comfort to those looking to use magnets in medical applications. On a 'per pound' basis, Sm-Co is the most expensive permanent magnet material. However, because of its high energy product, it has achieved considerable commercial success by decreasing the required volume of magnet material to fulfill a certain task. Sm-Co can typically be used up to 300 °C, though, of course, its actual performance at that temperature is governed strongly by the design of the magnetic circuit. The (approximately) linear demagnetization curve of Sm-Co materials allows repeatable performance over a wide range of operating conditions. As with all permanent magnet materials, extreme caution must be exe rcised when handling magnetized samples. Sm-Co can be prone to chipping and should not be used a structural component in an assembly. | Grade | Maximum
Energy
Product
BHmax | Residual
Induction
Br | Minimum
Intrinsic
Coercivity
Hci | Coercivity
Hc | Maximum
Operating
Temp
Tmo | Curie Temp
Tc | Coefficient
Induction
20-150 °C]
α | Coefficient
Coercivity
20-150 °C]
β | | MGOe | kG | kOe | kOe | °C | °C | % / °C | % / °C | | Type 2:17 | | | | | | | | | | S3010 | 30 | 11.2 | 10 | 9.2 | 300 | 825 | -0.03 | -0.17 | | S2610 | 26 | 10.5 | 10 | 8.8 | 300 | 825 | -0.03 | -0.17 | | S3212 | 32 | 11.5 | 12 | 10.0 | 300 | 825 | -0.03 | -0.17 | | S3012 | 30 | 11.3 | 12 | 9.8 | 300 | 825 | -0.03 | -0.17 | | S2612 | 26 | 10.6 | 12 | 9.4 | 300 | 825 | -0.03 | -0.17 | | S2212 | 22 | 9.9 | 12 | 9.0 | 300 | 825 | -0.03 | -0.17 | | S3315 | 33 | 11.7 | 15 | 10.7 | 300 | 825 | -0.03 | -0.22 | | S3215 | 32 | 11.5 | 15 | 10.5 | 300 | 825 | -0.03 | -0.22 | | S3015 | 30 | 11.3 | 15 | 10.3 | 300 | 825 | -0.03 | -0.22 | | S2816 | 28 | 11.0 | 16 | 10.3 | 300 | 825 | -0.03 | -0.22 | | S2616 | 26 | 10.8 | 16 | 10.1 | 300 | 825 | -0.03 | -0.22 | | S3218 | 32 | 11.6 | 18 | 10.8 | 300 | 825 | -0.03 | -0.22 | | S3018 | 30 | 11.3 | 18 | 10.6 | 300 | 825 | -0.03 | -0.22 | | S2618 | 26 | 10.7 | 18 | 10.1 | 300 | 825 | -0.03 | -0.22 | | S2820 | 28 | 11.0 | 20 | 10.4 | 300 | 825 | -0.03 | -0.22 | | S2620 | 26 | 10.8 | 20 | 10.3 | 300 | 825 | -0.03 | -0.22 | | S3022 | 30 | 11.3 | 19 | 10.5 | 300 | 825 | -0.03 | -0.22 | | S2825 | 28 | 11.1 | 25 | 10.5 | 300 | 825 | -0.03 | -0.22 | | S2625 | 26 | 10.8 | 25 | 10.2 | 300 | 825 | -0.03 | -0.22 | | S2425 | 24 | 10.3 | 25 | 9.8 | 350 | 825 | -0.03 | -0.22 | | S2225 | 22 | 9.7 | 25 | 9.2 | 350 | 825 | -0.03 | -0.22 | | S2830 | 28 | 11.0 | 30 | 10.5 | 300 | 825 | -0.03 | -0.22 | | S2630 | 26 | 10.8 | 30 | 10.3 | 300 | 825 | -0.03 | -0.22 | | S2430 | 24 | 10.3 | 30 | 9.8 | 350 | 825 | -0.03 | -0.22 | | S2230 | 22 | 9.7 | 30 | 9.3 | 350 | 825 | -0.03 | -0.22 | | S2435 | 24 | 10.3 | 35 | 9.9 | 350 | 825 | -0.03 | -0.22 | | S2235 | 22 | 9.7 | 35 | 9.3 | 350 | 825 | -0.03 | -0.22 | | Type 1:5 | | | | | | | | | | S2415 | 24 | 10.0 | 15 | 9.3 | 250 | 750 | -0.05 | -0.22 | | S2215 | 22 | 9.5 | 15 | 8.8 | 250 | 750 | -0.05 | -0.22 | | S2418 | 24 | 10.0 | 18 | 9.4 | 250 | 750 | -0.05 | -0.22 | | S2218 | 22 | 9.5 | 18 | 9.0 | 250 | 750 | -0.05 | -0.22 | | S2018 | 20 | 9.0 | 18 | 8.5 | 250 | 750 | -0.05 | -0.22 | | S1818 | 18 | 8.6 | 18 | 8.2 | 250 | 750 | -0.05 | -0.22 | | S2220 | 22 | 9.5 | 20 | 9.1 | 250 | 750 | -0.05 | -0.22 | | S2020 | 20 | 9.0 | 20 | 8.6 | 250 | 750 | -0.05 | -0.22 | | S1820 | 18 | 8.6 | 20 | 8.2 | 250 | 750 | -0.05 | -0.22 | | S2223 | 22 | 9.5 | 23 | 9.1 | 250 | 750 | -0.05 | -0.22 | | S2025 | 20 | 9.0 | 25 | 8.6 | 250 | 750 | -0.05 | -0.22 | | S1825 | 18 | 8.6 | 25 | 8.2 | 250 | 750 | -0.05 | -0.22 | | S2030 | 20 | 9.0 | 30 | 8.6 | 250 | 750 | -0.05 | -0.22 |
Typical Physical Properities - Type 2:17 | | Curie Temperature | 800 - 825 °C | *Coefficient of Thermal Expansion - Perpendicular to magnetization orientation | +11.0 - +12.0 x 10-6 °C-1 | *Coefficient of Thermal Expansion - Parallel to magnetization orientation | +9.0 - +10.0 x 10-6 °C-1 | Electrical Resistivity | 80 - 90 µΩ·cm | Density | 8.3 - 8.4 g·cm-3 | Vicker's Hardness | 550 - 650 Hv | Young's Modulus | 140 - 150 kN·mm-2 | Bending Strength | 0.09 - 0.15 kN·mm-2 | Compressive Strength | 0.65 - 0.80 kN·mm-2 | Typical Physical Properities -Type 1:5 | | Curie Temperature | 720 - 750 °C | *Coefficient of Thermal Expansion - Perpendicular to magnetization orientation | +12.0 - +13.0 x 10-6 °C-1 | *Coefficient of Thermal Expansion - Parallel to magnetization orientation | +6.0 - +7.0 x 10-6 °C-1 | Electrical Resistivity | 50 - 60 µΩ·cm | Density | 8.2 - 8.3 g·cm-3 | Vicker's Hardness | 550 - 550Hv | Young's Modulus | 100 - 110 kN·mm-2 | Bending Strength | 0.12 - 0.18 kN·mm-2 | Compressive Strength | 0.9 - 1.0 kN·mm-2 |
*Due to magnetostriction, all magnetic materials expand/contract at different rates, depending on magnetic orientation. |