Samarium cobalt 1:5 and 2:17 magnets for high-temperature, corrosion-critical and long-term stable magnetic circuits.
Samarium cobalt 1:5 and 2:17 magnets for high-temperature, corrosion-critical and long-term stable magnetic circuits.
SmCo is selected when flux stability, corrosion resistance and high-temperature operation dominate the design. Two families are used: SmCo₅ (1:5) and Sm₂Co₁₇ (2:17).
SmCo is often the safer answer when NdFeB thermal margin becomes uncertain.
| Application | Typical Spec | Why this material |
|---|---|---|
| High-temperature motors / actuators | SmCo 2:17 S24H–S30H | Stable flux and high coercivity at elevated temperature |
| Automotive sensors | S22H / S24H | Temperature stability and corrosion resistance |
| Downhole / harsh industrial | HTS series | High-temperature margin and chemical resistance |
| Microwave / instrumentation | SmCo 1:5 | High coercivity and predictable magnetic behavior |
| Medical / precision equipment | SmCo 2:17 | Stable output without relying on an external corrosion coating |
| Family | Energy / coercivity character | Temperature behavior | Processing note | Typical use |
|---|---|---|---|---|
| SmCo₅ (1:5) | Lower energy, high coercivity | Excellent | Fine/brittle; grinding only | Small parts, sensors, microwave devices |
| Sm₂Co₁₇ (2:17) | Higher energy product | Excellent to extreme-temperature classes | Grinding only; edge protection important | Motors, aerospace/industrial actuators, oil & gas |
| HTS 2:17 | Application-specific high-temperature family | Up to ~350°C class where validated | Test condition must be defined | Downhole, high-temperature actuation |
Use the table as a selection reference. Final acceptance limits follow the approved drawing/specification and agreed test method.
| Grade | Br mT (kGs) | Hcb kA/m (kOe) | Hcj kA/m (kOe) | (BH)max kJ/m³ (MGOe) | αBr %/°C | βHcj %/°C |
|---|---|---|---|---|---|---|
| S10H | 580-710 (5.8-7.1) | ≥422 (≥5.3) | ≥1990 (≥25) | 63-95 (8-12) | 0.03 | 0.2 |
| S12H | 650-760 (6.5-7.6) | ≥478 (≥6.0) | ≥1990 (≥25) | 79-111 (10-14) | 0.03 | 0.2 |
| S14H | 710-830 (7.1-8.3) | ≥525 (≥6.6) | ≥1990 (≥25) | 95-127 (12-16) | 0.03 | 0.2 |
| S16H | 790-860 (7.9-8.6) | ≥589 (≥7.4) | ≥1990 (≥25) | 119-143 (15-18) | 0.03 | 0.2 |
| S18H | 830-890 (8.3-8.9) | ≥605 (≥7.6) | ≥1990 (≥25) | 135-159 (17-20) | 0.03 | 0.2 |
| S20H | 870-930 (8.7-9.3) | ≥653 (≥8.2) | ≥1990 (≥25) | 151-175 (19-22) | 0.03 | 0.2 |
| S22H | 910-980 (9.1-9.8) | ≥693 (≥8.7) | ≥1990 (≥25) | 159-183 (20-23) | 0.03 | 0.2 |
| S24H | 960-1030 (9.6-10.3) | ≥724 (≥9.1) | ≥1990 (≥25) | 175-199 (22-25) | 0.03 | 0.2 |
| S26H | 1010-1060 (10.1-10.6) | ≥733 (≥9.2) | ≥1990 (≥25) | 191-215 (24-27) | 0.03 | 0.2 |
| S28H | 1040-1090 (10.4-10.9) | ≥749 (≥9.4) | ≥1990 (≥25) | 207-231 (26-29) | 0.03 | 0.2 |
| S30H | 1080-1110 (10.8-11.1) | ≥773 (≥9.7) | ≥1990 (≥25) | 222-247 (28-31) | 0.035 | 0.2 |
| S32H | 1120-1160 (11.2-11.6) | ≥812 (≥10.2) | ≥1990 (≥25) | 239-263 (30-33) | 0.038 | 0.2 |
| S34H | 1150-1180 (11.5-11.8) | ≥835 (≥10.5) | ≥1990 (≥25) | 247-270 (31-34) | 0.04 | 0.25 |
| S35H | 1170-1200 (11.7-12.0) | ≥860 (≥10.8) | ≥1990 (≥25) | 255-278 (32-35) | 0.04 | 0.25 |
| S10 | 580-710 (5.8-7.1) | ≥422 (≥5.3) | ≥1592 (≥20) | 63-95 (8-12) | 0.03 | 0.2 |
| S12 | 650-760 (6.5-7.6) | ≥478 (≥6.0) | ≥1592 (≥20) | 79-111 (10-14) | 0.03 | 0.2 |
