china sintered smco magnets samarium cobalt magnets manufacturer & supplierSintered SmCo magnets, i.e. sintered samarium cobalt magnets, are those permanent magnetic materials that based on a hexagonal crystal structure (1:5 type SmCo magnets) or a rhombohedral crystal structure (2:17 type SmCo magnets), and they are manufactured through a powder metallurgy process. They contain two basic elements samarium and cobalt. The samarium element can be substituted by a portion of other rare earth elements including praseodymium (Pr), cerium (Ce), gadolinium (Gd), erbium (Er), etc. The cobalt element can be substituted by a portion of iron (Fe) element to increase the magnets’ saturation magnetization (Ms). In order to control the microstructure and the microchemistry so as to meet required performance, it is also critical to add a small portion of copper (Cu), zirconium (Zr), titanium (Ti), etc. According to crystal structure, samarium cobalt magnets include SmCo5 magnets (1st generation of REPMs) and Sm2Co17 magnets (2nd generation of REPMs). They were invented/developed by K. Strnat’s team in the 1960s and T. Ojima’s team in the 1970s, respectively. Due to their high Curie temperature (Tc: 700-850 ºC), middle high maximum energy product ((BH)max: 110-260 kJ/m3), low temperature coefficients of remanence (α(Br): +0.01 to -0.05 %/°C) and coercivity (β(Hcj): -0.2 to -0.3 %/°C) and high corrosion resistance, sintered SmCo magnets are mainly applied in high temperature motors, servo motors, stepper/stepping motors, traveling wave tubes (TWTs), circulators, isolators, klystrons, undulators, gyroscopes, accelerometers, instruments and meters, etc.

Sintered SmCo Magnets’ Grades and Their Magnetic Properties

GradeBrHcbHcj(BH)maxTw
kGsTkOekA/mkOekA/mMGOekJ/m3ºC
XGS32H11.0-11.51.10-1.15≥10.2≥812≥25≥199030-32239-255≤350
XGS30H10.7-11.21.07-1.12≥9.9≥78828-30223-239
XGS28H10.4-10.91.04-1.09≥9.6≥76426-28207-223
XGS26H10.0-10.51.00-1.05≥9.2≥73224-26191-207
XGS24H9.7-10.20.97-1.02≥8.9≥70822-24175-191
XGS22H9.3-9.80.93-0.98≥8.5≥67620-22159-175
XGS20H9.0-9.50.90-0.95≥8.2≥65318-20143-159
XGS3211.0-11.51.10-1.15≥10.0≥796≥18≥143330-32239-255≤300
XGS3010.7-11.21.07-1.12≥9.7≥77228-30223-239
XGS2810.4-10.91.04-1.09≥9.4≥74826-28207-223
XGS2610.0-10.51.00-1.05≥9.0≥71624-26191-207
XGS249.7-10.20.97-1.02≥8.7≥69222-24175-191
XGS229.3-9.80.93-0.98≥8.3≥66020-22159-175
XGS209.0-9.50.90-0.95≥8.0≥63718-20143-159
XGS32M11.0-11.51.10-1.15≥9.0≥716≥12≥95530-32239-255≤300
XGS30M10.7-11.21.07-1.12≥8.7≥69228-30223-239
XGS28M10.4-10.91.04-1.09≥8.5≥67626-28207-223
XGS26M10.0-10.51.00-1.05≥8.5≥67624-26191-207
XGS24M9.7-10.20.97-1.02≥8.5≥67622-24175-191
XGS22M9.3-9.80.93-0.98≥8.2≥65320-22159-175
XGS20M9.0-9.50.90-0.95≥8.0≥63718-20143-159
XGS32L11.0-11.51.10-1.15≥6.8≥541≥8≥63630-32239-255≤250
XGS30L10.7-11.21.07-1.12≥6.8≥54128-30223-239
XGS28L10.4-10.91.04-1.09≥6.6≥52526-28207-223
XGS26L10.0-10.51.00-1.05≥6.6≥52524-26191-207
XGS24L9.7-10.20.97-1.02≥6.5≥51722-24175-191
XGS22L9.3-9.80.93-0.98≥6.5≥51720-22159-175
XGS20L9.0-9.50.90-0.95≥6.5≥51718-20143-159
XGS24LT9.7-10.20.97-1.02≥8.7≥692≥18≥143322-24175-191≤300
XGS22LT9.3-9.80.93-0.98≥8.3≥66020-22159-175
XGS20LT9.0-9.50.90-0.95≥8.0≥63718-20143-159
XGS18LT8.5-9.00.85-0.90≥7.5≥59716-18127-143
XGS16LT8.0-8.50.80-0.85≥7.0≥55714-16111-127
XGS14LT7.5-8.00.75-0.80≥6.5≥51712-1495-111
XG24H9.7-10.20.97-1.02≥9.2≥730≥23≥183022-24175-191≤250
XG22H9.3-9.80.93-0.98≥8.8≥70020-22159-175
XG20H9.0-9.50.90-0.95≥8.5≥67618-20143-159
XG18H8.5-9.00.85-0.90≥8.2≥65316-18127-143
XG16H8.0-8.50.80-0.85≥7.8≥62014-16111-127
XG249.7-10.20.97-1.02≥9.2≥730≥15≥119422-24175-191≤250
XG229.3-9.80.93-0.98≥8.8≥70020-22159-175
XG209.0-9.50.90-0.95≥8.5≥67618-20143-159
XG188.5-9.00.85-0.90≥8.2≥65316-18127-143
XG168.0-8.50.80-0.85≥7.8≥62014-16111-127

