Synthesis, Electromagnetic and Wave-Absorbing Properties of a FeNi Alloy Nano-Whisker/Particle Mixture

A Fe20Ni80 alloy nano-whisker/particle mixture was synthesized by a hydrazine hydrate reduction method at 60°C. Electromagnetic parameters of the alloy nano-whisker/particle mixture after a 0.3-T magnetic treatment were measured in the 1.0–8.0 GHz range using an E5063A vector network analyzer. The results showed that the real part (ε′) of the complex permittivity of the Fe20Ni80 alloy nano-whisker/particle mixture in the 1.0–8.0 GHz range was between 23 and 18, and the imaginary part (ε″) was approximately 4. The real part (μ′) of the complex permeability in 1.0–5.0 GHz range decreased greatly with increasing frequency, from a maximum of 2.5 to a minimum of 1. The imaginary part (μ″) presented a parabolic shape change; when the frequency was 4.0 GHz, there was a maximum of 1.5. After the 0.3-T magnetic treatment, both the real part (ε′) and the imaginary part (ε″) of the complex permittivity decreased: the real part (μ′) of the complex permeability increased sharply, and the imaginary part (μ″) decreased slightly. The dissipation factor (tgδ) of the Fe20Ni80 alloy nano-whisker/particle mixture in the 4.0–7.0 GHz range was approximately 1.0, which shows it has excellent wave-absorbing properties. The thickness of interference-absorbing was approximately 11 mm at 1.0 GHz; it decreased with increasing frequency. The thickness of interference-absorbing was 2.5–2 mm in the 4.0–8.0 GHz range, which shows that the Fe20Ni80 alloy nano-whisker/particle mixture has good interference-absorbing properties when the thickness is 2 mm.