2018 Volume 59 Issue 12 Pages 1920-1927
To improve the properties of powder magnetic core for motors, such as iron loss, resistivity and strength, pure iron powder was deformed into flaky-shaped and then annealed to decrease strain by deformation. It was confirmed that the strength of iron core increased with increasing the aspect ratio of powder. However, the resistivity extremely decreased. The iron core showed properties as follows; density d = 7.66 Mg·m−3, resistivity ρ = 2.5 × 104 µΩ·m, iron loss Pc (the maximum magnetic flux density, Bmax = 1 T, frequency, f = 400 Hz) = 30 W·kg−1, iron loss Pc (Bmax = 1 T, f = 800 Hz) = 63 W·kg−1, radial crushing strength σ = 95 MPa. Especially, eddy current loss coefficient Ke was 0.008 mWs2·kg−1, extremely lower than electromagnetic steel sheet and powder magnetic core reported ever.
This Paper was Originally Published in Japanese in J. Jpn. Soc. Powder Powder Metallurgy 64 (2017) 638–645. To show the shape of the powder more clearly, Fig. 2 was replaced.