The mixed powder and the wave absorber null which for the wave absorber show the radio wave absorption property which is superior vis-a-vis the high frequency of wide frequency

摘要

PPROBLEM TO BE SOLVED: To provide a wave absorber that shows an excellent wave absorbing characteristic to high frequencies in a wide frequency band from several MHz to several GHz. PSOLUTION: This wave absorber is constituted by scattering a mixed powder in a flexible thermoplastic resin or rubber. The mixed powder is prepared by mixing a flat metallic magnetic powder with another flat metallic magnetic powder. The first-mentioned flat metallic magnetic powder has a composition composed of 15-35 at.% Al or Si or both Al and Si, 0.1-20 at.% Ni, 0.1-10 at.% Cr, and the balance Fe and inevitable impurities, a mean thickness (d) of 0.5-3 μm, and grain sizes DSB50/SBof 5-30 μm for 50 wt.% powder having smaller grain sizes measured by means of a granulometer and adjusted in aspect ratio (DSB50/SB/d) to 2-60. The second-mentioned flat metallic magnetic powder is composed of stainless steel (SUS430) and the grain sizes DSB50/SBof this magnetic powder are 1.5-5 times as large as those DSB50/SBof the first-mentioned metallic magnetic powder. PCOPYRIGHT: (C)2003,JPO