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How to choose Iron Powder, Sendust, Koolmu, High Flux and MPP Cores(2)

DC Biased Inductor Operation.
20% Permeability Limits
Materials Initial Perm. Max. DC Bias (Oersteds)
MPP 60 < 50
125 < 30
160 < 20
High Flux 60 < 45
125 < 22
Sendust 60 < 40
125 < 15
Iron Powder
Mix #26 75 < 20
Mix #52 75 < 25
Mix #18 55 < 40
Mix #8/90 35 < 80
Under DC magnetizing conditions, all powder materials exhibit a reduction in permeability as shown in the charts. The data above assumes an AC flux density of 20 gauss. For application such as output chokes, where the inductors are DC biased, the magnetization force (H=0.4*PHI*N*l/l) needs to be calculated, and the number of turns increased to account for the reduction in permeability. If the magnetization force (H) calculated is within the above maximum DC biased limits, the designer only needs to increase the turns by a maximum of 20%.

Relative Cost Comparison Table
The relative costs of each material is based on prevailing products pricing and raw material costs. These numbers should be used as a guide only. In general Micrometal's Iron Powder #26 is most cost effective, and MPPs are the costliest materials.
There are many manufacturers and importers of iron powders cores, and most of them do not exhibit the quality level as those offered by Micrometals.
If you need cost down, we can use local in China core and raw materials.
Materials Relative Cost
Iron Powder
Mix#26 1.0
Mix#52 1.2
Mix#18 3.0
Mix#8/90 4.0

Sendust 3.0 to 5.0
High Flux 7.0 to 10.0
MPP 8.0 to 10.0


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