Note:
∗ The data in the above table were samples’ results tested at the temperature of 20 °C.
∗ The prefixes XGS and XG are for Sm2Co17 and SmCo5 magnets, respectively.
∗ The typical temperature coefficients of Br and Hcj are α(Br): -0.03~-0.05 %/ºC and β(Hcj): -0.20~-0.30 %/ºC, respectively.
∗ The suffix LT means low/near-zero temperature coefficient of Br (α(Br): +0.01 ~ -0.03 %/°C).
∗ The above data are only for reference, magnets can be tailored according to customers’ personalized requirements.

Sintered SmCo Magnets’ Shapes, Magnetization Direction and Size Range

ShapeGraphic DescriptionMagnetization DirectionSize Range
Disc/Cylinder Magnetcustom disc smco magnets size diagramdisc magnet pole, Disc permanent magnets Axially MagnetizedAxially MagnetizedD: 1-100 mm
T: 0.5-100 mm
disc magnet pole, Disc permanent magnets Diametrically MagnetizedDiametrically MagnetizedD: 1-100 mm
T: 0.5-100 mm
Ring Magnetcustom ring samarium cobalt magnets size diagramring magnet pole, ring permanent magnets Axially MagnetizedAxially MagnetizedOD: 5-100 mm
ID: 1-90 mm
T: 1-60 mm
ring magnet pole, ring permanent magnets Diametrically MagnetizedDiametrically MagnetizedOD: 5-100 mm
ID: 1-90 mm
T: 1-60 mm
Block/Rectangular Magnetcustom block smco magnets size diagramblock permanent magnets Thickness MagnetizedThickness MagnetizedL: 1-160 mm
W: 1-100 mm
T: 1-100 mm
Arc/Segment Magnetcustom arc smco magnets size diagramarc segment permanent magnets Diametrically magnetizationDiametrically MagnetizedOD-ID≥1 mm
L: 1-120 mm
W: 3-100 mm
H: 1-60 mm

Note:
∗ Other shapes of sintered SmCo magnets can also be tailored according to customers’ specific requirements.

Because of strong corrosion resistance, sintered SmCo magnets usually do not need any coating. If any coating is required, nickel, zinc, tin, epoxy, Teflon and other types are available.

Some Physical Properties of Sintered SmCo Magnets

ParameterUnitValue
Density (ρ)g/cm38.2-8.4
Curie Temperature (Tc)ºC700-850
Recoil Permeability (μrec)-1.05-1.10
Vickers Hardness (HV)MPa400-600
Bending Strength (σbb)MPa150-180
Compressive Strenght (σbc)MPa800-1000
Tensile Strength (σb)MPa35-40
Resistivity (ρ)μΩ·m0.5-0.9
Thermal Expansivity ∥ Magnetization (α)10-6/ºC5-9
Thermal Expansivity ⊥ Magnetization (α)10-6/ºC10-13

Note:
∗ The above data are only for reference, specific magnets maybe have different values.