Samarium Cobalt Magnets Manufacturer in China
Delivering superior magnetic solutions for aerospace, automotive, and industrial applications with exceptional temperature stability and magnetic strength.
A Brief Introduction to Samarium Cobalt Magnets
Samarium cobalt (SmCo) magnets are strong permanent magnets made of samarium, cobalt, and other minor elements. It is known for its high magnetic strength and good temperature stability. Samarium cobalt magnets are generally weaker than neodymium magnets at room temperature, but they perform reliably in extreme temperatures when neodymium magnets stop working. Since SmCo is highly resistant to corrosion and oxidation, coatings are generally not required. Since the samarium cobalt magnet is made by sintering, it is very brittle and cracks may appear inside.
Sm1Co5
SmCo5 alloy contains one samarium atom for every five cobalt atoms, and is the first generation of samarium cobalt magnets. The (BH)max of 1:5 SmCo alloys is from 15 MGOe to 25 MGOe and the service temperature is up to 250°C. SmCo5 mainly contains Sm and Co and does not contain iron, so it has better resistance to corrosion and demagnetization.
Sm2Co17
Compared with Sm1Co5, the magnetic properties of 2:17 SmCo alloy are better. Its (BH)max usually varies between 24 MGOe and 32 MGOe, and its working temperature can reach 300 °C. Sm2Co17 contains very few other elements such as iron, copper, and samarium and cobalt. The withdrawal of iron from this alloy means that it may corrode slightly in high humidity environments, so Sm2Co17 magnets are coated with nickel in some cases.
Industry Applications
SmCo magnets excel in demanding environments where other permanent magnets fail
Aerospace & Defense
Critical magnetic components for aircraft systems, satellites, and defense applications requiring exceptional reliability and temperature resistance.
- High-temperature stability
- Radiation resistance
- Precision engineering
Automotive
Advanced magnetic solutions for electric vehicles, sensors, and automotive systems demanding superior performance under extreme conditions.
- Vibration resistance
- Temperature cycling
- Compact designs
Medical Devices
Biocompatible magnetic components for MRI systems, surgical instruments, and medical equipment requiring the highest quality standards.
- Biocompatibility
- Precision tolerances
- Reliable performance
Industrial Equipment
Robust magnetic solutions for pumps, generators, and industrial machinery operating in harsh environments.
- Corrosion resistance
- Long service life
- High efficiency
Energy & Power
Magnetic components for wind turbines, generators, and renewable energy systems requiring maximum efficiency and durability.
- High energy density
- Weather resistance
- Maintenance-free
Electronics
Precision magnetic components for speakers, microphones, and electronic devices where size and performance are critical.
- Miniaturization
- High performance
- Cost-effective
Step-by-Step Manufacturing Process of Sintered Samarium Cobalt Magnets
1. Raw Material Preparation and Alloying
Start with high-purity elements: samarium (Sm: 25-35% for SmCo5 or 20-25% for Sm2Co17), cobalt (Co: 50-60%), and additives like iron (Fe), copper (Cu), or zirconium (Zr) for enhanced properties in 2:17 types.
- Materials are melted in a vacuum induction or arc furnace at 1,300-1,500°C to form an ingot, minimizing oxidation.
- The ingot is pulverized via jet milling, ball milling, or hydrogen decrepitation into fine powders (1-5 microns). For Sm2Co17, additional annealing may refine the microstructure.
Powder handling occurs in inert atmospheres to prevent reactions with oxygen or moisture.
2. Powder Blending and Compaction
Powders are blended for homogeneity, often with small amounts of lubricants or binders.
- The mixture is compacted in a die press under 500-1,000 MPa, forming a “green” compact with 50-70% density.
- For anisotropic magnets (the norm), a magnetic field (10,000-20,000 Oe) is applied during pressing to align grains, optimizing directional magnetism.
This step shapes basic forms like discs, blocks, or rings, with complex designs handled post-sintering.
3. Sintering and Densification
The green compact is sintered in a vacuum or argon-filled furnace at 1,100-1,250°C for 1-4 hours, achieving near-full density (8.0-8.5 g/cm³).
- Liquid-phase sintering aids bonding, especially in Sm2Co17 alloys where additives create a low-melting eutectic.
- Slow cooling or quenching follows to lock in the magnetic phases, preventing phase separation.
This high-heat fusion creates the magnet’s signature high-temperature stability.
4. Heat Treatment and Aging
Post-sintering, a multi-stage heat treatment optimizes properties:
- Solution annealing at 800-1,200°C dissolves phases uniformly.
- Aging at 350-900°C (with controlled cooling) precipitates fine magnetic domains, boosting coercivity.
For Sm2Co17, this step is critical to achieve high energy products without sacrificing temperature resistance.
5. Machining and Surface Treatment
Sintered SmCo is hard and brittle, so machining uses diamond grinding, EDM, or laser cutting for precision.
- Minimal coatings are needed due to inherent corrosion resistance, but options like nickel or epoxy are applied for extra protection in aggressive environments.
- Tolerances reach ±0.01 mm for aerospace-grade parts.
This ensures the magnet fits seamlessly into applications.
6. Magnetization and Quality Testing
The finished piece is magnetized using a high-field electromagnet or pulse system.
- Testing evaluates remanence (Br), coercivity (Hc), energy product (BHmax), and temperature stability via permeameters and thermal cycling.
- Microstructural analysis (e.g., SEM) checks for defects, ensuring compliance with MIL-STD or ISO standards.
Approved magnets are packaged with care to avoid chipping.
Get In Touch
Join hundreds of satisfied customers who trust HS Magnet for their critical magnetic applications.
Contact our expert team for technical consultations, custom solutions, or product inquiries