DongGuan Golds-magnets manufactures standard sintered Samarium Cobalt (SmCo) ring magnets engineered for high-temperature and demagnetization-resistant applications. Utilizing certified SmCo5 (1:5 series) and Sm2Co17 (2:17 series) rare-earth alloys, these ring magnets maintain magnetic stability in thermal environments exceeding 300°C where NdFeB grades degrade.
Supplied in anisotropic grades with predefined axial or diametral magnetization patterns from our ISO 9001 and IATF 16949 certified manufacturing lines, our standard ring inventory supports rapid prototyping and industrial integration. Each production batch undergoes hysteresis graph testing to verify magnetic output against standard specifications prior to release, with full DFARS-compliant material traceability available.
Technical Specifications
Engineering standard parameters for Jiuyi sintered SmCo ring magnets. Custom dimensions, DFARS compliance documentation, and tighter tolerances available upon request.
|
Parameter |
SmCo5 Grade (e.g., YXG16 - YXG24) |
Sm2Co17 Grade (e.g., YXG28 - YXG33) |
|
Remanence (Br) |
8.2 - 11.0 kGs (0.82 - 1.10 T) |
10.5 - 12.5 kGs (1.05 - 1.25 T) |
|
Coercivity (Hcb) |
6.5 - 9.0 kOe (517 - 716 kA/m) |
9.0 - 11.5 kOe (716 - 915 kA/m) |
|
Intrinsic Coercivity (Hcj) |
>= 15.0 kOe (>= 1194 kA/m) |
>= 25.0 kOe (>= 1989 kA/m) |
|
Max. Energy Product ((BH)max) |
16 - 24 MGOe (128 - 191 kJ/m3) |
28 - 33 MGOe (223 - 263 kJ/m3) |
|
Max. Operating Temperature |
250°C |
350°C |
|
Curie Temperature (Tc) |
700°C - 750°C |
800°C - 840°C |
|
Temp. Coefficient of Br (alpha) |
-0.045% / °C |
-0.030% / °C |
|
Density |
8.2 - 8.4 g/cm3 |
8.3 - 8.5 g/cm3 |
|
Standard Dimensional Tolerance |
+/- 0.1 mm (Grind finish) |
+/- 0.1 mm (Grind finish) |
Key Features
Thermal Stability: Low reversible temperature coefficient of remanence maintains consistent magnetic flux across operating ranges from -40°C to 350°C.
Corrosion Resistance: Contains minimal iron content in SmCo5 and stable metallurgical structures in Sm2Co17, eliminating the mandatory nickel or epoxy plating required for NdFeB in humid environments.
Demagnetization Resistance: High intrinsic coercivity (Hcj) prevents structural flux loss when exposed to opposing magnetic fields or high-temperature loads.
Anisotropic Alignment: Magnetic domains aligned during pressing in a magnetic field; restricted to designated axial or diametral vectors to optimize directional flux density.
Mechanical Rigidity: Sintered powder metallurgy structure provides high compressive strength, though brittle characteristics require controlled mechanical handling during press-fit assembly.
Applications
Aerospace Actuators: Brushless DC motors and rotary actuators operating under high ambient temperatures and vacuum conditions.
Defense Telemetry: Traveling-wave tubes (TWTs) and microwave frequency sources requiring focused annular magnetic fields.
Medical Equipment: MRI gradient coils, blood pump magnetic drives, and surgical robot micro-motors requiring autoclave sterilization compatibility.
Sensors & Instruments: Hall-effect sensors, cryogenic flow meters, and high-precision torque meters.
Industrial Couplings: Magnetic couplings and seal pumps transferring high-temperature chemical fluids without mechanical shaft penetration.
Customization
Standard inventory covers common outer diameter (OD), inner diameter (ID), and thickness ratios. Non-standard configurations are processed per engineering drawings:
Dimensional Parameters:
Outer diameters from 3 mm to 150 mm; inner diameters down to 1 mm; thicknesses from 0.5 mm to 50 mm.
Magnetization Patterns:
Multi-pole radial rings, skew-angled magnetization, and sector-segmented ring assemblies.
Surface Finishes:
Uncoated (standard passivated finish), Nickel-Copper-Nickel (Ni-Cu-Ni), or Parylene coating for specific outgassing or particle-containment requirements.
Tolerance Grinding:
Precision diamond-wheel grinding down to +/- 0.02 mm for critical air-gap clearance requirements.
Manufacturing & Quality Control
Production runs utilize automated jet milling, magnetic field pressing furnaces, and vacuum sintering lines within our controlled factory floor environment to maintain grain boundary uniformity and density.
Powder Processing: Closed-loop jet milling under inert nitrogen gas atmosphere prevents oxidation of raw Samarium and Cobalt raw materials.
Compaction: Isostatic pressing and magnetic field alignment ensure consistent flux distribution across the ring cross-section.
Sintering & Heat Treatment: Vacuum sintering furnaces operating at 1100°C to 1200°C followed by controlled aging cycles to lock intrinsic coercivity.
Inspection Equipment:
Hysteresis Graph Testers (Permagraph) measure Br, Hcb, Hcj, and (BH)max at ambient and elevated temperatures up to 300°C. 3D Optical Comparators and Air Gauges verify OD, ID, concentricity, and parallelism tolerances. Helmholtz Coil flux measurement systems verify total magnetic moment consistency (+/- 1% standard batch deviation).
Quality Certifications: ISO 9001 and IATF 16949 certified manufacturing systems with full raw material traceability and DFARS compliance options.
Packaging & Documentation
Packaging:
Individually separated non-magnetic plastic spacers inside iron-shielded corrugated cartons. Outer packaging meets air and ocean freight magnetic field containment limits (IATA Packing Instruction 953 compliance).
Documentation Supplied with Shipment:
Material Test Report (MTR) including chemical composition verification and DFARS statement of origin. Hysteresis loop test curves per production lot. Certificate of Conformance (CoC) referencing PO and drawing revision numbers. Material Safety Data Sheet (MSDS) for rare-earth metallic alloys.
FAQ
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