Golds-Magnets produces sintered high coercivity Samarium Cobalt disc magnets tailored for high-temperature motors, sensors, and aerospace actuators. Operating reliably up to 350°C, these Sm2Co17 and SmCo5 rare-earth magnets maintain stable magnetic output under severe thermal cycling and opposing magnetic fields. Vacuum induction melted and precision-ground, each disc provides consistent flux density and dimensional stability for critical industrial assemblies.
Technical Specifications
|
Parameter |
Specification Range |
Test Standard / Condition |
|
Material Grade |
26H to 33H, 28HE to 32HE (Sm2Co17 series) |
IEC 60404-8-1 |
|
Remanence (Br) |
10.5 - 11.8 kGs (1.05 - 1.18 T) |
Ambient (20°C) |
|
Coercivity (Hc) |
>= 9.5 kOe (756 kA/m) |
Ambient (20°C) |
|
Intrinsic Coercivity (Hci) |
>= 25 - 35 kOe |
Ambient (20°C) |
|
Max. Energy Product ((BH)max) |
26 - 33 MGOe (207 - 263 kJ/m3) |
Closed-circuit hysteresis graph |
|
Max. Operating Temperature |
300°C - 350°C |
Total flux loss < 3% after 1000 hrs |
|
Reversible Temp. Coefficient of Br |
-0.030% /°C |
Measured between 20°C and 200°C |
|
Density |
8.2 - 8.4 g/cm3 |
Archimedes method |
|
Standard Diameters (OD) |
3 mm - 100 mm |
+/- 0.05 mm standard, +/- 0.01 mm precision ground |
|
Standard Thickness (T) |
1 mm - 50 mm |
+/- 0.05 mm |
Key Features
High Hci values (>= 25 kOe) prevent irreversible magnetic loss in opposition fields and elevated ambient temperatures up to 350°C.
Low iron content in the base matrix eliminates the need for heavy protective plating in standard industrial atmospheric conditions.
Stable magnetic output across wide thermal swings ensures predictable sensor feedback and motor torque consistency.
Magnetic domains locked parallel to the polar axis during powder pressing maximize surface flux density on pole faces.
Applications
Aerospace Actuators: Brushless DC motors operating in high-altitude environments subject to intense thermal dissipation limits.
Downhole Petroleum Tools: MWD (Measurement While Drilling) sensors and high-temperature turbine alternators operating at 250°C+.
Defense Electronics: Traveling-wave tubes (TWTs), klystrons, and missile guidance gyroscopes.
Precision Instrumentation: Galvanometer movements, atomic clocks, and magnetically coupled pumps handling corrosive chemicals.
Customization
Golds-Magnets configures disc magnets to exact engineering blueprints.
• Dimensional Variations: Diameters from 2 mm to 120 mm; thicknesses down to 0.5 mm.
• Magnetic Orientation: Axial magnetization through thickness, diametral magnetization, multi-pole face magnetization on request.
Coatings & Finishes:
• Uncoated (standard, passivated surface)
• Nickel-Copper-Nickel (Ni-Cu-Ni, 15 - 25 um)
• Parylene coating for medical or hermetic sealing applications
Tolerances: Diamond-wheel surface grinding achieves parallel tolerances down to +/- 0.005 mm for tight-assembly rotor stacks.
Manufacturing & Quality Control
Manufacturing Process Flow
• Raw Material Melting: Vacuum induction melting of Samarium, Cobalt, Iron, Copper, and Zirconium ingots.
• Jet Milling: Closed-loop inert gas milling reduces alloy ingots to uniform particle distribution (3 - 5 um).
• Magnetic Alignment & Compaction: Isostatic pressing under a 2.5 T magnetic field to orient crystal anisotropy.
• Sintering: Liquid-phase sintering in a high-vacuum furnace at 1100°C - 1200°C, followed by multi-stage solution and aging heat treatments.
• Precision Machining: Wire-EDM slicing and diamond-wheel surface grinding to final blueprint dimensions.
• Magnetization: Pulse magnetization using custom electromagnet fixtures.
Quality Control Protocol
• Hysteresis Graph Testing: Every production lot is tested on an IC-C-500 hysteresis graph meter at 20°C and 150°C to verify Br, Hc, and (BH)max.
• Dimensional Verification: 100% optical sorting and automated laser micrometer inspection for outer diameter and thickness.
• Corrosion & Salt Spray Testing: ASTM B117 salt spray exposure testing conducted on random sample batches for plated variants.
Packaging & Documentation
Packaging Standards
• Magnetic Shielding: High-permeability cold-rolled steel shielding containers ensure external magnetic field leakage remains below IATA dangerous goods shipping limits (< 0.005 pt at 2.1 m).
• Physical Protection: Vacuum-sealed anti-static blister packs separated by high-density polyethylene foam blocks to prevent chipping and edge fracturing during transit.
Documentation Provided with Shipment
• Material Test Report (MTR) detailing lot-specific remanence (Br) and coercivity (Hci).
• Certificate of Conformance (CoC) referencing ISO 9001 and IATF 16949 quality standards.
• Material Safety Data Sheet (MSDS) for rare-earth alloy handling.
FAQ
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