Magnetic Shielding Properties of Compound Sheet Using Amorphous Metal Flakes

The magnetic shielding properties of laminated sheets, employing amorphous metal flakes prepared by a cavitation method, were studied. The results obtained may be summarized as follows: (1) A flake aspect ratio of more than 400 is sufficient. (2) Because of its zero magnetostriction and high initial permeability, (Co0.94Fe0.06)73 (Si0.63B0.37)27 alloy is suitable for shielding, particularly at low magnetic fields. (3) Similar efficiency is obtained for both vacuum- and dry-laminated sheets. (4) Higher densities of amorphous flakes in sheets result in higher efficiencies. For practical purposes, sheets should be prepared with an amorphous metal flake areal density of 0.25 kg/m². (5) The efficiency is generally independent of the frequency up to 100 kHz.