Lp. Lefebvre et al., EFFECT OF ELECTRICAL-RESISTIVITY ON CORE LOSSES IN SOFT-MAGNETIC IRON-POWDER MATERIALS, Journal of magnetism and magnetic materials, 176(2-3), 1997, pp. 93-96
Iron powder should be electrically insulated with a dielectric to redu
ce eddy current losses in components fabricated by powder metallurgy i
ntended for AC soft magnetic applications. However, most of the dielec
trics act as distributed air gaps and reduce the apparent permeability
of the material. To obtain materials with good magnetic properties, t
he dielectric amount should then be kept as low as possible while main
taining low eddy current losses. This paper presents the influence of
electrical resistivity on core losses in iron powder compacts at low f
requency (f < 1 kHz). The results obtained show that a resistivity one
order of magnitude higher than the resistivity of iron (similar to 0.
1 mu Omega m) is sufficient to maintain low eddy current losses in pow
der cores at frequencies below 100 Hz. (C) 1997 Elsevier Science B.V.
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