Sintered Samarium Cobalt (SmCo) block magnets deliver permanent magnetic flux stability in operational environments exceeding the thermal limits of NdFeB alternatives. Alloyed from rare-earth samarium and transition-metal cobalt, these blocks function continuously up to 300C to 350C in Sm2Co17 configurations. They provide high intrinsic resistance to thermal demagnetization and chemical oxidation, avoiding the mandatory nickel plating required for standard iron-containing magnets in humid operational conditions.
Technical Specifications
|
Parameter |
Standard Grade (SmCo5) |
High-Temperature Grade (Sm2Co17) |
|
Remanence (Br) |
8.5 – 10.5 kGs |
10.5 – 12.5 kGs |
|
Coercivity (Hc) |
8.0 – 9.5 kOe |
9.0 – 11.0 kOe |
|
Intrinsic Coercivity (Hcj) |
15.0 – 25.0 kOe |
20.0 – 30.0 kOe |
|
Max Energy Product ((BH)max) |
16 – 24 MGOe |
22 – 33 MGOe |
|
Max Operating Temperature |
250C |
300C – 350C |
|
Curie Temperature |
700C – 750C |
800C – 825C |
|
Reversible Temp. Coefficient of Br |
-0.045% / C |
-0.030% / C |
|
Density |
8.3 g/cm3 |
8.4 g/cm3 |
Key Features
High Intrinsic Coercivity (Hcj): Prevents self-demagnetization in high-ambient-temperature generators and strong opposing magnetic fields.
Anisotropic Uniformity: Powder metallurgy processing aligns crystal domains during pressing, securing high directional energy density across the block dimensions.
Applications
Control surface actuators and telemetry sensors exposed to extreme aerodynamic heating.
Permanent magnet brushless motors operating above 200C in aerospace propulsion and industrial turbomachinery.
Measurement-while-drilling sensors and magnetic couplings functioning under high mechanical vibration and elevated downhole temperatures.
Klystrons, traveling-wave tubes, and particle accelerator beam focusers requiring strict magnetic field linearity.
Customization
Dimensions: Block lengths from 2 mm to 130 mm, widths from 0.5 mm to 100 mm, and thicknesses from 0.3 mm to 50 mm.
Tolerances: Standard unground blocks at +/-0.1 mm; precision diamond wire slicing and surface grinding achieve dimensional tolerances down to +/-0.015 mm.
Magnetization Axis: Through-thickness (axial), length, width, or specific multi-pole angles; unmagnetized delivery available for post-assembly charging.
Coatings: Uncoated (passivated surface) or electroplated with Nickel (Ni-Cu-Ni), Epoxy, or Parylene C for specialized fluid immersion requirements.
Manufacturing & Quality Control
Alloy Melting: Vacuum induction melting (VIM) combines raw samarium and cobalt metals under strict stoichiometric control.
Jet Milling: Inert-gas (nitrogen/argon) jet milling breaks down alloy ingots to micro-powders with controlled particle size distribution.
Magnetic Alignment & Pressing: Wet or dry pressing under an applied magnetic field (>20 kOe) or isostatic pressing to align crystal axes prior to green body consolidation.
Sintering & Aging: Solid-state sintering in high-vacuum induction furnaces above 1100C, followed by multi-stage aging heat treatments to stabilize coercivity.
Metrology & Testing: Hysteresis graph (BH loop tracer) verification at room and elevated temperatures up to 350C; dimensional inspection via CMM optical systems.
Packaging & Documentation
Packaging:
Packed in high-density polyurethane foam blocks enclosed inside heavy-duty corrugated cartons, lined with iron shielding plates to restrict magnetic stray fields below IATA dangerous goods shipping limits.
Documentation Provided:
Material Test Report (MTR) detailing Br, Hcj, and (BH)max per heat lot; hysteresis curve measurement data; Certificate of Conformance (CoC) complying with ASTM specifications; DFARS compliance certification for raw material origin.
FAQ
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