2001 Volume 48 Issue 1 Pages 15-20
A fundamental study was subsequently made on the AC magnetic properties of Fe-Si type magnetic alloys, prepared by means of diffusion-sintering soft-iron/Fe-21(wt%)Si-B mixed powders. In this case, Fe-21Si (eutectic) mother alloy fines with B content: 0-0.4 wt% was made by high-pressure water atomization and was blended with soft-iron powder to Fe-0-8(wt%)Si compositions.
The results obtained were summarized as follows:
(1) Maximum flux density (Bm), specific permeability (μa) and core loss (Pcv) show almost the same dependence upon Si content and sintering temperature in the low frequency region.
(2) The maximum flux density (Bm), typical of AC magnetic properties, has the maximum value in the Si content:6-7 wt%, under roughly no influence of sintering temperature (1473-1623 K).
(3) This AC tendency of Bm-Si relationship, differently from the magnetic induction (B10)'s one of DC magnetic properties, is indicative of large dependence upon electrical resistivity (ρ) through the so-called skin effect.
(4) The maximum flux density (Bm) of Fe-6-7Si-B compacts sintered at 1573 K can be enhanced by-20% due to the small B ingredient which generally has some deoxidizing effect in liquid phase.
(5) This small amount of B: 0.05-0.1 wt% tends to remove impurities and hence, to clean the microstructure of sintered specimens but excess B may possibly pin the domain wall in AC magnetic field as inclusions.
