Magnetic Materials Comparison
Side-by-side tables to help you choose between NdFeB, SmCo, ferrite, AlNiCo, SmFeN, bonded and flexible magnets. Each table comes with "when to choose X / when to choose Y" guidance and links to related products.
Overview matrix
Core specs for the 7 main magnet families at a glance.
| Material | Energy product (BH)max | Max operating temp | Br temp coefficient | Corrosion resistance | Cost |
|---|---|---|---|---|---|
| Sintered NdFeB | 35–52 MGOe | 80–200 °C (grade N/M/H/SH/UH/EH) | −0.12 %/°C | Low — requires coating (NiCuNi, Zn, epoxy) | $$$ |
| SmCo (Sm₂Co₁₇ / SmCo₅) | 16–32 MGOe | 250–350 °C | −0.03 %/°C | Excellent — no coating usually needed | $$$$ |
| Ferrite (ceramic) | 3.5–4.5 MGOe | 250 °C | −0.18 %/°C | Excellent — oxide, inherently stable | $ |
| AlNiCo | 5–9 MGOe | 500 °C | −0.02 %/°C | Excellent | $$ |
| SmFeN (bonded) | 14–25 MGOe | 150 °C | −0.05 %/°C | Excellent — powder nitrogen-treated, binder-sealed | $$$ |
| Bonded NdFeB | 8–12 MGOe | 120–150 °C | −0.11 %/°C | Good — binder protects powder | $$ |
| Flexible (ferrite/NdFeB) | 1.5–2.5 MGOe (ferrite) / up to 9 MGOe (NdFeB) | 80–120 °C | −0.18 %/°C (ferrite) | Good — polymer encapsulated | $ |
Pair-by-pair comparisons
Side-by-side tables and decision guidance for the most-asked comparisons.
Sintered NdFeB vs SmCo
Highest energy vs highest temperature stability — the classic rare-earth trade-off.
| Property | Sintered NdFeB | SmCo (Sm₂Co₁₇ / SmCo₅) |
|---|---|---|
| Max energy product (BH)max | 35–52 MGOe | 16–32 MGOe |
| Max operating temperature | 80–200 °C (grade-dependent) | 250–350 °C |
| Temperature coefficient of Br | −0.12 %/°C | −0.03 %/°C |
| Corrosion resistance | Low — coating required | Excellent — usually no coating |
| Cost (relative) | $$$ | $$$$ (1.5–3× NdFeB) |
| Mechanical toughness | Brittle, hard to machine | Brittle, slightly easier to machine |
| ||
AWhen to choose Sintered NdFeB
Choose NdFeB when you need the highest flux per unit volume (motors, sensors, consumer electronics) and operating temperature stays below 180 °C with the correct grade (SH/UH/EH).
BWhen to choose SmCo (Sm₂Co₁₇ / SmCo₅)
Choose SmCo when operating temperature exceeds 200 °C, when temperature coefficient must be very low (instruments, gyroscopes), or in corrosive environments where coating is undesirable.
Related products
Sintered NdFeB vs Ferrite
Performance vs cost — the most common high-volume trade-off.
| Property | Sintered NdFeB | Ferrite (ceramic) |
|---|---|---|
| Max energy product (BH)max | 35–52 MGOe | 3.5–4.5 MGOe |
| Max operating temperature | 80–200 °C | 250 °C |
| Temperature coefficient of Br | −0.12 %/°C | −0.18 %/°C |
| Corrosion resistance | Low — coating required | Excellent — oxide, no coating |
| Cost (relative) | $$$ | $ |
| Rare-earth content | Nd + Dy/Tb (heavy rare earth) | None — strontium/barium ferrite |
| ||
AWhen to choose Sintered NdFeB
Choose NdFeB when miniaturisation matters (EV motors, headphones, sensors) or when flux density must be high in a small footprint.
BWhen to choose Ferrite (ceramic)
Choose ferrite for cost-sensitive high-volume applications (speakers, fridge magnets, magnetic chucks, simple motors) where size is not constrained and the environment is corrosive or humid.