| S14 | 710-830 (7.1-8.3) | ≥525 (≥6.6) | ≥1592 (≥20) | 95-127 (12-16) | 0.03 | 0.2 |
| S16 | 790-860 (7.9-8.6) | ≥589 (≥7.4) | ≥1592 (≥20) | 119-143 (15-18) | 0.03 | 0.2 |
| S18 | 830-890 (8.3-8.9) | ≥605 (≥7.6) | ≥1592 (≥20) | 135-159 (17-20) | 0.03 | 0.2 |
| S20 | 870-930 (8.7-9.3) | ≥653 (≥8.2) | ≥1592 (≥20) | 151-175 (19-22) | 0.03 | 0.2 |
| S22 | 910-980 (9.1-9.8) | ≥693 (≥8.7) | ≥1592 (≥20) | 159-183 (20-23) | 0.03 | 0.2 |
| S24 | 960-1030 (9.6-10.3) | ≥724 (≥9.1) | ≥1592 (≥20) | 175-199 (22-25) | 0.03 | 0.2 |
| S26 | 1010-1060 (10.1-10.6) | ≥733 (≥9.2) | ≥1592 (≥20) | 191-215 (24-27) | 0.03 | 0.2 |
| S28 | 1040-1090 (10.4-10.9) | ≥749 (≥9.4) | ≥1592 (≥20) | 207-231 (26-29) | 0.03 | 0.2 |
| S30 | 1080-1110 (10.8-11.1) | ≥773 (≥9.7) | ≥1592 (≥20) | 222-247 (28-31) | 0.035 | 0.2 |
| S32 | 1100-1130 (11.0-11.3) | ≥804 (≥10.1) | ≥1592 (≥20) | 231-255 (29-32) | 0.038 | 0.2 |
| S33 | 1120-1160 (11.2-11.6) | ≥812 (≥10.2) | ≥1592 (≥20) | 239-263 (30-33) | 0.038 | 0.2 |
| S34 | 1150-1180 (11.5-11.8) | ≥835 (≥10.5) | ≥1592 (≥20) | 247-270 (31-34) | 0.04 | 0.25 |
| S35 | 1170-1200 (11.7-12.0) | ≥860 (≥10.8) | ≥1592 (≥20) | 255-278 (32-35) | 0.04 | 0.25 |
| S24M | 960-1030 (9.6-10.3) | 597-756 (7.5-9.5) | 796-1273 (10-16) | 175-199 (22-25) | 0.03 | 0.2 |
| S26M | 1010-1060 (10.1-10.6) | 597-820 (7.5-10.3) | 796-1273 (10-16) | 191-215 (24-27) | 0.03 | 0.2 |
| S28M | 1040-1090 (10.4-10.9) | 621-836 (7.8-10.5) | 796-1273 (10-16) | 207-231 (26-29) | 0.03 | 0.2 |
| S30M | 1080-1110 (10.8-11.1) | 621-836 (7.8-10.5) | 796-1273 (10-16) | 222-247 (28-31) | 0.035 | 0.2 |
| S32M | 1110-1150 (11.1-11.5) | 717-844 (9.0-10.6) | 796-1273 (10-16) | 239-263 (30-33) | 0.038 | 0.2 |
| S24L | 960-1030 (9.6-10.3) | 438-716 (5.5-9) | 478-796 (6-10) | 175-199 (22-25) | 0.03 | 0.2 |
| S26L | 1010-1060 (10.1-10.6) | 438-716 (5.5-9) | 478-796 (6-10) | 191-215 (24-27) | 0.03 | 0.2 |
| S28L | 1040-1090 (10.4-10.9) | 438-716 (5.5-9) | 478-796 (6-10) | 207-231 (26-29) | 0.03 | 0.2 |
| S30L | 1080-1120 (10.8-11.2) | 438-757 (5.5-9.5) | 478-796 (6-10) | 222-247 (28-31) | 0.035 | 0.2 |
| S32L | 1110-1150 (11.1-11.5) | 438-757 (5.5-9.5) | 478-796 (6-10) | 231-255 (29-32) | 0.038 | 0.2 |
| HTS20H | 870-930 (8.7-9.3) | ≥653 (≥8.2) | ≥1990 (≥25) | 151-175 (19-22) | 0.05 | 0.2 |
| HTS22H | 910-980 (9.1-9.8) | ≥693 (≥8.7) | ≥1990 (≥25) | 159-183 (20-23) | 0.05 | 0.2 |
| HTS24H | 960-1030 (9.6-10.3) | ≥724 (≥9.1) | ≥1990 (≥25) | 175-199 (22-25) | 0.05 | 0.2 |
| LTS14 | 730-800 (7.3-8.0) | ≥565 (≥7.1) | ≥1592 (≥20) | 103-127 (13-16) | 0.005–0.01 | 0.3 |
| LTS16 | 790-860 (7.9-8.6) | ≥613 (≥7.7) | ≥1592 (≥20) | 119-143 (15-18) | 0.01–0.015 | 0.3 |
| LTS18 | 830-890 (8.3-8.9) | ≥645 (≥8.1) | ≥1592 (≥20) | 135-159 (17-20) | 0.015–0.02 | 0.3 |
| LTS20 | 870-930 (8.7-9.3) | ≥653 (≥8.2) | ≥1592 (≥20) | 151-175 (19-22) | 0.02–0.025 | 0.3 |
| PS16H | 790-860 (7.9-8.6) | ≥605 (≥7.6) | ≥1990 (≥25) | 119-143 (15-18) | 0.05 | 0.3 |
| PS18H | 840-910 (8.4-9.1) | ≥645 (≥8.1) | ≥1990 (≥25) | 135-159 (17-20) | 0.05 | 0.3 |
| PS20H | 870-930 (8.7-9.3) | ≥653 (≥8.2) | ≥1990 (≥25) | 151-175 (19-22) | 0.05 | 0.3 |
| PS22H | 910-980 (9.1-9.8) | ≥693 (≥8.7) | ≥1990 (≥25) | 159-183 (20-23) | 0.05 | 0.3 |
| PS24H | 950-1010 (9.5-10.1) | ≥717 (≥9.0) | ≥1990 (≥25) | 175-199 (22-25) | 0.05 | 0.3 |
| Characteristic | SmCo 1:5 | SmCo 2:17 |
|---|---|---|
