Yuchang Qing
材料科学技术（英文）
Microwave absorbing properties of the carbonyl iron particles filled epoxy-silicone resin coatings showed visible degression when the coatings were heat treated at 300°C with different time. The complex permittivity and permeability of the coatings before and after heat treatment were measured. After heat treatment at 300°C, the real part of permittivity of the coatings increased with increasing treatment time and showed frequency dependence dielectric response. The complex permeability showed remarkable variation while the resonance frequency of the coatings heat treated at 300°C shifted from 7 to 12 GHz. The electromagnetic results indicated that microwave absorbing properties of the coatings showed more dependent on the complex permeability. The results showed that the difference of the electromagnetic and microwave absorbing properties before and after heat treatment was mainly attributed to the crystalline state transition of carbonyl iron particles.
关键词:
Microwave absorption
,
Dielectric properties
,
Magnetic properties
,
Heat treatment.
Zhigao Xie
材料科学技术（英文）
The structure, magnetic and microwave-absorption properties of graphite-coated (Fe, Ni) alloy nanocapsules, synthesized by the arc-discharge method, have been studied. High-resolution transmission electron microscopy shows that the nanocapsules have a core/shell structure with (Fe, Ni) alloy as the core and graphite as the shell. All (Fe, Ni) alloy nanocapsules/paraffin composites show good microwave-absorption properties. The optimal reflection loss (RL) was found for (Fe70Ni30)/C nanocapsules/paraffin composites, being -47:84 dB at 14.6 GHz for an absorber thickness of 1.99 mm, while the RL values exceeding -10 dB were found in the 12.4-17.4 GHz range, which almost covers the Ku band (12.4-18 GHz). For (Fe70Ni30)/C nanocapsules/paraffin
composites, RL values can exceed -10 dB in the 11.4-18 GHz range with an absorber thickness of 1.91 mm, which cover the whole Ku band.
关键词:
Magnetic