Related products
Sintered vs Bonded NdFeB
Maximum performance vs complex shapes and tight tolerances.
| Property | Sintered NdFeB | Bonded NdFeB |
|---|---|---|
| Max energy product (BH)max | 35–52 MGOe | 8–12 MGOe |
| Shape complexity | Limited — grinding/slicing from blocks | High — injection or compression moulded |
| Dimensional tolerance | ±0.05 mm (machined) | ±0.02 mm (as-moulded) |
| Magnetisation direction | Anisotropic — single direction | Isotropic or anisotropic |
| Max operating temperature | 80–200 °C | 120–150 °C (binder-limited) |
| Cost (relative) | $$$ | $$ (less waste, no machining) |
| ||
AWhen to choose Sintered NdFeB
Choose sintered NdFeB for maximum magnetic performance (traction motors, high-end sensors) where shape is simple (blocks, rings, cylinders) and machining is acceptable.
BWhen to choose Bonded NdFeB
Choose bonded NdFeB when the magnet must have a complex shape (thin walls, intricate profiles, integrated features), very tight tolerances, or when isotropic magnetisation (any direction) is needed.
SmCo vs AlNiCo
Two high-temperature rare-earth-free options compared.
| Property | SmCo (Sm₂Co₁₇ / SmCo₅) | AlNiCo |
|---|---|---|
| Max energy product (BH)max | 16–32 MGOe | 5–9 MGOe |
| Max operating temperature | 250–350 °C | 500 °C |
| Intrinsic coercivity Hcj | ≥ 800 kA/m | ≈ 60–120 kA/m |
| Temperature coefficient of Br | −0.03 %/°C | −0.02 %/°C |
| Rare-earth content | Samarium (~25%) | None (Fe, Al, Ni, Co, Cu, Ti) |
| Cost (relative) | $$$$ | $$ |
| ||
AWhen to choose SmCo (Sm₂Co₁₇ / SmCo₅)
Choose SmCo when you need high energy product at high temperature (250–350 °C) and high Hcj — sensors, motors, aerospace.
BWhen to choose AlNiCo
Choose AlNiCo when temperature is extreme (up to 500 °C) and the magnet is protected from external demagnetising fields (low Hcj) — instruments, holding magnets, education.
Sintered NdFeB vs SmFeN
Established rare-earth vs the fourth-generation alternative.
| Property | Sintered NdFeB | SmFeN (bonded) |
|---|---|---|
| Max energy product (BH)max | 35–52 MGOe (sintered) | 14–25 MGOe (bonded) |
| Max operating temperature | 80–200 °C | 150 °C (binder-limited) |
| Temperature coefficient of Br | −0.12 %/°C | −0.05 %/°C |
| Corrosion resistance | Low — coating required | Excellent — nitrogen-treated powder, no coating |
| Curie temperature | 310–400 °C | ~470 °C |
| Cost (relative) | $$$ | $$$ (SmFeN powder is premium but coating cost saved) |
| ||
AWhen to choose Sintered NdFeB
Choose NdFeB when you need the absolute highest (BH)max and the application does not involve skin contact, humidity or strict corrosion requirements.
BWhen to choose SmFeN (bonded)
Choose SmFeN for wearables, magnetic-health products and consumer electronics that touch skin — its excellent corrosion resistance and lower temperature coefficient make it safer and more stable without coating.
Rigid NdFeB vs Flexible magnets
High-flux rigid magnets vs bendable polymer-bonded sheets and strips.
| Property | Sintered NdFeB | Flexible (ferrite/NdFeB) |
|---|---|---|
| Max energy product (BH)max | 35–52 MGOe | 1.5–2.5 MGOe (ferrite) / up to 9 MGOe (NdFeB) |
| Bendability | Rigid — cannot bend | Bendable, rollable, cuttable |
| Form factor | Blocks, rings, cylinders, arcs | Sheets, strips, profiles, extrusions |
| Max operating temperature | 80–200 °C | 80–120 °C (binder-limited) |
| Cost (relative) | $$$ | $ |
| Typical uses | Motors, sensors, encoders, holding fixtures | Door seals, gaskets, magnetic signage, latches |
| ||
AWhen to choose Sintered NdFeB
Choose rigid NdFeB (sintered or bonded) when you need high flux density, precise pole geometry or tight mechanical tolerances.
BWhen to choose Flexible (ferrite/NdFeB)
Choose flexible magnets when the surface is curved, the magnet must be cut to shape on-site, or the application is a seal, latch, gasket, sign or door strip.
Related products
Still unsure which material fits your application?
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