Technical

Magnetic Powder Core Classification: IEC 63299 Guide

2026-08-14 · 7 Min. Lesezeit

Quick answer

IEC 63299:2022 classifies magnetic powder cores by material family and effective initial permeability. The families are iron (I), iron-silicon (K), iron-silicon-aluminum/Sendust (S), iron-nickel/high flux (H), iron-nickel-molybdenum/MPP (M), iron-based amorphous (A) and iron-based nanocrystalline (N), each with a permeability code such as H060 or M125. Choose the family by saturation, DC-bias behavior, power loss and temperature coefficient, then pick the permeability grade that meets your inductance with practical turns.

Magnetic powder cores come in several material families with very different properties, and the same permeability is available from multiple suppliers. IEC 63299:2022 defines a uniform classification so engineers can compare cores across manufacturers. This guide explains the classification system and how to read a powder core designation.

1. The classification code

Each powder core is designated by a material family letter plus a three-digit permeability code. For example, H060 means iron-nickel (Fe-Ni) powder with an effective initial permeability of 60. The families defined by IEC 63299 are:

Code	Material family	Common industry name
I	Iron powder (Fe)	Iron powder core
K	Iron-silicon (Fe-Si)	Iron-silicon core
S	Iron-silicon-aluminum (Fe-Si-Al)	Sendust
H	Iron-nickel (Fe-Ni)	High Flux core
M	Iron-nickel-molybdenum (Fe-Ni-Mo)	MPP / molypermalloy powder
A	Iron-based amorphous (Fe-Si-B)	Amorphous powder core
N	Iron-based nanocrystalline (Fe-Si-B-Cu-Nb)	Nanocrystalline powder core

2. Permeability code and grades

The subclassification is based on effective initial permeability, written as a three-digit code — 010, 026, 035, 040, 055, 060, 075, 090, 125, 147, 160, 173. Typical published grades include iron powder I060/I075, iron-silicon K060/K090, Sendust S060/S090, high flux H060/H125/H160, MPP M060/M125/M160/M173, amorphous A060/A090 and nanocrystalline N060.

3. Properties that define a powder core

Initial permeability — the classification basis and the inductance-per-turn driver
Saturation magnetic flux density (Bs) — measured at 50 Hz and 20 kA/m
DC-bias characteristic — how much inductance holds at a given DC field
Power loss density — quoted in kW/m³ at defined frequency and flux (e.g., 100 kHz / 100 mT)
Temperature coefficient of permeability — stability over temperature
Plus density, mechanical strength and thermal conductivity for mechanical design

4. Core shapes covered

Powder cores are produced as rings (toroids), blocks, cylinders, ellipses, E types, EQ types, EER types, U types and pot types. The shape and dimensions are agreed in the detailed specification, while the material class and permeability code define the magnetic performance.

5. Where each family fits

High-current power inductors (AI GPU VRM, server POL, EV) → Fe-Ni high flux (Bs ≥1.5 T, stable bias)
Lowest-loss powder-core filtering → Fe-Ni-Mo (MPP)
PFC and EMI filter roles → Sendust (Fe-Si-Al)
Cost-sensitive benign applications → iron powder
High-frequency / high-permeability niches → amorphous and nanocrystalline powder cores

Ferrite is a different material family (ceramic, not powder); the Ferrite Core Guide and High Flux Cores Guide compare the two sides of the decision. Test methods for these properties are defined in IEC 63300, and the Core Selection Tool applies the classification to real design inputs. Full property tables for every subclass (I010–I075, K026–K090, S026–S125, H026–H160, M026–M200, A060–A090, N060) are on the Technical Data page.

YUTE Magnetics manufactures Fe-Ni powder cores and inductors with full-process testing. Send your inductance, current and frequency targets through the engineering RFQ for a free technical evaluation.

Frequently Asked Questions

What is IEC 63299?

IEC 63299:2022 is the standard that classifies magnetic powder cores by material family and effective initial permeability, so cores from different manufacturers can be compared on a common basis.

How do I read a powder core designation?

The designation combines a material family letter with a three-digit permeability code. For example, H060 indicates iron-nickel (Fe-Ni) powder with an effective initial permeability of 60.

What material families does the standard define?

Iron (I), iron-silicon (K), iron-silicon-aluminum or Sendust (S), iron-nickel or high flux (H), iron-nickel-molybdenum or MPP (M), iron-based amorphous (A) and iron-based nanocrystalline (N).

Which family suits high-current power inductors?

The iron-nickel (H) family is the usual choice where high saturation and DC bias stability matter, since it offers Bs ≥1.5 T. The MPP (M) family is preferred where lowest loss and stable permeability matter more than stored energy.

Does the classification cover core shapes?

The standard defines material classes and permeability codes; the detailed specification separately covers available shapes including toroids, blocks, cylinders, E, EQ, EER, U and pot types, along with dimensions.