Manufacturing Process
Samarium, Cobalt, and a few transition metals will be made into the SmCo powder, then fine SmCo powder will be compacted in a die and sintered, fusing the powder into a solid material. There are 2 forms of pressing: die pressing and isostatic pressing. Sintered parts normally need some finish machining in order to meet final tolerances.
Machining & Tolerance
Generally, SmCo magnets must be machined using diamond-grinding techniques. Sometimes, machining operations may be performed on SmCo materials using carbide tools, but surface finishes thus obtained may be less than optimal.
The Standard tolerances for SmCo magnets are +/- 0.1mm for ground dimensions, but sticter tolerances are possible if specially required.
Surface treatments
The corrosion resistance of SmCo magnets is considered good. Although Surface coating or plating is not generally required for SmCo magnets, all kinds of surface coating are also available, like Nickel, Zn, Ni-Cu-Ni, Gold, Silver, Sn,Chrome, ABS coating, Rubber coating, PTFE(Telfon) coating, stainless steel case, etc.
Magnetizing & Packing
SmCo magnets require extremely high magnetizing fields, and can be magnetized in any direction as long as it is aligned properly. In some instances multiple pole magnetization is possible with special fixtures. All SmCo magnets are anisotropic, and can only be magnetized in the orientation direction, so particular consideration must be given to this when designing complex assemblies, if it is intended to magnetize after assembly.
SmCo magnets are mechanically weak, and magnetically very strong. They should be packed properly in order to help user to use and handle them.
Magnetic properties of SmCo magnets
Grade | Residual Induction | Coercive Force | Intrinsic Coercive Force | Maximum Energy Product | Maximum Working Temperature | |
Br | Hcb | Hcj | (BH)max | Tw | ||
mT | kA/m | kA/m | kJ/m3 | |||
[kGs] | [kOe] | [kOe] | [MGOe] | |||
SmCo5 | YX18 | 820-920 | 639-756 | 1194-1751 | 127-159 | 250° |
[8.2-9.2] | [8-9.5] | [15-22] | [16-20] | |||
YX20 | 870-950 | 639-756 | 1194-1751 | 143-175 | ||
[8.7-9.5] | [8-9.5] | [15-22] | [18-22] | |||
YX22 | 930-1000 | 660-772 | 1194-1751 | 159-191 | ||
[9.3-1.0] | [8.3-9.7] | [15-22] | [20-24] | |||
YX24 | 960-1040 | 660-780 | 1194-1751 | 175-207 | ||
[9.6-10.4] | [8.3-9.8] | [15-22] | [22-26] | |||
Sm2Co17 | YXS24M | 960-1040 | 318-772 | 398-955 | 175-207 | 350° |
[9.6-10.4] | [4-9.7] | [5-12] | [22-26] | |||
YXS24 | 960-1040 | 660-780 | ≥1194 | 175-207 | ||
[9.6-10.4] | [8.3-9.8] | [≥15] | [22-26] | |||
YXS24H | 960-1040 | 660-780 | ≥1592 | 175-207 | ||
[9.6-10.4] | [8.3-9.8] | [≥20] | [22-26] | |||
YXS26M | 1170-1220 | 318-796 | 398-955 | 191-223 | ||
[10-10.7] | [4-10] | [5-12] | [25-28] | |||
YXS26 | 1170-1220 | 677-820 | ≥1194 | 191-223 | ||
[10-10.7] | [8.5-10.3] | [≥15] | [25-28] | |||
YXS26H | 1170-1220 | 677-820 | ≥1592 | 191-223 | ||
[10-10.7] | [8.5-10.3] | [≥20] | [25-28] | |||
YXS28M | 1040-1110 | 318-796 | 398-955 | 207-239 | ||
[10.4-11] | [4-10] | [5-12] | [26-30] | |||
YXS28 | 1040-1110 | 677-820 | ≥1194 | 207-239 | ||
[10.4-11] | [8.5-10.3] | [≥15] | [26-30] | |||
YXS28H | 1040-1110 | 677-820 | ≥1592 | 207-239 | ||
[10.4-11] | [8.5-10.3] | [≥20] | [26-30] | |||
YXS30M | 1070-1120 | 318-796 | 398-955 | 223-247 | ||
[10.7-11.2] | [4-10] | [5-12] | [28-31] | |||
YXS30 | 1070-1120 | 677-820 | ≥1194 | 223-247 | ||
[10.7-11.2] | [8.5-10.3] | [≥15] | [28-31] | |||
YXS32M | 1090-1150 | 318-796 | 398-955 | 238-262 | ||
[10.9-11.5] | [4-10] | [5-12] | [29-32] | |||
YXS32 | 1090-1150 | 677-820 | ≥1353 | 238-262 | ||
[10.9-11.5] | [8.5-10.3] | [≥12] | [29-32] | |||
Low Temp Coeff Sm2Co17 | YXL22LT | 930-1000 | 677-756 | ≥1194 | 159-191 | 350° |
[9.3-10] | [8.5-9.5] | [≥15] | [20-24] | |||
YXL24LT | 960-1040 | 677-756 | ≥1194 | 175-207 | ||
[9.6-10.4] | [8.5-9.5] | [≥15] | [22-26] | |||
YXL26LT | 1000-1070 | 677-812 | ≥1433 | 191-223 | ||
[10-10.7] | [8.5-10.2] | [≥18] | [25-28] |
Physical properties of SmCo magnets
Grade | Modulus of elasticy | Ultimate tensile strength | Density | Electrical Resistivity | Curie temperature | Recoil permeability | Temp.Coeff.of Br |
SmCo5 | 23 x 106 psi | 6 x 103 psi | 8.2 g/cm3 | 5 µ-ohm-cm/cm2 | 750-770℃ | 1.05 | From -0.043 to -0.045% / ℃ |
Sm2Co17 | 17 x 106 psi | 5 x 103 psi | 8.4 g/cm3 | 86 µ-ohm-cm/cm2 | 825-850℃ | 1.05 | From -0.03 to -0.032% / ℃ |