Description

Technical Parameters

Custom Samarium Cobalt (SmCo) block magnets maintain stable magnetic flux in environments where NdFeB grades suffer thermal demagnetization. Sintered from rare-earth alloys, these rectangular blocks operate up to 350°C and resist oxidation without mandatory plating. Designated for high-temperature actuators, aerospace assemblies, and precision sensors requiring uncompromised field consistency under extreme thermal shifts.

Technical Specifications

Parameter	Standard / Range
Alloy Grades	SmCo5 (1:5), Sm2Co17 (2:17)
Remanence (Br)	8.2 – 11.5 kGs (0.82 – 1.15 T)
Max Energy Product ((BH)max)	16 – 32 MGOe (128 – 254 kJ/m³)
Intrinsic Coercivity (Hci)	15 – 30 kOe
Max Operating Temperature	250°C (SmCo5) to 350°C (Sm2Co17)
Curie Temperature	700°C – 800°C
Dimensional Tolerance	±0.05 mm (ground); tighter via wire EDM
Magnetization Axis	Through-thickness, length, width, or custom multi-pole

Key Features

Thermal Stability:

Extremely low reversible temperature coefficient (≈ -0.03%/°C for Sm2Co17), ensuring predictable flux output across wide operational temperature deltas.

Demagnetization Resistance:

High intrinsic coercivity (Hci) prevents irreversible flux loss against strong opposing magnetic fields at elevated temperatures.

Corrosion Resistance:

Stoichiometric intermetallic matrix contains no free iron phase, eliminating rapid red-rust oxidation common in unplated neodymium.

Mechanical Hardness:

High compressive strength, though brittle structure mandates abrasive or electrical discharge machining techniques.

Applications

Aerospace Actuators: Brushless DC motors and rotary actuators operating within unconditioned aircraft nacelles.

Defense Electronics: Traveling wave tubes (TWTs), klystrons, and missile guidance sensor stabilization packages.

High-Temperature Couplings: Magnetic drives inside industrial pumps and flow meters handling hot process fluids.

Sensors & Metrology: Hall-effect sensors and particle accelerator beam steering arrays requiring tight field longevity.

Design & Engineering Guidelines

SmCo is an intermetallic, ceramic-like material requiring specific mechanical design integration:

Minimum Wall Thickness:

Maintain structural walls >= 0.8 mm for standard builds; down to 0.4 mm via wire-EDM subject to aspect ratio review.

Edge Protection:

Specify a 0.1 mm × 45° chamfer or R0.2 mm corner radius to prevent micro-chipping on sharp outer edges.

Mounting Method:

Prohibit direct tensile loading or through-hole bolting. Secure blocks via structural epoxy bonding, mechanical clamping, or stainless-steel containment sleeves.

Flux Matching:

Specify magnetic moment sorting tolerances (±1% or ±0.5%) for multi-block dynamic rotors to eliminate unbalanced air-gap forces.

Customization Capabilities

Production parameters adapt directly to engineering envelope requirements supplied via CAD or PDF blueprints:

Geometry: Blocks, steps, rectangles, and curved segments processed to print specifications.

Surface Treatments: Supplied bare (as-ground), passivated, or coated with Nickel (Ni-Cu-Ni), Epoxy, or Parylene to eliminate particle shedding in clean environments.

Magnetic Sorting: Calibrated and binned into tight magnetic moment ranges for balanced multi-pole synchronous assemblies.

Manufacturing & Quality Control

Raw materials undergo vacuum induction melting (VIM), jet milling, magnetic field alignment compaction, and liquid-phase sintering.

Machining Centers:

Multi-axis CNC surface grinders and wire-EDM systems prevent structural micro-cracking during shaping.

Dimensional Verification:

Optical comparators and 3-axis CMM (Coordinate Measuring Machines) record critical dimensions against drawing callouts.

Lot Traceability:

Material Test Reports (MTR) document chemical composition, density, and magnetic properties for every individual sintering lot.

Testing Standards & Deliverables

Production batches validate against international material and test standards:

Execution Standards: Testing executed in accordance with ASTM A977 (Permanent Magnet Room Temperature Measurement) and IEC 60404 frameworks.

Testing Equipment:High-Field Hysteresisograph: Evaluates J-H and B-H demagnetization curves from ambient up to 300°C.Helmholtz Coil Systems: Verifies total magnetic flux and magnetic moment parameters.

Shipment Documentation: Formal Certificate of Analysis (CoA) and MTR detailing actual Br, Hci, and (BH)max test metrics.

Packaging & Hazardous Logistics

Shielding:

Packed in heavy-gauge magnetically shielded iron/steel lined cartons complying with IATA dangerous goods regulations for external magnetic field limits.

Physical Protection:

Individual high-density polyethylene (HDPE) foam compartmentalization prevents transit impact and edge chipping.

Compliance Documentation:

Includes CoA, MSDS, and RoHS/REACH regulatory declarations.

FAQ

Q: Do Sm2Co17 block magnets require protective plating?

A: Plating is optional. SmCo does not readily oxidize in standard atmospheric conditions. Nickel or epoxy coatings are applied strictly to prevent minor particle dusting in high-vibration environments.

Q: What is the minimum wall thickness achievable for custom block geometries?

A: Standard structural wall thickness is limited to 0.8 mm due to material brittleness. Sections down to 0.4 mm are achievable via wire-EDM processing, subject to mechanical aspect ratio review.

Q: How do SmCo blocks behave under mechanical stress?

A: SmCo is hard and brittle (similar to structural ceramics). Components cannot withstand tensile loads or act as structural load-bearing members; mounting designs must rely on clamping, epoxy bonding, or stainless-steel containment sleeves.

Q: Can SmCo magnets be re-magnetized after assembly?

A: Yes, provided the magnetic circuit geometry permits access for an impulse magnetizer coil capable of generating magnetic fields exceeding 30 kOe.

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