抄録
The Magnetocrystalline anisotropy constant Kc and the magnetostriction λs of a Sendust alloy in composition of 9.6% Si-5.4% Al–bal. Fe are almost equal to zero. Therefore this alloy shows high permeability, but its brittleness makes it hard to roll the alloy. With the object of developing a new alloy having higher permeability and workability, we have studied the effects of the addition of Ni as a fourth element on the magnetic properties of 6% Si-4% Al–bal. Fe alloy showing a second largest value of maximum permeability μm in the Fe–Si–Al system.
The experimental results obtained are summarized as follows:
(1) In the 6% Si-4% Al–bal. Fe alloy the addition of 2%–4% Ni makes the coercive force Hc decrease and the maximum permeability μm increase considerably.
(2) An alloy with the composition of 3.15% Ni-5.33% Si-4.22% Al–bal. Fe was annealed at 700°C for 1 h in hydrogen and cooled to room temperature at a rate of 1.7°C/s. The magnetic properties obtained were: μm=56800, Hc=7.64 A/m, Br=0.81 T and Kf(Br⁄Bm)=86.6%.
(3) The effect of magnetic field cooling is striking. By applying a magnetic field 20 Oe during cooling from 700°C to room temperature after annealing at 1250°C for 1 h in hydrogen, the magnetic properties obtained were: μm=165000, Hc=2.39 A/m, Br=0.95 T, Bm=1.09 T and Kf=87.5%.
(4) The value of magnetostriction λs, magnetic moment σs, Curie point Tθ, electrical resistivity ρ and Vickers hardness Hv of the new alloy were affected considerably by the addition of 2–4% Ni.