| Typical use | Small / complex, high-coercivity parts | Higher-energy, high-temperature applications |
| Energy product | Lower to medium | Higher |
| Temperature coefficient | Excellent | Excellent / typically better |
| Coercivity | Very high | High to very high |
| Manufacturing note | Fine-grain / brittle | Brittle; grinding only |
Axial or diametric magnetization.
As-sintered or ground.
Axial or radial orientation; precision ID/OD grinding.
Motor poles and high-temperature rotor segments.
Grinding only; avoid drilling/tapping after sintering.
Chamfers and packaging reduce chipping risk during handling and assembly.
| Process | Typical Tolerance | Notes |
|---|---|---|
| As-sintered | ±0.1 mm | Non-critical faces |
| Ground | ±0.05 mm | Standard mating dimensions |
| Precision ground | ±0.02 mm | Locating / press-fit dimensions |
| Parallelism / perpendicularity | Per drawing | DFM confirmation |
Sm-Co based alloy chemistry is controlled for the target magnetic family.
Powder preparation and field alignment establish the anisotropic structure.
Vacuum sintering / heat treatment develops the target coercivity and energy product.
Final dimensions are normally created by diamond grinding; conventional drilling/tapping is avoided.
Chamfers and careful packaging reduce chipping risk.
Magnetization fixture and BH/flux verification follow the agreed project specification.
High-temperature validation should define open/closed magnetic circuit, fixture, magnetization direction and measurement method before production.
Review rare-earth composition and product specifications for the applicable export-control route.
Prepare product, material and technical documentation needed for customs / licensing review.
Support lawful export-license application information where the product is controlled.
Where a complete magnetic assembly is commercially preferable, evaluate it as an integrated product—not as a regulatory workaround.
Actual classification is determined by applicable laws and the real product at time of shipment.
CoA / magnetic-property results can include Br, Hcb, Hcj and (BH)max according to the agreed inspection plan.
Gauge, optical inspection or CMM/3D optical measurement can be used according to geometry and critical dimensions.
Before shipment, we can provide a real-time inspection video showing the product, equipment, measurement process and actual displayed data for remote customer verification.
FAI / PPAP / RoHS / REACH / traceability documents are available according to project and customer requirements.
All technical PDFs in this library are hosted locally on empiremagnets.com and use the current Ningbo Empire document identity and revision format.
Choose SmCo when temperature stability, intrinsic corrosion resistance or resistance to demagnetization is more important than maximum energy density or lowest material cost.
Usually not for ordinary environments because the material is intrinsically corrosion resistant. Project-specific coatings can still be considered for aggressive chemical or salt environments.
Yes. Geometry, chamfer, packaging and assembly load paths should be reviewed to reduce edge chipping and point loading.
Yes, test conditions should be defined before production because magnetic performance depends on geometry, circuit condition, fixture and measurement method.
