Description

Technical Parameters

Samarium Cobalt (SmCo) arc segments deliver high magnetic flux density and thermal stability for permanent magnet synchronous motors (PMSM) and high-speed BLDC rotors. Formed from Sm2Co17 and SmCo5 alloys, these magnets retain magnetic integrity at continuous operating temperatures up to 350°C and resist demagnetization under severe armature reaction fields.
Their intermetallic chemical structure eliminates the requirement for protective electroplating (such as Ni-Cu-Ni or epoxy), preventing coating delamination failures in hermetic or high-vibration environments. Supply chain risks tied to raw material price fluctuations are managed via index-linked pricing frameworks and secured rare-earth reserves.

Technical Specifications

Parameter	Standard Grade (SmCo5)	High-Performance Grade (Sm2Co17)
Remanence (Br), Gauss	8,500 - 9,500	10,500 - 12,000
Energy Product ((BH)max), MGOe)	16 - 22	24 - 32
Coercivity (Hcb), Oe)	>= 8,000	>= 9,500
Intrinsic Coercivity (Hcj), kOe)	>= 15	>= 20 - 30
Max. Operating Temperature	250°C	350°C
Reversible Temp. Coefficient of Br	-0.045% / °C	-0.030% / °C
Density (g/cm3)	8.2 - 8.4	8.3 - 8.5
Electrical Resistivity (uOmega · cm)	50 - 60	80 - 90

Standard Geometries: Outer Radius (OR), Inner Radius (IR), Arc Angle (15° to 180°), Axial Length (L up to 100mm).

Dimensional Tolerance: +/- 0.05 mm standard; +/- 0.015 mm via diamond wheel contour grinding.

Magnetic Orientation:
• Radial: Flux lines converge/diverge along the central rotational axis.
• Diametral: Flux lines run parallel across the physical diameter.
• Parallel Arc: Unidirectional flux lines perpendicular to the chord line.
• Batch Consistency: Total magnetic moment variance controlled within +/- 1% per production lot via automated Helmholtz coil sorting.

Key Features

Thermal Stability:

Minimal magnetic flux loss at continuous temperatures exceeding 300°C, outperforming NdFeB alternatives that degrade above 150°C.

Corrosion Resistance:

Stable rare-earth composition without free iron phases, removing the need for surface passivation in standard industrial conditions.

High Coercivity:

Resists irreversible demagnetization during high-torque overload cycles.

Controlled Anisotropy:

Aligned via 2-Tesla pulsed magnetic fields during compaction to ensure uniform flux distribution across multi-segment rotor arrays.

Applications

Aerospace Actuators: BLDC motors driving flight control surfaces under extreme thermal gradients.

Motorsport Powertrains: KERS and auxiliary drive units operating at high rotational speeds.

High-Speed Turbomachinery: Generator rotors operating above 50,000 RPM.

Defense & Avionics: Gyroscopes, inertial navigation systems, and radar gimbals requiring zero flux drift.

Customization

Alloy Selection:

SmCo5 for lower thermal coefficients; Sm2Co17 for maximum energy product at elevated temperatures.

Complex Machining:

Multi-axis CNC diamond tooling for custom step cuts, chamfers, keyways, and tight-tolerance radii.

Magnetic Matching:

Rotor-specific flux sorting into matched sets (+/- 1% variance) to ensure dynamic rotor balance.

Manufacturing & Quality Control

Process Chain
• Vacuum Induction Melting: Raw elements melted under an inert argon atmosphere.
• Jet Milling: Ingots pulverized into 3 - 5 um micro-powders under controlled nitrogen.
• Magnetic Alignment & Pressing: Powder oriented in a 2-Tesla field and compacted via hydraulic or isostatic pressing.
• Sintering & Solution Treatment: Vacuum densification at 1,100°C - 1,200°C with rapid gas quenching.
• Aging Treatment: Controlled thermal precipitation at 800°C - 900°C to lock in coercivity.
• Precision Machining: Wire-EDM slicing and diamond-wheel contour grinding.

Quality Verification
• Hysteresis Graph Testing: Br, Hcb, Hcj, and (BH)max verified at 20°C and 150°C.
• Dimensional Inspection: 100% CMM and optical profile projection for radius and angle verification.
• Defect Screening: Fluorescent dye penetrant inspection and acoustic microscopy for micro-crack detection.
• Traceability: Raw material batch certification and magnetic test reports supplied with every lot.

Packaging & Documentation

Packaging Engineering:

Individual separation using non-magnetic high-density polyethylene (HDPE) spacers in anti-static vacuum-sealed foil bags. Inner shielding with iron sheets limits stray magnetic fields below IATA Packing Instruction 953 air transport limits.

Documentation Package:

Material Test Report (MTR), dimensional inspection sheet, Certificate of Conformance (CoC), and dangerous goods declaration.

FAQ

Q: What distinguishes SmCo from NdFeB in motor designs?

A: SmCo sustains operation up to 350°C with superior resistance to oxidation and demagnetization, whereas NdFeB degrades above 150°C and requires protective plating.

Q: Are protective coatings necessary for SmCo arc segments?

A: Uncoated SmCo exhibits high inherent corrosion resistance. Parylene or epoxy encapsulation is optional for specialized chemical immersion.

Q: How is magnetic orientation specified on engineering drawings?

A: Specify the orientation type (Radial, Diametral, or Parallel) alongside pole configuration (e.g., North-outer / South-inner) prior to tooling setup.

Q: What are the standard lead times?

A: Prototype tooling requires 3 to 4 weeks. Volume production orders ship within 5 to 7 weeks.

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