Quick AnswerPowder cores are magnetic cores made from insulated metal alloy powder pressed with a distributed air gap, giving stable inductance under DC bias. FeNi (iron nickel) offers the highest saturation (Bs ≥1.5T) for high-current power; Sendust balances cost and loss; MPP delivers the lowest core loss among metal powders. Choose by current, frequency and loss budget.
If you have opened a power inductor, you have probably seen a gray or brown toroid made of compressed metal powder. These are powder cores, and they are the quiet workhorses of DC-DC converters, PFC stages and EMI filters. Here is what they are and how to tell the main types apart.
A powder core starts as a metal alloy powder. Each particle is coated with an insulating layer, mixed with a binder, and pressed into a core shape. The insulation between particles creates a distributed air gap throughout the magnetic path, unlike ferrite or silicon steel cores that need a physical air gap.
FeNi (50%Fe-50%Ni) is the high-performance option: saturation flux density Bs ≥1.5T, permeability range about 14–160, and stable behavior from −40°C to +180°C. It is the material of choice for high-current inductors in AI GPU VRM, EV chargers and server power where ferrite would saturate or grow too large.
Sendust is an iron-silicon-aluminum alloy with saturation around 1.05T and very low magnetostriction noise. It offers a good balance of cost and core loss for PFC inductors, buck converters and EMI filters in the 20kHz–1MHz range.
MPP has the lowest core loss among common metal powder cores and a stable temperature coefficient, making it ideal for precision filters, high-Q resonant circuits and applications with tight inductance tolerance. Its saturation is lower (about 0.75T), so size grows at high current.
| Material | Saturation Bs | Typical μ range | Best for |
|---|---|---|---|
| FeNi (Iron Nickel) | ≥1.5T | 14–160 | High-current power, AI GPU VRM, EV |
| Sendust | ~1.05T | 26–125 | PFC, buck converters, EMI filters |
| MPP | ~0.75T | 14–550 | Precision filters, resonant circuits |
YUTE Magnetics manufactures FeNi powder cores and custom inductors for power electronics. Contact us for a free material selection review with loss and temperature data.
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