Custom Samarium Cobalt (SmCo) ring magnets maintain magnetic flux stability across thermal and corrosive operating environments. Manufactured via powder metallurgy, these rare-earth permanent magnets retain performance up to 300°C (572°F) without significant irreversible thermal losses.
Engineering specifications focus on applications requiring demagnetization resistance and minimal field drift across wide temperature swings. Unlike NdFeB alternatives, SmCo exhibits inherent oxidation resistance in standard atmospheres due to its cobalt matrix, eliminating mandatory plating for dry environments. Each ring is produced to custom engineering blueprints, adhering to exact inner diameter, outer diameter, thickness, and magnetic orientation requirements.
Technical Specifications
|
Parameter |
Specification Range / Standard |
|
Material Grades |
SmCo5 (16H - 28H), Sm2Co17 (200M - 32H) |
|
Remanence (Br) |
8.2 - 11.5 kG (0.82 - 1.15 T) |
|
Energy Product ((BH)max) |
16 - 32 MGOe (128 - 254 kJ/m³) |
|
Intrinsic Coercivity (Hci) |
>= 15 - 30 kOe (1190 - 2388 kA/m) |
|
Max Operating Temp (Tmax) |
250°C to 350°C (Dependent on grade and Hci) |
|
Curie Temperature |
700°C - 800°C |
|
Standard Dimensions |
ID: 2 mm to 150 mm; OD: 6 mm to 200 mm; Thickness: 1 mm to 50 mm |
|
Dimensional Tolerance |
± 0.05 mm standard (Precision grinding to ± 0.01 mm available) |
|
Magnetization Direction |
Axial, Diametral, Radial, or Multi-pole configuration |
|
Surface Treatment |
Passivated raw finish, Nickel (Ni-Cu-Ni), Epoxy, or Parylene coating |
Key Features
Thermal Stability: Low reversible temperature coefficient (alpha ≈ -0.03%/°C for Sm2Co17) ensures consistent output across fluctuating operational temperatures.
Coercivity: High intrinsic coercive force prevents permanent flux degradation under severe thermal loads or opposing magnetic fields.
Corrosion Resistance: High cobalt content protects against oxidation in humid industrial environments without external coatings.
Anisotropic Alignment: Magnetic domains align during powder compaction inside an external magnetic field, directing maximum flux vector output along the specified axis.
Mechanical Rigidity: Retains structural stability under high rotational centrifugal forces in high-speed rotor configurations.
Applications
Aerospace & Defense: Flight control actuators, guidance systems, and instrumentation operating under wide thermal gradients.
High-Temperature Motors: Rotors of brushless DC motors, synchronous motors, and generators operating continuously above 200°C.
Fluid Handling: Magnetic couplings for chemical process pumps and hermetically sealed equipment.
Medical Devices: MRI gradient coils, radiation therapy delivery systems, and high-frequency surgical tool drives.
Industrial Instrumentation: Traveling-wave tubes, gyroscopes, particle accelerators, and sensor assemblies.
Customization
Production parameters are engineered directly from customer-supplied CAD files, engineering drawings, and performance requirements.
Geometry:
Custom inner diameters, outer diameters, stepped profiles, countersunk holes, and segmented ring configurations.
Alloy Grading:
Selection between SmCo5 and Sm2Co17 alloy formulations based on specific energy product and operational temperature thresholds.
Field Orientation:
Multi-pole patterns on inner/outer diameters or skewed axial vectors for cogging torque reduction in motor designs.
Tolerances:
Precision diamond wheel grinding to sub-millimeter tolerances with controlled edge-breaking to prevent material chipping during assembly.
Coatings:
Electrolytic nickel plating or polymer layers for specific chemical or fluid immersion isolation.
Manufacturing & Quality Control
Production Process
• Vacuum Induction Melting: Smelt raw Samarium, Cobalt, Iron, Copper, and Zirconium ingots under strict vacuum or inert gas conditions.
• Jet Milling: Pulverize alloy ingots into micro-powders under a controlled nitrogen atmosphere to prevent premature oxidation.
• Magnetic Field Compaction: Press micro-powders inside a hydraulic die while applying an aligning magnetic field.
• Sintering: Densify green compacts in a high-vacuum furnace at temperatures ranging from 1100°C to 1250°C.
• Heat Treatment: Execute solution and aging cycles to stabilize the microcrystalline precipitation structure and lock in coercivity.
• Machining & Grinding: Shape components using diamond wire-cutting and surface grinders to meet drawing dimensions.
• Magnetization & Testing: Expose rings to high-energy pulse magnetization fields and run initial magnetic verification.
Quality Inspection Standards
• Hysteresis Loop Testing: Measure Br, Hcb, Hci, and (BH)max using hysteresis graph analyzers at ambient and elevated thermal limits.
• Dimensional Metrology: Verify ID, OD, thickness, and parallelism using optical comparators and coordinate measuring machines (CMM).
• Visual & Structural Inspection: Perform 100% surface checks under magnification to detect micro-cracks, edge chipping, or material inclusions.
• Flux Verification: Test total magnetic moment consistency across production lots using Helmholtz coil systems.
Packaging & Documentation
Non-magnetic plastic separation fixtures, inner vacuum-sealed anti-static foil bags, and heavy-duty corrugated cartons lined with high-density foam to prevent material chipping during transit.
Steel-lined wooden export crates utilized for air and ocean freight to comply with international regulations and restrict stray magnetic fields below shipping thresholds.
Material Test Report (MTR) detailing chemical composition, hysteresis loop test data, Certificate of Conformance (CoC), and dimensional inspection sheets.
FAQ
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