Technical Resources
Useful background information for magnetic materials, cores, wound components, terminology, selection and supply.
Magnet Terminology
Definitions including remanence, coercivity, (BH)max, Curie temperature, anisotropic and isotropic materials.Permanent Magnet Materials
High-level comparison of NdFeB, SmCo, AlNiCo and Ferrite, including magnetic strength, temperature behaviour, corrosion resistance and typical applications.Cores & Wound Components
Background information covering soft magnetic cores, inductors, chokes, transformers and related selection considerations.Compliance
How RoHS, REACH and other product-compliance requirements are handled for supplied components.Common magnetic terms
A short reference for terminology commonly used when specifying permanent magnets and soft magnetic materials.
| Term | Meaning |
|---|---|
| Br / Remanence | Residual magnetic flux density remaining after magnetisation. |
| Hc / Coercivity | Resistance of a magnetic material to demagnetisation. |
| (BH)max | Maximum energy product; a common indicator of permanent-magnet material performance. |
| Permeability | A measure of how readily a magnetic material supports magnetic flux; particularly relevant to soft magnetic cores. |
| Curie Temperature | Temperature above which a ferromagnetic material loses its ferromagnetic properties. |
| Anisotropic | Material manufactured with a preferred direction of magnetisation. |
| Isotropic | Material with no preferred orientation, allowing magnetisation in different directions. |
Permanent magnet materials
A high-level comparison only. Final material selection depends on grade, geometry, operating temperature, environment, required magnetic performance and cost.
| Material | General magnetic strength | Temperature behaviour | Corrosion behaviour | Typical fit |
|---|---|---|---|---|
| NdFeB | Very high | Grade-dependent; standard and higher-temperature grades available | Protective coating is commonly used | Compact, high-performance motors, sensors, actuators and assemblies |
| SmCo | High | Excellent stability at elevated temperature | Generally very good | High-temperature, precision and demanding industrial applications |
| AlNiCo | Moderate | Excellent temperature stability | Generally good; application-dependent | Instrumentation, sensors, audio and specialist cast or sintered shapes |
| Ferrite / Ceramic | Low to moderate | Good thermal stability | Naturally corrosion resistant | Cost-sensitive, high-volume motors, loudspeakers and general industrial uses |
Cores & wound components
Soft magnetic cores and wound components are usually selected around electrical performance as well as geometry, temperature and mechanical constraints.
Core selection
Typical considerations include material family, permeability, operating frequency, flux density, core loss, temperature, geometry, air gap and mounting arrangement.
Wound-component selection
Typical considerations include inductance or turns ratio, current, voltage, frequency, losses, insulation system, winding arrangement, package size and mounting format.
For inductors, chokes, filters, transformers and current-sensing components, sending an existing part number, drawing or electrical specification is normally the quickest starting point.
Compliance & documentation
Where applicable, Stratton Magnetics supports customer requirements relating to RoHS, REACH, conflict minerals reporting and product documentation.
Evidence
Compliance evidence is based on supplier declarations, material information, available test documentation and the requirements of the individual product.
At enquiry stage
Tell us about any specific regulatory, material, inspection or documentation requirement early so it can be confirmed for the relevant manufacturing route.