| 摘要 |
PROBLEM TO BE SOLVED: To display the radio wave absorbing power at the mega/giga frequency band, without using classified powders by specifying the content of an Fe-base flat nano-crystal soft magnetic powder in a bond resin and the imaginary part of the complex permeability. SOLUTION: The compsn. of a nano-crystal soft magnetic powder contains Fe as a main component which reveals a superior soft magnetic characteristic and the imaginary partμ" of the complex permeability is large. Part of Fe may be substituted by a kind of elements M such as Co and/or Ni, a mother alloy is dissolved in the atmospheric air, the melt at 1500 deg.C is atomized by the high pressure water atomizing method to make a powder of amorphous alloy Fe72.5 Cu1 Nb3 Si13.5 B9 (atm.%) of 40μm in mean grain size and 1μm thick, and the powder is heat treated in an N gas atmosphere at 500 deg.C for 1 hr. to obtain a nano-crystal soft magnetic powder having a fine structure of 10 nm in crystal grain size. The real partμ' of the complex permeability of a radio wave absorber sheet exceeds 1 from 1 MHz to 1 GHz and its imaginary partμ" rises abruptly from 10 MHz to several GHz, superior in radio wave absorption characteristic.
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